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Effect of Garlic and Aged Black Garlic on Hyperglycemia and Dyslipidemia in Animal Model of Type 2 Diabetes Mellitus
Abstract
Control of hyperglycemia and dyslipidemia is strongly correlated with decreased risk for cardiovascular disease, the most common and fatal diabetic complication. The purpose of this study is to determine the effects of garlic and aged black garlic on glycemic control and blood lipid profile in animal model of type 2 diabetes. Three week-old db/db mice (C57BL/Ks, n=21) were fed AIN-93G semipurified diet or diet containing 5% freeze-dried garlic or aged black garlic for 7 weeks after 1 week of adaptation. Fasting serum glucose, insulin, triglyceride, total cholesterol, and HDL-cholesterol and blood glycated hemoglobin were measured. Body weight and food intake of garlic and aged black garlic group were not significantly different from those of the control group. Fasting serum glucose and blood glycated hemoglobin levels were significantly decreased and insulin level was significantly increased in garlic group compared with control group (p<0.05). Consumption of aged black garlic significantly decreased homeostasis model assessment for insulin resistance (HOMA-IR) and tended to decrease serum glucose. Garlic consumption significantly decreased total cholesterol, while aged black garlic significantly reduced serum total cholesterol and triglyceride and increased HDL-cholesterol levels. These results suggest that garlic exerts hypoglycemic and hypocholesterolemic effect and aged black garlic improved insulin sensitivity and dyslipidemia in db/db mice.
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- ... It has been reported that both antioxidant nutrients and antioxidant phytochemicals can give an advantage in alleviating diabetes and diabetic complications (Lean et al., 1999, Sinclair et al., 1992). Several studies have reported that garlic (Allium sativum L.) could have hypoglycemic (Al-Qattan et al., 2008; Eidi et al., 2006; Seo et al., 2009) and antioxidant effects (Banerjee et al., 2003). Consumption of 80% ethanol extract of garlic decreased serum glucose (Eidi et al., 2006) and injection of garlic extract attenuated hypoglycemia and structural nephropathy progression in streptozotocin (STZ)-induced diabetic rats (Al-Qattan et al., 2008). ...... Consumption of 80% ethanol extract of garlic decreased serum glucose (Eidi et al., 2006) and injection of garlic extract attenuated hypoglycemia and structural nephropathy progression in streptozotocin (STZ)-induced diabetic rats (Al-Qattan et al., 2008). Consumption of diet containing 5% garlic powder significantly decreased serum glucose and total cholesterol in db/db mice, an animal model of type 2 diabetes (Seo et al., 2009). Garlic extract showed 1,1-diphenyl-2-picrylhydrazyl (DPPH)Querioz et al., 2009) and superoxide dismutase (SOD) activity in vitro (Jang et al., 2008). ...... It was reported that aged black garlic showed stronger antioxidant activity in vitro than garlic (Jang et al., 2008). In the previous study, we reported that consumption of diet containing 5% aged black garlic improved insulin resistance, decreased serum total cholesterol and triglyceride, and increased HDL-cholesterol levels in db/db mice (Seo et al., 2009). Therefore, aged black garlic could be more useful than garlic in prevention of diabetic complications. ...Hyperglycemia in the diabetic state increases oxidative stress and antioxidant therapy can be strongly correlated with decreased risks for diabetic complications. The purpose of this study is to determine antioxidant effect of garlic and aged black garlic in animal model of type 2 diabetes. The antioxidant activity of garlic and aged black garlic was measured as the activity in scavenging free radicals by the trolox equivalent antioxidant capacity (TEAC) assay. Three week-old db/db mice were fed AIN-93G diet or diet containing 5% freeze-dried garlic or aged black garlic for 7 weeks after 1 week of adaptation. Hepatic levels of lipid peroxides and activities of antioxidant enzymes were measured. TEAC values of garlic and aged black garlic were 13.3 +/- 0.5 and 59.2 +/- 0.8 micromol/g wet weight, respectively. Consumption of aged black garlic significantly decreased hepatic thiobarbituric acid reactive substances (TBARS) level compared with the garlic group which showed lower TBARS level than control group (p<0.05). Activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) of garlic and aged black garlic group were significantly elevated compared to the control group. Catalase (CAT) activity of aged black garlic group was increased compared with the control group. These results show that aged black garlic exerts stronger antioxidant activity than garlic in vitro and in vivo, suggesting garlic and aged black garlic, to a greater extent, could be useful in preventing diabetic complications.
- ... Yet, to date, only limited studies for beneficial effect of ABG is available. Several studies have investigated that ABG exerted hypoglycemic and hypocholsterolemic effects in animal model of type 2 diabetes mellitus or in vitro antioxidant effect on human low density lipoprotein (LDL) (Yang, 2007;Lee et al., 2009;Seo et al., 2009). Therefore, little is known about the effect of ABG on regulation of body weight, level of lipid parameters and antioxidant activity in vivo animal model of obesity. ...... In association with lower body weight, reduced WAT weights in the abdominal and perirenal were observed in the ABG extract-administered groups to the level of the normal group although the food intake was approximately the same for all groups. Previous studies reported that ABG consumption at the level of 5% of the diet did not influence body weight in db/db mice, type 2 diabetes mellitus animal model, during 7 weeks (Seo et al., 2009). This finding is shown the possibility that the body weight-lowering effect of ABG extract on high-fat diet induced obese male rats. ...... In this study, consumption of ABG extract significantly decreased serum TG, hepatic TC and TG compared with the control group. However,Seo et al. (2009)reported that ABG significantly decreased not only serum TC concentration, but also serum TG concentration.Pourkabir et al. (2010)also reported that garlic powder supplementation at the level of 2.5 and 5% of the diet improved serum TG, TC, VLDL-C and LDL-C levels in hypercholesterolemic guinea pigs.Gorinstein et al. (2006)reported that the garlic samples of raw and boiled at 100°C for 20 min significantly hindered the cholesterolinduced increases in plasma TC and LDL-C but not plasma TG. In agreement with our research results,demonstrated that, by means of red garlic extract (light color than black garlic) supply, the TC level of serum did not show significant differences between obese group (control) and the groups fed red garlic extract while a significant decrease of TG level was observed in the groups fed red garlic extract compared to the control groups. ...The present study was conducted to evaluate the effectiveness of aged black garlic (ABG) extract in alleviating obesity and hyperlipidemia, and regulating antioxidant properties in rats fed high-fat diet. Six-week old male Sprague-Dawley rats were separately fed for 5 weeks with two types of diets; a normal diet (ND) or high-fat diet (HD). Then rats fed HD were randomly assigned into five groups and fed one of the followings: a carrier (control), ABG extract (100, 250 and 500 mg/kg body weight) or simvastatin (1 mg/kg body weight) for another 5 weeks. The body and fat-pad weight, lipid parameter, antioxidant enzyme activity and lipid peroxidation (LPO) in serum and hepatic was investigated. ABG extract significantly lowered body and adipose tissue weight relative to the control. ABG extract significantly improved lipid profile by decreasing serum triglyceride and hepatic total cholesterol compared with the control. ABG extract-treated groups were also observed significant increases glutathione (GSH):oxidized GSH ratio in serum and hepatic compared with the control and near to the level of the normal. Consumption of ABG extract significantly decreased serum LPO level relative to the control. Based on these results, we suggest that the administration of ABG extract improves the body weight gain and dyslipidemia via the suppression of body fat and alteration in lipid profiles and antioxidant defense system.
- ... Black garlic has sweet taste and eliminates unpleasant odor of raw garlic. It possesses many bioactivities including inhibition of colon and gastric cancer cells growth, antioxidant, alteration of lipid profile in diabetes, antiobesity, anti-inflammatory, and antiallergic activities [16][17][18]. Furthermore, black garlic extract has proven its ameliorating effect on A -induced neurotoxicity and cognitive impairment [19]. ...... There is a growing body of evidences linking black garlic with amelioration of human diseases, especially in liver disease. In previous study, Seo et al. (2009) suggested that black garlic extract could improve the lipid profile in type 2 diabetes mellitus [16]. Moreover, Jung et al. (2014) reported that consumption of black garlic extract increased HDL-cholesterol as well as ratio of LDLcholesterol/lipoprotein B and exerted cardioprotective effect in hypercholesterolemic patients [28]. ...... There is a growing body of evidences linking black garlic with amelioration of human diseases, especially in liver disease. In previous study, Seo et al. (2009) suggested that black garlic extract could improve the lipid profile in type 2 diabetes mellitus [16]. Moreover, Jung et al. (2014) reported that consumption of black garlic extract increased HDL-cholesterol as well as ratio of LDLcholesterol/lipoprotein B and exerted cardioprotective effect in hypercholesterolemic patients [28]. ...Single clove garlic is the product of atypical bulbing process of garlic under specific conditions. Therefore, the number of researches on single clove garlic bioactivity is limited. Recently, the hepatoprotective effect of single clove garlic has been demonstrated. In this study, we investigated amelioration of single clove black garlic aqueous extract, a processed product from single clove garlic, on dyslipidemia and hepatitis induced by chronic administration of CCl 4 . Mice were randomly divided into four groups: control, extract control, CCl 4 intoxication, and coadministrated CCl 4 and extract group. Mice were orally given a dose of 1 ml/kg body weight of CCl 4 for 28 days twice a week to establish chronic liver injury model. To evaluate the hepatoprotective effect of single clove black garlic, mice were cotreated with CCl 4 and single clove black garlic extract (200 mg/kg body weight) via gastric gauge for 30 days. Cotreatment with CCl 4 and extract could improve the changes of body weight, liver weight, and relative liver weight as compared to CCl 4 intoxicated mice. Single clove black garlic ameliorated dyslipidemia and the elevation of ALT and AST levels induced by chronic CCl 4 intoxication. Histological studies revealed that single clove black garlic could prevent mononuclear cells infiltration and hepatocyte necrosis.
- ... Like the previous reports [9,[24][25][26], this study showed the hypoglycemic effects of black garlic extract in rats fed a high fat diet. The effect was more potent with the addition of 1.5% black garlic extract than 0.5%, demonstrated by decreases in blood glucose levels and increases in plasma insulin level herein. ...... It was clearly demonstrated herein that black garlic, dosedependently, has hypolipidemic effects. These results were consistent with many previous studies [18,20,[23][24][25][26]. However, the amounts of garlic supplemented in previous animal studies were quite different from those used herein. ...... However, the amounts of garlic supplemented in previous animal studies were quite different from those used herein. Some studies reported that 3-5% fresh garlic or black garlic extract significantly decreased blood cholesterol and triglyceride (TG) levels in diabetic or hypercholestemic mice [23][24][25][26]. The amounts of 3-5% garlic in the rat's diet are quite high, and are not applicable for the normal diet of humans [28]. ...The mechanism of how black garlic effects lipid metabolism remains unsolved. Therefore, the objectives of this study were to determine the effects of black garlic on lipid profiles and the expression of related genes in rats fed a high fat diet. Thirty-two male Sqrague-Dawley rats aged 4 weeks were randomly divided into four groups (n=8) and fed the following diets for 5 weeks: normal food diet, (NF); a high-fat diet (HF); and a high-fat diet + 0.5% or 1.5% black garlic extract (HFBG0.5 or HFBG1.5). Body weights and blood biochemical parameters, including lipid profiles, and expressions of genes related to lipid metabolism were determined. Significant differences were observed in the final weights between the HFBG1.5 and HF groups. All blood biochemical parameters measured in the HFBG1.5 group showed significantly lower values than those in the HF group. Significant improvements of the plasama lipid profiles as well as fecal excretions of total lipids and triglyceride (TG) were also observed in the HFBG1.5 group, when compared to the HF diet group. There were significant differences in the levels of mRNA of sterol regulatory element binding protein-1c (SREBP-1c), acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and glucose-6-phosphate dehydrogenase (G6PDH) in the HFBG1.5 group compared to the HF group. In addition, the hepatic expression of (HMG-CoA) reductase and Acyl-CoA cholesterol acyltransferase (ACAT) mRNA was also significantly lower than the HF group. Consumption of black garlic extract lowers SREBP-1C mRNA expression, which causes downregulation of lipid and cholestrol metahbolism. As a result, the blood levels of total lipids, TG, and cholesterol were decreased.
