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Quantification of quercetin in different parts of onion and its DPPH radical scavenging and antibacterial activity

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Quantification of quercetin in different parts of onion and its DPPH radical scavenging and antibacterial activity

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Abstract

Levels of quercetin in different parts of onion were investigated using high performance liquid chromatography (HPLC) and liquid chronlatography mass spectrometry (LC/MS) suitable for use with functional food material. Two main peaks were observed on HPLC chromatograms from the extracts of the skin, and the outer, middle, and core parts of onion. Using LC/MS peak I was tentatively identified as quercetin monoglucoside at m/z 466.4, and peak 2 as quercetin with [M]+ at m/z 303.3. The levels of quercetin in the skin, and the outer, middle and core parts of the plant were 16.83, 2.67, 0.95, and 0.35 mg/g, respectively. In the study of 1,1-diphenyl-2-picylhydrazyl (DPPI-I) radical scavenging activity, skin, the nonedible part, contained the highest amount of quercetin, compared to the other edible parts, and showed the highest DPPH radical scavenging activity. Levels of quercetin and DPPH radical scavenging activity increased from core to skin. All parts of onion exhibited the strongest antibacterial activity only against Staplaylococcus aureus and Vibro parahaemolyticus. Antibacterial activities of onion exhibited that S. aureus was more sensitive than V. porahaemolyticus. Among the four onion extracts, the middle part showed the strongest inhibitory activity against S. aureus but all onion extracts showed similar antibacterial activities against l! parahaenrolylicus.

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... Onion bulbs also serve as a major source of dietary polyphenols, which include a great range of molecular structures showing important antioxidant activities in dietary plants (Kim and Kim et al., 2006). Indeed, they protect human organism against cellular damage, such as oxidation of DNA, proteins and lipids caused by reactive oxygen species (ROS) which plays an important role in aging and in a wide range of diseases. ...
... Thiosulphinates and cepaenes (α-sulphinyl-disulphides) were identified as the active components, mediating their effects through suppression of cyclooxygenase and lipoxygenase, which initiate eicosanoid metabolism and lead to bronchial restriction. ACSOs also show antifungal and antibacterial properties (Kim and Kim, 2006). ...
... As flavonoids affect onion AOA at high extent and direct correlation between these parameters has been demonstrated (Lu et al., 2011), it can be inferred that the outer scales have the highest AOA (Kim & Kim, 2006). In red onion, AOA is mainly dependent on anthocyanins concentration; in particular, bulb red colour of several cultivars of A. cepa is due to the presence of cyanidin and its glucoside derivatives, of which 25 forms have been identified (Slimestad et al., 2007). ...
Chapter
Onion (Allium cepa L.) bulbs are commonly used as food or as a herb, showing pharmacological activities connected to natural beneficial compounds such as thiosulfinates, saponins, polyphenols, and flavonoids. The free amino acids arginine and glutamine are correlated with the taste intensity. Onion is a hyperaccumulator of selenium which reduces heavy metals and pungency, the latter precursors and sulfur compounds being a function of concurrent effects exerted by cultivar, temperature, soil type and fertility, and water supply. Flavonoids synthesis is affected by light intensity, temperature, humidity, and farming practices. Bulb dry weight is positively correlated with temperature; total soluble solids are enhanced by the soil moisture increase. The interaction of onion plants with humic substances and arbuscular mycorrhizal fungi has beneficial effects on bulb soluble sugars and proteins. In the future, a more detailed chemical profiling of onion bulb composition may lead to the identification of further components resulting in enhanced health benefits.
... Onion (Allium cepa L.) is considered to be one of the most important and widely consumed crops in many countries (1)(2)(3) and its production ranked third in the world among seven major vegetables, namely onion, garlic, cauliflower, green peas, cabbage, tomato, and green beans (3). Onion has long been used as both spice and food during processing and cooking because of its distinctive flavor and taste (4,5). ...
... Flavonoids, particularly quercetin derivatives, have received special attention as dietary constituents due to their possible role in preventing cardiovascular diseases and cancer. Onion contains very high level of flavonids, especially quercetin and its glycosides (1). Onion ranked highest in quercetin content in a survey of 28 vegetables and nine fruits (6). ...
Article
Response surface methodology (RSM) was used for the optimization of the baking process of cookies made with onion powders (onion cookie). Experiments were carried out according to a central composite design, selecting onion powder content (1.15?8.86%) and baking temperature (155.9?184.1oC) as independent variables and pH, titratable acidity, moisture content, density, spread factor, CIE color parameters (L*-, * a-, and b*-values), and hardness as response variables. pH decreased with increasing amount of onion powder and baking temperature. Moisture content also decreased as the baking temperature increased. L*- and b*-values decreased but a*-values increased with increasing onion content and baking temperature. Most polynomial models developed by RSM were highly effective to describe the relationships between the studied factors and the responses. Overall optimization, conducted by overlaying the contour plots under investigation, was able to point out the optimal range of the independent variables within which the six responses were simultaneously optimized. The point chosen as representative of this optimal region corresponded to 4.01% onion powder content and 161.84°C baking temperature. The predicted dependent or response values in the optimal region were: pH?6.87, moisture content? 2.77%, L*-value?68.45, a*-value?1.98, b*-value?34.64, and spread factor?9.41.
... Qualitative composition of the main polyphenolic compounds in OSWE corresponds with the composition of onion skin as reported by Kim and Kim (2006), where these authors found only two main peaks (quercetin monoglucoside and quercetin). ...
... Also, a strong positive linear correlation (R 2 = 0.927) between AOA and TPC in meat patties was found, which is illustrated Figure 3. Kim and Kim (2006) reported that DPPH radical scavenging activity is affected by the quercetin level in onion, which is the main phenolic compound in onion skin. ...
Article
Onion waste as a rich source of antioxidants for meat products. Czech J. Food Sci., 37: 00-00. Abstract: Onion skin is a waste produced in thousands of tons annually in the European Union. It is a rich natural source of flavonoids and its water extracts (as an environmentally friendly solvent) could be used as an antioxidant material for meat products. Therefore, antioxidant properties of onion skin water extracts (OSWEs) were tested on cooked pork patties. Pork patties were divided into five treatments: control (no antioxidant), 10 and 20% (w/w) of yellow OSWE, and 10 and 20% (w/w) of red OSWE. Antioxidant activity, total polyphenols, thiobarbituric acid re-active substances (TBARS), and sensory analysis were assessed. Patties with added antioxidants showed significantly (P < 0.05) higher antioxidant activity and total polyphenol content. Samples with OSWEs, after 5-day storage (5°C), had significantly (P < 0.05) lower TBARS values compared to control. Two main phenolic compounds were identified in OSWEs by liquid chromatography-mass spectrometry using electrospray ionisation in negative mode: quercetin (m/z 301) and quercetin monoglucoside (m/z 463). OSWEs demonstrated the potential to be used as a source of natural antioxidants with strong antioxidant activity in meat products. Natural materials and ingredients are increasingly more preferred by consumers because of health concerns , thus the utilization of them is an emerging field in food science. Onion (Allium cepa L.) is one of the most common species of vegetable in the world, and it is a very important source of flavonoids in the
... Prakash et al. (8) demonstrated that antioxidant and free radical scavenging activities were higher in the outer dry layers of red onion than in their middle and inner layers. Nuutila et al. (9) observed that antioxidant activities of onions were clearly higher than those of garlic, and that onion skin extracts are more active than the edible part of onions, and Kim and Kim (11) reported that the quantity of quercetin increases with greater distance from the onion core. Utilizing onion peel would not only solve the environmental problem derived from disposing of onion waste, but could also provide the natural antioxidant food ingredients to replace the artificial ingredients. ...
... These results are in agreement with those obtained by earlier researchers who reported the effectiveness of natural antioxidants for controlling lipid oxidation in meat products (35)(36)(37). The ability of onion peel to inhibit lipid oxidation must be related to the ability of quercetin to suppress reactive oxygen species (11). Samples with OPE significantly reduced the TBARS values throughout storage compared to those of the control and ascorbic acid samples (p<0.05). ...
Article
Onion peels extracted with various concentrations of ethanol were examined for their extraction yield, total phenolic content, DPPH scavenging activity, and reducing power. Onion peel extracted with 50% ethanol exhibited higher extraction yields, total phenolic content, and DPPH scavenging activity than extracts from distilled water, 70 or 95% ethanol. Thus, the antioxidative efficiency to inhibit lipid oxidation of ascorbic acid (0.05%) and 50% ethanol extract of onion peel (0.05, 0.1, and 0.2%) in raw ground pork was investigated during chilled storage (16 days). The pH of the samples decreased considerably during storage (p<0.05). Addition of ethanol onion peel extract significantly improved the thiobarbituric acid reactive substances and peroxide values in raw ground pork meat (p<0.05). Therefore, onion peel extract by 50% ethanol is a very effective inhibitor of lipid oxidation and has potential as a natural antioxidant in raw ground pork.
... Onion (Allium cepa L.) is considered as one of the most important and widely consumed crops in many countries (1)(2)(3) and its production ranks third in the world (4). Onion is semi-perishable and has a short storage life. ...
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Onion slices were dehydrated in a single layer at drying air temperatures ranging from 50̃70oC in a laboratory scale convective hot-air dryer at an air velocity of 0.66 m/s. The effect of drying air temperature on the drying kinetic characteristics were determined. It was found that onion slices would dry within 210̃460 min under these drying conditions. Moisture transfer during dehydration was described by applying the Fick's diffusion model and the effective diffusivity changed between 1.345×10-8 and 2.658×10-8 m2/s. A non-linear regression procedure was used to fit 9 thin layer drying models available in the literature to the experimental drying curves. The Logarithmic model provided a better fit to the experimental drying data as compared to other models. Temperature dependency of the effective diffusivity during the hot-air drying process obeyed the Arrhenius relationship with estimated activation energy being 31.36 kJ/mol. The effect of the drying air temperature on the drying model constants and coefficients were also determined.
... Onion (Allium cepa L.) is considered to be one of the world's oldest cultivated vegetable, and contains high level of dietary flavonoids (Slimestad et al., 2007), which are present in much higher concentrations in the onion skin than they are in the fleshy bulb (Kim and Kim, 2006; Yao et al., 2004; Sellappan and Akoh, 2002). There is a growing body of evidence indicating that flavonoids may exhibit health-promoting effects (Griffiths et al., 2002). ...
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Full-text available
p class="Abstract">To investigate the anti-proliferative activity of flavonoids from onion skins, extraction by 50% ethanol (v/v), soxhlet polar fractionation, pH gradient separation, thin-layer chromatography, and recrystallization methods were used to isolate and purify flavonoids from dry onion skins. Anti-proliferative activities of some flavonoids obtained on leukemia K562 cell line were deter-mined by MTT assay. Results showed that flavonoids of onion skins were mainly in form of quercetin, kaempferol, isorhamnetin, apigenin-7-O-β-D-glucopyranoside, quercetin-3-O-β-D-glucopyranoside, kaempferol-7-O-β-D-glucopyranoside and rutin. Quercetin and kaempferol decreased K562 cell viability, and quercetin had stronger effect. However, isorhamnetin and rutin exhibited certain proliferation-promoting effects. It suggests that ortho hydroxyl groups on B ring of onion flavonoids might be the key structural elements of their cytotoxic effects on K562 cells, and hydroxyl groups in position 3 or carbonyl groups in position 4 might be one of the structural effect elements. </p
... Onion (Allium cepa L.) is one of the world's oldest cultivated vegetable which contains high level of dietary flavonoids [32]with higher concentrations in the onion skin than the fleshy bulb [33]. The onion skin, actually not edible, is fast removed before sorting out, but it is unsuitable as fodder or landfill disposal because of its composition and smell. ...
