No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Effect of the pretreatment with acerola (Malpighia emarginata DC.) juice on ethanol-induced oxidative stress in mice – Hepatoprotective potential of acerola juice
Abstract
Background and objectives
Acerola (Malpighia emarginata DC.) is a tropical fruit known for its nutritional and functional properties due to its great contents vitamin C, carotenoids and anthocyanins. The antioxidant potential from plants extracts associated to hepatoprotective activity has been widely studied. However, the effect of antioxidants in natural fruit juice has not been fully searched. The aim of this work was to investigate the antioxidant properties of acerola juice and its hepatoprotective potential against acute ethanol-induced stress.
Materials and methods
Ripe acerola were collected, processed into juice and initially analyzed to antioxidant properties in vitro. Afterwards, in vivo hepatoprotective activity was evaluated in mice. The animals received the juice by gavage as pretreatment for 15 consecutive days and then, were submitted to ethanol-induced stress in single dose (5 g/kg). The activities of serum enzymes as well as lipid peroxidation degree were evaluated. The activities of serum marker enzymes for liver damage as well as lipid peroxidation degree were evaluated.
Results
Acerola juice presents great vitamin C (1799.5 mg/100 g FW) and total phenolic (188.4 mg GAE/100 g FW), anthocyanins (9.2 mg/100 g FW), flavonols (7.8 mg/100 g FW) contents and high activity of superoxide dismutase (1053.6 UA/g DM) with a total antioxidant activity of 137.5 μmol Trolox/g FW. The juice treatment inhibited lipid peroxidation and reduced the activities of aminotransferases (p ≤0.05), in mice liver.
Conclusion
These results indicate that acerola juice is able to prevent the hepatic damage induced by ethanol, probably as a result of an enhancement of the antioxidant status in the animals.
... flowers (figure self-made). References for Activity: Antioxidative: [22][23][24][25]; Anti-inflamatory: [16], Antihyperglycemic: [16], antitumor: [26] Antigenotoxic: [27]; Hepatoprotective: [16,28,29], Antimutagenic: [16], Antimicrobial: [17,24], Antiobesity: [25]; Antifungal: [22,30], , Free radical scavenging: [30]. Woodson et al. (1980) and Brücher (1989) [20,21]. ...
... flowers (figure self-made). References for Activity: Antioxidative: [22][23][24][25]; Anti-inflamatory: [16], Antihyperglycemic: [16], antitumor: [26] Antigenotoxic: [27]; Hepatoprotective: [16,28,29], Antimutagenic: [16], Antimicrobial: [17,24], Antiobesity: [25]; Antifungal: [22,30], Free radical scavenging: [30]. ...
... No literature was found concerning the properties of the Malpighia spp flowers (figure self-made). References for Activity: Antioxidative: [22][23][24][25]; Anti-inflamatory:[16 Antihyperglycemic: [16], antitumor: [26] Antigenotoxic: [27]; Hepatoprotective: [16,28,29 Antimutagenic: [16], Antimicrobial: [17,24], Antiobesity: [25]; Antifungal: [22,30], , Free radica scavenging: [30]. ...
This study reviews the many uses for waste generated from acerola (Malpighia spp.) production, a tropical fruit renowned for its nutrient-rich content. Traditionally considered an environmental burden, this waste is now gaining attention for its sustainable applications in green technology. This review outlines the extraction of valuable bioactive compounds, like polyphenols, carotenoids, and pectin, that can be extracted from the acerola fruit and acerola waste, and it also delves into its potential in materials science, particularly in the creation of pharmaceutical formulations, nanomaterials, composites, biofuels, and energy applications. On the medical front, the paper highlights the promise that acerola waste holds in anti-inflammatory, antihyperglycemic, and anticancer therapies. By outlining challenges and opportunities, the review emphasizes the untapped potential of acerola waste as a resource for high-value products. These findings suggest a paradigm shift, turning what has been considered waste into a sustainable asset, thereby encouraging environmentally responsible practices within the fruit industry.
... Reactive nitrogen and oxygen species are produced during metabolic reactions and exert many important functions in cellular defense mechanisms; however, these components are overpowered in pathological situations, which can generate adverse effects [70]. As mentioned, antioxidants play a protective role by inhibiting free radical-induced reactions and reducing oxidative damage, preventing the peroxidative deterioration of the cell membrane lipids and DNA damage [71]. Nagamine et al. (2004) studied the hepatoprotective effect of dry extract powders of fruit purees and grind leaves of acerola [72]. ...
... The animals were pretreated with acerola juice for 15 consecutive days and then subjected to ethanol-induced stress, evaluating serum enzymes and the degree of lipid peroxidation. Compared to the ethanol-only treated group, the liver of acerola juicefed animals before acute ethanol administration showed a significant reduction of lipid peroxidation, similar to control levels, proving that acerola juice can prevent hepatic damage [71]. ...