- ... Several studies have reported that garlic has hypoglycaemic and antioxidant effects (7,28) . Others have reported that consumption of a diet containing 5 % garlic powder significantly decreased serum glucose and total cholesterol in type 2 diabetic db/db mice (29) . Commercially available garlic preparations in the form of oil, powder and pills are widely used for certain therapeutic purposes to lower blood sugar and to improve lipid profile. ...... The hypoglycaemic potency of garlic has been attributed to allicinderived organosulphur compounds, which protect insulin from -SH inactivation by reacting with endogenous thiolcontaining molecules such as cysteine, glutathione and serum albumin (9) . Garlic significantly decreased the blood glucose level in glucose-loaded diabetic rats, which may be due to the inhibition of glucose absorption from the intestine and/or the enhancement of glucose utilisation by restoring the impaired insulin response through increasing the pancreatic secretion of insulin from existing b-cells (9,29) . Moreover, the antidiabetic effect of garlic was more effective than that of glibenclamide, a sulfonylurea drug that is used clinically to lower serum glucose by stimulating b-cells to release insulin and by promoting peripheral tissue uptake as well as utilisation of glucose (9) . ...Spices which show hypoglycaemic, hypolipidaemic and antioxidant activities may have a role in the treatment of diabetes and its complications. The present study aimed to compare the modulatory effects of garlic, ginger, turmeric and their mixture on the metabolic syndrome and oxidative stress in streptozotocin (STZ)-nicotinamide diabetic rats. Diabetes was induced in overnight fasted rats by a single intraperitoneal injection of STZ (65 mg/kg body weight) and nicotinamide (110 mg/kg body weight, 15 min before STZ injection). Diabetic rats orally received either distilled water (as vehicle) or 200 mg/kg body weight of garlic bulb, ginger rhizome or turmeric rhizome powder suspension separately or mixed together (GGT mixture) for twenty-eight consecutive days. The results showed that these spices and their mixture significantly alleviated (80-97 %, P < 0·05-0·001) signs of the metabolic syndrome (hyperglycaemia and dyslipidaemia), the elevation in atherogenic indices and cellular toxicity in STZ-nicotinamide diabetic rats by increasing the production of insulin (26-37 %), enhancing the antioxidant defence system (31-52 %, especially GSH) and decreasing lipid peroxidation (60-97 %). The greatest modulation was seen in diabetic rats that received garlic and the GGT mixture (10-23 % more than that in the ginger and turmeric groups). In conclusion, garlic or the mix including garlic appears to have an impact on each of the measures more effectively than ginger and turmeric and may have a role in alleviating the risks of the metabolic syndrome and cardiovascular complications.
- ... Black garlic is obtained by a multi-step heating process at a controlled temperature and humidity during a variable period of time from raw garlic [2][3][4][5][6][7]. During the production process, a series of physico-chemical changes of the fresh garlic are produced. ...... With regard to the manufacturing process, regardless of the variety used and only taking into account the physicochemical parameter evolution, the values obtained were similar to those published by different authors [2][3][4][5][6]8]. ...Black garlic is made from the fresh kind, submitting it to a controlled temperature (~65 °C) and humidity (>85 °C) for a prolonged period of time. The aim of this study was to assess the differences in the process and in the final product as a result of employing three garlic varieties (Spanish Roja, Chinese Spring and California White), and to check the influence of the storage time on fresh garlic in the quality of the final product by using garlic obtained in two different agricultural seasons, that of the current year (2014) and of the previous one (2013). The results revealed some differences in the parameters analysed during the manufacturing of the black garlic from the three varieties used, and even according to the harvest in question. However, when comparing initial and final values of the samples, a very similar evolution in their acidity, reducing sugars, °Brix, pH, polyphenol content, and antioxidant capacity was noted.
- ... It has been reported that unstable compounds of raw garlic are converted into stable compounds, such as Sallylcysteine (SAC), after this processing. ABG was shown to have stronger antioxidant activity than raw garlic both in vitro and in vivo (11,15). It was also reported that ABG is beneficial for prevention of cancer and diabetes (11,16,17). ...... However, HFD-induced increase in body fat was significantly suppressed by ABG treatment. In contrast to our results, AGE was previously shown to suppress the increase in body weight and body fat and enhance plasma lipid profile in HFD-fed rats (15). In addition, Jung et al. (16) reported that the administration of yeast (Saccharomyces cerevisiae)-fermented black garlic extract also attenuated HFD-induced increase in body weight, body fat and plasma lipids, including TC, LDL-C, HDL-C and TG, in mice. ...In this study, we investigated the hepatoprotective effects of aged black garlic (ABG) in rodent models of liver injury. ABG inhibited carbon tetrachloride-induced elevation of aspartate transaminase (AST) and alanine transaminase (ALT), which are markers of hepatocellular damage, in SD rats. D-galactosamineinduced hepatocellular damage was also suppressed by ABG treatment. However, ABG does not affect the elevation of alkaline phosphatase (ALP), a marker of hepatobilliary damage, in rats treated with carbon tetrachloride or D-galactosamine. We also examined the effect of ABG on high-fat diet (HFD)-induced fatty liver and subsequent liver damage. ABG had no significant effect on body weight increase and plasma lipid profile in HFD-fed mice. However, HFD-induced increase in AST and ALT, but not ALP, was significantly suppressed by ABG treatment. These results demonstrate that ABG has hepatoprotective effects and suggest that ABG supplementation might be a good adjuvant therapy for the management of liver injury.
- ... According to the previous report, compared with fresh garlic, the black one had a sevenfold increase in the polyphenol content (Sato et al., 2006), which indicated the increase in the antioxidant activity, the amino acid content increased 2.5-fold (Chao et al., 2012), carbohydrate content increased from 28.7 to 47.0%, the amount of SAC was almost 8 times (Sasaki et al., 2007). It is showed black garlic exhibited a wide range of biological activities, such as antioxidant (Kim et al., 2012), anticancer (Seo et al., 2009), hypoglycemic (Wang et al., 2012), hypolipidemic (Kim et al., 2011a), antiinflammatory property (Lee et al., 2011), hepatoprotective (Kim et al., 2011b) and immunostimulatory activities (Purev et al., 2012). Furthermore, black garlic showed stronger antioxidant activity in vivo (Zhu et al., 2008) and higher free radical scavenging properties in vitro (Kim et al., 2012) compared with fresh garlic. ...... Drosophila melanogaster is an excellent animal model to examine antiaging effect of compounds for it has a short lifespan and complete genome can be raised on simple diet (Boyd et al., 2011). Laboratory mice and cell lines were employed as model system to investigate antioxidant, anticancer and immunostimulatory activities of black garlic extracts were common (Sasaki et al., 2007;Seo et al., 2009;Zhu et al., 2008), but the antioxidant activity of black garlic extract in Drosophila melanogaster has never been reported yet. ...Black garlic was created by keeping whole ordinary garlic in a humidity controlled room at 70-80°C for 10-15 days without any artificial treatments and additives. The black garlic was extracted with 80% ethanol and concentrated to obtain black garlic ethanol extracts. The saccharides of the extracts were analyzed according to the method of Phenol Sulphate colorimetry, DNS and High Performance Liquid Chromatography (HPLC). The antioxidant capacity in vitro of the extracts was assessed by measuring the scavenging activities on 1, 1-Diphenyl-2-Picrylhydrazyl (DPPH). Drosophila melanogaster were employed to explore the effect of black garlic extract on lifespan and antioxidant index in vivo. The results showed that the total sugar content in the black garlic extracts was 55.5% including monosaccharide, disaccharide and polysaccharide, the content of reducing sugar was 25.22%. The results from this study demonstrated black garlic extracts possessed strong antioxidant capacity in vitro in a dose-dependent manner, the longevity of Drosophila melanogaster treated with black garlic extract was prolonged evidently and the content of MDA was decreased by improving SOD (including CuZn-SOD and Mn-SOD) and CAT activities.
- ... Aged black garlic (ABG), an aged garlic preparation, is known as a functional food and is popular in Asia. ABG is produced by application of high temperature and humidity over 10 days [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. ...... Administration of yeast (Saccharomyces cerevisiae) fermented ABG attenuated HFD-increased body fat and plasma lipids in diabetic obese mice [64]. ABG reduces insulin resistance and serum total cholesterol and triglyceride levels, and increases the high density lipoprotein (HDL) cholesterol levels in db/db mice through antioxidant activity [21]. The SAC enriched black garlic juice gives anti-diabetic effects in streptozotocin-induced insulin deficient mice [65]. ...Garlic (Allium sativum) has been used as a medicinal food since ancient times. However, some people are reluctant to ingest raw garlic due to its unpleasant odor and taste. Therefore, many types of garlic preparations have been developed to reduce these attributes without losing biological functions. Aged black garlic (ABG) is a garlic preparation with a sweet and sour taste and no strong odor. It has recently been introduced to Asian markets as a functional food. Extensive in vitro and in vivo studies have demonstrated that ABG has a variety of biological functions such as antioxidant, anti-inflammatory, anti-cancer, anti-obesity, anti-diabetic, anti-allergic, cardioprotective, and hepatoprotective effects. Recent studies have compared the biological activity and function of ABG to those of raw garlic. ABG shows lower anti-inflammatory, anti-coagulation, immunomodulatory, and anti-allergic effects compared to raw garlic. This paper reviews the physicochemical properties, biological activity, health benefits, adverse effects, and general limitations of ABG.
- ... (Kang, Lee, Sung, & Shin, 2013). In rat or mouse models, the administration of BG extract was found to lower the initially high levels of fasting blood glucose and blood glycated hemoglobin through raising the insulin sensitivity and plasma insulin level (Ha et al., 2015;Seo et al., 2009). ...Black garlic (BG) is essentially a processed food and obtained through the transformation of fresh garlic (FG) (Allium sativum L.) via a range of chemical reactions (including the Maillard reaction) and microbial fermentation. This review provides the up‐to‐date knowledge of the dynamic and complicated changes in major components during the conversion of FG to BG, including moisture, lipids, carbohydrates (such as sugars), proteins, organic acids, organic sulfur compounds, alkaloids, polyphenols, melanoidins, 5‐hydroxymethylfurfural, vitamins, minerals, enzymes, and garlic endophytes. The obtained evidence confirms that BG has several advantages over FG in certain product attributes and biological properties (especially antioxidant activity), and the factors affecting the quality of BG include the type and characteristics of FG and processing technologies and methods (especially pretreatments, and processing temperature and humidity). The interactions among garlic components, and between garlic nutrients and microbes, as well as the interplay between pretreatment and main manufacturing process, all determine the sensory and nutritional qualities of BG. Before BG is marketed as a novel snack or functional food, more research is required to fill the knowledge gaps related to quantitative monitoring of the changes in metabolites (especially those taste‐active and/or biological‐active substances) during BG manufacturing to maximize BG's antioxidant, anticancer, antiobesity, anti‐inflammatory, immunostimulatory, anti‐allergic, hepatoprotective, cardioprotective and oxidative stress‐/hangover syndrome‐reducing functions, and beneficial effects on memory/nervous systems. Assessments of the quality, efficacy, and safety of BG should be performed considering the impacts of BG production conditions, postproduction handling, and intake methods.
- ... Lee et al. (2009) indicated that supplementation with black garlic decreased the hepatic thiobarbituric acid reactive substances (TBARS) level and increased the activities of SOD, GPx, and catalase in db/db mice, a model for diabetic dyslipidemia. Seo et al. (2009) also illustrated that db/ db mice fed a diet containing 5% black garlic had decreased serum triacylglyceride, cholesterol, fasting blood glucose, and blood glycated haemoglobin levels, in addition to increased highdensity lipoprotein levels and improved insulin sensitivity, compared with mice fed diets without black garlic. ...The objective of this study was to determine if methanolic extract of black garlic (MEBG) has antiobesity effects via regulating lipid metabolism in an animal model. The results indicate that supplementation with MEBG decreased the final body weight; the relative masses of the liver and fat tissues; serum triacylglyceride levels; and hepatic oxidative stress and increased faecal lipid contents in HFD rats. Supplementation with MEBG upregulated AMPK, FOXO1, Sirt1, ATGL, HSL, perilipin, ACO, CPT-1, and UCP1 in the adipose tissues of HFD rats, whereas it downregulated CD36. Meanwhile, MEBG upregulated adiponectin and downregulated PAI-1, resistin, TNF-α, and GLUT4 in the adipose tissues of HFD rats. Regarding hepatic gene expression, MEBG upregulated AMPK, Sirt1, and PPARα but downregulated SREBP-1c, ACC, FAS, and SCD1. Therefore, MEBG can be developed as a potential nutraceutical ingredient for the prevention of obesity in a niche market.
- ... This is reportedly attributable to melanoidins [35,36,46,49], which are the browning substance in aged heat-treated garlic. Also, black garlic is known to variable bioactivities such as antioxidant [45,46], improvement of cardiovascular complications of diabetes [42], decline of lipids accumulation in hypercholesterolemic rats [22]. It was demonstrated that S-allyl cysteine [10,20] and polyphenol compounds in garlic exert strong antioxidant effect [48]. ...This study tested the anti-obesity and hypolipidemic effects of red garlic extract in obese rats induced by a high fat diet over a period of 4 weeks. Red garlic extract of 15 brix was added in 1, 3, 5 and 7% ratios in diets. The obesity index and body fat content significantly decreased in rats fed a diet with over 3% red garlic extract compared to the control group. There was no significant difference in weight of visceral and epididymal fat in rats fed red garlic extract. Total lipid and triglyceride levels in serum were significantly decreased in a dose-dependent manner, and AI and CRF also fell. ALT and AST activities in groups fed red garlic extract were decreased compared to the control group. Total lipid level in liver tissue of the groups fed 5-7% red garlic extract exhibited a significant decrease compared to the control group. Total cholesterol and triglyceride levels in feces were significantly increased in rats fed a diet with over 5% red garlic extract. Lipid peroxide levels were significantly decreased in the groups fed diets with 5-7% red garlic and antioxidant activity in serum was significantly increased in the group fed a diet with 7% red garlic extract compared to the control group. Our results suggest that red garlic extract could have anti-obesity and hypolipidemic effects for suppressing obesity index and decreasing lipid profiles.