Research
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The consumption of fruits and vegetables in our regular diet has been associated with a significant source of nutrients. The presence of abundant organic compounds (Xanthorrihzol, Thymol, Terpenoids, Carvarol, Capsaicin, Phenolic compounds as flavonoid, Benzene propane nitrile etc.) in unused chunk of fruits and vegetables can play an amazing role to nourish human health. Among all organic compounds phenolic compound flavonoid is the most opulent compound which can take part a major role to prohibit many health problems like cardiovascular disease, alzimer, colonial cancer, hypertension, morbidly obese, liver cancer, diabetes etc. The waste parts of fruits and vegetables can also be used as prevention of many chronic diseases, inhibitor of apoptosis and also shown its properties as chemo-preventive, anti-atherogenic, anti-carcinogenic, anti-inflammatory, anti-diarrheal, and antimicrobial. The bioactive compounds of waste parts can also include motivation of carcinogen detoxification, preventing the initiation of cancer, control of cell cycle progression, inhibiting cell proliferation, reducing oncogene activity, prohibit in metastasis and angiogenesis, as well as modulating hormone or growth factor activity.
... Onions are rich in natural sulfur compounds of low molecular weight, these are the flavonoids and the alk(en)nyl cysteine sulfoxides. Compounds from onion have been reported to have a range of health benefits which include anticarcinogenic properties, antithrombotic activity, antioxidative, antiasthmatic and antibiotic effects (Griffiths et al., 2002;Kim and Kim, 2006). Onion extract provides not only beneficial effects to human health but it is effective inhibitor on browning against PPO. ...
Article
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The inhibitory effect of onion extract on cassava leaf polyphenol oxidase was investigated. The polyphenol oxidase from cassava leaves was strongly inhibited by various anti-browning agents such as L-ascorbic acid and L-cysteine. The percentage of inhibition increased with the increased of anti-browning agents concentrations. The addition of heated onion extract exhibited a stronger inhibitory effect on cassava leaf polyphenol oxidase than the fresh onion extract. The highest percentage of inhibition was exhibited with heated onion extract in the presence of glucose and glycine, which was 87.18%. The onion extract inhibited the cassava leaf polyphenol oxidase non-competitively.
... Changes in S. aureus also could be observed morphologically as shown in Fig. 9(F-H). The antibacterial activity of quercetin has been previously reported [45][46][47]. ...
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Statement of significance: The Qu-Ach@SeNPs have low cytotoxicity when tested on normal human cells in vitro. Qu-Ach@SeNPs are effective against MDRs, such as Methicillin-resistant S. aureus (MRSA), at a low dose. Importantly, Qu-Ach@SeNPs showed no emergence of resistance. These results suggest that Qu-Ach@SeNPs have excellent antibacterial activities. These agents can serve as good antibacterial agents against superbugs. Our data suggest that these antibacterial agents may have widespread application in the field of medicine for combating infectious diseases caused by MDRs, as well as other infectious diseases.
... The onion (Allium cepa L.) is one of the most widely consumed vegetables (Kim & Kim, 2006), and is rich in two chemical groups that have perceived health benefits for humans: Flavonoids and alk(en)yl cysteine sulfoxides (Park, Kim, & Kim, 2007). In particular, onions are a rich source of flavonols such as quercetin 3,4′-O-diglucoside and 4′-O-glucoside (Bonaccorsi, Caristi, Gargiulli, & Leuzzi, 2008). ...
... Shim et al. (2012) reported that the addition of onion peel extract significantly reduced the TBARS values of ground pork throughout storage. Kim and Kim (2006) reported that both the quercetin levels and free radical scavenging activity of onion skin, were higher than those of any other part of the onion. For this reason, our results suggest that onion peel extract may retard lipid oxidation of emulsion sausage prepared All values are mean±SD. ...
Article
This study was conducted to investigate the effects of kimchi powder and onion peel extract on the quality characteristics of emulsion sausage manufactured with irradiated pork. The emulsion sausages were formulated with 2% kimchi powder and/or 0.05% onion peel extract. The changes in pH value of all treatments were similar, depending on storage periods. The addition of kimchi powder increased the redness and yellowness of the emulsion sausage. The addition of onion peel extract decreased the thiobarbituric acid reactive substances value of the emulsion sausages prepared with irradiated pork. The volatile basic nitrogen value of the emulsion sausage prepared with kimchi powder was the highest, whereas that of the emulsion sausage prepared with onion peel extract was the lowest. The treatment without kimchi powder or onion peel extract and the treatments prepared with onion peel extract showed lower microbial populations than the other treatment. Sensory evaluations indicated that a higher acceptability was attained when kimchi powder was added to the emulsion sausages manufactured with irradiated pork. In conclusion, our results suggest that combined use of kimchi powder and onion peel extract could improve quality characteristics and shelf stability of the emulsion sausage formulated with irradiated pork during chilled storage.
... Onion (Allium cepa L.) is considered to be one of the world's oldest cultivated vegetable, and contains high level of dietary flavonoids (Slimestad et al., 2007), which are present in much higher concentrations in the onion skin than they are in the fleshy bulb (Kim and Kim, 2006; Yao et al., 2004; Sellappan and Akoh, 2002). There is a growing body of evidence indicating that flavonoids may exhibit health-promoting effects (Griffiths et al., 2002). ...
Article
Full-text available
To investigate the anti-proliferative activity of flavonoids from onion skins, extraction by 50% ethanol (v/v), soxhlet polar fractionation, pH gradient separation, thin-layer chromatography, and recrystallization methods were used to isolate and purify flavonoids from dry onion skins. Anti-proliferative activities of some flavonoids obtained on leukemia K562 cell line were determined by MTT assay. Results showed that flavonoids of onion skins were mainly in form of quercetin, kaempferol, isorhamnetin, apigenin-7-O-β-Dglucopyranoside, quercetin-3-O-β-D-glucopyranoside, kaempferol-7-O-β-Dglucopyranoside and rutin. Quercetin and kaempferol decreased K562 cell viability, and quercetin had stronger effect. However, isorhamnetin and rutin exhibited certain proliferation-promoting effects. It suggests that ortho hydroxyl groups on B ring of onion flavonoids might be the key structural elements of their cytotoxic effects on K562 cells, and hydroxyl groups in position 3 or carbonyl groups in position 4 might be one of the structural effect elements. © 2016, Bangladesh Journal of Pharmacology. All Rights Reseved.
... Phenolic compounds in fruits and vegetables play an important role in the defense mechanism against oxidative stress caused by ROS and free radicals. Additionally, phenolic compounds show multiple biological activities such as antiproliferative, antiinflammatory, antimutagenic and antibacterial [4]. Their antiradical activity is based on the structural relation between the different parts of their chemical identity [5]. ...
Article
Several studies have shown that phenolic and carotenoid compounds protect against oxidative stress, reducing the risk of cardiovascular diseases and some types of cancers. The objective of this research was to determine the individual contribution of the main phenolic compounds from the papaya fruit skin and the individual contribution of main caro-tenoids from the pulp for total antioxidant capacity at four ripening stages; and the individual and combined radical scavenging ability used the essays DPPH (radical 2, 2-diphenyl-1-picryhydrazyl) and ABTS (radical 2, 20-azino-bis (3-ethylbenzothiazoline)-6 sulphonic acid). Phenolic acids standards for this study were ferulic (FA), caffeic (CA) and p-coumaric (pCA) acids and carotenoids studied were Lycopene, β-carotene and β-cryptoxanthin. The phenol that showed the best DPPH • and ABTS • + radical scavenging ability was CA, with 89.47% and 92.98%, respectively. Lyco-pene contributed the greatest to the TAC (11.9-43.2). Lycopene also showed the best DPPH • and ABTS • + radical scavenging ability with 62.12% and 94.26%, respectively. Antiradical ability of phenolics and carotenoids depended on the structure of the compound and its concentration.
... Functional ingredients, such as stevioside, cinnamon, bitter melon, garlic and onion, ginseng, Gymnema sylvestre and fenugreek, have been addressed for their specific actions towards different reactions involved in diabetes development (Ballali and Lanciai, 2012). Among these plant foods Allium species, onions and garlic have long been used for a large range of purposes including medicine, nutrition, flavoring, condiment, foodstuff, and the treatment of common ailments as folk medicine (Kim et al., 2006). Diabetes is characterized as an imbalance in carbohydrate, fat, and protein metabolism, primarily due to increased insulin resistance and relatively impaired insulin secretion . ...
Article
Full-text available
From many reports it is clear that diabetes will be one of the major diseases in the coming years. Diabetes shows a wide range of variation in prevalence around the world and it is expected to affect 300 million by the year 2025. In a prevention framework where banning policies and educational strategies lead the interventions, functional foods (FFs) with their specific health effects could, in the future, indicate a new mode of thinking about the relationships between food and health in everyday life. Functional ingredients, such as cinnamon, garlic and onion have been addressed for their specific actions towards different reactions involved in diabetes development. This study was undertaken to assess the effect of garlic (Allium sativum L.) and onion (Allium cepa L.) consumptions on metabolic parameters related to diabetes. The animals were divided into six groups: one control and five experimental groups. All injections (onion and garlic extracts 200 mg/kg b.w./daily for 15 days) were oral administered (per os = p.o.) at the volume of 100 μl. Thirty minutes after the last injection animals were anaesthetized and decapitated. The blood samples were collected from the carotid artery. The results indicate that the application of onion and garlic extracts were reduced glucose, cholesterol and triglyceride concentrations in blood serum of the mice with induced experimental diabetes.
... Onion (allium cepa L.) is one of the oldest and most frequently cultivated food plants highly valued for its pharmacological properties, such as antioxidant, antimicrobial and antitumor ones, reduction of cancer risk and protection against cardiovascular diseases (Lachman et al. 1999;Ly et al. 2005). Though it is not specifically considered as a medicinal herb, the onion has shown health-promoting effects based on its secondary metabolites, such as flavonoids to which the strong antioxidant properties of onion have been attributed (Lachman et al. 2003;Nuutila et al. 2003;Kim & Kim 2006). The onion bulb presents the most health-promoting properties when used raw. ...
Article
Total phenolics and anthocyanins in ten samples of Romanian red onion cultivars, extraction optimisation and pH/thermal stability were investigated. Extraction with 80% aqueous ethanol leads to an increased anthocyanin yield. The level of phenolics and anthocyanins in bulbs is highly variable and was found higher in the Red of Turda cultivar. The highest value of 99.66 mg/100 g FM was obtained for red onion dry skins. Strong acidic conditions favoured the better stability of anthocyanin extracts during 10-day storage. The first order rate constant value of anthocyanin degradation during storage calculated at different pH increased almost 17 times when pH increased from 1.0 to 9.0. Results of thermal analysis performed by differential scanning calorimetry showed that temperatures over 45 degrees C already induced anthocyanin degradation in extracts. These results may become useful for establishing the appropriate conditions of processing and storage of anthocyanin-based foods. The obtained data on total phenolics and anthocyanins in Allium cepa L. may become relevant for future estimation studies of their daily consumption and for completing the national food composition databases.
... Onion shows a variety of pharmacological effects such as growth inhibition of tumor and microbial cells, reduction of cancer risk, scavenging of free radicals, and protection against cardiovascular disease, which are attributed to specific sulfur-containing compounds and flavonoids [147]. In addition, onions have been found to have antioxidant properties in different in vitro models [118]. Recent studies of Roldan et al. [208] have shown that sulfhydryl (SH or thiol) groups are good inhibitors of the enzyme polyphenol oxidase (PPO) [75]. ...
Article
Every year almost 45 billion kg of fresh vegetables, fruits, milk, and grain products is lost to waste in the United States. According to the EPA, the disposal of this costs approximately $1 billion. In the United Kingdom, 20 million ton of food waste is produced annually. Every tonne of food waste means 4.5 ton of CO(2) emissions. The food wastes are generated largely by the fruit-and-vegetable/olive oil, fermentation, dairy, meat, and seafood industries. The aim of this chapter is to emphasize existing trends in the food waste processing technologies during the last 15 years. The chapter consists of three major parts, which distinguish recovery of added-value products (the upgrading concept), the food waste treatment technologies as well as the food chain management for sustainable food system development. The aim of the final part is to summarize recent research on user-oriented innovation in the food sector, emphasizing on circular structure of a sustainable economy.