Acerola (Malpighia spp.) is a tropical plant genus of shrubs and trees whose fruit is rich in nutrients and bioactive compounds. However, its production generates significant waste that could pose an environmental issue. This review aims to summarize recent research on the potential uses of acerola wastes, including the extraction of bioactive compounds such as polyphenols, carotenoids, and pectins, as well as the development of materials such as nanomaterials, chitosan, and biofuels. Additionally, the paper discusses the potential medical applications of acerola wastes, such as wound healing, antioxidant, and anticancer effects. Finally, the paper explores the challenges and opportunities of using acerola waste as a sustainable source of raw materials and energy. The findings suggest that acerola waste could be a valuable resource for developing high-value products and promoting sustainable production practices in the fruit industry.
... Reactive nitrogen and oxygen species are produced during metabolic reactions and exert many important functions in cellular defense mechanisms; however, these components are overpowered in pathological situations, which can generate adverse effects [70]. As mentioned, antioxidants play a protective role by inhibiting free radical-induced reactions and reducing oxidative damage, preventing the peroxidative deterioration of the cell membrane lipids and DNA damage [71]. Nagamine et al. (2004) studied the hepatoprotective effect of dry extract powders of fruit purees and grind leaves of acerola [72]. ...
... The animals were pretreated with acerola juice for 15 consecutive days and then subjected to ethanol-induced stress, evaluating serum enzymes and the degree of lipid peroxidation. Compared to the ethanol-only treated group, the liver of acerola juicefed animals before acute ethanol administration showed a significant reduction of lipid peroxidation, similar to control levels, proving that acerola juice can prevent hepatic damage [71]. ...
Acerola (Malpighia spp.) is a tropical plant genus of shrubs and trees whose fruit is rich in nutrients and bioactive compounds. However, its production generates significant waste that could pose an environmental issue. This review aims to summarize recent research on the potential uses of acerola wastes, including the extraction of bioactive compounds such as polyphenols, carotenoids, and pectins, as well as the development of materials such as nanomaterials, chitosan, and biofuels. Additionally, the paper discusses the potential medical applications of acerola wastes, such as wound healing, antioxidant, and anticancer effects. Finally, the paper explores the challenges and opportunities of using acerola waste as a sustainable source of raw materials and energy. The findings suggest that acerola waste could be a valuable resource for developing high-value products and promoting sustainable production practices in the fruit industry.
... Acerola (Malpighia emarginata DC.) is indigenous to the Caribbean and is renowned for its numerous health benefits, including its antihyperglycemic effect [1], hepatoprotective effect [2], skin lightening [3], and its potential in preventing hyperglycemia and dyslipidemia in diabetic individuals [4]. Acerola fruits are particularly notable for their exceptionally high vitamin C content, ranging from 1500 to 4500 mg per 100 g, which is approximately 50 to 100 times higher than that of oranges or lemons [5]. ...
Acerola (Malpighia emarginata DC.) is a sub-tropical and tropical fruit renowned for its high levels of vitamin C and phenolic compounds, which offer health benefits. This study aimed to optimize the spray drying process by determining the inlet and outlet temperatures using response surface methodology (RSM) with the central composite design. Additionally, it aimed to evaluate the release kinetics in the hydrophilic food simulation environment and the stability of the resulting powder under various storage temperatures. The RSM method determined the optimal inlet and outlet temperatures as 157 °C and 91 °C, respectively. High-accuracy prediction equations (R² ≥ 0.88) were developed for moisture content (3.02%), process yield (91.15%), and the encapsulation yield of total polyphenol content (61.44%), total flavonoid content (37.42%), and vitamin C (27.19%), with a predicted monolayer moisture content below 4.01%, according to the BET equation. The powder exhibited good dissolution characteristics in the acidic hydrophilic food simulation environment and showed greater stability when stored at 10 °C for 30 days, compared to storage at 35 °C and 45 °C.
... Various studies have found that acerola has a number of health benefits for the human body: hepatoprotective, anticarcinogenic activity, antihyperglycemic effect, antigenotoxicity activity, etc. [18][19][20][21]. The fortification of the product with acerola is usually done for the purpose of increasing the antioxidant activity and enriching the product with vitamin C. ...
In this study, a new product was evaluated: enriched dark chocolate with two encapsulated plant extracts: Salvia Lavandiulaefolia and Salvia officinalis with the addition of fruit extract Malpighia glabra (acerola). Physico-chemical characteristics, antioxidant, and sensory properties of chocolate with extracts (AC300, AC400, and AC500) were determined in relation to chocolate without additives (DC). The analysis showed that according to the hardness, enthalpy, and sensory analysis, AC 400 chocolate (sample with 36.34 g of dark chocolate, 0.256 g Acerola extract, and 0.4 g Cognivia™ extract) had the best characteristics, while the rheology and particle size distribution was almost identical in all three samples of functional chocolates. A small amount of extracts did not cause changes in the structure of chocolate, but it significantly improved the polyphenolic status of chocolate and antioxidant activity. The results of the antioxidant activity tests showed that the best sample was AC 500 (sample with 36.24 g of dark chocolate, 0.256 g Acerola extract, and 0.5 g Cognivia™ extract), in which the total polyphenol content was the highest, as well as a level of compounds that inhibit AChE activity.