- ... It was reported that black garlic showed strong antioxidant properties compared with raw garlic Kim et al. 2013a). Aged black garlic extract had hypoglycemic and hypercholesterolemic effects in an animal model of type 2 diabetes mellitus and in vitro antioxidant effects on human low-density lipoproteins (Yang 2007;Lee et al. 2009;Seo et al. 2009). A chloroform extract of aged black garlic exhibited anti-inflammatory properties on human umbilical vein endothelial cells via inhibition of Reactive Oxygen Species generation, VCAM-1 (Vascular Cell Adhesion Molecule-1) expression, NF-κB activation and monocyte adhesiveness (Lee et al. 2011). ...Because freezing treatment can destroy the cell structure of garlic, we investigated the effect of freezing pretreatment on black garlic processing with the traditional processing method as contrast. Results showed that freezing for 30 h had the greatest impact on the reducing sugar content. The control garlic processing 21–24 days had the best quality. Freezing pretreatment can affect the black garlic quality through the browning degree, reducing sugar content, amino-N content, total phenolic content and 5-hydroxymethyl-2-furaldehyde (5-HMF) levels. The freezing garlic had a faster color change than control samples. When the processing ended, the reducing sugar content, total phenols content and 5-HMF content of freezing pretreated garlic were increased by 51.88, 58.54, 25%, respectively, compared with the control samples. The amino-N content of freezing-pretreated garlic decreased 50.97% compared with the control one. The results indicated that freezing pretreatment can promote the generation of functional materials.Practical ApplicationsAlthough garlic has been used worldwide as food or herbal supplement, some people feel discomfort because of its strong pungent odor. Black garlic is one of the garlic-processed products, eliminating its stimulating odor. However, the quality of black garlic products on the market is varied and the processing time is long. As is known, freezing is widely used to destroy cell structure. In the present study, the use of freezing pretreatment in black garlic processing can promote the generation of functional materials and significantly reduce processing time from 60–90 to 22 days. These provided potential method to the black garlic processing.
- ... 13 Furthermore, hypoglycemic effect of garlic in glucose-loaded diabetic rats illustrated previously which might be due to the inhibition of glucose absorption from the intestine and/or the enhancement of glucose utilization by increasing the pancreatic secretion of insulin from existing b-cells. 17,18 In this study the increased plasma glucose concentration might be due to the enhancement of gluconeogenesis process by garlic supplemented diet. As reported previously, ruminal propionate is considered the most important single precursor of glucose when its availability is high. ...To evaluate the effects of garlic on some blood metabolites in pre-partum dairy goats, the ration was supplemented with raw garlic at the doses of 0, 30, 50 and 70 g kg(-1) of Dry matter (DM) in eight pregnant Mahabadi breed goats (59 ± 1 kg initial live weight) in a replicated Latin square design during the last two months of pregnancy. Each experimental period lasted 14 days with the first 12 days used for diet adaptation and two days of data collection with a 3-days wash-out period between treatments. The results revealed a beneficial increasing effect of garlic (at the level of 70 g kg(-1) of DM) on serum glucose concentration (p < 0.05). No effects of garlic supplementation on blood non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), total triglycerides, total protein, and albumin concentration were observed, except for serum cholesterol concentration, which was reduced (p < 0.05) with 70 g kg(-1) of DM of garlic supplementation. Dry matter intake was the same between the different treatment groups and throughout the trial period. Concerning the blood indicators of negative energy balance, no significant effects were found for NEFA and BHB in pre-partum goats however, serum glucose was improved significantly, which showed that garlic supplementation may improve the efficiency of feed utilization. In conclusion, garlic, as feed additives in ruminant nutrition, holds promise for improving feed efficiency and controlling the negative energy balance.
- ... There are many reports of bioassays on the beneficial effects on health of black garlic Sato, Kohno, Hamano, & Niwano, 2006;Seo et al., 2009;Wang et al., 2010). However, few reports describe black garlic processing. ...
- ... This indicates that the black garlic extracts worked first on both T lymphocytes and macrophages to activate them, and cytokines released from these activated cells enhanced the activity of NK cells to attack abnormal cells like tumor cells. Aged black garlic can enhancement of the immune system because have rich SAC than fresh garlic (Wang et al., 2010) Hyperglycemia and Dyslipidemia Effect Seo et al., (2009) reported consumption of aged black garlic (ABG) significantly decreased homeostasis model assessment for insulin resistance (HOMA-IR) and tended to decrease serum glucose. Garlic consumption significantly decreased total cholesterol but did not decrease triglyceride and HDL-cholesterol levels, while aged black garlic significantly reduced serum total cholesterol and triglyceride and increased HDLcholesterol levels. ...Black garlic is garlic fermented in high temperature and humidity, and the fermentation compound chemical in garlic changes to new chemicals, such as S-allyl cysteine (SAC), S-allylmercapto-cysteine, and arginine. The color changed to dark brown during the aging period because of the Maillard reaction, known as non-enzymatic browning reaction. Black garlic has 57.14% of fructose, 6.78% of glucose, and 7.62% of sucrose, which were mainly saccharides in black garlic to answer for its sweet taste. It is such a pharmacological activity which contains antioxidant, anti-cancer, hepatoprotective, can improve the immune system, reduce hyperglycemia, dyslipidemia, and anti-allergic. We summarize the current knowledge of a change in the components, bioactivity, production, and applications of black garlic, as well as the proposed future prospects on their possible applications as a functional pharmacy product.
- ... Experiments with small white rats reported that black garlic had antibiosis and antitumor functions, which could induce the human body to produce intense immune response of TH1 [8]. Black garlic could restrain the development of atherosclerosis by cleaning cholesterol to improve hyperlipidemia [9], and reduce weight and blood lipids [10,11]. Furthermore, researchers found that black garlic had a strong antioxidant activity both in vivo and in vitro [12]. ...Black garlic produced from fresh garlic under controlled high temperature and humidity has strong antioxidant properties. To determine these compounds, five fractions (from F1 to F5) were separated and purified by elution with chloroform:methanol at different ratios (8:1, 6:1, 4:1, 2:1, and 0:1; v/v). The antioxidant activity of each fraction was analyzed. The results showed that F3 and F4 had higher phenolic contents and stronger 2,2-diphenyl-2-picrylhydrazyl radical scavenging activity than the others. Seven purified individual components were further separated using semipreparation high-performance liquid chromatography from these two intensely antioxidant fractions (F3 and F4), their structures were elucidated by high-performance liquid chromatography coupled to diode array detection, electrospray ionization, mass spectrometry, 1H nuclear magnetic resonance, and 13C nuclear magnetic resonance spectrometry. Three compounds including adenosine, uridine, and 2-acetylpyrrole were first identified in black garlic, except for 5-hydroxymethylfurfural, (1S, 3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid, and (1R, 3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid. The cellular antioxidant activities of uridine, adenosine, carboline alkaloids, 5-hydroxymethylfurfural, and ethyl acetate extracts were consistent with the results of in vitro experimental antioxidant properties. The results provide useful information for understanding the health benefits of black garlic products.
- ... According to Choi, Cha, and Lee (2014) and Toledano-Medina, Pérez-Aparicio, Moreno-Rojas, and Merinas-Amo (2016) black garlic extracts have more total polyphenol content and antioxidant activity than raw garlic extracts. Furthermore, in vivo assays carried out in models of rats with different pathologies have shown enough evidences that the intake of black garlic exerts hepatoprotective action (Kim et al., 2011), antioxidant effect (Lee, Gweon, Seo, Kang, & Kim, 2009), improvement of the general status via regulation of lipid metabolism (Chen, Kao, Tseng, Chang, & Hsu, 2014) and potential antihypertensive effect (Miao et al., 2014), being these properties related to the formation of bioactive compounds during the manufacturing process of black garlic (Li, Lu, Pei, & Qiao, 2014). ...This study reports the formation of 2-furoylmethyl amino acids (2-FM-AA) as indicators of Maillard reaction (MR) in black garlic elaboration, followed by the determination of furosine by ion-pair RP-HPLC-UV. The method was assessed for accuracy, repeatability and detection and quantitation limits indicating its adequacy. Traditional procedure of black garlic production and the inclusion of convective drying (CDP) and ohmic heating (OHP) were assayed. For comparison purposes, three commercial black garlic samples were used. Together with furosine (2-FM-lysine), 2-furoylmethyl-γ-aminobutyric acid and 2-FM-arginine were detected. Levels of furosine were higher in CDP (46.6–110.1 mg/100 g protein) than in OHP (13.7–42.0 mg/100 g protein) samples, probably due to the more severe processing conditions used in the former. These results highlight the suitability of 2-FM-AA as chemical indicators to monitor the process of black garlic elaboration in order to obtain high quality products.
- ... Black garlic is a product of garlic breeding development, especially for medicinal purposes. It has many bioactivities including inhibition of colon and gastric cancer cell growth, antioxidant, alteration of lipid profile in diabetes, antiobesity, anti-inflammatory, and antiallergic activities (Seo et al. 2009;Ha et al. 2015;Kimura et al. 2017). Processing method and garlic cultivars affect the quality and bioactive value of black garlic (Kimura et al. 2017;Chen et al. 2013;Bae et al. 2014). ...Setiyoningrum F, Pribadi G, Afiati F, Herlina N, Solikhin A, Lisani N. 2018. Functional properties of Saccharomyces kluyveri Y97-fermented solo black garlic. Asian J Agric 2: 48-51. Saccharomyces kluyveri Y97-fermented solo black garlic was made by fermentation of fresh solo garlic in medium containing S. kluyveri aging in 70C and relative humidity close to 60%. The fermentation period of fresh solo garlic in the medium was 0, 2, 4 dan 6 days. The black aging period was 0 (fresh garlic), 7, 14 dan 21 days. Antioxidant capacity, flavonoid content and total poliphenol were observed. S. kluyveri Y97-fermented solo black garlic had higher antioxidant capacity, flavonoid content and total polifenol compared to solo black garlic without fermentation. Fermentation of fresh solo garlic by S. kluyveri Y97 before aging process could increase solo black garlic’s functional properties.
- ... Elevated serum NO levels in rats with DM and CIH-DM suggested that oxidative stress (OS) was enhanced in DM and CIH-DM rats. Seo et al (38) reported elevated TBARS levels in erythrocytes and the liver in rats with DM, indicating that hyperglycemia may increase the OS. The results of the present study supported the above hypothesis. ...The present study investigated the effect of garlic (G) on serum, liver, renal and cerebral parameters of rats with chronic intermittent hypoxia (CIH) combined with diabetes mellitus (DM). A total of 32 rats were divided into eight groups, with 4 rats/group. A total of three models were established, including CIH, DM and CIH‑DM, and an additional healthy control (C) group. Rats in C‑G, CIH‑G, DM‑G and CIH‑DM‑G groups were injected with a G extract daily. Serum, liver, renal and cerebral parameters were detected. The results demonstrated that the rats' weight increased gradually, but at a slower rate in the CIH, DM and CIH‑DM groups compared with the healthy rats. Blood glucose increased in the DM and CIH‑DM groups compared with the healthy control group, while insulin level increased in the CIH group, but decreased in the DM and CIH‑DM groups, resulting in increased homeostatic model assessment of insulin resistance (HOMA‑IR) value in the CIH group, compared with healthy controls. Serum thiobarbituric acid reactive substances (TBARS), glutathione S‑transferase (GST), uric acid (UA), urine protein (UP), total cholesterol (TC), triglycerides (TG), total lipids (TL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and acid phosphatase (ACP) increased in the CIH, DM and CIH‑DM groups, while albumin and superoxide dismutase (SOD) decreased in all model groups compared with healthy controls. Nitric oxide (NO) increased in the DM and CIH‑DM groups but decreased in the CIH group, compared with the control group. Glutathione peroxidase (GSH‑Px) increased in the CIH group but decreased in the DM and CIH‑DM groups, compared with the control group. Glutathione reductase (GR) increased in the DM group but decreased in the CIH and CIH‑DM groups, compared with the control group. Liver TBARS and GST increased, while AST, ALT, LDH, ALP, ACP, catalase activity (CAT) and SOD decreased in the CIH, DM and CIH‑DM groups, compared with the control group. Liver GSH‑Px decreased in the DM and CIH‑DM groups, compared with the control group. Renal TBARS in the DM and CIH‑DM groups increased compared with the control group. Renal GST increased while CAT and SOD decreased in the CIH, DM and CIH‑DM groups, compared with the control group. Cerebral TBARS increased in the CIH, DM and CIH‑DM groups and LDH increased in the DM and CIH‑DM groups, compared with the control group. Cerebral LDH in CIH decreased compared with the control group. G treatment improved weight gain, blood insulin and HOMA‑IR in the DM and CIH‑DM groups, reduced blood glucose in the DM and CIH‑DM groups, and insulin and HOMA‑IR in the CIH group, compared with the respective G‑untreated groups. G treatment increased serum SOD in CIH‑G, DM‑G and CIH‑DM‑G groups, GSH‑Px and albumin in the DM‑G and CIH‑DM‑G groups, and GR in the DM‑G group, compared with the respective G‑untreated groups. G treatment decreased serum TBARS, UA, UP, TC, TG, TL, AST, ALT, LDH and ACP in the CIH‑G, DM‑G and CIH‑DM‑G groups; NO in the DM‑G group; GST and GR in the CIH‑G and CIH‑DM‑G groups; and ALP in the DM‑G and CIH‑DM‑G groups, compared with the respective G‑untreated groups. Liver AST, ALT, LDH, ALP, CAT, SOD in the CIH‑G, DM‑G and CIH‑DM‑G groups increased as a result of G treatment. GSH‑Px increased in the DM‑G and CIH‑DM‑G groups, ACP in the CIH‑G and DM‑G groups, renal CAT in the CIH‑DM‑G group, and renal SOD in the CIH‑G and CIH‑DM‑G groups, compared with the respective G‑untreated groups. Liver and cerebral TBARS decreased in all G‑treated experimental groups, and liver and renal GST, and cerebral LDH decreased in the DM‑G and CIH‑DM‑G groups, compared with the respective G‑untreated groups. The present study concluded that G aided in the recovery of homeostasis and metabolism in rats with CIH combined with DM, and protected rats' organs from damage induced by CIH combined with DM.