... And Kiassos et al. (20) optimized the extraction of phenolics from the solid waste of the onion. Here, practical methods for extracting quercetin and its glycosides from dried onion skin were investigated, because the most flavonoids in onion are distributed in the outer skin (23). The highest yield of several extraction processes was estimated and the effect of independent variables on each method was evaluated using response surface methodology (RSM), which has been employed for the optimization in industrial applications and other processes due to its practical convenience (24). ...
Article
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Quercertin and typical flavonoids present in onion skin draw interest due to bioactive properties. For utilizing quercetin from onion skin, conventional solvent extraction (CSE), microwave assisted extraction (MAE), and ultrasound assisted extraction (UAE) were employed. Statistic models of each method were proposed to estimate the best possible yield of quercertin employing response surface methodology (RSM). The effects of several independent variables including concentration of ethanol, provided power or the temperature, and reaction time were investigated. From 1 g sample of dried onion skin, the highest yield of each method could be achieved at 16.5 min of process time under 59.2°C for CSE with 59.3% ethanol, 117 s for MAE with 69.7% ethanol, and 21.7 min for UAE using power of 606.4 W with 43.8% ethanol. The most productive method was MAE, whose maximum yield was 20.3 and 30.8% higher than UAE and CSE, respectively.
... (b) Type B samples increase in drying time or by reduction of moisture content, as revealed by comparison with the study of Kim et al [14][15]. Based on the results of the Freeman-Carroll method, the conveyor-belt hot-air drying apparatus was operated properly to produce satisfactory drying results. ...
... Onion shows a variety of pharmacological effects such as growth inhibition of tumor and microbial cells, reduction of cancer risk, scavenging of free radicals, and protection against cardiovascular disease, which are attributed to specific sulfur-containing compounds and flavonoids [147]. In addition, onions have been found to have antioxidant properties in different in vitro models [118]. Recent studies of Roldan et al. [208] have shown that sulfhydryl (SH or thiol) groups are good inhibitors of the enzyme polyphenol oxidase (PPO) [75]. ...
Chapter
Every year almost 45 billion kg of fresh vegetables, fruits, milk, and grain products is lost to waste in the United States. According to the Environmental Protection Agency (EPA), the disposal of this costs approximately $1 billion. In the United Kingdom, 20 million ton of food waste is produced annually. Every tonne of food waste means 4.5 ton of CO2 emissions. The food wastes are generated largely by the fruit-and-vegetable/olive oil, fermentation, dairy, meat, and seafood industries. The aim of this work is to provide a comprehensive literature survey on food waste management techniques and processing technologies, developed during the last 20 years. The article consists of three major parts, which distinguish recovery of added-value products (the upgrading concept), the food-waste-treatment technologies, as well as the food-chain management for sustainable food system development. This article summarizes recent research on user-oriented innovation in the food sector, emphasizing on circular structure of a sustainable economy.
... The other main anti-oxidative parameters, SOD, GSH-PX, and T-AOC, in the CON group were lower in the DIQ group on the first and tenth days, which was consistent with previous reports [8][9][10]. Quercetin is one of the most widely distributed bioflavonoids and exhibits metal chelation and freeradical scavenging activities to fight oxidative stress [21]. A previous study demonstrated that supplementation with QUE could relieve the upregulation of MDA and downregulation of GSH-PX and SOD in jejunal tissue [14]. ...
Article
Objective: This study was designed to investigate the hypothesis that dietary quercetin and coated sodium butyrate supplementation alleviate oxidative stress in the small intestine of diquat-challenged pullets. Methods: A total of 200 13-week-old pullets were divided into four groups: the control group (CON), the diquat group (DIQ), the quercetin group (QUE), and the coated sodium butyrate group (SB), and injected intraperitoneally with either saline (CON) or diquat (DIQ, QUE, and SB) to induce oxidative stress on day 0. Results: On the first day, the malondialdehyde (MDA) and superoxide dismutase (SOD) concentrations in the SB group were significantly different from those in the DIQ and QUE groups (P < 0.05), and dietary supplementation with sodium butyrate increased serum glutathione peroxidase (GSH-PX) levels compared with the DIQ group (P < 0.05). Quercetin and sodium butyrate increased the levels of CLAUDIN-1 and ZO-1 (Zonula occludens-1) in the jejunum. On the tenth day of treatment, quercetin attenuated the decrease in GSH-PX levels compared to those of the CON group (P < 0.05), while sodium butyrate increased SOD, GSH-PX, and T-AOC (Total antioxidant capacity) levels compared to those of the DIQ group. NRF2 (Nuclear factor erythroid 2-related factor 2) and HO-1 (Heme oxygenase-1) mRNA levels in the QUE and SB groups increased (P < 0.05) and CLAUDIN-1 mRNA levels in the QUE and SB groups were upregulated compared to those in the DIQ group ileum tissue. Conclusion: Supplementation of quercetin and sodium butyrate demonstrated the ability to relieve oxidative stress in pullets post diquat-injection with a time-dependent manner and quercetin and sodium butyrate may be potential antioxidant additives for relieving oxidative stress and protecting the intestinal barrier of pullets.
... This evidences that antioxidant found in the extract interacting with the free radicals (Kedare and Singh, 2011). Levels of radical scavenging activity increase from onion core to skin (Kim and Kim, 2006). ...
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Determination of antioxidant activity is one of the key elements for understanding the biological properties of a widely used spice onion (A. cepa). In contrast, physical properties help understand the textural quality of onion necessary for postharvest operations of sorting and grading in particular. Considering the physicochemical importance of onion, the present study focused on the determination of physical attributes and antioxidant content of the onion germplasm in Bangladesh using visual methods and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. The five-onion germplasms (BARI Piaz-2, BARI Piaz-3, BARI Piaz-4, BARI Piaz-5, Faridpuri Vati) collected from selected onion growers of the Department of Agricultural Extension (DAE) of the southwestern part of Bangladesh were used as treatments for physicochemical analysis at the Horticulture laboratory of the Agrotechnology Discipline, Khulna University, Khulna, Bangladesh during the period from February to August 2019. The laboratory study was laid out in Completely Randomized Design (CRD) with three replications. Most of the physical characteristics of onion were highest in germplasm-1 than those of the other germplasm tested. The results showed that the DPPH free radicals were scavenged by all onion germplasm extracts in a concentration-dependent pattern. The highest IC 50 value (238.10 ppm) was noticed in germplasm-3 and the lowest in germplasm-5 (161.29 ppm) with no statistical difference from germplasm-4 (172.41 ppm). The lower IC 50 value indicating that onion germplasms-5 and-4 extracts were more potent in scavenging free radicals than the other onion germplasms. Thus, the low IC 50 value facilitated the germplasm-5 and-4 to be enriched with antioxidant compounds significantly in higher amounts than the others.
... In fact, onion had been shown to possess antioxidant activity in different invitro models, ability to scavenge free radicals and to protect against cardiovascular disease. All these properties were attributed to specific sulfur-containing compounds and flavonoids [11,45]. In the present study we determined the scavenging properties of onion extracts and their antiradical activity in in-vitro model systems. ...
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Onion powder is a worldwide food ingredient with great commercial value due to its culinary and medicinal properties in “Nutraceuticals”, which has not been investigated. This study aimed at evaluating the effect of drying treatment on the nutritional, functional and sensory properties of onion powder from three varieties (Violet of Galmi, Goudami and White of Galmi). The fresh harvested onions were dried by two drying methods (solar drying and air electric drying) and milled into fine particle. The proximate composition, the functional properties, the bioactive molecules total phenolics, flavonoids, tanins and vitamin C contents were evaluated. The 1,1-diphenyl-2-picrilhydrazyl (DPPH) radical scavenging activity and the Ferric-reducing power (FRP) were equally determined. Descriptive sensory analysis and the general acceptability of powders alone and sprinkled on grilled meat were also determined. The results showed that the variety Violet of Galmi was rich in carbohydrate and proteins, variables highly positively correlated to the ability to absorb water, to solubilise and to form gel. In contrast, the variety White of Galmi was higher in fat content, variable correlated to the high ability to absorb oil, and the odor and taste of onion. Based on its violet/red colour characteristic of high phenol content, flavonoid and tannin, Violet of Galmi exhibited the highest DPPH scavenging activity and ferrous reducing power. However, not only the phenol (60–85%, loss) was lost during powder production, but also the antioxidant activity (78–85%, loss). Nevertheless the powder offered high level of phenols and antioxidant activity and was well accepted by the panel.
... The most abundant source of quercetin is onion (Allium cepa), which is one of the most popular vegetables used both as an edible and medicinal plant. Other sources of quercetin include tea, red wine, kales and apples [4]. Many medicinal plants such as Hypericum perforatum, Ginkgo biloba also contain quercetin [3]. ...
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Quercetin, an essential plant flavonoid, possesses a variety of pharmacological activities. Extensive literature investigates its antimicrobial activity and possible mechanism of action. Quercetin has been shown to inhibit the growth of different Gram-positive and Gram-negative bacteria as well as fungi and viruses. The mechanism of its antimicrobial action includes cell membrane damage, change of membrane permeability, inhibition of synthesis of nucleic acids and proteins, reduction of expression of virulence factors, mitochondrial dysfunction, and preventing biofilm formation. Quercetin has also been shown to inhibit the growth of various drug-resistant microorganisms, thereby suggesting its use as a potent antimicrobial agent against drug-resistant strains. Furthermore, certain structural modifications of quercetin have sometimes been shown to enhance its antimicrobial activity compared to that of the parent molecule. In this review, we have summarized the antimicrobial activity of quercetin with a special focus on its mechanistic principle. Therefore, this review will provide further insights into the scientific understanding of quercetin’s mechanism of action, and the implications for its use as a clinically relevant antimicrobial agent.
... The possible reason might be the presence of high levels of quercetin in onion fleshy peels and dry skin as compared to that of bulb. Quercetin is the most abundant phenol found in onion and Kim and Kim (2006) reported that quercetin concentration in the methanolic extract of onion dry scales, outer skin, middle layers and inner core was 16.83, 2.67, 0.95, and 0.35 mg/g respectively which highlights that quercetin concentration decreases from outside towards the core. All these findings highlight the strong antioxidant potential of onion peel extract and paves way for incorporating such extracts in food products for enhancing their nutraceutical value. ...
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Allium cepa L. is a commonly consumed vegetable that belongs to the Amaryllidaceae family and contains nutrients and antioxidants in ample amounts. In spite of the valuable food applications of onion bulb, its peel and outer fleshy layers are generally regarded as waste and exploration of their nutritional and therapeutic potential is still in progress with a very slow progression rate. The present study was designed with the purpose of doing a comparative analysis of the antioxidant potential of two parts of Allium cepa, i.g., bulb (edible part) and outer fleshy layers and dry peels (inedible part). Moreover, the inhibitory effect of the onion bulb and peel extracts on rat intestinal α-glucosidase and pancreatic α-amylase of porcine was also evaluated. The antioxidant potential of onion peel and bulb extracts were evaluated using 2,2-diphenyl- 1-picryl hydrazyl (DPPH), ferric-reducing antioxidant power assay (FRAP), 2,2’-azino-bis- 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay, H2O2 radical scavenging activity and Fe2+ chelating activity. Total flavonoids and phenolic content of ethanolic extract of onion peel were significantly greater as compared to that of onion bulb. Ethanolic extract of onion peel also presented better antioxidant and free-radical scavenging activity as compared to the ethanolic extract of bulb, while the aqueous extract of bulb presented weakest antioxidative potential. Onion peel extract’s α-glucosidase inhibition potential was also correlated with their phenolic and flavonoid contents. The current findings presented onion peel as a possible source of antioxidative agents and phenolic compounds that might be beneficial against development of various common chronic diseases that might have an association with oxidative stress. Besides, outer dry layers and fleshy peels of onion exhibited higher phenolic content and antioxidant activities, compared to the inner bulb. The information obtained by the present study can be useful in promoting the use of vegetable parts other than the edible mesocarp for several future food applications, rather than these being wasted.