... By-products from orange juice production have also been widely studied and applied as a DF source in various products, such as bakery products (Romero-Lopez, Osorio-Diaz, Bello-Perez, Tovar, & Bernardino-Nicanor, 2011), functional dairy products (Sendra et al., 2008), and meat products (Sayas-Barberá, Viuda-Martos, Fernández-López, Pérez-Alvarez, & Sendra, 2012). Acerola, as well as passion fruit and orange by-products, presents significant amounts of DF, especially pectin, polyphenols, anthocyanins, phenolic compounds, and α-glucosidase inhibitors (Assis, Lima, & Faria Oliveira, 2001;Paz et al., 2015;Rochette et al., 2013). Mango by-products have important bioactive compounds to improve health and reduce the risk of diseases, and studies have demonstrated their use as food ingredients in many products (Ajila et al., 2010;Jahurul et al., 2015). ...
The ability of different fruit by-products, okara, and amaranth flour, to support the growth of probiotic and non-probiotic strains was evaluated. The tests were conducted with three commercial starter cultures (Streptococcus thermophilus), ten probiotic strains (seven Lactobacillus spp. and three Bifidobacterium spp. strains), and two harmful bacteria representative of the intestinal microbiota (Escherichia coli and Clostridium perfringens). In vitro fermentability assays were performed using a modified MRS broth supplemented with different fruits (acerola, orange, passion fruit, and mango), and soy (okara) by-products or amaranth flour. Orange and passion-fruit by-products were the substrates that most promoted the growth of bacterial populations, including pathogenic strains. On the other hand, the acerola by-product was the substrate that showed the highest selectivity for beneficial bacteria, since the E. coli and Cl. perfringens populations were lower in the presence of this fruit by-product. Although the passion fruit by-product, okara, and amaranth stimulated the probiotic strains, the growth of the pathogenic strains studied was higher compared to other substrates. Different growth profiles were verified for each substrate when the different strains were compared. Although pure culture models do not reflect bacterial interaction in the host, this study reinforces the fact that the ability to metabolize different substrates is strain-dependent, and acerola, mango, and orange by-products are the substrates with the greatest potential to be used as prebiotic ingredients.
The consumption of fruit has increased in the last 20 years, along with the growing recognition of its nutritional and protective values. Many of the benefits of a diet rich in fruit are attributed to the presence of different bioactive substances, such as vitamins, carotenoids and phenolic compounds. Flavanoids, a class of phenolic compounds, present particular antioxidant activity and thus provide protection against cellular damage caused by reactive oxygen species. Research suggests that an increased intake of plant foods is associated with a reduced incidence of chronic disease. There is currently a great deal of interest in the study of antioxidants, in particular due to the discovery of the damaging effects of free radicals to the body. Thus, this review aims to address the beneficial effects of the antioxidants present in fruits, on the neutralization of reactive species and the reduction of any damage they may cause.
A standard method is proposed for the quantitative determination and reporting of cranberry pigments.
The tropical fruit juices are gaining ever greater space in the consumer market, and Brazil is one of the main producer countries in this market. There is a great diversity of products derived from fruits and new products for consumption are launched constantly, often without the necessary research into their active properties and beneficial activities to health. The objective of this work was to determine some properties of in natura wild tropical fruit and commercialized frozen fruit pulps. Considered as a method of great applicability, 2.2-difenyL-1-picrylhydrazyl radical (DPPH·) was used to determine the antioxidant activity; the Folin-Ciocalteu method was used to determine the total polyphenol concentration and the pH difference was used for anthocyanins. The fruit pulps of greater market consumption in Southern Brazil under analysis were mulberry, grapes, açai, guava, strawberry, acerola, pineapple, mango, graviola, cupuaçu and passion fruit, and the wild fruits were jambolão and baguaçu. When represented in TEAC (Trolox equivalent antioxidant activity), the global antioxidant activity of the frozen fruit pulps oscillated between minimal and maximal TEAC values of 0.5 and 53.2mmol g-1, or between 64.8 and 1198.9mg100 g-1 for VCEAC (vitamin C equivalent antioxidant activity) values. For the in natura fruit pulp extracts, TEAC oscillated between 13.3 and 111.2mmol g-1, and between 42.8 and 2533.1mg100g-1 for VCEAC. The descending order of antioxidant capacity was acerola> mango> strawberry> grapes> açaí> guava> mulberry> graviola> passion fruit> cupuaçu> pineapple. Among the wild fruits, baguaçu presents a greater antioxidant activity than jambolão.