- ... The antioxidant capacity of black garlic is related to polyphenols [7]. Black garlic can prevent the development of atherosclerosis by clearing cholesterol [8]. In black garlic, the content of allicin, which gives a harsh aroma taste, is reduced and allisin in the browning process is transformed into antioxidant compounds such as bioactive alkaloid and flavonoid compounds [9]. ...Black garlic is a processed garlic product with a moisture-controlled high temperature heat treatment for a long time. In order to determine the secondary metabolites of black garlics treated in the study, firstly, in vitro antioxidant activities of black garlics purchased from Edovital company, Kastamonu, Turkey were determined, followed by qualitative and quantitative measurement of the phenolic compound content by HPLC and finally the electronic nose analysis of the content of nebulizer vapors in wood vinegar extract of black garlics were done successfully. Chlorogenic acid, vanillic acid, benzoic acid, gallic acid contents in detected 13 phenolic acids were quitely high. All quantitative results were expressed as mg gallic acid equivalent (GAE) per g dry matter of black garlic sample. ABTS and DPPH antioxidant activities were very low according to BHT standart and 2-Methylene-4-pentenal (18%) and Furfural (25%) were detected in high amount with electronic nose in nebulvapor contents of black garlic wood vinegar extract.
- ... The effect of garlic in glucose concentrations was not addressed significantly in the searched literature, and the studies carried out had inconsistent results. Chi et al. [35] and Seo et al. [43] showed a significant reduction in glucose levels in rats fed with a high content cholesterol diet supplemented with garlic powder. Thomson et al. [40] showed in a study that aqueous extract of fresh garlic ingested in small quantities (50mg/ kg) reduces the concentration of cholesterol and triglyceride and does not alter the glucose level in the plasma. ...Garlic has antioxidant and hypocholesterolemic properties that are attributed to its organosulfur compounds being allicin, which is reported to be the most active of these compounds. We hypothesized that allicin content could reduce plasma concentrations of triglycerides (TG), total cholesterol (TC), HDL (high density lipoproteins), VLDL (very low density lipoproteins), and glucose. Two different cultivars of commercial garlic, Peruano and Jinxiang, were used. Thirty male Wistar rats were distributed into 6 groups and fed for 15 days with standard diet (Control), Control with Peruano garlic treatment (CGP), Control with Jinxiang garlic treatment (CGCH), cholesterol-added control diet (CholC), cholesterol-added diet with Peruano garlic treatment (CholGP), and cholesterol-added diet with Jinxiang garlic treatment (CholGCH). Garlic treatment consisted of a daily oral dose of 1ml of lyophilized garlic. We observed that garlic treatment in Control group significantly reduced plasma TG and VLDL concentrations. The CGCH group presented a significant increase in plasma TC levels (25.5%) and glucose (11%). No significant changes in TC, HDL, TG and VLDL were observed in CholGP and CholGCH, but levels of fasting plasma glucose were increased: CholGP (23%) and CholGCH (27.5%). Results suggested allicin treatments alter lipid profile in rats. Nevertheless, further studies are necessary to address the increase in plasma glucose levels.
- ... Black garlic administration in high-fat diet improved plasma insulin and glucose level as well as homeostatic model assessment insulin resistance. These results are consistent with the results of Seo et al. [30]'s study, which shown that black garlic consumption increased serum insulin levels by 12.1% and decreased HOMA-IR value. The anti-diabetic effect of black garlic is known to be caused by substances called organosufur compounds, which is produced during processing of black garlic, to stimulate beta-cells to increase insulin secretion [31][32]. ...BACKGROUN/OBJECTIVES Although studies have revealed that black garlic is a potent antioxidant, its antioxidant mechanism remains unclear. The objective of this study was to determine black garlic's antioxidant activities and possible antioxidant mechanisms related to nuclear factor erythroid 2-like factor 2 (Nrf2)-Keap1 complex. METHODS/MATERIALS After four weeks of feeding rats with a normal fat diet (NF), a high-fat diet (HF), a high-fat diet with 0.5% black garlic extract (HF+BGE 0.5), a high-fat diet with 1.0% black garlic extract (HF+BGE 1.0), or a high-fat diet with 1.5% black garlic extract (HF+BGE 1.5), plasma concentrations of glucose, insulin,homeostatic model assessment of insulin resistance (HOMA-IR) were determined. As oxidative stress indices, plasma concentrations of thiobarbituric acid reactive substances (TBARS) and 8-isoprostaglandin F2α (8-iso-PGF) were determined. To measure antioxidant capacities, plasma total antioxidant capacity (TAC) and activities of antioxidant enzymes in plasma and liver were determined. The mRNA expression levels of antioxidant related proteins such as Nrf2, NAD(P)H: quinone-oxidoreductase-1 (NQO1), heme oxygenase-1 (HO-1), glutathione reductase (GR), and glutathione S-transferase alpha 2 (GSTA2) were examined. RESULTS Plasma glucose level, plasma insulin level, and HOMA-IR in black garlic supplemented groups were significantly (P < 0.05) lower than those in the HF group without dose-dependent effect. Plasma TBARS concentration and TAC in the HF+BGE 1.5 group were significantly decreased compared to those of the HF group. The activities of catalase and glutathione peroxidase were significantly (P < 0.05) increased in the HF+BGE 1.0 and HF+BGE 1.5 groups compared to those of the HF group. The mRNA expression levels of hepatic Nrf2, NQO1, HO-1, and GSTA2 were significantly (P < 0.05) increased in the HF with BGE groups compared to those in the HF group. CONCLUSIONS The improvements of blood glucose homeostasis and antioxidant systems in rats fed with black garlic extract were related to mRNA expression levels of Nrf2 related genes.
- Herbs have high medicinal value in Indian homes and proved to arrest, reduce and terminate most of the disease by the use of active constituents prepared out of them. From the ancient time onwards, Trigonella was found on the continents of Asia, Europe, Africa and Australia. The species name "foenum-graecum" means "Greek hay" indicating its use as a forage crop in the past. Trigonella foenum-graecum was used as a traditional remedy for the treatment of various diseases. In this study after a general discussion of chemical constituents, the biological and pharmacological actions of fenugreek such as Anti-diabetic activity, Hypocholesterolaemic properties, Immunomodulatory activity, Anti-toxic activity, Anti-cataract activity and Anti-oxidant activity were briefly reviewed. This review article summarizes the published experimental research and scientific literature from the databases including PubMed, Google and local library searches. The results of these studies provide a complete understanding of the biological action of fenugreek.
- The objectives of this study were to isolate and identify garlic endophytes, and explore the characteristics of dominant strains. Garlic endophytes were studied through phenotypical characterization and comparative sequence analysis of 16S rDNA based on culture-dependent approaches. Representative strains inferred from 16S rDNA sequencing were selected for further identification by gyrA and rpoB gene loci and phylogenetic analysis based on concateneted house-keeping sequences. Seven kinds of Bacillus were found from garlic and black garlic, respectively. Further studies demonstrated that the total bacteria and endophytes showed a sharp decrease firstly, followed by a rapid rise, then maintained at a certain level, and finally slowed down during the black garlic processing. B. subtilis, B. methylotrophicus, and B. amyloliquefaciens were the dominant strains. The selected strains were capable of fermenting glucose, lactose, sucrose, and garlic polysaccharide to produce acid but no gas, with a strong ability of heat resistance. The results indicated that there were a certain number of garlic endophytes during the black garlic processing, and Bacillus was the dominant strains under the conventional culture-dependent methods. This report provided useful information for the presence and type of garlic endophytes during the black garlic processing, which were of great significance to study the formation mechanism and quality improvement of black garlic in the future, as well as the security of garlic powder.
- Freezing pretreatment can destroy the cell membrane of garlic and may improve some food-quality of garlic. Therefore we investigated the effect of freezing pretreatment at -20^{\circ}C and -70^{\circ}C on quality of aged black garlic, compared with traditional processing methods. Our results showed that freezing pretreatment at -70^{\circ}C had the greatest impact on qualities and antioxidant activities of black garlic. Browning degree and pH of black garlic after both the freezing pretreatment and aging process were 3.14 and 3.55, respectively. Furthermore, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity and reducing power of aged black garlic can be enhanced by pre-freezing processing. Reducing sugar and 5-hydroxymethyl-2-furaldehyde (5-HMF) contents of freezing pretreated and aged black garlic were increased by 1.69 and 1.14 fold, respectively, compared with the control samples. The results indicated that freezing pretreatment had improved the overall qualities (such as browning degree, pH, reducing sugar) and functional materials of black garlic.
- This study aimed to explore the alliin, saccharides, antioxidant and some other physicochemical changes of black garlic during the thermal processing steps. The contents of alliin and polysaccharides decreased significantly after 10 days of heat treatment, whereas the content of reducing sugars increased correspondingly. The 57.14% of fructose, 6.78% of glucose and 7.62% of sucrose were mainly saccharides in black garlic to answer for its sweet taste. The color value of black garlic increased over time, whereas the pH decreased continually from 6.25 to 4.25 after heating at 70–80C for 10 days, which contributed a characteristic black appearance and a sour taste mouthfeel. The antioxidant activities, including 1,1-diphenyl-2-picrilhydrazyl, hydroxyl radical scavenging and ferric reducing/antioxidant power activities, increased gradually during thermal processing.Practical ApplicationsBlack garlic has been used as foods and herbal remedies mainly in Japan, Korea and China, which has a wide range of health benefits, significantly antioxidant properties. Various physicochemical changes have been found to take place during thermal processing of garlic, including alliin, allicin, saccharides, pH, color and antioxidant activities. This is the first study to investigate the changes in the molecular weight distribution of polysaccharides and the monosaccharide composition of black garlic. These changes in saccharide contents and composition could be utilized as quality factors for the production of black garlic. Therefore, the results may have some useful practical implications at both the food technology and nutritional level.
- Özet: Sarımsak (Allium sativum L.) insan sağlığına yararlı bir tür olmasına karşın, karakteristik kokusu ve tadı nedeniyle çiğ tüketimi sınırlıdır. Sarımsağın keskin kokusunu gidermek ve lezzetini artırmak için ısıl işlem, kurutma ve fermentasyon gibi çeşitli işleme teknikleri kullanılmaktadır. "Siyah sarımsak", doğal sarımsak başlarının yüksek sıcaklık (60°C ve üzeri) ve oransal nemde (%85-90), 30-40 gün süre ile ısıl işleme tabi tutulması ile üretilen kokusuz, tatlı, elastik yapılı siyah renkli dişlerden oluşan işlenmiş bir üründür. Isıl işlem, sarımsağın besin değerinde değişime ve üründeki insan sağlığına yararlı bileşiklerin düzeyinde artışa yol açmaktadır. Bu derlemede, siyah sarımsağın insan sağlığına etkisi, üretim teknolojisi ve fonksiyonel kullanımına yönelik bilgiler verilerek geleceğe dönük hedefler tartışılacaktır. Abstract: Although garlic (Allium sativum L.) is a beneficial species for human health, fresh garlic consumption is limited due to its strong smell and taste. Various processing techniques such as heat treatment, drying and fermentation has been used to remove to remove strong smell of the garlic and enhance its flavor. "Black garlic" is a processed product which is produced by heat treatment of natural garlic bulbs at high temperature (60°C and above) and relative humidity (85-90%) for 30-40 days, and it consists of odorless, sweet black teeth elastic texture. Heat treatment leads to change in the nutritional value of garlic and increase in level of health benefit compounds. In this paper future targets will be discussed by reviewing the effect of black garlic on human health, its production technology and its functional usage.
- The antioxidative and anti‐allergic activities of fresh and aged black garlic extracts were investigated. The garlic samples were extracted with 70% ethanol (v/v) and the total phenolic content was measured. The antioxidant capacity of extracts was assessed by determining the scavenging activities on 1,1‐diphenyl‐2‐picrylhydrazyl and hydroxyl radicals, ferricyanide reducing power, ferrous ion‐chelating ability and inhibitory effect on linoleic acid peroxidation. The anti‐allergic activity of extracts was analysed by measuring their inhibitory effects against β‐hexosaminidase release. The aged black garlic exhibited significantly higher phenolic content and greater antioxidative activity than fresh garlic. Both garlic extracts showed strong antioxidant capacity in a dose‐dependent manner. On the other hand, a considerably higher suppression of β‐hexosaminidase release was found in fresh garlic extract at lower concentration compared with that of the black garlic. Results of this study illustrate that ageing of garlic could enhance its antioxidant capacity, but could decrease its anti‐allergic activity.
- White and three types of black garlic (13, 32 and 45 days of fermentation, named 0C1, 1C2 and 2C1 respectively) were selected in order to check possible differences in their nutraceutic potential. For this purpose, garlic were physico-chemically characterised, and both in vivo and in vitro assays were carried out. Black garlic showed higher polyphenol content and antioxidant capacity than white garlic. The biological studies have shown that only white garlic was not safe showing toxicity effect. Furthermore, none garlic exert protective effects against H2O2, except the 0C1 black garlic. Moreover, garlic was non-genotoxic with the exception of the highest concentration of white garlic. On the other hand, 0C1 was the most antigenotoxic substance. The in vivo longevity assays yielded significant extension of lifespan results in some concentrations of white and 0C1and 1C2 black garlic. The in vitro experiments showed that all studied garlic induced a decrease in leukaemia cells growth. However, none type of garlic was able to induce proapoptotic internucleosomal DNA fragmentation. Taking into account the physicochemical and biological data, black garlic could be considered as a potential functional food and used in preventive treatment of age-related diseases. In addition, our findings could be relevant for the black garlic processing agrifood companies as the economical and timing costs are significantly reduced to 13 days aging.