... In several studies, onion and onion extracts were shown to decrease the level of blood lipid, increase fibrinolysis, decrease platelet aggregation, and lower blood pressure (Saleheen et al. 2004). These biological activities are exerted by phenolic and sulfur compounds (Hovius and Goldman 2005;Kim et al. 2006Kim et al. , 2012Lee et al. 2005). ...
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This study was conducted to evaluate the quality of onion juices that had been heat-treated for different times as well as their use as a table sugar substitute in Kimchi. The onions were steamed at 100 ∘C for 30 min and boiled at 90 ∘C for 30, 60, and 120 min. The highest cycloalliin (0.76 mM), free-sugar (sucrose 1.66 g/L, glucose 8.62 g/L, and fructose 7.64 g/L), and malic acid (0.82 g/L) contents were observed in onion boiled at 90 ∘C for 120 min. The possibility of using heat-treated onion juices as an alternative to table sugar in Kimchi was evaluated by comparing the lactic acid bacteria count, pH, acidity, organic acid, and free-sugar in these juices with those in Kimchi prepared using table sugar (control). The total viable bacteria and lactic acid bacteria showed similar growth patterns as in the control. The average pH reduction and increase in titratable acidity (%) in all treated Kimchi samples during fermentation for 4 weeks were 1.18 ± 0.05 and 0.81 ± 0.06, respectively. Kimchi with onion juice heat-treated for 120 min (K120) had the most similar lactic acid and acetic acid contents to that in the control after fermentation for 4 weeks. The highest mannitol level after fermentation for 4 weeks was detected in K120, which showed better sensory qualities compared to the control.
... The possible reason might be the presence of high levels of quercetin in onion fleshy peels and dry skin as compared to that of bulb. Quercetin is the most abundant phenol found in onion and Kim and Kim (2006) reported that quercetin concentration in the methanolic extract of onion dry scales, outer skin, middle layers and inner core was 16.83, 2.67, 0.95, and 0.35 mg/g respectively which highlights that quercetin concentration decreases from outside towards the core. All these findings highlight the strong antioxidant potential of onion peel extract and paves way for incorporating such extracts in food products for enhancing their nutraceutical value. ...
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Allium cepa L. is a commonly consumed vegetable that belongs to the Amaryllidaceae family and contains nutrients and antioxidants in ample amounts. In spite of the valuable food applications of onion bulb, its peel and outer fleshy layers are generally regarded as waste and exploration of their nutritional and therapeutic potential is still in progress with a very slow progression rate. The present study was designed with the purpose of doing a comparative analysis of the antioxidant potential of two parts of Allium cepa, i.g., bulb (edible part) and outer fleshy layers and dry peels (inedible part). Moreover, the inhibitory effect of the onion bulb and peel extracts on rat intestinal α-glucosidase and pancreatic α-amylase of porcine was also evaluated. The antioxidant potential of onion peel and bulb extracts were evaluated using 2,2-diphenyl-1-picryl hydrazyl (DPPH), ferric-reducing antioxidant power assay (FRAP), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay, H 2 O 2 radical scavenging activity and Fe 2+ chelating activity. Total flavonoids and phenolic content of ethanolic extract of onion peel were significantly greater as compared to that of onion bulb. Ethanolic extract of onion peel also presented better antioxidant and free-radical scavenging activity as compared to the ethanolic extract of bulb, while the aqueous extract of bulb presented weakest antioxidative potential. Onion peel extract's α-glucosidase inhibition potential was also correlated with their phenolic and flavonoid contents. The current findings presented onion peel as a possible source of antioxidative agents and phenolic compounds that might be beneficial against development of various common chronic diseases that might have an association with oxidative stress. Besides, outer dry layers and fleshy peels of onion exhibited higher phenolic content and antioxidant activities, compared to the inner bulb. The information obtained by the present study can be useful in promoting the use of vegetable parts other than the edible mesocarp for several future food applications, rather than these being wasted. Resumo Allium cepa pertence à família Liliaceae e é rica em nutrientes e antioxidantes. Apesar das expressivas aplicações alimentares do bulbo da cebola, sua casca e outras camadas externas são geralmente consideradas resíduos, e seu potencial nutricional e terapêutico ainda é pouco explorado. O presente estudo foi delineado com o objetivo de investigar comparativamente o potencial antioxidante de duas partes de Allium cepa, por exemplo o bulbo (parte comestível) e camadas externas e cascas secas (parte não comestível). Além disso, o efeito inibitório dos extratos do bulbo de cebola e casca sobre a α-glucosidase intestinal de ratos e α-amilase pancreática suína também foi avaliado. O potencial antioxidante dos extratos da casca de cebola e bulbo foi avaliado utilizando-se 2,2-difenil-1-picrilhidrazil (DPPH), método de poder antioxidante de redução do ferro (FRAP), método 2,2'-azino-bis-3-etilbenzotiazolina-6-ácido sulfônico (ABTS) de eliminação de radicais, atividade de eliminação de radicais H 2 O 2 e atividade quelante do Fe 2+. Os flavonoides totais e os teores fenólicos do extrato de etanol da casca de cebola Antioxidant potential and α-glucosidase inhibitory activity of onion (Allium cepa L.) peel and bulb extracts Atividade antioxidante e potencial inibidor de α-glucosidase de extratos de casca e bulbo de cebola (Allium cepa) preparados por etanol e água
... Fruits and vegetables have been shown to possess antioxidant activities in different in vitro models, ability to scavenge free-radicals and to protect against cardiovascular disease. These properties were attributed to specific sulfur-containing compounds and flavonoids [54,55]. One of the antioxidant mechanisms is to provide hydrogen atoms to free-radicals and to stop the chain reaction. ...
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In this study, the overripe plantain has been used to produce high-antioxidant powders, using Adansonia digitata L. pulp and Hibiscus sabdariffa L. calyces as antioxidant supplements. The constrained mixture design (ranged between 0.9–1.0 for plantain and 0–0.1 for supplements) was used to generate ten powder formulations. The obtained powders were evaluated for physicochemical properties and antioxidant activities. Generally, significant differences (p < 0.05) were found between moisture, proteins, ash, fibers, carbohydrates and fat contents of different raw material powders. The increase in the proportions of A. digitata L. and H. sabdariffa L. significantly increased (p < 0.05) the levels of polyphenols (40.19–583.46 mg GAE/100 g DM), flavonoids (18.27–103.46 mg RE/100 g DM), condensed tannins (28.73–276.47 mg CE/100 g DM), carotenoids (8.41–9.48 mg/100 g DM) and vitamin C (31.55–77.30 mg/100 g DM) in the formulated powders. The antioxidant properties of the powder formulations revealed higher radical-scavenging activities DPPH (IC50 of 0.80 mg/mL) and ABTS (IC50 of 1.51 mg/mL) for M10 formulation consists of 91.67% overripe plantain, 1.67% A. digitata L. and 6.66% Hibiscus sabdariffa L. The best reducing powers were found in M5, M6 and M10 formulations which improved by more than 2 to 3 times the value of M1 (2.66 mg AAE/g DM) not containing antioxidant supplements. M10 was the powder formulation that exhibited the best antioxidant activities despite its low hydration capacity. A. digitata L. pulp and H. sabdariffa L. calyces revealed the potential for an efficient improve of antioxidant activity of overripe plantain powder. High-antioxidant powders from the mixtures showed promise in helping to combat oxidative stress in Africa and other countries where chronic diseases pose a threat.
... 17 The content of rutin in Spanish white onions (varieties white onion, and Calcot de Vall) extracts ranged from 0.56 ± 0.06 to 11.5 ± 0.93 mg rutin /g dry weight. 18 Earlier studies 14,[19][20][21][22] and our investigation showed that leaves of the Allium species contain more rutin than other parts of the plant. ...
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Rutin is quercetin heteroside widely present in plants that exhibit many health-beneficial effects, such as strengthening the capillary walls, reducing the harmful effects of LDL cholesterol, and reducing the risk of cardiovascular diseases. Rutin was determined from three Allium species ( A. cepa , A. sativum , and A. ursinum ) collected in Bosnia and Herzegovina by the HPLC method associated with electrochemical detection. The analysis was performed from methanol extracts of bulb and leaf of garlic, bulb and leaf of onion, and leaves of wood garlic. Rutin was present in all of the examined samples. The highest rutin content was found in garlic leaves (0.78 ± 0.09 mg g<sup>–1</sup>), and the lowest in onion bulbs (0.04 ± 0.10 mg g<sup>–1</sup>). The contents of rutin were higher in leaf samples, suggesting that leaves of onion and garlic are recommended as a better natural source of this glycoside.
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Onion peels is a natural source of high-value functional ingredients produced in the onion industry without suitable processing. The objective of this study was to evaluate characteristics of onion peel extract (OPE), including its biological activities, obtained from solvent extraction in 3 times pilot scales (Lot A, B, and C). Mineral analysis showed that K was present in the largest amount (13,767.56-15,506.78 ppm), followed by Na and Ca at 8,602.44-9,796.00 ppm and 4,255.78-4,903.33 ppm, respectively. The amounts of total phenol, total flavonoid, and quercetin in the OPE were in the ranges of 598.57~626.73, 211.73~233.64, and 93.78~107.29 mg/g, respectively. The biological activities such as antioxidant and effects of fibrinolysis increased in parallel with the concentration of OPE. The value of DPPH radical scavenging activity was in the range of 517.58~557.32 ppm in the OPE. The value for superoxide dismutase (SOD)-like activity was in the range of 11,900.91~12,690.35 ppm. A clear zone of OPE (20,000 ppm) in fibrinolysis test was three times higher than the plasmin as a reference. In conclusion, OPE could be used as a good source of antioxidants and fibrinolytic activities.
Purpose: The COVID-19 pandemic created heavy pressure on firms, by increasing the challenges and disruptions that they have to deal with on being sustainable. For this purpose, it is aimed to reveal the role of the Smart Circular Supply Chain (SCSC) and its enablers towards achieving Sustainable Development Goals (SDGs) for post pandemic preparedness. Methodology: Total interpretive structural modelling and MICMAC have been applied to analyse the SCSC enablers which are supported by the natural-based resource view in Turkey’s food industry. In this context, industry experts working in the food supply chain (meat sector) and academics came together to interpret the result and discuss the enablers that the supply chain experienced during the pandemic for creating a realistic framework for post pandemic preparedness. Findings: The results of this study show that "governmental support" and "top management involvement" are the enablers that have the most driving power on other enablers, however, none of them depend on any other enablers. Originality: The identification of the impact and role of enablers in achieving SDGs by combining smart and circular capabilities in the supply chain for the post pandemic.
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Yaltinskiy onion is one of the symbols of the Crimea, the very name of which is tied to the famous resort, which emphasizes belonging to the Crimean Peninsula. Salad sweet onion is in constant demand among the guests of the peninsula and locals. Its price is several times higher than the price of other onion varieties. Unfortunately, under the guise of Yaltinskiy sortotype, products that are much inferior to it according to taste peculiarities are often sold. In this regard, creation of new cultivar of sweet salad onion, exceeding palatability of the existing cultivar Yaltinskiy Rubin is an urgent task, having an undeniable economic direction. The source material was collected at various zones of the Crimean Peninsula. During the research, hybridization and selection in hybrid progeny were carried out. The plants were analyzed using various methods of evaluation. Much attention was paid to biochemical analysis. The palatability traits are important for the onion cultivars of salad direction. The best indicators for sugars and vitamin C were identified in salad onion of a new cultivar Yaltinskiy plus. Reducing the content of essential oil has improved the taste and its consumer properties. Useful properties were also supplemented by the fact that the presence of selenium antioxidant 68 μg/kg and anthocyanins of 1.66 mg/100 g in salad onions was established, which is 1.5 and 2.3 times higher than the standard sample showed. The content of quercetin and other polyphenols was also noted. The cultivar is characterized by high agronomic stability (90%), product quality (88%), and productivity (49 tons per ha).