Various hepatoprotective herbal products from plants are available in Mexico, where up to 85% of patients with liver disease use some form of complementary and alternative medicine. However, only few studies have reported on the biological evaluation of these products.
Using a model of carbon tetrachloride (CCl4)-induced hepatotoxicity in rats, we evaluated the effects of commercial herbal extracts used most commonly in the metropolitan area of Monterrey, Mexico.
The commercial products were identified through surveys in public areas. The effect of these products given with or without CCl4 in rats was evaluated by measuring the serum concentrations of aspartate amino transferase (AST) and alanine amino transferase (ALT), and histopathological analysis. Legalon(®) was used as the standard drug.
The most commonly used herbal products were Hepatisan(®) capsules, Boldo capsules, Hepavida(®) capsules, Boldo infusion, and milk thistle herbal supplement (80% silymarin). None of the products tested was hepatotoxic according to transaminase and histological analyses. AST and ALT activities were significantly lower in the Hepavida+CCl4-treated group as compared with the CCl4-only group. AST and ALT activities in the silymarin, Hepatisan, and Boldo tea groups were similar to those in the CCl4 group. The CCl4 group displayed submassive confluent necrosis and mixed inflammatory infiltration. Both the Hepatisan+CCl4 and Boldo tea+CCl4 groups exhibited ballooning degeneration, inflammatory infiltration, and lytic necrosis. The silymarin+CCl4 group exhibited microvesicular steatosis. The Hepavida+CCl4- and Legalon+CCL4-treated groups had lower percentages of necrotic cells as compared with the CCl4-treated group; this treatment was hepatoprotective against necrosis.
Only Hepavida had a hepatoprotective effect.
Chemical composition and antioxidant activity of juice from immature and mature acerola and of concentrated juice from immature acerola were determined. Tartaric, malic and citric acids and a high content of ascorbic acid were found in all the juices. Vitamin C contents were 4.80, 1.90 and 0.97 g/100 g for the concentrated immature, the immature, and the mature acerola juices respectively. The total phenol contents decreased during ripening, from 3.8 mg of catechin/g for immature acerola juice to 1.4 mg of catechin/g for mature acerola juice. The concentrated immature juice had a content of 9.2mg of catechin/g of juice. Catechin, gallic acid, coumaric acid, syringic acid, caffeic acid and ferrulic acid were detected in immature acerola juice by HPLC analysis whereas mature acerola juice showed only one predominant peak with a retention time similar to that of ferrulic acid. The concentrated juice from immature acerola reduced the oxidation of methyl linoleate by 57.2% while the juice from immature acerola reduced the oxidation by 28.1%. These results stated that the antioxidant potential of the acerola juice depended on its content of phenolic compounds and the vitamin C.
The first suggestion that physical exercise results in free radical-mediated damage to tissues appeared in 1978, and the past three decades have resulted in a large growth of knowledge regarding exercise and oxidative stress. Although the sources of oxidant production during exercise continue to be debated, it is now well established that both resting and contracting skeletal muscles produce reactive oxygen species and reactive nitrogen species. Importantly, intense and prolonged exercise can result in oxidative damage to both proteins and lipids in the contracting myocytes. Furthermore, oxidants can modulate a number of cell signaling pathways and regulate the expression of multiple genes in eukaryotic cells. This oxidant-mediated change in gene expression involves changes at transcriptional, mRNA stability, and signal transduction levels. Furthermore, numerous products associated with oxidant-modulated genes have been identified and include antioxidant enzymes, stress proteins, DNA repair proteins, and mitochondrial electron transport proteins. Interestingly, low and physiological levels of reactive oxygen species are required for normal force production in skeletal muscle, but high levels of reactive oxygen species promote contractile dysfunction resulting in muscle weakness and fatigue. Ongoing research continues to probe the mechanisms by which oxidants influence skeletal muscle contractile properties and to explore interventions capable of protecting muscle from oxidant-mediated dysfunction.
Problem statement: Flavonoids and related polyphenols, have been known to possess cardioprotective, anti-tumor, anti-inflammatory, an ti-allergic and anti-viral activities. Previous stu dies have shown that flavonoid, quercetin significantly downregulates expression of pro-inflammatory cytokines in cultured cells via modulation of NF κB and p38MAPK signaling pathways. In the current study, we hypothesize that quercetin exerts anti-HI V activity by differential modulation of pro-and anti-inflammatory cytokine expression in normal PBMCs. Approach: Cultures of PBMC received either different concentrations of quercetin (1-50 µM) or media alone. The anti-HIV effects of quercetin was evaluated in an in vitro infection model by quantitaing the HIV-1 LTR gene suppression by quantitative Real Time PCR, HIV-1 p24 antigen production by ELISA and viral infectivity by MAGI cell assay. Results: Our results showed that quercetin significantly do wnregulates p24 antigen production, LTR gene expression and viral infectivi ty in a dose dependent manner (5-50 μM) as compared to HIV infected untreated control PBMCs. Further, we reported that quercetin significantly downregulated the expression of the pro-inflammator y cytokine, TNF-α with concomitant upregulation of anti-inflammatory cytokine IL-13 as determined b y measurement of gene expression and protein production. A higher level of IL-13 is known to inh ibit TNF-α production and also HIV-1 infection. Thus, differential modulation of pro-and anti-infla mmatory cytokines could be one of the possible mechanisms for the anti-HIV effects of quercetin. Conclusion: Better understanding of the mechanisms underlying the anti-HIV effects of quercetin may help to develop a new neutraceutical agent useful in the treatment of HIV-1 infected sub jects in conjunction with conventional therapeutic regimens.