- Garlic (Allium sativum L.) is a vegetable that is known to be medically beneficial and has been around since the past in the world cuisine. The unique taste and smell of garlic affects its raw consumption negatively. One of the functional uses of garlic, ‘black garlic’ is produced by fermenting white garlic under certain temperature and humidity conditions. Thus, the bitter taste and smell of garlic disappears and also changes occur in its nutritional value. Studies show that black garlic has anticancer, antitumor, antiallergic and antimicrobial effects. It also plays protective and therapeutic role against diabetes, obesity, cardiovascular diseases. This product, which is new for many countries, is not well known and consumed in our country too. In this study, the bioavailability of black garlic was highlighted and information was given about its production and antioxidant activity.
- Allium sativum (garlic) has been very popular in Asian kitchen as one of the major spices. The strong smelling juice of bulb contains volatile oils composed of sulphur-containing compounds: allicin, diallyl disulfide and diallyl trisulfide, which are responsible for anti-microbial activity. Recently garlic, its oil, extracts in different organic and aqueous solvents and individual components of essential oils have been examined as a feed additive to manipulate rumen function for controlling enteric methane emission and improving feed conversion efficiency. The results reported so far indicate that garlic and its essential oils inhibit methanogenesis significantly accompanied with a lower acetate to propionate ratio indicating a diversion of fermentation in a favourable direction. As methanogenesis is the major hydrogen sink in the rumen, its inhibition requires the disposal of reducing equivalents produced during fermentation of feed. The propionate synthesis serves as an alternate hydrogen sink. The anti-microbial compounds present in garlic appear to be selective inhibitors of methanogenesis, as there is no adverse effect on feed degradation in the rumen. Garlic and its oil adversely affect the protein degrading bacteria and deamination activity of the rumen contents. Only a few in vivo experiments have been conducted using garlic as a feed additive, and it appears to have good potential for rumen manipulation for eco-friendly (with minimum methane emission) and economic livestock production.
- This study examined the bioactivity of yeast (Saccharomyces cerevisiae)-fermented aged black garlic (FBG) on obese mice supplied a high-fat diet (HFD) and its in vitro antioxidant activity. Aged black garlic (BG) exhibits potent antioxidative effects and has been subjected to extensive research. In addition, the bioactivity of some natural products is increased by fermentation. In a preliminary test, this study found that the antioxidant activity of FBG is stronger than that of BG. Therefore, it was hypothesized that the bioactivity of BG would be increased by yeast fermentation and would be a good candidate as a nutraceutical product for improving the oxidative defense systems in older patients or patients affected by various oxidative stresses, for example, diabetes and diabetic complications. To test this hypothesis, the bioactivities of FBG in diabetic and obese mice as well as the antioxidant activity in vitro were examined. After 91 days of continuous HFD supply, the mice showed marked obesity, hyperglycemia, hyperlipemia, and liver and kidney damages. Black garlic and all 3 different doses of FBG showed favorable hepatoprotective, nephroprotective, hypolipidemic, and antiobesity effects compared with the HFD control, but no hypoglycemic effects. In particular, more favorable bioactivity against all 4 HFD-induced diabetic complications was detected in the FBG-treated groups compared with the group given equivalent doses of BG. These findings suggest that the bioactivities of BG can be improved by yeast fermentation.
- Preliminary trials have suggested possible hypoglycaemic, hypolipidaemic and immunomodulatory properties of the fenugreek plant. Here, we evaluated and compared the efficacy of Egyptian fenugreek seed powder (FSP, 0·5 and 1·0 g/kg body weight) in alleviating the experimentally induced metabolic syndrome (in type 1 diabetic and obese rat models) and experimentally induced immunosuppression and delay in burn-healing (in cyclophosphamide (CP)-treated rats). FSP significantly alleviated (P < 0·05-0·001) most signs of the metabolic syndrome resulting from experimentally induced type 1 diabetes and obesity by 40-76 and 56-78 %, respectively, including hyperglycaemia, hyperlipidaemia, elevation in atherogenic indices, impairment of liver functions, severe changes in body weight and oxidative stress. Besides, FSP (especially the high dose) completely modulated the immunosuppressive activity of CP including leucopenia (resulting from neutropenia and lymphopenia), decrease in weights and cellularity of lymphoid organs, serum γ-globulin level, delayed type of hypersensitivity response and delay in the skin-burning healing process. FSP decreased the immunosuppressive activity of CP by 57-108 %. These beneficial effects of FSP were dose dependent in most cases, and FSP doses used here were considered safe in general. FSP was more efficient in alleviating the signs of the metabolic syndrome in the obese animals (over 9 %) than in the type 1 diabetic animals. Moreover, the immunostimulant activity of fenugreek seeds exceeded their anti-metabolic syndrome activity by 15-24 %. In conclusion, fenugreek seeds may be useful not only as a dietary adjunct for the control of the metabolic syndrome in diabetic/obese patients, but also as an immunostimulant in immunocompromised patients such as those under chemotherapeutic interventions.
- Producing method for aging-fermentation black garlic using artemisia fumigation
- Duksan Food Co
- Ltd
- A method for manufacturing aged garlic using garlic aging room. Korean Patent
- Gp Kang
- Functional Food Available from: http://hfoodi.kfda.go.kr
- Korea Food
- Drug Administration
- The effect of intensive treatment of diabetes on the development and progression of long-term complications in the diabetes control in insulin-dependent diabetes mellitusThe Diabetes Control and Complications Trial Research Group. 1993. The effect of intensive treatment of diabetes on the development and progression of long-term complications in the diabetes control in insulin-dependent diabetes mellitus. N Engl J Med 329: 977-986.
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- Management of dyslipidemia in adults with diabetes (Position Statement)American Diabetes Association. 1999. Management of dyslipidemia in adults with diabetes (Position Statement). Diabetes Care 22(s01): 56-59.
- The relative contributions of insulin resistEffect of Garlic and Aged Black Garlic on Hyperglycemia and Dyslipidemia 7
- Se Kahn
Kahn SE. 2003. The relative contributions of insulin resistEffect of Garlic and Aged Black Garlic on Hyperglycemia and Dyslipidemia 7 - In this study, black garlic was produced by aging under high temperature (70°C) and high humidity (90% RH) conditions. Then, the physiological activity and antioxidative effects of its extract were compared to those of normal garlic extract. The black garlic extract had a 2.5-fold higher total polyphenol content than that of the normal garlic extract, showing levels of 10.0 mg/g and 3.7 mg/g, respectively. At the 1,000 μg/mL concentration, the black garlic and normal garlic extracts had electron donating abilities of 101.9% and 12.9%, respectively. For their nitritescavenging effects, the normal garlic extract showed slightly higher scavenging activity than the black garlic extract at the 5 mg/mL concentration; whereas the black garlic extract had a slightly higher effect at concentrations above 20 mg/mL. In terms of their superoxide dismutase activities, the black garlic extract showed a 10-fold higher activity as compared to the normal garlic extract at the 20 mg/mL concentration. Furthermore, at 50 mg/mL, the angiotensin converting enzyme inhibitory effects of the normal garlic and black garlic extracts were approximately 52.7% and 88.8%, respectively. These results indicate that the antioxidant activity and ACE inhibitory effects of the black garlic extract were greater than those of the normal garlic extract.
- BACKGROUND Long-term microvascular and neurologic complications cause major morbidity and mortality in patients with insulin-dependent diabetes mellitus (IDDM). We examined whether intensive treatment with the goal of maintaining blood glucose concentrations close to the normal range could decrease the frequency and severity of these complications. METHODS A total of 1441 patients with IDDM -- 726 with no retinopathy at base line (the primary-prevention cohort) and 715 with mild retinopathy (the secondary-intervention cohort) were randomly assigned to intensive therapy administered either with an external insulin pump or by three or more daily insulin injections and guided by frequent blood glucose monitoring or to conventional therapy with one or two daily insulin injections. The patients were followed for a mean of 6.5 years, and the appearance and progression of retinopathy and other complications were assessed regularly. RESULTS In the primary-prevention cohort, intensive therapy reduced the adjusted mean risk for the development of retinopathy by 76 percent (95 percent confidence interval, 62 to 85 percent), as compared with conventional therapy. In the secondary-intervention cohort, intensive therapy slowed the progression of retinopathy by 54 percent (95 percent confidence interval, 39 to 66 percent) and reduced the development of proliferative or severe nonproliferative retinopathy by 47 percent (95 percent confidence interval, 14 to 67 percent). In the two cohorts combined, intensive therapy reduced the occurrence of microalbuminuria (urinary albumin excretion of ≥ 40 mg per 24 hours) by 39 percent (95 percent confidence interval, 21 to 52 percent), that of albuminuria (urinary albumin excretion of ≥ 300 mg per 24 hours) by 54 percent (95 percent confidence interval, 19 to 74 percent), and that of clinical neuropathy by 60 percent (95 percent confidence interval, 38 to 74 percent). The chief adverse event associated with intensive therapy was a two-to-threefold increase in severe hypoglycemia. CONCLUSIONS Intensive therapy effectively delays the onset and slows the progression of diabetic retinopathy, nephropathy, and neuropathy in patients with IDDM.
- Peter Warner – Astra Zeneca, Mereside, Alderley Park, Macclesfield, Cheshire 5K10 4T9, UK Modulating the absorption of dietary fats and carbohydrates is a conceptually attractive strategy for the control of hyperglycaemia in type-2 diabetes. Orlistat, which reduces fat absorption by inhibition of lipases, also promotes weight loss in obese patients. Although reducing the absorption of dietary fats and carbohydrates delivers only modest glucose-lowering efficacy and is associated with unpleasant gastrointestinal side effects, interesting data are now emerging that suggest that this strategy might be efficacious in preventing the development of type-2 diabetes. Professor Josse has made significant contributions to this field by studying the efficacy of the α-glycosidase inhibitor acarbose in reducing the progression of impaired glucose tolerance to type-2 diabetes in the clinic.
- The hypocholesterolemic effect of dietary garlic was studied. 4 experimental groups were established. The control group (group-C) received a standard diet; the second group (group-G) received a supplement with 10% fresh garlic, the third group (group-Ch) received 2% cholesterol and the forth group (group-ChG) received 2% cholesterol and 10% fresh garlic. The serum cholesterol level was significantly lower in group-G (63.21 ± 7.24) than in group-C (72.00 ± 8.32) (p < 0.05). On the other hand, hypercholesterolemia induced by cholesterol feeding (group-Ch: 94.33 ± 24.50) was significantly reduced by garlic (group-ChG: 65.03 ± 10.57) (p < 0.005). Garlic supplementation increased high density lipoprotein and decrease low density lipoprotein in normal and hypercholesterolemic rats. The reduction in the plasma cholesterol by feeding garlic was in low density lipoprotein and very low density lipoprotein cholesterol fractions. However, the liver weight was influenced by supplementation of garlic. Feeding the garlic diet decreased liver weight in group-G (3.00 ± 0.13) compared with group-C (3.33 ± 0.26) (p < 0.005) and in group-ChG (3.66 ± 0.24) compared with group-Ch (3.35 ± 0.15) (p < 0.05). The plasma glucose in rats fed the cholesterol diet supplemented with garlic was reduced, but not significantly, compared with those fed the cholesterol diet without garlic. The results demonstrate that garlic exerts hypocholesterolemic effects in normal or cholesterol-fed rats and reduces the liver weight.
- Background & aims Diabetic nephropathy is a consequence of metabolic abnormalities spearheaded by hyperglycemia. This study investigated the hypoglycaemic effects of garlic and ginger on the kidney structure of streptozotocin-induced diabetic rats. Method Diabetic Sprague Dawley rats received a single daily intraperitoneal dose (500 mg/kg) of extracts of raw garlic (n = 10) or ginger (n = 10) for seven weeks. Normal rats (n = 10) and non-treated diabetic rats (n = 10) acted as reference. At the last week, serum glucose and 24-h protein clearance were determined, and kidneys were processed for light microscopy examination. Results Compared to normal levels, non-treated diabetic serum glucose and protein clearance were 330% and 185%, respectively (P < 0.05). Compared to non-treated diabetic rats, garlic or ginger-treated diabetic rats serum glucose and protein clearance levels decreased by 45% and 50%, respectively (P < 0.05). Images of non-treated diabetic kidneys showed characteristic histopathological changes (e.g. capsular space shrinkage, glomerular hypertrophy and diffusion, glomerular and microvascular eosinophilic precipitation, and cytoplasm fragmentation and retraction). In garlic or ginger-treated rats, these renal structural changes although evident were less prominent. Conclusions The hypoglycaemic effects of garlic and ginger concurred with attenuation in the progression of diabetic structural nephropathy.