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This study aimed to examine the antioxidant, tyrosinase inhibitory, and anti-proliferative activities (A549, G361, HT-29, and MDA-MB-231) of fermented gochujang (made from sword bean cheonggukjang powder (SBC) for 90 days. Gochujang was prepared by adding 0 (SBC 0), 2 (SBC 2), 5 (SBC 5), 8 (SBC 8) and 10% (SBC 10) levels with SBC, and all experiments were measured at diluted levels of 20, 50 and 100 times. The antioxidant activity and tyrosinase inhibitory effect demonstrated that SBC 10 increased approximately 1.2 and 1.1 times compared with SBC 0, respectively, at diluted levels of 50 and 100 times. The anti-proliferative effects of A549, G361, and HT-29 presented that SBC 10 were 2.8, 1.1, and 8.9 times higher compared with SBC 0, respectively, at diluted levels of 50, 20, and 100 times. In the case of MDA-MB-231, SBC 10 was 3.7 times higher compared with SBC 5 at diluted level of 20 times. As a result, we confirmed that SBC gochujang was improved for physiological activities and anti-proliferative effects.
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The present study investigated the cytotoxic activity of ethanol extract of onion peel (OPE) in HT-29 human colon carcinoma cells. High-performance liquid chromatography (HPLC) analysis was performed to determine the amounts of phenolic acids and flavonoids in OPE. In addition, the influence of OPE on antioxidant- and inflammation-associated gene expression was also determined in a model of lipopolysaccharide (LPS)-stimulated HT-29 cells. HPLC analysis showed that OPE contained well-known antioxidant compounds, including p-coumaric acid, vanillic acid, epicatechin, and morin. After incubation with OPE, HT-29 cells showed either a loss of normal nuclear architecture or detachability from each other. The cytotoxic effects of OPE on HT-29 cells were confirmed by MTT and LDH release assays. LPS-induced oxidative conditions effectively downregulated TNF-α mRNA expression in OPE pretreated HT-29 cells compared with cells only stimulated with LPS. In addition, the expression of heme oxygenase-1 (HO-1) and glutathione S-transferase (GSTs) detoxification genes (i.e., GSTM1, GSTT1, and GSTP1) was upregulated after treatment with LPS at sublethal concentrations. However, the LPS-induced mRNA expression of HO-1 and GSTs was significantly attenuated by treatment with OPE. Therefore, onion peel extract is a promising component of future nutraceuticals and value-added products.
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Physicochemical properties of onion powder as influenced by drying methods were investigated. Moisture contents of onion powder were 13.29%, 12.99%. and 10.78% for samples dried using hot-air dryer, freeze dryer, and vacuum dryer, respectively. There were no significant differences in crude fat, crude protein, and crude ash content (P>0.05) depending on the drying methods. Samples prepared by freeze drying showed a significantly higher L-value as compared with those prepared by hot-air and vacuum drying (p<0.05). Scanning electron micrographs showed that freeze drying produced smaller particle-sized sample which in turn resulted in the higher porosity of the sample. Freeze dried samples revealed significantly lower degree of rehydration than other samples (p<0.06) probably due to small particle size of the sample. Water solubility of freeze dried sample appeared to be higher than that of other drying methods while the swelling ratio of the same sample appeared to be lower than that of the others. Browning index was significantly lower in samples prepared by freeze drying (p<0.05) but not significantly different between samples dried by hot-air and vacuum drying. Vitamin C content was higher in freeze dried onion powder due to the lower temperature applied to the sample. Freeze dried onion powder contained significantly lower amount of total polyphenol and higher amount of total sugar as compared to other samples (P<0.05).
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The antioxidant substance in black onion was identified. The assays that used 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazo line-6-sulphonic acid) () radicals showed that the ethyl acetate fraction of black onion methanol extract had a higher level of radical-scavenging activity than the other fractions. Two antioxidative compounds were purified and isolated from the ethyl acetate fraction via column chromatographies of silica gel and Sephadex LH-20 using the guided DPPH radical-scavenging assay. The isolated compounds were identified as 3,4-dihydroxybenzoic acid (1) and quercetin (2) based on mass spectrometry and nuclear magnetic resonance. The isolated compounds showed a high level of DPPH and ABTS+ radical-scavenging activity. Compound 2 had a higher level of radical-scavenging activity than 1.
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After a mixed carbohydrate diet, inhibition of -amylase and -glucosidase involved in the digestion and absorption of carbohydrates can significantly decrease the postprandial increase of blood glucose level. In the course of screening these useful enzyme inhibitors, we selected five kinds of bean, using an in-vitro enzyme inhibition assay method. To evaluate the effect of germination process on the functionality of the bean, we investigated the inhibitory activities of the water extracts of non-germinated bean and germinated bean against -amylase and -glucosidase, relevant to postprandial hyperglycemia. We also investigated the oxygen radical absorbance capacity(ORAC), total phenolics content, and postprandial blood glucose lowering effect in rats(Sprague-Dawley rat model). Most germinated beans showed significantly higher -glucosidase inhibitory activity, compared with non-germinated beans. Among germinated beans, Glycine max had the highest -glucosidase inhibitory activity(53.3%). The water extract of germinated Phaseolus vulgaris L. had the highest -amylase inhibitory activity(95.1%), followed by Glycine max(58.7%), and Glycine max L. Merr(54.1%). Furthermore, the five germinated beans also showed high antioxidant activities in ORAC assay. Results suggested that the germination process may improve and enhance the anti-hyperglycemia potential and antioxidant activity of the bean.
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This study investigated the antioxidant activity of onion peels extracted from onion byproducts by hot water treatment. Hot water extraction of freeze dried onion peel powder was analyzed for total polyphenol content, 2,2′-diphenyl-1-picryllhydrazyl (DPPH), and 2,2′-azino-bis(3- ehtylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities, reducing power, oxygen radical absorbance capacity (ORAC). Total polyphenol content was the highest (233.90 mg/g) in onion peel extract mix with ethanol (OPME-1). The DPPH radical scavenging activity (IC50), reducing power, and ORAC obtainbed from onion peel extract mix with ethanol precipitation (OPMPE-1) were the highest at 1.15 mg/mL, 1.69 A700, and 318,509 μM TE/mL, respectively. The ABTS radical scavenging activity was the highest at 432.78 mg amino acids (AA) eq/g in the OPM. The results of this study suggest that onion peel extracts have marked antioxidant activity, which can have significant health benefits.
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The objectives of this study were to identify antioxidant substance in heated onion. The isolation of active compound was performed in three steps: silica gel column chromatography, preparative TLC, and preparative HPLC. The structure of the purified compound was determined using spectroscopic methods, i.e., ultraviolet, mass spectrometry, 1H-NMR, 13C-NMR, and DEPT. The antioxidant activities of isolated compound were evaluated and compared with α-tocopherol, ascorbic acid, and butylated hydroxytoluene (BHT) using DPPH and ABTS assay. The isolated compound was identified as 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP). The DPPH radical-scavenging activity (IC 50) of the DDMP was in the following order: ascorbic acid (45.3 μg/mL)>α-tocopherol (69.2 μg/mL)>DDMP (241.6 μg/mL)>BHT (268.0 μg/mL). In addition, DDMP showed strong ABTS radical-scavenging activity of 569.0 mg AA eq/g.
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This experiment was conducted to evaluate the effects of quercetin supplementation on intestinal integrity, intestinal reactive oxygen species (ROS) levels and intestinal inflammation in pigs under transport stress. A total of 170 finishing pigs were randomly assigned into two groups. Animals in the control group consumed a basal diet, while those in the treatment group consumed the same diet supplemented with 25 mg quercetin per kg feed. After a 4-week period, pigs were transported for 5 hr. The quercetin-supplemented pigs showed decreased serum levels of endotoxin (P<0.05), increased height of jejunum villi (P<0.05), and increased occludin and zonula occudens-1 (ZO-1) mRNA expression in the jejunum (P<0.05). These parameters are associated with intestinal health and were markedly improved by quercetin supplementation. Pigs consuming the quercetin-supplemented diet had lower intestinal levels of ROS and malondialdehyde (MDA) compared with the control group (P<0.05). This finding coincided with greater inhibition of the innate immune system (P<0.05), including mitogen-activated protein kinase (MAPK), protein kinase B (Akt) and nuclear factor κB (NF-κB) signaling pathways, as well as decreased expression of inflammatory cytokines in the jejunum. These results indicate that quercetin alleviates intestinal injury in pigs during transport, probably through modulation of intestinal oxidative status and inflammation.
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Fruits and vegetables play an important part in the diets of global human population. During processing, the unused residues such as peels, stalks, rinds, stem, leaves etc. come out as waste. Due to the high moisture content of these perishable wastes, they undergo rapid decomposition that leads to foul odour and growth of pathogens. Almost, 30% of the loss occurs at the supply, retail, consumer, post-harvest and processing level. The perishable waste like peels, pomace, seeds etc. act as threat for the environment and degrade pollution-free model. The wastes are rich in protein, carbohydrates, minerals, vitamins and other phytochemicals and bioactive compounds such as pigments, dietary fibre, essential oils etc. Recent researches have shown that there is an increase in the utilization of these wastes for the extraction of value-added products such as bioactive compounds, bio-colorants, organic acids, Single cell protein (SCP), organic minerals, enzymes and others. The present review paper deals with the recent studies conducted on valorisation of the fruit & vegetable waste.
Chapter
The food processing sector is a very prominent section of the international market and increased up to approximately $4.5 trillion by 2024 (Businesswire in Global food processing market report, 2019: trends, forecasts, and competitive analysis (2013–2024), 2019 [1]). The increasing demand for healthy fruits and vegetables, organic processed foods, nutraceuticals and functional foods, seafood with packaged food products like ready-to-eat, and frozen processed foods is expected to drive the market growth after pandemic COVID-19 incidence. During processing and handling of horticultural crops, generate large volumes of wastes annually and become a major concern to the whole world. Fruits and vegetables have many bioactive compounds (polyphenols, flavonoids, organic acids, aroma, and flavoring agents, etc.) which have a positive impact on human health because of anti-inflammation, anti-allergic, anti-cancer, anti-atherogenic, and antioxidants properties, depending upon extraction their methods from wastes, efficacy, and bioavailability to the body. Applications of conventional (soxhlet, maceration, percolation, hydro-distillation) and green techniques (solid-phase, supercritical, accelerated solvent, microwave, and ultrasound extractions) for the valorization of horticultural wastes’ conversion in many bioactive components are followed by the potentiality, scalability, and sustainability of the extraction process and highlight the concept of the circular economy as “Waste to Wealth.”
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Two flavonoids from fennel seeds quercetin and isoquercetin have been evaluated for virostatic efficacy against Bluetongue virus (BTV) in in vitro. They showed expressive effect on virus growth in BHK cell cultures by inhibiting the development of virus induced cytopathic effects at an effective concentration of 0.75±0.11 µM and 1.07±0.17 µM and the selective indexes was calculated accordingly and found that quercetin was highly selective than isoquercetin with SI 50 values of 167 and 58 respectively. They exhibited low cytotoxicity on BHK cells at an inhibitory concentration of 125µM and 62.5µM respectively. These observations suggest that both the compounds are suitable for development of efficacious anti BTV agents.