Fresh ripen fruit of 45 different clones of West Indian Cherry were cropped from a commercial orchard located at Limoeiro do Norte Country, Ceara State. They were analyzed for weight and firmness at the Laboratory of Physiology and Post Harvest Technology of Embrapa, in Fortaleza, Ceara, Brazil. After frozen, they were processed and analyzed for total soluble solids (TS), pH, total titrable acidity (TA), TS/TA ratio, vitamin C, anthocyanin and (a) over cap -carotene. The results showed that some clones have potential to be used in the industry of vitamin C once its high content in ripen fruits suggests that this vitamin content is still higher in green fruits. The Monami clone, for instance, presented the lowest TS, pH and TS/TA ratio, although its vitamin C content was above the general average of the clones.
A method for the screening of antioxidant activity is reported as a decolorization assay applicable to both lipophilic and hydrophilic antioxidants, including flavonoids, hydroxycinnamates, carotenoids, and plasma antioxidants. The pre-formed radical monocation of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS*+) is generated by oxidation of ABTS with potassium persulfate and is reduced in the presence of such hydrogen-donating antioxidants. The influences of both the concentration of antioxidant and duration of reaction on the inhibition of the radical cation absorption are taken into account when determining the antioxidant activity. This assay clearly improves the original TEAC assay (the ferryl myoglobin/ABTS assay) for the determination of antioxidant activity in a number of ways. First, the chemistry involves the direct generation of the ABTS radical monocation with no involvement of an intermediary radical. Second, it is a decolorization assay; thus the radical cation is pre-formed prior to addition of antioxidant test systems, rather than the generation of the radical taking place continually in the presence of the antioxidant. Hence the results obtained with the improved system may not always be directly comparable with those obtained using the original TEAC assay. Third, it is applicable to both aqueous and lipophilic systems.
The study of free radical reactions is not an isolated and esoteric branch of science. A knowledge of free radical chemistry and biochemistry is relevant to an understanding of all diseases and the mode of action of all toxins, if only because diseased or damaged tissues undergo radical reactions more readily than do normal tissues. However it does not follow that because radical reactions can be demonstrated, they are important in any particular instance. We hope that the careful techniques needed to assess the biological role of free radicals will become more widely used.
A method for the screening of antioxidant activity is reported as a decolorization assay applicable to both lipophilic and hydrophilic antioxidants, including flavonoids, hydroxycinnamates, carotenoids, and plasma antioxidants. The pre-formed radical monocation of 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) is generated by oxidation of ABTS with potassium persulfate and is reduced in the presence of such hydrogen-donating antioxidants. The influences of both the concentration of antioxidant and duration of reaction on the inhibition of the radical cation absorption are taken into account when determining the antioxidant activity. This assay clearly improves the original TEAC assay (the ferryl myoglobin/ABTS assay) for the determination of antioxidant activity in a number of ways. First, the chemistry involves the direct generation of the ABTS radical monocation with no involvement of an intermediary radical. Second, it is a decolorization assay; thus the radical cation is pre-formed prior to addition of antioxidant test systems, rather than the generation of the radical taking place continually in the presence of the antioxidant. Hence the results obtained with the improved system may not always be directly comparable with those obtained using the original TEAC assay. Third, it is applicable to both aqueous and lipophilic systems.
Punarnavashtak kwath (PN) a classical Ayurvedic formulation reported in “Bhaishyajyaratnavali” consisting of eight medicinal plants was evaluated for its in vitro and in vivo antioxidant activity and hepatoprotective effect. In vitro antioxidant activity of PN kwath was investigated by DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity, superoxide anion and nitric oxide radical scavenging activity and reducing power assay. In vitro antioxidant activity was found to be dose dependent. Hepatoprotective and in vivo antioxidant effect was evaluated by ethanol (3.7 g/kg, p.o for 45 days in all group except control) induced hepatic damage in rats. Pretreatment with PN kwath 100 mg/kg p.o for 45 days) significantly prevented physical (increased liver wt), biochemical (serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), bilirubin and total protein level), histological (damage to hepatocytes) and functional changes (thiopentone induced sleeping time) induced by ethanol in liver. Further PN kwath showed antioxidant activity by increasing activity of GSH, SOD and CAT and by decreasing the level of thiobarbituric acid reactive substance (TBARS). The results were compared to that of reference standard silymarin (50 mg/kg p.o for 45 days). The findings suggest that PN kwath protects the liver cell from ethanol induced liver damages due to its antioxidative effect on hepatocytes.