- This study was designed to investigate the effect on treatments of garlic and the improvement of lipids in dietary-induced hyperlipidemic rats. Rats were administrated 1% cholesterol to induce hyperlipidemia and were fed diets containing fresh garlic powder (FGP), steamed garlic powder (SGP) and black garlic powder (BGP) by 3% (w/w) for 4 weeks. Body weight gain and food efficiency was not significantly different between control and garlic powder fed groups. Liver weight was significantly higher in control and SGP fed groups. Blood glucose was decreased in FGP and BGP fed groups than control group. The concentration of total lipid was significantly decreased in BGP group. Total cholesterol and triglyceride of serum were significantly lower in garlic powder fed groups than control group. HDL-cholesterol was significantly higher, LDL-, and VLDL-cholesterol were significantly lower in the garlic powder fed groups than the control group. Activities of serum GOT was lower in SGP fed group than control group. Total hepatic lipid and cholesterol concentration were conspicuously decreased by garlic powder fed groups. TBARS concentration of liver was significant different for the added garlic powder administration. Antioxidant activity of liver tended to increase in garlic powder fed groups compared with control group. In this result, we suggest the preventive effect of black garlic against the atherosclerotic process and the improvement of hyperlipidemia through the removal of cholesterol.
- An increase in oxidative stress is postulated to contribute to the development of diabetic complications and the use of antioxidant therapy could be protective against these processes. This study was performed to investigate the role of the antioxidant S-allylcysteine (SAC), a water-soluble component of aged garlic, for reducing levels of oxidative stress that occurs in diabetic rats.
- Cirrhosis is one of the most common causes of mortality worldwide, because hepatic dysfunction constitutes a potentially lethal condition. Having demonstrated the hepatoprotective effect of adenosine against CCl4-induced cirrhosis, the present study was aimed at assessing adenosine's effect on an already-established micronodular cirrhosis. Chronic administration of CCl4 (10 weeks) induced a cirrhotic state, characterized by increased liver fibronectin and collagen types I and III content, enhanced expression of -1 (I) collagen mRNA, portal hypertension, and liver dysfunction. After CCl4 discontinuation (5 weeks), increased persitance of -1 (I) collagen mRNA expression and deposition, enhanced proline incorporation into collagen and prolyl hydroxylase activity evidenced active fibrogenesis. Several weeks after CCl4 withdrawal, deposited collagen showed an enhanced type I/III ratio, which was associated with deficient collagenolytic activity in cirrhotic livers. Liver expression of some metalloproteinases (MMPs) and of tissue inhibitors of MMPs (TIMPs) also indicated decreased collagen breakdown in cirrhotic livers. Parameters indicative of oxidative stress (mainly protein oxidation) were persistently augmented. These events were coincident with diminished regenerative capacity of the cirrhotic liver. Intraperitoneal adenosine administration to CCl4-induced cirrhotic rats blocked active fibrogenesis and increased the collagen degradation (most probably by decreasing liver TIMPs levels), normalizing collagen-type ratios. In addition, the nucleoside promoted an effective hepatocyte's proliferation in the cirrhotic liver and accelerated normalization of parameters indicative of liver function and oxidative stress. Thus, adenosine readily reversed an experimental cirrhosis through stimulating liver collagenolytic and proliferative capacities, as well as by accelerating functional recovery.
- Developmental and homeostatic remodeling of the extracellular matrix (ECM) is a highly regulated process orchestrated by a family of zinc-containing, calcium-dependent neutral proteases known as the matrix metallo-proteinases (MMP). This family of enzymes, which now contains twenty members, can collectively degrade all structural proteins of the ECM including interstitial collagens (I, II, III, and V), basement membrane collagens (IV), fibronectin, laminin, proteoglycan, and elastin (Table 1). The enzymatic activity of MMP family members is controlled by a group of inhibitor proteins known as the Tissue Inhibitors of Metalloproteinases (TIMPs), which consist of four family members (Table 2). Whereas all four TIMPs can inhibit all MMPs in vitro, preferential TIMP-MMP interactions and tissue-restricted TIMP expression suggest that each TIMP has a specific function (Table 2). Table 1 The Matrix Metalloproteinases (MMPs) MMP family member Common names Substrates Selected references MMP-1 Collagenase-1 Collagens I, II, III, VI, X, gelatins, aggrecan, entactin (154–158) MMP-2 72 kDa Gelatinase, Gelatinase A Gelatins, collagens I,IV, V, VII, X, XI, fibronectin, laminin, aggrecan, elastin, large tenascin C, vitronectin, β-amyloid protein precursor (157–159) MMP-3 Stromelysin-1 Aggrecan, gelatins, fibronectin, laminin, collagen III, IV, IX, X, large tenascin C, vitronectin (28,157,158,160,161) MMP-7 Matrilysin, Pump Aggrecan, fibronectin, laminin, collagen IV, elastin, entactin, small tenascin C, vitronectin (157,158,162,163) MMP-8 Collagenase-2, Neutrophil Collagenase Collagens I, II, III, aggrecan (157,158,164) MMP-9 92 kDa Gelatinase, Gelatinase B Gelatins, collagens IV, V, XIV, aggrecan, elastin, entactin, vitronectin (157,158,165,166) MMP-10 Stromelysin-2 Aggrecan, fibronectin, laminin, collagen IV (157,158,167) MMP-11 Stromelysin-3 Fibronectin, laminin, collagen IV, aggrecan, gelatins (141,158) MMP-12 Metalloelastase Elastin (147,158) MMP-13 Collagenase-3 Collagens I, II, III (88,89,124,158,168,169) MMP-14 Membrane-type-1 -MMP Collagens I, II, III, fibronectin, laminin, vitronectin, proteoglycan, ProMMP-2, ProMMP-13 (158,170) MMP-15 Membrane-type-2-MMP Not known (158,171) MMP-16 Membrane-type-3-MMP ProMMP-2 (158,172) MMP-17 Membrane-type-4-MMP Not known (158,173) MMP-18 Collagenase-4,XenopusCollagenase Collagen I (158,174,175) MMP-19 Not Known (158,176,177) MMP-20 Enamelysin Amelogenin (The major tooth enamel matrix protein) (178) Table 2 Tissue Inhibitors of Metalloproteinases (TIMPs) Family Reported functions Selected References TIMP-1 Inhibition of all known MMP family members. Associates with proMMP-9. Inhibits angiogenesis. Erythroid-potentiating actvity. (179–181) TIMP-2 Inhibitions all known MMP family members. Associates with MT1-MMP and MMP-2 at cell surface and regulates MMP-2 activation. (181–184) TIMP-3 Inhibition of all known MMP family members. Extracellular matrix-associated. Mutation associated with Sorsby's fundus dystrophy. (55,181,185–188) TIMP-4 Inhibition of all known MMP family members. Restricted expression suggests tissue specific TIMP function. (181,189,190)
- The technique involves estimation of cholesterol after a double precipitation procedure to separate subfractions of high density lipoprotein (HDL). Cholesterol estimation by a colorimetric method compares favourably with the enzymatic method. This simple method is acceptable for the routine estimation of HDL-Cholesterol (HDL-C) and its subclasses.
- Garlic (Allium sativum) and onion (Allium cepa) are two food ingredients widely used in our gastronomy. Moreover, garlic and onion extracts have been recently reported to be effective in cardiovascular disease, because of their hypocholesterolemic, hypolipidemic, anti-hypertensive, anti-diabetic, antithrombotic and anti-hyperhomocysteinemia effects, and to possess many other biological activities including antimicrobial, antioxidant, anticarcinogenic, antimutagenic, antiasthmatic, immunomodulatory and prebiotic activities. Given the importance of these vegetables and derived supplements as much in feeding as in therapeutic, in the present work, their main biological activities have been reviewed, indicating the compounds responsible for each one of them. In addition, the influence of the processing on the bioactivity and the adverse effects and interactions with different medications have also been considered.
- We describe a totally enzymatic method for determination of serum triglycerides (triacylglycerols) specifically adaptable to the CentrifiChem system. The method involves lipolysis with lipase from Rhizopus arrhizus alone and quantitation of the resulting glycerol with glycerol dehydrogenase in a kinetic, fixed-time mode. Hydrolysis by the lipase is complete, for concentrations up to at least 5.0 g/liter, in 10 min at room temperature. The unfavorable equilibrium for the oxidation of glycerol is overcome by increasing the pH and adding excess NAD+. Under these conditions the glycerol determination is linear to at least 4.0 g of glycerol per liter, as triglyceride. The test exhibits acceptable accuracy and precision, and results correlate well with those by an alternative totally enzymatic procedure. The present method is unaffected by phosphatase and a considerably simplified reagent is used.
- Allicin (diallyl disulphide-oxide), an ether soluble and volatile substance isolated from Allium sativum Linn., was found, on oral administration, to produce a hypoglycemic action comparable to tolbutamide in rabbits with mild alloxan diabetes. It significantly improves the serum insulin effect and glucose tolerance, as observed with the standard drug tolbutamide. Its effect on liver glycogen synthesis was also found to be very significant. A mechanism of action of the hypoglycemic substance is proposed.
- A new enzymatic method for the determination of cholesterol in serum and plasma was evaluated in 8 separate laboratories in comparison with routine and reference methods. Investigation of the analytical reliability in the 2-26 mmol/l measurement range showed the following results: At the set reading points (10 min at 25 degrees C and 5 min at 37 degrees C) the reaction shows complete substrate conversion. The colour complex is stable over a period of 60 min. The response to cholesterol is linear up to 26 mmol/l. Precision within the series was 0.6-2.8% in 20 determinations (coefficient of variation). Day to day precision was 0.5-3.3% in triple determinations of 10 days (coefficient of variation). Accuracy was studied with 2 samples (assigned value: 3.52 and 6.70 mmol/l respectively). In the case of sample 1 the mean for the 8 laboratories was 3.44, with a median of 3.44; for sample 2 the values were 6.68 and 6.72. The results demonstrate an excellent transferability. In comparison with other enzymatic procedures, the values found with the new test were 5-10% higher; these results agree at all concentration ranges with the reference methods of Abell & Kendall and with those from mass spectrometry.
- We present a "high-performance" liquid-chromatographic method for determination of HbA1c with use of a carboxylate cation-exchange column, ethanolic mobile phases, and a hemolysate-storage reagent that stabilizes a sample for up to five weeks at 4 degrees C. Temperature control and the addition of ethanol to the phosphate step-gradient increase precision by stabilizing peak shape and column activity. Lengthy equilibration of the column between samples is not necessary, because the pKa of the cation-exchange resin is decreased from 6.10 in aqueous media to 5.59 in ethanol/water (5/95 by vol) at 25 degrees C. We identified interfering heme compounds, distinct from HbA1d or HbA1e, that elute with the glycosylated hemoglobins and developed a method of correcting for their presence. The day-to-day coefficient of variation was 3.5%, and the reference interval for a mixed group of 20 healthy adults between the ages of 20 and 56 was 3.2--5.2% HbA1c.
- The antioxidant properties of three garlic preparations and organosulfur compounds in garlic have been determined. Aged garlic extract inhibited the emission of low level chemiluminescence and the early formation of thiobarbituric acid-reactive substances (TBA-RS) in liver microsomal fraction initiated by t-butyl hydroperoxide. However, the water extracts of raw and heat-treated garlic enhanced the emission of low level chemiluminescence. Among the variety of organosulfur compounds, S-allylcysteine (SAC) and S-allylmercaptocysteine (SAMC), the major organosulfur compounds found in aged garlic extract, showed radical scavenging activity in both chemiluminescence and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, indicating that these compounds may play an important role in the antioxidative activity of aged garlic extract.
- Gel-filtered sera of patients with various inflammatory and autoimmune rheumatic diseases (N = 354) were screened for the presence of the inflammation marker Cu-thionein. The concentrations of Cu-thionein were significantly diminished in patients with connective tissue diseases (P < 0.001). Sera of patients suffering from inflammatory rheumatic diseases were almost totally depleted of this low-molecular-weight copper protein that exerts pronounced superoxide dismutase activity and scavenges effectively hydroxyl radicals and singlet oxygen. Cortisone treatment of patients with rheumatoid arthritis, systemic lupus erythematosus, and polymyalgia rheumatica replenished impressively the serum concentration of Cu-thionein. The partial oxidation of the EPR-silent Cu(I)-chromophore to Cu(II)/Cu(I)-thionein, which is essential for the catalytic dismutation of superoxide, was monitored by electron paramagnetic resonance in the presence of activated neutrophils and monocytes. Release of Cu-thionein during the oxidative burst of peripheral blood monocytes was demonstrated in vitro. The role of prooxidant-antioxidant imbalances in the pathogenesis of rheumatic diseases is discussed.
- An increasing body of experimental evidence is emerging to incriminate oxidative stress as a pivotal signal for liver fibrogenesis. This paper reviews the results from our studies testing this hypothesis. In the rat model of alcoholic liver disease, the importance of oxidative stress was supported by marked accentuation of liver fibrosis by dietary supplementation of iron, a pro-oxidant, and the significant correlation of the liver malondialdehyde (MDA) and 4-hydroxynonenal (4HNE) levels with the hepatic collagen accumulation. Both MDA and 4HNE adduct epitopes were detected intensely and diffusely in close association with collagen deposition. The direct cause and effect relationship between MDA/4HNE and Ito cell stimulation was indicated by the demonstration of Ito cell collagen gene induction by these aldehydes in culture. In primary cultures of rat Kupffer cells (KC), addition of antioxidants such as alpha-tocopherol acetate and succinate suppressed mRNA expression and the release of interleukin (IL)-6 and tumour necrosis factor alpha (TNF alpha). In rats with biliary fibrosis, an increase in the liver MDA level was accompanied by enhanced mRNA expression of procollagen alpha 1(I) and transforming growth factor beta 1 in Ito cells; and that of TNF alpha and IL-6 in KC. Furthermore, the gel shift assay of KC nuclear extracts showed enhanced NF-kB DNA binding activity. These results support the proposal that enhanced oxidative stress constitutes an important signal for activation of Kupffer and Ito cells in experimental liver fibrogenesis.