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Objective: The present study is investigation in the rice bran oil from four rice varieties in term of anti-inflammatory and antioxidant activities. Methods: This research studied the effects of anti-inflammatory and antioxidant activity from cold press rice bran oil. For anti-inflammatory, their inhibitory activity of nitric oxide (NO) production using RAW267.4 cell lines was evaluated. And two methods for antioxidant activities, DPPH radical scavenging assay (DPPH assay) and Ferric Reducing Antioxidant Power (FRAP) assay were used and compared with gallic acid standard and ferric sulfate (FeSO4), respectively. Results: For the Oryza Sativa L. Khaw-khaw exhibited the highest activity against the NO production with an IC50 value of 41.96 μg/ml, followed by O. Sativa L. Hom Pathum (46.58 μg/ml), O. Sativa L. Hom Mali (53.84 μg/ml) and O. Sativa L. Hom Mali Gorkho (59.43 μg/ml). However, the antioxidant activity, DPPH method found O. Sativa L. Hom Mali Gorkho displayed the most potent effect with IC50 value of 0.08 mg/ml, followed by O. Sativa L. Hom Pathum (0.11mg/ml), O. Sativa L. Hom Mali (0.12mg/ml) and O. Sativa L. Khaw khaw (0.88 mg/ml), respectively. The assay of FRAP showed the highest in O. Sativa L. Hom Mali Gorkho with an IC50value 2.27 mg/ml, followed by O. Sativa L. Hom Pathum (4.30 mg/ml), O. Sativa L. Khaw khaw (6.67 mg/ml) and O. Sativa L. Hom Mali (7.68 mg/ml), respectively. Conclusion: This study indicated that cold press rice bran oil from rice varieties in Thailand is responsible for anti-inflammatory and antioxidant activity. Therefore, this study supports the tradition use of cold press rice bran oil for treatment of inflammatory related diseases though the inhibition of nitric oxide release.
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Excessive adipose accumulation, which is the main driver for the development of secondary metabolic complications, has reached epidemic proportions and combined pharmaceutical, educational and nutritional approaches are required to reverse the current rise in global obesity prevalence rates. Brown adipose tissue (BAT) is a unique organ able to dissipate energy and thus a promising target to enhance BMR to counteract a positive energy balance. In addition, active BAT might support body weight maintenance after weight loss to prevent/reduce relapse. Natural products deliver valuable bioactive compounds that have historically helped to alleviate disease symptoms. Interest in recent years has focused on identifying nutritional constituents that are able to induce BAT activity and thereby enhance energy expenditure. This review provides a summary of selected dietary phytochemicals, including isoflavones, catechins, stilbenes, the flavonoids quercetin, luteolin and resveratrol as well as the alkaloids berberine and capsaicin. Most of the discussed phytochemicals act through distinct molecular pathways e.g. sympathetic nerve activation, AMP-kinase signalling, SIRT1 activity or stimulation of oestrogen receptors. Thus, it might be possible to utilise this multitude of pathways to co-activate BAT using a fine-tuned combination of foods or combined nutritional supplements.
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The concentrations of phenolics and other phytochemicals present in the peels, pulp/pomace and seeds of many fruits and vegetables namely citrus, apples, peaches, pears, banana, pomegranate, berries, mangoes, onions, potatoes, tomatoes and sugar beet are generally substantially higher than in their respective edible tissues, suggesting these wastes and residues to be the potential sources for isolating bio-active compounds. The antioxidants (polyphenolic and other phytochemicals) and other bio-active compounds from these sources exhibit anti-cancer, anti-microbial (pathogens), anti-oxidative and immune-modulatory effects. In addition they reduce incidence of cardiovascular diseases and capillary fragility, inhibit platelet aggregation and prevent thrombosis, oxidative stress, osteoporosis and diabetes in vertebrates. Specifically, the phenolics and flavonoids present in apple, date pit, rambutan (Nephelium lappaceum) peel, tomato peel extracts strongly inhibit tumour-cell proliferation. Penta-O-galloyl-glucoside (PGG) present in mango seed kernel extract and mango peel is used in pharmaceutical industries as it possesses anti-tumor, antioxidant, anticardiovascular and hepato-protective effects. The terpenoid and flavonoids in banana foliage exhibit anthelmintic properties. Pomace of apple, pear, orange, peach, blackcurrant, cherry, artichoke, asparagus, onion, raspberry, tomato and carrot, durian seeds (gelling and thickening agents), mango peels, date pits, cauliflower trimmings, empty pea pods and okara are used as dietary fibre supplements and as a functional ingredient in processed food products due to the presence of pectins and carotenoids and bound antioxidants. Some of the fruit and vegetable wastes are excellent source of biopigments; examples being betalains in beet root pulp and carotenoid in carrot pulp. Tomato seeds, banana peel, rambutan and mango seed kernel, passion fruit seed, black currant, date pits are good sources of edible oil rich in polyunsaturated fatty acids. Many fruit and vegetable wastes are used as a substrate for the production of organic acids (citric, lactic and ferulic acids), single cell protein, essential oils, exogenous enzymes, bio-ethanol/methanol, bio-pesticides, bio-sorbants, bio-degradable plastic, bio-fertilizers, bio-preservatives and edible mushrooms. Some have potential to decrease the emission of enteric methane.
Background An earlier study demonstrated significant antioxidant and anticholinesterase activities of hydromethanol extract (HME) of Allium cepa . The aim of the study was to investigate the component responsible for these activities followed by an in vivo study. Methods In vitro antioxidant and anticholinesterase activities of standardized ethylacetate fraction (EAF) of HME were assessed. Bioactivity-guided fractionation showed that, as compared with its subfractions, EAF had most significant activity in 2,2-diphenyl-1-picrylhydrazyl and Ellman assays. Thus, EAF was further examined using a streptozotocin (STZ)-induced model of Alzheimer’s disease in mice. STZ was injected intracerebroventricularly on days 1 and 3 (3 mg/kg) in mice. EAF was thereafter administered (42, 84, and 168 mg/kg b.w./day p.o.) from days 9 to 22. The Morris water maze test was used to evaluate learning and memory in mice. Acetylcholinesterase (AChE) activity and oxidative stress markers were assessed in the brain homogenates of mice. Additionally, histopathological studies were performed to observe effects in the brain at the cellular level. EAF was standardized based on quercetin and quercetin 4′-O-glucoside content using a validated thin layer chromatography densitometric method. Results STZ produced significant (p < 0.05) memory impairment along with oxidative stress and a cholinergic deficit in mice. EAF treatment ameliorated STZ-induced behavioral deficits and biochemical alterations in mice in a significant and dose-dependent manner. Conclusions Our results show that EAF is efficacious in improving memory and learning via AChE inhibition and antioxidant activity in the mice brain. Thus, AC could be explored further to find out a lead candidate for Alzheimer’s disease.
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The concentrations of phenolics and other phytochemicals present in the peels, pulp/pomace and seeds of many fruits and vegetables namely citrus, apples, peaches, pears, banana, pomegranate, berries, mangoes, onions, potatoes, tomatoes and sugar beet are generally substantially higher than in their respective edible tissues, suggesting these wastes and residues to be the potential sources for isolating bio-active compounds. The antioxidants (polyphenolic and other phytochemicals) and other bio-active compounds from these sources exhibit anti-cancer, anti-microbial (pathogens), anti-oxidative and immune-modulatory effects. In addition they reduce incidence of cardiovascular diseases and capillary fragility, inhibit platelet aggregation and prevent thrombosis, oxidative stress, osteoporosis and diabetes in vertebrates. Specifically, the phenolics and flavonoids present in apple, date pit, rambutan (Nephelium lappaceum) peel, tomato peel extracts strongly inhibit tumour-cell proliferation. Penta-O-galloyl-glucoside (PGG) present in mango seed kernel extract and mango peel is used in pharmaceutical industries as it possesses anti-tumor, antioxidant, anticardiovascular and hepato-protective effects. The terpenoid and flavonoids in banana foliage exhibit anthelmintic properties. Pomace of apple, pear, orange, peach, blackcurrant, cherry, artichoke, asparagus, onion, raspberry, tomato and carrot, durian seeds (gelling and thickening agents), mango peels, date pits, cauliflower trimmings, empty pea pods and okara are used as dietary fibre supplements and as a functional ingredient in processed food products due to the presence of pectins and carotenoids and bound antioxidants. Some of the fruit and vegetable wastes are excellent source of biopigments; examples being betalains in beet root pulp and carotenoid in carrot pulp. Tomato seeds, banana peel, rambutan and mango seed kernel, passion fruit seed, black currant, date pits are good sources of edible oil rich in polyunsaturated fatty acids. Many fruit and vegetable wastes are used as a substrate for the production of organic acids (citric, lactic and ferulic acids), single cell protein, essential oils, exogenous enzymes, bio-ethanol/methanol, bio-pesticides, bio-sorbants, bio-degradable plastic, bio-fertilizers, bio-preservatives and edible mushrooms. Some have potential to decrease the emission of enteric methane.
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Quercetin (QT) is a flavonoid that exhibits anti-oxidant and chemo-preventive activity. This research work aimed to develop surface-modified bilosomes (BS) of QT. The BS was prepared by the solvent evaporation method and optimized by the Box-Behnken design. The optimized QT-BS (QT-BS3opt) displayed vesicle size (143.51 nm), PDI (0.256), zeta potential (−15.4 mV), and entrapment efficiency (89.52%). Further, the optimized QT-BS formulation was coated with chitosan (CS). The XRD diffractogram of CS-QT-BS3opt1 did not exhibit extensive peaks of QT, revealing that QT is properly encapsulated in the polymer matrix. The QT-BS3opt and CS-QT-BS3opt1 exhibited sustained-release (86.62 ± 3.23% and 69.32 ± 2.57%, respectively) up to 24 h with the Korsmeyer-Peppas kinetic model (R2 =0.9089). CS-QT-BS3opt1 exhibited significantly (P < .05) high flux, i.e. 4.20-fold more than pure QT dispersion and 1.27-fold higher than QT-BS3opt. CS-QT-BS3opt1 showed significantly greater bio-adhesion (76.43 ± 2.42%) than QT-BS3opt (20.82 ± 1.45%). The antioxidant activity showed that QT from CS-QT-BS3opt1 has more remarkable (P < .05) antioxidant activity at each concentration than pure QT. The CS-QT-BS3opt1 exhibited 1.61-fold higher cytotoxicity against MFC7 and 1.44-fold higher cytotoxicity against MDA-MB-231 than pure QT. The CS-QT-BS3opt1 displayed a significantly greater antimicrobial potential against E. coli than against S. aureus. From all these findings, it could be concluded that surface-modified QT-BS might be an effective approach for increasing the efficacy of QT in the treatment of certain ailments.
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The antioxidant activities of the flavonol aglycones, quercetin and myricetin, and their selected glycosides were compared in bulk methyl linoleate oxidized at 40°C. Methyl linoleate hydroperoxide formation, hydroperoxide isomer distribution, and ketodiene formation were followed by using high-performance liquid chromatography (HPLC) analysis. The aglycones, quercetin and myricetin, were consistently more active in bulk methyl linoleate than their glycosides and more active than α-tocopherol at 500 and 1000 µM. At 50 µM, the order of activity was myricetin > α-tocopherol > quercetin, and the order of activity of quercetin and its derivatives was quercetin > quercitrin > isoquercitrin > rutin. Myricitrin was slightly less active than myricetin. The sugar moiety was shown to have a marked effect on the antioxidant activity of flavonols. The rhamnoside derivatives, quercitrin and myricitrin, both possessed activity close to that of their corresponding aglycones. The different activities of glycosides could be partly explained by different solubilities and by differences in oxidizability of glycosides containing a monosaccharide or disaccharide at the C3 position. The effect on hydroperoxide isomer distribution indicates that α-tocopherol was a more effective hydrogen donor than flavonoids, although flavonoids were more effective in inhibiting oxidation of methyl linoleate.