Acerola (Malpighia emarginata DC.) is a wild plant from Central America. This fruit is well known as an excellent food source of vitamin C, and it also contains phytochemicals such as carotenoids and polyphenols. The present work evaluates the antioxidant capacity of hydrophilic extracts of acerola pulps and juices by 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ORAC and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods. Antioxidant activity values obtained for acerola juice were higher than those reported for other fruit juices particularly rich in polyphenols such as strawberry, grape and apple juices, among others. Vitamin C, total phenol index (TPI), total anthocyanins and polyphenolic compounds by high performance liquid chromatography (HPLC), as main factors responsible for antioxidant activity, were determined. Contents in total ascorbic acid ranged from 6.32 to 9.20gkg−1 of pulp and 9.44 to 17.97gL−1 of juice. Five different polyphenolic compounds were identified in the samples by means of HPLC and diode-array detection: chlorogenic acid, (−)-epigallocatechin gallate, (−)-epicatechin, procyanidin B1 and rutin, being the two last predominant. By means of solid phase extraction (SPE) three soluble polyphenolic fractions (phenolic acids, anthocyanins and flavonoids) were separated from the different sample extracts, and their respective antioxidant activities calculated. Among them, phenolic acids are the main contributors to the antioxidant activity.
The flavanol composition and caffeine content of green tea leaf, black tea quality parameters of theaflavins, thearubigins, liquor brightness and total colour varied more among clones than with time of the year. In green leaf, either (-)epicatechin gallate or (-)epigallocatechin gallate was the dominant flavanol present. Regression analysis of tasters' preferences for black teas against green leaf chemical components showed positive and significant correlations for (-)epicatechin gallate (r = 0·498, P ⩽ 0·05 for taster A; r = 0·665, P ⩽ 0·01 for taster B, and r = 0·678, P ⩽ 0·01 for both tasters' overall ranking), (-)epigallocatechin gallate (r = 0·513, P ⩽ 0·05 for taster B; r = 0·532, P ⩽ 0·05 for both tasters' overall ranking and caffeine (r = 0·523, P ⩽ 0·05 for taster A; r = 0·657, P ⩽ 0·01 for taster B; and r = 0·686, P ⩽ 0·01 for both tasters' overall ranking). Similar regressions against black tea theaflavins, thearubigin content, liquor brightness and total colour were not significant. The results suggest that the green leaf chemical components, (-)epicatechin gallate, (-)epigallocatechin gallate and caffeine could be used as quality potential indicators during clonal selection and propagation. © 1997 SCI.
Fresh or processed berries are considered to be beneficial for health by many consumers. Fruits of closely related species of plants sometimes possess strikingly different phytochemistry and biological activities. Therefore, even though similar research has been conducted on a number of Rubus berries, there is much relevance associated with the investigation of species that have not been previously studied. In the current report, the fruits of three wild Jamaica-grown species: Rubus jamaicensis, Rubus rosifolius and Rubus racemosus, and of the Michigan-grown Rubus acuminatus, Rubus idaeus cv. Heritage and Rubus idaeus cv. Golden were analyzed for their anthocyanin contents, and lipid peroxidation, cyclooxygenase enzyme and human tumor cell proliferation inhibitory activities. It was revealed that the fruits contained superior levels of anthocyanins (146–2199 mg/100 g fresh weight) to those previously reported for other raspberry and blackberry species, and their hexane, EtOAc and MeOH extracts showed good antioxidant activity, the majority of the extracts exhibiting over 50% lipid peroxidation inhibitory activity at 50 μg/mL. The hexane extracts of the Jamaican Rubus spp. demonstrated moderate COX inhibitory activity (27.5–33.1%) at 100 μg/mL, and exhibited the greatest potential to inhibit cancer cell growth, inhibiting colon, breast, lung, and gastric human tumor cells by 50, 24, 54 and 37%, respectively. The high anthocyanin content and biological activities of these fruits indicate that their consumption would be beneficial to health, and that they may be useful in the production of functional foods containing an efficacious dose of anthocyanins.