- Both insulin resistance and decreased insulin secretion have been shown to predict the development of NIDDM. However, methods to assess insulin sensitivity and secretion are complicated and expensive to apply in epidemiological studies. The homeostasis model assessment (HOMA) has been suggested as a method to assess insulin resistance and secretion from the fasting glucose and insulin concentrations. However, this method has not been extensively evaluated, particularly in different ethnic groups. We applied the HOMA model to cross-sectional analyses of the San Antonio Heart Study (n = 2,465). HOMA insulin resistance (IR) was very strongly correlated with fasting insulin (r = 0.98) and HOMA beta-cell function (beta-cell) was moderately correlated with the 30-min increment in insulin concentration over the 30-min increment in glucose concentration (delta I30/delta G30) in an oral glucose tolerance test (OGTT) (r = 0.44). NIDDM was characterized by both high HOMA IR and low HOMA beta-cell function. In Mexican-Americans, HOMA IR in NIDDM subjects was 9.5 compared with 2.7 in normal glucose tolerance (NGT) subjects. In contrast, HOMA beta-cell function showed only small differences in Mexican-Americans (176 NIDDM; 257 NGT). However, the delta I30/delta G30 (pmol/mmol) showed much larger differences (75 NIDDM; 268 NGT). When modeled separately, impaired glucose tolerance (IGT) was characterized by high HOMA IR and high HOMA beta-cell function. However, when analyzed in the same regression model, high HOMA IR and low HOMA beta-cell function characterized subjects with IGT. These results were similar in both ethnic groups. Mexican-Americans had increased insulin resistance (as judged by both HOMA IR and fasting insulin) and insulin secretion (by HOMA beta-cell and delta I30/delta G30) relative to non-Hispanic whites. We conclude that HOMA provides a useful model to assess insulin resistance and beta-cell function in epidemiological studies in which only fasting samples are available and that, further, it is critical to take into account the degree of insulin resistance in assessing insulin secretion by the HOMA model.
- Experimental hypercholesterolemia and its modulation by some natural dietary supplements (pectin, garlic and ginseng) and by the drug gemfibrozil were studied. Experimental hypercholesterolemia was induced by feeding rabbits a 2% cholesterol-enriched diet for 28 days. Hypercholesterolemic rabbits were classified into five groups. One group did not receive treatments and served as a control hypercholesterolemic group. The other four groups were fed the cholesterol-enriched diet in conjunction with either 10% pectin, 2% garlic, 2% ginseng or 135 mg g-1 b.w gemfibrozil in a daily oral dose. A normal group of rabbits fed a plain chow diet was also included in the study. The hypolipidemic effect of the above treatments was examined by estimating serum triglycerides (TG), total-, LDL- and HDL-cholesterol. Post-heparin total and hepatic lipase activities were estimated in post-heparin plasma obtained 10 min after an intravenous injection of heparin (200 IU kg-1 b.w). In order to evaluate the antioxidant status of the rabbits, plasma malondialdehyde (MDA) level and erythrocyte superoxide dismutase (SOD) activity were measured. After killing, aorta from all rabbits were subjected to histopathological examination. Results of the study demonstrated that feeding the cholesterol-enriched diet caused a significant increase in total-, LDL-, and HDL-cholesterol, plasma MDA and post-heparin total and hepatic lipase activities. On the other hand, serum TG and erythrocyte SOD were not changed. Histopathological examination revealed marked alteration in the aortic wall with the appearance of large multiple atheromatous plaques. Both garlic and pectin were successful in a significant reduction of the hypercholesterolemia in a way comparable to gemfibrozil. Garlic was the only treatment that has antilipid peroxidative property. Erythrocyte SOD activity was not affected by hypercholesterolemia or by any of the treatments. Also, none of the treatments were able to modify the significant elevation of post-heparin lipolytic activities associated with the hypercholesterolemia or to significantly affect the serum triglycerides level. Finally, among the hypercholesterolemic groups that received treatments, the least changes in the aortic wall were shown in the animals of the gemfibrozil group. Slight degeneration was observed in the aorta of animals treated with pectin or garlic. Ginseng administration failed to exert any significant protection from the remarkable hypercholesterolemia or atherosclerosis associated with the cholesterol- enriched diet.
- To examine the health burden associated with concomitant depressive symptoms and diabetes in older Mexican Americans. Data from the Hispanic Established Population for the Epidemiologic Study of the Elderly were used to assess the association between high levels of depressive symptoms, measured with the Center for Epidemiologic Studies of Depression scale, and comorbid chronic health conditions, diabetic complications, functional disability, health service use, and medication use among 636 older diabetic Mexican Americans, in comparison with 2,196 older nondiabetic Mexican Americans. Overall, 31.1% of the older diabetic individuals reported high levels of depressive symptoms. The risks of comorbid myocardial infarction, hypertension, arthritis, and angina were significantly higher in the presence of concomitant depressive symptoms, as were the risks of diabetic complications, functional disability, incontinence, vision impairment, poorer perceived health status, and health service use among both diabetic and nondiabetic individuals. Rates were substantially higher among depressed diabetic individuals, however, in comparison to depressed nondiabetic individuals. Importantly, this increased health burden was evident even when controlling for sociodemographic risk factors, including sex, age, level of education, marital status, immigrant status, and living arrangements. The presence of concomitant depressive symptoms among older diabetic Mexican Americans is associated with a substantially greater health burden than is seen among diabetic individuals without depression or depressed individuals without diabetes. This association of depression with higher rates of chronic conditions, poorer functioning, and increased health service use is particularly significant in that this study was conducted among community-dwelling adults and was not confounded by the potential association of health care-seeking behavior that might occur in a medically ill sample.
- Water-extracted Touchi, a traditional Chinese food, exerts a strong inhibitory activity against rat intestinal alpha-glucosidase in foodstuffs, and Touchi-extract (TE) has been shown to have an antihyperglycemic effect in rats and humans after a single oral administration. In the present complementary study, the effects of powdered Houji-tea with or without (placebo) TE, a formula designed to enhance good compliance, were monitored in a 3-mo double-blind randomized group comparison study with placebo controls in humans with borderline and mild type-2 diabetes (n = 36). All subjects ingested Houji-tea with or without 0.3 g of TE before each of three meals per day for 3 mo. In the TE group, initial fasting blood glucose (6.9 +/- 0.1 mmol/L) and glycated hemoglobin (HbA(1c); 6.1 +/- 0.1%) levels gradually decreased; fasting blood glucose decreased significantly after 3 mo (6.4 +/- 0.3 mmol/L; P < 0.05) as did HbA(1c) (5.6 +/- 0.2%; P < 0.01) levels at 2 mo postingestion of TE and thereafter. In contrast, fasting blood glucose and HbA(1c) levels did not change in the placebo group. In this study, other biochemical variables were not affected in any of the subjects, and no one complained of any side effects or abdominal distension. Moreover, there was no deterioration as assessed by fasting blood glucose and HbA(1c) levels after withdrawal of TE ingestion. Thus, the alpha-glucosidase inhibitory TE demonstrated an antihyperglycemic effect and may prove useful for improving glycemic control in subjects suffering from borderline and type-2 diabetes mellitus.
- Although garlic has been used for its medicinal properties for thousands of years, investigations into its mode of action are relatively recent. Garlic has a wide spectrum of actions; not only is it antibacterial, antiviral, antifungal and antiprotozoal, but it also has beneficial effects on the cardiovascular and immune systems. Resurgence in the use of natural herbal alternatives has brought the use of medicinal plants to the forefront of pharmacological investigations, and many new drugs are being discovered. This review aims to address the historical use of garlic and its sulfur chemistry, and to provide a basis for further research into its antimicrobial properties.
- There has been an impressive gain in individual life expectancy with parallel increases in age-related chronic diseases of the cardiovascular, brain and immune systems. These can cause loss of autonomy, dependence and high social costs for individuals and society. It is now accepted that aging and age-related diseases are in part caused by free radical reactions. The arrest of aging and stimulation of rejuvenation of the human body is also being sought. Over the last 20 years the use of herbs and natural products has gained popularity and these are being consumed backed by epidemiological evidence. One such herb is garlic, which has been used throughout the history of civilization for treating a wide variety of ailments associated with aging. The role of garlic in preventing age-related diseases has been investigated extensively over the last 10-15 years. Garlic has strong antioxidant properties and it has been suggested that garlic can prevent cardiovascular disease, inhibit platelet aggregation, thrombus formation, prevent cancer, diseases associated with cerebral aging, arthritis, cataract formation, and rejuvenate skin, improve blood circulation and energy levels. This review provides an insight in to garlic's antioxidant properties and presents evidence that it may either prevent or delay chronic diseases associated with aging.
- Subjects with diabetes have a greatly increased risk of CHD, which is only partially related to their elevated glucose. Other factors such as insulin resistance and dyslipidemia are likely to be important. The type of dyslipidemia that is most characteristic of type 2 diabetic subjects is elevated triglycerides and decreased HDL cholesterol levels, although all lipoproteins have compositional abnormalities. Surprisingly few good prospective studies of lipoprotein levels in relation to CHD have been done in diabetic subjects. Available studies suggest that low HDL cholesterol may be the most important risk factor for CHD in observational studies. In studies in which total cholesterol and triglyceride were done, cholesterol and triglycerides were risk factors for CHD, although triglycerides were often a stronger predictor. However, the strength of triglyceride as a risk factor for CHD may depend partially on its association with other variables (e.g., hypertension, plasminogen activator inhibitor 1 [PAI-1], etc.). In clinical trials in diabetic subjects, LDL reduction with statins has led to significant reductions in CHD incidence. In addition, overall mortality was reduced with statin therapy, although the results were not statistically significant. Gemfibrozil has led to reductions in CHD incidence in diabetic subjects, although the results were not statistically significant perhaps because of low sample size. Regarding lipoproteins and CHD risk in diabetic patients, the very positive results of statin trials point to LDL cholesterol being more important than previously realized. Apparently, having a borderline high LDL cholesterol (between 130 and 160 mg/dl) in a diabetic patient is equivalent to a much higher LDL cholesterol in terms of CHD risk for a nondiabetic subject. Therefore, the primary target of therapy in diabetic patients is lowering LDL cholesterol (or possibly, non-HDL cholesterol). Statins are the preferred pharmacological agent in this situation. Once LDL cholesterol levels have been lowered, attention can be given to treatment of residual hypertriglyceridemia and low HDL. The goal here is weight reduction and increased exercise. However, for selected patients, combining a fibric acid (or low-dose nicotinic acid) with a statin also can be considered. Reduction of LDL levels should take priority over reduction of triglycerides in combined hyperlipidemia because of the proven safety of the statin class of drugs as well as greater reduction in CHD incidence.
- Garlic has played an important dietary and medicinal role throughout the history of mankind. In some Western countries, the sale of garlic preparations ranks with those of leading prescription drugs. The therapeutic efficacy of garlic encompasses a wide variety of ailments, including cardiovascular, cancer, hepatic and microbial infections to name but a few. However, the elucidation of its mechanism for therapeutic action has proved to be more elusive and a unifying theory, which could account for its reported multifarious activities, is yet to emerge. Reactive oxygen species (ROS) seem to be at the core of many disease processes and it is an attractive and convenient hypothesis that garlic might exert its activities through modulatory effects on ROS. A literature search on garlic and its antioxidant potential churned up a surprisingly large amount of data, some of it good, some bad and some of its definitely ugly. Various preparations of garlic, mainly aged garlic extract (AGE), have been shown to have promising antioxidant potential. However, the presence of more than one compounds in garlic, with apparently opposite biological effects, has added to the complexity of the subject. Raw garlic homogenate has been reported to exert antioxidant potential but higher doses have been shown to be toxic to the heart, liver and kidney. So where do we stand today on this issue of garlic? Is garlic always good for health? How safe is it? Is it necessary to isolate the antioxidant compounds for its medicinal use in a more effective way? These issues are addressed in this review. Copyright
- Increasing evidence in both experimental and clinical studies suggests that oxidative stress plays a major role in the pathogenesis of both types of diabetes mellitus. Free radicals are formed disproportionately in diabetes by glucose oxidation, nonenzymatic glycation of proteins, and the subsequent oxidative degradation of glycated proteins. Abnormally high levels of free radicals and the simultaneous decline of antioxidant defense mechanisms can lead to damage of cellular organelles and enzymes, increased lipid peroxidation, and development of insulin resistance. These consequences of oxidative stress can promote the development of complications of diabetes mellitus. Changes in oxidative stress biomarkers, including superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, glutathione levels, vitamins, lipid peroxidation, nitrite concentration, nonenzymatic glycosylated proteins, and hyperglycemia in diabetes, and their consequences, are discussed in this review. In vivo studies of the effects of various conventional and alternative drugs on these biomarkers are surveyed. There is a need to continue to explore the relationship between free radicals, diabetes, and its complications, and to elucidate the mechanisms by which increased oxidative stress accelerates the development of diabetic complications, in an effort to expand treatment options.