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For the quantitative determination of individual flavonoid glycosides in plant materials, the glycosides are normally hydrolysed and the resulting aglycones are identified and quantified. However, the hydrolysis conditions which result in optimal breakdown of glycosides are too harsh for some of the other phenolic compounds present in the same plant material. Therefore, the effects of different hydrolysis conditions and different antioxidants on pure flavonoid glycones and aglycones were studied. On the basis of the results obtained with standards, suitable hydrolysis methods for red spring onion and spinach were developed. The best results from these vegetables were obtained by refluxing at 80 °C for 2 h with 1.2 M HCl in 50% aqueous methanol with addition of 2 mg ascorbic acid as an antioxidant. The method developed in this study is suited to the screening of flavonoids in vegetables and leafy vegetables.
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Antimicrobial activity of different concentrations (50, 100, 200, 300 and 500 ml/l) of essential oil extracts of three type of onions (green, yellow and red) and garlic against two bacteria, Staphylococcus aureus, Salmomella Enteritidis, and three fungi, Aspergillus niger, Penicillium cyclopium and Fusarium oxysporum, was investigated. The essential oil (EO) extracts of these Allium plants (garlic and onions) exhibited marked antibacterial activity, with garlic showing the highest inhibition and green onion the lowest. Comparatively, 50 and 100 ml/l concentrations of onions extracts were less inhibitory than 200, 300 and 500 ml/l concentrations. However, with garlic extract, high inhibitory activity was observed for all tested concentrations. S. aureus showed less sensitivity towards EO extracts inhibition, however S. Enteritidis was strongly inhibited by red onion and garlic extracts. The fungus F. oxysporum showed the lowest sensitivity towards EO extracts, whereas A. niger and P. cyclopium were significantly inhibited particularly at low concentrations. Conclusively, where seasoning is desired, essential oil extracts of onions and garlic can be used as natural antimicrobial additives for incorporating in various food products.
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Several vegetables were selected to study their flavonoid contents and antioxidant activities. The results showed that both green and purple leaves of sweet potatoes (185.01 and 426.82 mg kg(-1) respectively) and the outer leaves of onion (264.03 mg kg(-1)) possessed higher amounts of flavonoids, and more than 85% of free radical scavenging activities were evaluated by using 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide and hydroxyl radicals. In addition, green leaves of sweet potatoes and the outer leaves of onion showed higher reducing power and higher antioxidant activity in a Linoleic acid system as compared to cabbage, spinach, potato and crown daisy. Blanching of green leaves of sweet potatoes for 30-60 s retained more flavonoids and higher free radical scavenging activities as compared to more than 1 min of blanching. The storage test showed that green leaves of sweet potatoes stored at 4-10 degrees C maintained better quality than those stored at room temperature. (C) 2000 Society of Chemical Industry.
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Quercetin 3,7,4′-O-β-triglucopyranoside together with quercetin, quercetin 4′-O-β-glucopyranoside and quercetin 3,4′-O-β-diglucopyranoside were isolated from the pigmented scales of Allium cepa var. ‘Red Baron’. The former flavonol has previously been reported to be formed when cell cultures of a Vitis hybrid is fed with quercetin. Minor amount of taxifolin 4′-O-β-glucopyranoiside, a rare dihydroflavonol, was also detected. The structures were established on the basis of acid hydrolysis, chromatography (TLC and HPLC) and homo- and heteronuclear NMR spectroscopic techniques.
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METHODS for measuring antioxidants and appraising antioxidant activity appear to be of two general types. If the chemical nature of the antioxidant is known, one may strive for a test specific for the compound or group of interest; for example, the nitroprusside test for sulphydryl groups. Alternatively one may observe the inhibition of some natural oxidative process such as the β-oxidation of fats, as a function of the added antioxidant.
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Quantitative estimates of conjugated flavonoid content were obtained by using HPLC to analyze the level of free flavonoids present in acid-hydrolyzed extracts from commercial fruits and vegetables. Cherry tomatoes contained 17−203 μg of quercetin g-1 fresh weight compared to 2.2−11 μg g-1 detected in normal-sized Scottish, Spanish, and Dutch beef tomatoes. The quercetin levels in onions ranged from 185 to 634 μg of quercetin g-1 fresh weight. “Round” lettuce contained 11 μg of quercetin g-1 fresh weight compared to 911 μg g-1 in the outer leaves and 450 mg g-1 in the inner leaves of “Lollo Rosso” lettuce. The conjugated flavonoid content of celery was very variable, ranging from undetectable to 40 μg of luteolin and 191 μg of apigenin g-1 fresh weight. Cooking lowered the quercetin content of both tomatoes and onions with greater reductions being detected following microwaving and boiling than after frying. Keywords: HPLC; quantitative analysis; flavonoids; tomatoes; onions; lettuce; celery; diet
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Seven major flavonoid compounds in onions were separated, isolated, and identified by Sephadex LH-20 chromatography, high-performance liquid chromatography, thin-layer chromatography, mass spectroscopy, and nuclear magnetic resonance spectroscopy. The flavonoids were quercetin, quercetin monoglucoside, quercetin diglucoside, isorhamnetin, isorhamnetin glycoside, rutin, and kaempferol. Glucosylation of the glucose moiety of isorhamnetin glucoside was the 4‘-O-glucoside. Keywords: Flavonoids; flavonols; flavonol glycoside; quercetin, isorhamnetin 4‘-glucoside; onions
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Total flavonol and flavone contents of foods have been determined with validated state-of-the-art methods. Quercetin dominates, and flavonol levels found in vegetables and fruits are below 10 mg kg−1. However, high concentrations are found in onions (300 mg kg−1), kale (450 mg kg−1), broccoli (100 mg kg−1), beans (50 mg kg−1), apples (50 mg kg−1), blackcurrants (40 mg kg−1), and tea (30 mg l−1). The dietary intake of flavonols varies 10-fold between countries (6–60 mg day−1). Flavones are of minor importance in the diet. Tea, wine and fruits are the most important sources of flavanols, but there are gaps in our knowledge on flavanol levels of many foods. The absorption of dietary quercetin glycosides in humans ranges from 20 to 50%. The sugar moiety is an important determinant of the bioavailability of flavonols. The presence of a glucose moiety significantly enhances absorption. The extent of absorption of flavanols in humans seems similar to that of flavonols but has been little studied. Flavonols and flavanols are extensively metabolised, as only 1–2% of them are excreted with an intact flavonoid backbone. Hepatic biotransformations include glucuronidation and sulphatation of the phenolic hydroxyls and O-methylation of catechol groups. Bacteria of the colon cleave the C-ring of the flavonoid nucleus to phenolic acids which are subsequently absorbed. Apart from conjugates, virtually no metabolites have been characterised in humans. Absorption of flavanols is rather fast, with times to reach peak values between 0.5 and 4 h. Flavanols are rapidly excreted, with elimination half-lives of 1–6 h. Quercetin glycosides show rapid to slow absorption; peak values are reached between  < 0.5 and 9 h. The type of glycoside determines the rate of absorption. Excretion of quercetin glycosides is slow: elimination half-lives are 24 h, independent of the type of glycoside. Analytical data for flavanols in foods are needed. Tea, as an important dietary source, has to be studied. Research on the bioavailability of flavonols and flavanols has to be expanded. Attention is needed for the identification and quantification of their metabolites in body fluids.© 2000 Society of Chemical Industry
Article
Flavonoids are polyphenolic compounds that occur ubiquitously in foods of plant origin. Over 4000 different flavonoids have been described. Flavonoids have a variety of biological effects in numerous mammalian cell systems, in vitro as well as in vivo. Recently much attention has been paid to their antioxidant properties and to their inhibitory role in various stages of tumour development in animal studies. Hitherto, analytical research on flavonoids was mainly aimed at identification and not at quantification. As a consequence, no data were available for epidemiological investigations of flavonoid intake and chronic diseases. Flavonoids in foods are mostly linked to sugars, the so-called glycosides. As one parent compound or aglycone, e.g. quercetin, may be linked to a number of different sugars, quantification in foods is complex. Hydrolysis of the glycosides and subsequent determination of the parent aglycones simplifies this task. Following this approach we developed and validated an HPLC method and determined the flavonol and flavone content of vegetables, fruits and beverages commonly consumed. Subsequent epidemiological evaluation showed that the intake of flavonols and flavones was inversely associated with coronary heart disease in both a prospective cohort study and in a cross-cultural study. However, no relation with cancer risk could be established.
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Antibacterial activity of 11 essential oil constituents against Escherichia coli, E. coli O157:H7, Salmonella typhimurium, Listeria monocytogenes, and Vibrio vulnificus was tested at 5, 10, 15, and 20% in 1% Tween 20 using a paper disk method. Eight constituents were then tested in liquid medium to determine minimum inhibitory and minimum bactericidal concentrations (MIC and MBC, respectively). V. vulnificus was most susceptible using disk assay. Carvacrol showed strong bactericidal activity against all tester strains, while limonene, nerolidol, and β-ionone were mostly inactive. Carvacrol was highly bactericidal against S. typhimurium and V. vulnificus in liquid medium (MBC 250 μg/mL). Citral and perillaldehyde had MBCs of 100 and 250 μg/mL against V. vulnificus. Terpineol and linalool were least potent against tester strains, with MBCs of 1000 μg/ mL. Citral, geraniol, and perillaldehyde at 500 μg/mL completely killed E. coli, E. coli O157:H7, and S. typhimurium, while citronellal at 250 μg/mL killed V. vulnificus. Therefore, these compounds could serve as potential antibacterial agents to inhibit pathogen growth in food.
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A high-performance liquid chromatographic (HPLC) separation method with photo-diode array (PDA) and mass spectrometric (MS) detection was developed to determine and quantify flavonols, flavones, and flavanones in fruits, vegetables and beverages. The compounds were analysed as aglycones, obtained after acid hydrolysis of freeze-dried food material. Identification was based on retention time, UV and mass spectra by comparison with commercial standards, and the UV peak areas were used for quantitation of the flavonoid contents. Examples of HPLC-MS, analyses of orange pulp, tomato, and apple are presented. The method has been used to screen foods on the Danish market, and the contents of flavones, flavonols, and flavanones were measured.
Article
A rapid method based on RP-HPLC with UV detection is presented for the quantitative determination of five major flavonoid aglycons, viz. quercetin, kaempferol, myricetin, luteolin, and apigenin, in freeze-dried vegetables and fruits, after acid hydrolysis of the parent glycosides. Completeness of hydrolysis and extraction have been optimized by testing systematically different conditions such as acid concentration, reaction period, and methanol concentration in the extraction solution using samples containing various types of flavonoid glycosides. Optimum hydrolysis conditions are presented for flavonol glucuronides, flavonol glucosides, and flavone glycosides. Identity of the flavonoids was confirmed with diode array. Repeatability of the method was good, with coefficients of variation of 2.5-3.1 % for quercetin, 4.6-5.6 % for kaempferol, 4.6 % for myricetin, 3.3 % for luteolin, and 2.8 % for apigenin. CV of the within-laboratory reproducibility was less than 2 times the CV of repeatability. Recoveries of the flavonols quercetin, kaempferol, and myricetin ranged from 77 to 110 %, and recoveries of the flavones apigenin and luteolin ranged from 99 to 106 %. The method presented allows a fast, quantitative, and reproducible determination of five flavonoids in freeze-dried foods.