Twenty-eight different fruits were analysed for antioxidant activities using two different methods, one that determines the inhibition of ascorbate/iron-induced peroxidation of phosphatidylcholine, by means of thiobarbituric acid-reactive substances (TBARS) measurement, and another that evaluates the scavenging of the radical cation of 2,2′-azinobis (3-ethyl-benzothiazoline-6-sulphonate) (ABTS) relative to Trolox C, a water-soluble vitamin E analogue. The values of the antioxidant capacities of the analysed fruits were in a wide range from 50 g to more than 5 mg for the IW50 (dry weight causing 50% inhibition of lipidic peroxidation) and from it 406 μmol/g for the TEAC (μmol Trolox equivalents g−1). There was no significant correlation between antioxidant activity (IW50 and TEAC) and the contents of flavanol of the samples. The antioxidant activities of the analysed fruits cannot only be attributed to their flavanol contents, but to the result of the action of different antioxidant compounds present in the fruits and to possible synergic and antagonist effects still unknown.
The bioactive compounds and antioxidant capacities of polyphenolic extracts of 18 fresh and dry native non-traditional fruits from Brazil were determined using ABTS, DDPH, FRAP and β-carotene bleaching methods. The study provides an adaptation of these methods, along with an evaluation of the compounds related to antioxidant potential. The results show promising perspectives for the exploitation of non-traditional tropical fruit species with considerable levels of nutrients and antioxidant capacity. Although evaluation methods and results reported have not yet been sufficiently standardised, making comparisons difficult, our data add valuable information to current knowledge of the nutritional properties of tropical fruits, such as the considerable antioxidant capacity found for acerola – Malpighia emarginata and camu-camu – Myrciaria dubia (ABTS, DPPH and FRAP) and for puçá-preto – Mouriri pusa (all methods).
Acerola fruits (Malpighia emarginata D.C.) were harvested from 12 different genotypes cultivated at the Active Germplasm Bank in Federal Rural University of Pernambuco, in the northeast region of Brazil. The effects of maturity stages and weather conditions on total phenolics and carotenoids content were analysed. Mature fruits harvested in the dry season showed the highest and the lowest levels of total phenolics and carotenoids, respectively. During the maturation process, phenolics degradation and carotenoids biosyntheses were observed. Among the acerola genotypes, fruits from genotype number 05 stood out, presenting the highest phenolic and carotenoid contents.
The anthocyanins from acerola and açai, two tropical fruits known for their bioactive compounds, were studied. Two varieties of acerola in natura and one brand of frozen pulp of açai were analyzed by high-performance liquid chromatography connected to photodiode array and mass spectrometry detectors (HPLC–PDA–MS/MS). The açai pulp presented 282–303 mg/100 g of total anthocyanin, with predominance of cyanidin 3-glucoside and cyanidin 3-rutinoside, in average proportions of 13% and 87%, respectively. The composition of the two acerola varieties (Waldy Cati 30 and Olivier) were similar, being cyanidin 3-rhamnoside (76–78%) the major anthocyanin, followed by pelargonidin 3-rhamnoside (12–15%). The acerola Waldy variety showed total anthocyanin content of 6.5–7.6 mg/100 g, while 7.9–8.4 mg/100 g were found in the Olivier variety, for fruits harvested in 2003 and 2004. No statistical differences were found between varieties and harvests for the total anthocyanin content in acerola fruits.
Nine tropical fruits were analyzed for total phenol contents, ascorbic acid contents and antioxidant activities. The antioxidant activities were evaluated based on the ability of the fruit extracts to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH), reduce iron(III) to iron(II) and to bind to iron(II) ions. The results were compared to those of orange. It was found that guava, papaya and star fruit have higher primary antioxidant potential, as measured by scavenging DPPH and iron(III) reducing assays. Banana, star fruit, water apple, langsat and papaya have higher secondary antioxidant potential as measured by the iron(II) chelating experiment.
It has been suggested that some food components, such as bioflavonoids, affect the bioavailability of ascorbic acid in humans. Since little is known in Japan about the effective intake of this dietary requirement, we tested young Japanese males after the ingestion of commercial ascorbic acid or acerola (Malpighia emarginata DC.) juice to compare the quantities absorbed and excreted. Healthy Japanese subjects received a single oral dose of ascorbic acid solution (50, 100, 200 or 500 mg) and received distilled water as a reference at intervals of 14 d or longer. All subjects were collected blood and urine until 6 h after ingestion and evaluated for time-dependent changes in plasma and urinary ascorbic acid levels. Predictably, the area under the curve (AUC) values in plasma and urine after ingestion increased dose-dependently. Next, each subject received diluted acerola juice containing 50 mg ascorbic acid. Likewise, their plasma and urinary ascorbic acid concentrations were measured. In plasma, the AUC value of ascorbic acid after ingestion of acerola juice tended to be higher than that from ascorbic acid alone. In contrast, the urinary excretion of ascorbic acid at 1, 2 and 5 h after ingestion of acerola juice were significantly less than that of ascorbic acid. These results indicate that some component of acerola juice favorably affected the absorption and excretion of ascorbic acid.