- Flavonoids are reported to exhibit a wide variety of biological effects, including antioxidant and free radical-scavenging activities. Evidence of oxidative reactions is often associated with various chronic disease processes characterized by accumulation of connective tissue. This study was aimed to investigate the protective effects of chronic administration of the flavonoid quercetin (150 micromol/kg body wt/day intraperitoneally) in rats with carbon tetrachloride-induced fibrosis. In animals rendered cirrhotic by administration of carbon tetrachloride for 16 weeks, cell necrosis, fibrosis, and inflammatory infiltration were found. Histological abnormalities were accompanied by a higher hepatic content of collagen and thiobarbituric acid-reactive substances. Expression of inducible nitric oxide synthase (iNOS) was significantly increased in the liver. Treatment with quercetin during 3 weeks improved liver histology and reduced collagen content, iNOS expression, and lipid peroxidation. Those effects were associated with an increased total peroxyl radical-trapping antioxidant capacity of liver. We conclude that quercetin is effective in this model of liver damage.
- Numerous animal studies have reported that garlic can protect against atherosclerosis. However, a comparable number of studies do not support this observation. This contradiction may result from differences in study design, use of different animal models, and use of different garlic formulations and preparations. Here, we investigated the effect of the chemically well-characterized and production-controlled garlic powder printanor on atherosclerosis in the APOE*3-Leiden transgenic mouse, a mouse model well suited for evaluating anti-atherosclerotic properties of drugs and food components under human-like conditions. APOE*3-Leiden mice were fed a Western diet supplemented with either 5 or 50 g kg(-1) printanor. As a reference, the commercially available fermented garlic kyolic was included (1.6 g kg(-1) diet). Treatment with printanor demonstrated reduced body weight, coinciding with increased feces production and fecal fatty acids excretion. Printanor and kyolic treatment did not affect plasma lipids, markers of inflammation (serum amyloid A, serum-soluble intercellular adhesion molecule-1, and blood-leukocytes tumor necrosis factor-alpha (TNFalpha) production) and vascular activation (plasma von Willebrand factor (vWF)). As analyzed after 28 weeks of treatment, printanor and kyolic did not affect atherosclerotic lesion type, area or composition. Under conditions relevant to the human situation, the well-characterized and production-controlled garlic powder printanor does not display hypolipidemic, anti-inflammatory or anti-atherosclerotic properties.
- Since ages, botanical substances are in use for the remedy of diabetes with considerable degree of success. One of the such; an extract of Commelina communis L. (CE-L) after decoction in water has been traditionally used for the treatment of diabetes in Korea. However, its action mechanism has not yet been established. To explore the inside of its action-mechanism, in this study, the effect of the aqueous extract of C. communis L. (CE-L) on the activity of alpha-glucosidase was evaluated in vitro and in vivo. Aqueous extract of CE-L showed inhibitory activity of the alpha-glucosidase in a dose-dependent manner, in vitro. CE-L also seems to be by and large free from exerting any cytotoxic effect at least in CHO-K1 fibroblast and 3T3-L1 adipocyte. CE-L alleviated hyperglycemia caused by maltose or starch loading in normal and Streptozotocin (STZ)-induced diabetic mice with better efficacy than that of acarbose. In addition, prolonged administration of CE-L tends to normalize hyperglycemia in STZ-induced diabetic mice. Such results suggest that inhibitory activity of CE-L on alpha-glucosidase may contribute to delay in carbohydrate digestion and glucose absorption. Thus, CE-L has potential for use in the management of non-insulin-dependent diabetes.
- The relative contributions of insulin resistance and beta-cell dysfunction to the pathophysiology of Type 2 diabetes have been debated extensively. The concept that a feedback loop governs the interaction of the insulin-sensitive tissues and the beta cell as well as the elucidation of the hyperbolic relationship between insulin sensitivity and insulin secretion explains why insulin-resistant subjects exhibit markedly increased insulin responses while those who are insulin-sensitive have low responses. Consideration of this hyperbolic relationship has helped identify the critical role of beta-cell dysfunction in the development of Type 2 diabetes and the demonstration of reduced beta-cell function in high risk subjects. Furthermore, assessments in a number of ethnic groups emphasise that beta-cell function is a major determinant of oral glucose tolerance in subjects with normal and reduced glucose tolerance and that in all populations the progression from normal to impaired glucose tolerance and subsequently to Type 2 diabetes is associated with declining insulin sensitivity and beta-cell function. The genetic and molecular basis for these reductions in insulin sensitivity and beta-cell function are not fully understood but it does seem that body-fat distribution and especially intra-abdominal fat are major determinants of insulin resistance while reductions in beta-cell mass contribute to beta-cell dysfunction. Based on our greater understanding of the relative roles of insulin resistance and beta-cell dysfunction in Type 2 diabetes, we can anticipate advances in the identification of genes contributing to the development of the disease as well as approaches to the treatment and prevention of Type 2 diabetes.
- Unlabelled: In the present study the effect of garlic, in a form more similar to how most people eat garlic, on lipid and antioxidant metabolism in rats was investigated. The antioxidant activity was determined by the efficacy to scavenge 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) derived radicals in garlic samples. The highest results were estimated in aqueous fraction in comparison with other extracts divided on the basis of polarity. Wistar male rats were randomly divided into 10 diet groups, each with seven animals. The groups were named: Control, RG (raw garlic), BG (boiled garlic for 20 min), AERG (aqueous extract of raw garlic), AEBG (aqueous extract of boiled garlic), Ch (Cholesterol), Ch/RG, Ch/BG, Ch/AERG and Ch/AEBG. All experimental diets were supplemented with 25 mg of lyophilized garlic/kg body weight obtained from raw, boiled and their aqueous extracts over a period of 30 days. Serum lipid (total cholesterol, LDL-cholesterol and triglycerides) concentrations were higher in all groups fed cholesterol (Ch); however, the increase was significant only in Ch group, without garlic supplementation. In groups of rats fed diets with cholesterol, garlic samples significantly hindered the rise of TC and LDL-C (P < 0.05). A significant increase (P < 0.05) in the plasma antioxidant activity was registered in experimental groups of rats fed cholesterol-free diets supplemented with garlic; oppositely, a significant decrease was only in group of rats given food containing cholesterol without garlic. The protein spectra has shown that during short boiling some proteins change their functional properties such as solubility and mobility, resulting in a number of protein bands in SDS-electrophoresis. Conclusions: Raw and boiled garlic improved plasma lipid metabolism and plasma antioxidant activity in an experiment on rats. Thus, dietary hypolipidemic garlic was effective in reducing the oxidant stress, which was indicated by an increase of antioxidant activity and a decrease of lipids in the rats' blood. It was found that garlic boiled for 20 min has the same bioactivity as raw garlic in its antioxidant and protein spectra. Therefore it should be added at this time to foods. The selenium and copper content of raw garlic is not altered by boiling. The protein electrophoretic pattern of raw garlic is altered by boiling.
- Type 2 diabetes is the most prevalent and serious metabolic disease affecting people all over the world. Pancreatic beta-cell dysfunction and insulin resistance are the hallmark of type 2 diabetes. Normal beta-cells can compensate for insulin resistance by increasing insulin secretion and/or beta-cell mass, but insufficient compensation leads to the onset of glucose intolerance. Once hyperglycemia becomes apparent, beta-cell function gradually deteriorates and insulin resistance aggravates. Under diabetic conditions, oxidative stress and endoplasmic reticulum stress are induced in various tissues, leading to activation of the c-Jun N-terminal kinase pathway. The activation of c-Jun N-terminal kinase suppresses insulin biosynthesis and interferes with insulin action. Indeed, suppression of c-Jun N-terminal kinase in diabetic mice improves insulin resistance and ameliorates glucose tolerance. Thus, the c-Jun N-terminal kinase pathway plays a central role in pathogenesis of type 2 diabetes and could be a potential target for diabetes therapy.
- The anti-diabetic efficacy of Du-zhong (Eucommia ulmoides Oliver) leaves water extract (WDZ) was investigated in type 2 diabetic animals. The WDZ was given to C57BL/KsJ-db/db mice as a dietary supplement based on 1% dried whole Du-zhong leaves (0.187 g WDZ/100 g standard diet) for 6 weeks. The WDZ supplementation significantly lowered the blood glucose level and enhanced the glucose disposal in an intraperitoneal glucose tolerance test. The plasma insulin and C-peptide levels were significantly higher in the WDZ group than in the control group, while the glucagon level was lower. The hepatic glucokinase activity was significantly higher in the WDZ group, whereas, the glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities were significantly lower. The WDZ supplementation also significantly lowered the hepatic fatty acid synthase, HMG-CoA reductase and ACAT activities compared to the control group, while it elevated the lipoprotein lipase activity in the skeletal muscle. The WDZ also altered the plasma and hepatic lipid levels by lowering the cholesterol and triglyceride concentrations, while elevating the plasma HDL-cholesterol level. Therefore, these results suggest that WDZ may partly ameliorate hyperglycemia and hyperlipidemia with type 2 diabetes through increasing glycolysis, suppressing gluconeogenesis and the biosynthesis of fatty acid and cholesterol in the liver.
- Advance metastasized cancers are generally incurable; hence an effort to prolong the process of carcinogenesis through chemoprevention has emerged consistent with this notion. In recent years, a considerable attention has been placed to identify naturally occurring chemopreventive substances capable of inhibiting, retarding or reversing the process of carcinogenesis. A number of phenolic substances, particularly those present in dietary and medicinal plants, have been shown to possess substantial anticarcinogenic and antimutagenic activities. Epidemiological observations and laboratory studies, both in cell culture and animal models have indicated anticarcinogenic potential of garlic and its constituents, which has been traditionally used for varied human ailments around the world. Chemical analysis has indicated that protective effects of garlic appear to be related to the presence of organosulfur compounds mainly allyl derivatives. Several mechanisms have been presented to explain cancer chemopreventive effects of garlic-derived products. These include modulation in activity of several metabolizing enzymes that activate and detoxify carcinogens and inhibit DNA adduct formation, antioxidative and free radicals scavenging properties and regulation of cell proliferation, apoptosis and immune responses. Recent data show that garlic-derived products modulate cell-signaling pathways in a fashion that controls the unwanted proliferation of cells thereby imparting strong cancer chemopreventive as well as cancer therapeutic effects. This review discusses mechanistic basis of cancer chemopreventive effects of garlic-derived products, their implication in cancer management and ways and means to take these agents from bench to real life situations.
- The antidiabetic effect of garlic ethanolic extract (Allium sativum L.) was investigated in normal and streptozotocin-induced diabetic rats. In the present study, oral administration of garlic extract (0.1, 0.25 and 0.5 g/kg body wt.) for 14 days on the level of serum glucose, total cholesterol, triglycerides, urea, uric acid, creatinine, aspartate amino transferase (AST) and alanine amino transferase (ALT) in normal and streptozotocin-induced diabetic rats were evaluated. Oral administrations of the garlic extract significantly decreased serum glucose, total cholesterol, triglycerides, urea, uric acid, creatinine, AST and ALT levels, while increased serum insulin in diabetic rats but not in normal rats (p<0.05). A comparison was made between the action of garlic extract and glibenclamide (600 microg/kg), the known antidiabetic drug. The antidiabetic effect of the extract was more effective than that observed with glibenclamide. It is concluded that the plant must be considered as excellent candidate for future studies on diabetes mellitus.
- Eucommia ulmoides Oliver (Du-zhong) leaf extract was investigated for its antioxidant effects in type 2 diabetic animals, C57BL/KsJ-db/db mice. Du-zhong extract equivalent to 1% dried whole Du-zhong leaf (0.187 g of extract/100 g of diet) was added to the experimental diets for 6 weeks. The Du-zhong extract supplement significantly lowered blood glucose concentrations and elevated plasma paraoxonase activity compared with the control group. The activities of erythrocyte superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were significantly higher in the Du-zhong group compared with the control group, while glutathione reductase (GR) activity was not different between groups. The activities of SOD, GSH-Px, and GR in liver and kidney were not affected by Du-zhong extract supplementation, whereas the CAT activity was significantly higher in the Du-zhong group than in the control group. Du-zhong extract supplementation resulted in lower levels of hydrogen peroxide and lipid peroxide in erythrocytes, liver, and kidney. These results suggest that the antioxidant activity of Du-zhong extract is potentially beneficial for the prevention and management of complications of type 2 diabetes.
- Hyperglycaemia causes increased protein glycation and the formation of advanced glycation endproducts which underlie the complications of diabetes and ageing. Glycation is accompanied by metal-catalysed oxidation of glucose and Amadori products to form free radicals capable of protein fragmentation. Aged garlic extract is a potent antioxidant with established lipid-lowering effects attributed largely to a key ingredient called S-allyl cysteine. This study investigated the ability of aged garlic extract and S-allyl cysteine to inhibit advanced glycation in vitro. Bovine serum albumin (BSA) was glycated in the presence of Cu(2+) ions and different concentrations of aged garlic extract and protein fragmentation was examined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Lysozyme was glycated by glucose or methylglyoxal in the presence of different concentrations of aged garlic extract or S-allyl cysteine with subsequent analysis of glycation-derived crosslinking using SDS-PAGE. Amadori-rich protein was prepared by dialysing lysozyme that had been glycated by ribose for 24 h. This ribated lysozyme was reincubated and the effects of aged garlic extract, S-allyl cysteine and pyridoxamine on glycation-induced crosslinking was monitored. Aged garlic extract inhibited metal-catalysed protein fragmentation. Both aged garlic extract and S-allyl cysteine inhibited formation of glucose and methylglyoxal derived advanced glycation endproducts and showed potent Amadorin activity when compared to pyridoxamine. S-allyl cysteine inhibited formation of carboxymethyllysine (CML), a non-crosslinked advanced glycation endproduct derived from oxidative processes. Further studies are required to assess whether aged garlic extract and S-allyl cysteine can protect against the harmful effects of glycation and free radicals in diabetes and ageing.