Article
The content of the potentially anticarcinogenic flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin of 28 vegetables and 9 fruits was determined by RP-HPLC with UV detection. Fresh foods were purchased in a supermarket, agrocery, and a street market and combined to composites. Processed foods were purchased additionally. Sampling was carried out in spring, summer, winter, and spring of the following year. Quercetin levels in the edible parts of most vegetables were generally below 10 mg/kg except for onions (284-486 mg/kg), kale (110 mg/kg), broccoli (30 mg/kg), French beans (32-45 mg/kg), and slicing beans (28-30 mg/kg). Kaempferol could only be detected in kale (211 mg/kg), endive (15-91 mg/kg), leek (11-56 mg/kg), and turnip tops (31-64 mg/kg). In most fruits the quercetin content averaged 15 mg/kg, except for different apple varieties in which 21-72 mg/kg was found. The content of myricetin, luteolin, and apigenin was below the limit of detection (
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The mutagenic activities of several flavonoids and flavonoid metabolites were examined by means of Salmonella typhimurium mutants that reveal base-pair substitution and frameshift mutagens. Of the compounds tested (naringin, rutin, neohesperetin, hesperetin, dihydroquercetin, quercetin, quercetin pentaacetate, permethylquercetin, m-hydroxyphenylacetic acid, and m,p-dihydroxyphenylacetic acid), only quercetin was mutagenic without microsomal activation. With activation, however, the mutagenic activity of quercetin was increased significantly and that of quercetin pentaacetate was revealed. The health implications of these findings and aspects of flavonoid structural requirements for mutagenic activity are discussed.
Article
40 compounds structurally related to the plant flavonol quercetin were tested for mutagenic activity in Salmonella typhimurium strain TA98. 10 flavonols, quercetin, myricetin, rhamnetin, galangin, kaempferol, tamarixetin, morin, 3'-O-methylquercetin, 7,4'-di-O-methylquercetin and 5,7-di-O-methyl-quercetin, exhibited unequivocal mutagenic activity. 4 compounds, quercetin, myricetin, rhamnetin and 5,7-di-O-methylquercetin, were active without metabolic activation, although metabolic activation markedly enhanced their activity. All 4 have free hydroxyl groups at the 3' and 4' positions of the B ring. The other active compounds required an in vitro rat-liver metabolizing system for significant activity. Structural features which appear essential for mutagenic activity in this strain are a basic flavanoid ring structure with (1) a free hydroxyl group at the 3 position, (2) a double bond at the 2, 3 position, (3) a keto group at the 4 position, and (4) a structure which permits the proton of the 3-hydroxyl group to tautomerise to a 3-keto compound. The data are consistent with the requirement for a B ring structure that permits oxidation to quininoid intermediates. Free hydroxyl groups in the B ring are not essential for activity if a rat-liver metabolic activating system is employed. Data from 12 compounds which differ only at the essential sites described above indicate that the structural requirements for mutagenicity in strain TA100 are the same as those for activity in strain TA98. Based on the above structural requirements, a metabolic pathway for flavonol activation to DNA-reactive species is proposed.
Article
Over 70 naturally occurring and synthetic flavonoids were screened for mutagenicity with 5 tester strains in the Salmonella/mammalian microsome assay: TA1535, TA100, TA1537, TA1538 and TA98. Frameshift mutagenicity was confined to the flavonols (flavon-3-ols) in strain TA98, TA1537 and TA100. The two most mutagenic falvonols, namely, quercetin (3,3',4',5,7-pentahydroxyflavone) and kaempferol (3,4',5,7-tetrahydroxyflavone), exhibiting 12 and 7 revertants/nmol in TA98 respectively, are also the most common flavonols occurring in plants. Other flavonols exhibited less activity (revertants/nmol): galangin (2.0), rhamnetin (0.45), kaempferide (0.24), fisetin (0.14), myricetin (0.12), robinetin (0.06) and morin (0.05). All of these flavonols apparently exhibited significant activation by Aroclor 1254 induced rat-liver microsome preparations (S9). However, subsequent study revealed that only those flavonols either lacking or possessing one B ring hydroxyl group had an absolute requirement for microsomal activation. Alternatively, quercetin with two B-ring OH groups is not activated by microsomal enzymes, but by soluble (S100) enzymes from liver which are apparently constitutive and not subject to the usual chemical induction. 3 flavonol glycosides, namely, quercetrin (quercetin-3-O-rhamnoside), rutin (quercetin-3-O-rutinoside) and robinin (kaempferol-3-O-galactosido-rhamnoside-7-O-rhamnoside), were found to be nonmutagenic. They could, however, be activated by a variety of mixed glycosidases incorporated in the usual pour plate procedure. The most effective enzyme mixtures were obtained from rat cecal bacteria and from the snail Helix pomatia.
Article
Flavonoids are polyphenolic antioxidants naturally present in vegetables, fruits, and beverages such as tea and wine. In vitro, flavonoids inhibit oxidation of low-density lipoprotein and reduce thrombotic tendency, but their effects on atherosclerotic complications in human beings are unknown. We measured the content in various foods of the flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin. We then assessed the flavonoid intake of 805 men aged 65-84 years in 1985 by a cross-check dietary history; the men were then followed up for 5 years. Mean baseline flavonoid intake was 25.9 mg daily. The major sources of intake were tea (61%), onions (13%), and apples (10%). Between 1985 and 1990, 43 men died of coronary heart disease. Fatal or non-fatal myocardial infarction occurred in 38 of 693 men with no history of myocardial infarction at baseline. Flavonoid intake (analysed in tertiles) was significantly inversely associated with mortality from coronary heart disease (p for trend = 0.015) and showed an inverse relation with incidence of myocardial infarction, which was of borderline significance (p for trend = 0.08). The relative risk of coronary heart disease mortality in the highest versus the lowest tertile of flavonoid intake was 0.42 (95% CI 0.20-0.88). After adjustment for age, body-mass index, smoking, serum total and high-density-lipoprotein cholesterol, blood pressure, physical activity, coffee consumption, and intake of energy, vitamin C, vitamin E, beta-carotene, and dietary fibre, the risk was still significant (0.32 [0.15-0.71]). Intakes of tea, onions, and apples were also inversely related to coronary heart disease mortality, but these associations were weaker. Flavonoids in regularly consumed foods may reduce the risk of death from coronary heart disease in elderly men.
Article
Although there have been numerous topical applications of plant extracts having flavonoids known as anti-inflammatory compounds, only a few studies were reported concerning effects of flavonoids on epidermal cyclooxygenase/lipoxygenase. In this investigation, effects of naturally occurring flavonoids on epidermal cyclooxygenase/lipoxygenase were studied using five selected derivatives: flavanone, apigenin (flavone), quercetin (flavonol), amentoflavone and ginkgetin (biflavone) because eicosanoids generated in the epidermis are believed to be involved in various biological activities of the skin. Microsomal and cytosolic fractions were obtained from guinea-pig epidermal homogenate by centrifugation and used as a source for cyclooxygenase and lipoxygenase. It was found that quercetin inhibited both cyclooxygenase and lipoxygenase, being more potent against lipoxygenase, while flavanone and apigenin did not show any inhibition. Amentoflavone, one of the biflavones tested, showed potent and selective inhibitory activity on cyclooxygenase (IC50 = 3 microM) which was comparable to indomethacin (IC50 = 1 microM). In contrast, structurally similar ginkgetin possessed weak inhibitory activity on cyclooxygenase. The in vivo effects of these flavonoids on the normal and diseased skin remain to be studied.
Article
Resveratrol and quercetin are polyphenols which have been detected in significant amounts in green vegetables, citrus fruits and red grape wines. Beneficial effects attributed to these compounds include anti-inflammatory, antiviral and antitumor properties. The effect of resveratrol and quercetin on growth of human oral cancer cells is unknown. Resveratrol and quercetin, in concentrations of 1 to 100 microM, were incubated in triplicates with human oral squamous carcinoma cells SCC-25 in DMEM-HAM's F-12 supplemented with fetal calf serum and antibiotics in an atmosphere of 5% CO2 in air at 37 degrees C for 72 h. Cell growth was determined by counting the number of viable cells with a hemocytometer. Cell proliferation was measured by means of incorporation of [3H]thymidine in nuclear DNA. Resveratrol at 10 and 100 microM induced significant dose-dependent inhibition in cell growth as well as in DNA synthesis. Quercetin exhibited a biphasic effect, stimulation at 1 and 10 microM, and minimal inhibition at 100 microM in cell growth and DNA synthesis. Combining 50 microM of resveratrol with 10, 25 and 50 microM of quercetin resulted in a gradual and significant increase in the inhibitory effect of quercetin on cell growth and DNA synthesis. We conclude that resveratrol or a combination of resveratrol and quercetin, in concentrations equivalent to that present in red wines, are effective inhibitors of oral squamous carcinoma cell (SCC-25) growth and proliferation, and warrant further investigation as cancer chemopreventive agents.
Article
Twenty-seven Citrus flavonoids were examined for their antiproliferative activities against several tumor and normal human cell lines. As a result, 7 flavonoids were judged to be active against the tumor cell lines, while they had weak antiproliferative activity against the normal human cell lines. The rank order of potency was luteolin, natsudaidain, quercetin, tangeretin, eriodictyol, nobiletin, and 3,3',4',5,6,7,8-heptamethoxyflavone. The structure-activity relationship established from comparison among these flavones and flavanones showed that the ortho-catechol moiety in ring B and a C2-C3 double bond were important for the antiproliferative activity. As to polymethoxylated flavones, C-3 hydroxyl and C-8 methoxyl groups were essential for high activity.
Article
The flavonoids are plant polyphenols found frequently in fruits, vegetables, and grains. Divided into several subclasses, they include the anthocyanidins, pigments chiefly responsible for the red and blue colors in fruits, fruit juices, wines, and flowers; the catechins, concentrated in tea; the flavanones and flavanone glycosides, found in citrus and honey; and the flavones, flavonols, and flavonol glycosides, found in tea, fruits, vegetables, and honey. Known for their hydrogen-donating antioxidant activity as well as their ability to complex divalent transition metal cations, flavonoids are propitious to human health. Computer-controlled high-performance liquid chromatography (HPLC) has become the analytical method of choice. Many systems have been developed for the detection and quantification of flavonoids across one, two, or three subclasses. A summary of the various HPLC and sample preparation methods that have been employed to quantify individual flavonoids within a subclass or across several subclasses are tabulated in this review.
Article
In the present study, we investigated whether onion has antithrombotic effect in streptozotocin (STZ)-induced diabetic rats. In diabetic rats, serum thromboxane B(2) (TXB(2)) level was elevated compared to that in normal, and this elevation in diabetes was significantly inhibited by treatment with onion (0.5 g/ml/kg/day, i.p.) for 4 weeks. In normal rats, the serum TXB(2) level remained unaltered after the treatment with onion. To investigate in vitro effect of onion, we examined its effect on TXB(2) formation, platelet aggregation and arachidonic acid (AA)-release in platelets from diabetic and normal rats. Onion showed a significant inhibitory effect on collagen- or AA-induced TXB(2) formation with greater potency in diabetic platelets than in normal. Similarly, more potent inhibitory effects of onion in diabetes were observed in collagen- or AA-induced platelet aggregation and collagen-induced AA release response. In conclusion, these results suggest that onion can produce more beneficial antithrombotic effect in diabetes.
Article
Quercetin, a dietary-derived flavonoid, suppresses tumor growth in vitro and in vivo, and inhibits the activity of tyrosine kinase. The effects of quercetin on the angiogenic process were examined in this study. Quercetin was found to inhibit several important steps of angiogenesis including proliferation, migration, and tube formation of human microvascular dermal endothelial cells in a dose-dependent manner. Additionally, the effect of quercetin on endothelial cell proliferation was confirmed using human umbilical vein endothelial cells. The activity of quercetin on the proliferation of endothelial cells was stronger than that on A549, BEL-7402, MKN-45 tumor cells and NIH-3T3 fibroblast cells. The chicken chorioallantoic membrane assay revealed that addition of quercetin displayed an antiangiogenic effect in vivo. After exposure to quercetin, a decrease in the expression and activity of matrix metalloproteinase-2, which is involved in the angiogenic process of migration, invasion, and tube formation, was observed by reverse transcription-polymerase chain reaction (RT-PCR) and gelatin zymography. These findings suggest that quercetin has antiangiogenic potential and that this effect may be related to an influence on the expression and activity of matrix metalloproteinase-2.