We attempted to isolate the constituent(s) responsible for the suppressive effect of the juice of shekwasha, a citrus produced in Okinawa Prefecture, on D-galactosamine (GalN)-induced liver injury in rats. Liver injury-suppressive activity, as assessed by plasma alanine aminotransferase and aspartate aminotransferase activities, was found only in the fraction that was extracted with n-hexane when three fractions were added to the diet and fed to rats. Of five compounds isolated from the n-hexane-soluble fraction by silica gel column chromatography, three compounds had liver injury-suppressive effects when five compounds were singly force-fed to rats at a level of 300 mg/kg body wt 4 h before the injection with GalN. The structures of the three active compounds were determined as 3',4',5,6,7,8-hexamethoxyflavanone (citromitin), 4',5,6,7,8-pentamethoxyflavone (tangeretin) and 3',4',5,6,7,8-hexamethoxyflavone (nobiletin), which are known flavonoids mainly existing in citrus. Nobiletin, the most important compound in the n-hexane-soluble fraction, also had suppressive effects on liver injuries induced by carbon tetrachloride, acetaminophen and GalN/lipopolysaccharide (LPS) in addition to liver injury induced GalN. Nobiletin suppressed GalN/LPS-induced increases in plasma tumor necrosis factor (TNF)-alpha and nitric oxide (NO) concentrations and hepatic mRNA levels for inducible NO synthase and DNA fragmentation. These results suggest that nobiletin suppressed GalN/LPS-induced liver injury at least by suppressing the production of both TNF-alpha and NO. The results obtained here indicate that the hepatoprotective effect of shekwasha juice is mainly ascribed to several polymethoxy flavonoids included in the juice.
Intact spinach chloroplasts scavenge hydrogen peroxide with a peroxidase that uses a photoreductant as the electron donor, but the activity of ruptured chloroplasts is very low [Nakano and Asada (1980) Plant & Cell Physiol . 21 : 1295]. Ruptured spinach chloroplasts recovered their ability to photoreduce hydrogen peroxide with the concomitant evolution of oxygen after the addition of glutathione and dehydroascorbate (DHA). In ruptured chloroplasts, DHA was photoreduced to ascorbate and oxygen was evolved in the process in the presence of glutathione. DHA reductase (EC 1.8.5.1) and a peroxidase whose electron donor is specific to L-ascorbate are localized in chloroplast stroma. These observations confirm that the electron donor for the scavenging of hydrogen peroxide in chloroplasts is L-ascorbate and that the L-ascorbate is regenerated from DHA by the system: photosystem I→ferredoxin→NADP→glutathione. A preliminary characterization of the chloroplast peroxidase is given.
Problem statement: Flavonoids and related polyphenols, have been known to possess cardioprotective, anti-tumor, anti-inflammatory, anti-allergic and anti-viral activities. Previous studieshave shown that flavonoid, quercetin significantly downregulates expression of pro-inflammatory cytokines in cultured cells via modulation of NFkB and p38MAPK signaling pathways. In the currentstudy, we hypothesize that quercetin exerts anti-HIV activity by differential modulation of pro-and anti-inflammatory cytokine expression in normal PBMCs. Approach: Cultures of PBMC receivedeither different concentrations of quercetin (1-50 μM) or media alone. The anti-HIV effects of quercetin was evaluated in an in vitro infection model by quantitaing the HIV-1 LTR gene suppressionby quantitative Real Time PCR, HIV-1 p24 antigen production by ELISA and viral infectivity by MAGI cell assay. Results: Our results show that quercetin significantly downregulates p24 antigenproduction, LTR gene expression and viral infectivity in a dose dependent manner (5-50 mM) as compared to HIV infected untreated control PBMCs. Further, we report that quercetin significantlydownregulated the expression of the pro-inflammatory cytokine, TNF-α with concomitant upregulation of anti-inflammatory cytokine IL-13 as determined by measurement of gene expression and proteinproduction. A higher level of IL-13 is known to inhibit TNF-a production and also HIV-1 infection. Thus, differential modulation of pro-and anti-inflammatory cytokines could be one of the possiblemechanisms for the anti-HIV effects of quercetin. Conclusion: Better understanding of the mechanisms underlying the anti-HIV effects of quercetin may help to develop a new neutraceutical agent useful in the treatment of HIV-1 infected subjects in conjunction with conventional therapeutic regimens.
The pathogenesis and progression of alcoholic liver disease (ALD) are associated with free radical injury and oxidative stress, which could be partially attenuated by antioxidants and free radical scavengers. Quercetin, one of the most widely distributed flavonoids in plants, is a natural antioxidant. The hypothesis that quercetin could prevent the ethanol-induced oxidative damage in hepatocytes was investigated. The ethanol-intoxicated (100mM for 8h) rat primary hepatocytes were post-treated (2h), simultaneously treated or pre-treated (2h) with quercetin respectively, while the time-dependent (0.5-8h) and dose-dependent (25-200muM) quercetin pre-treatment were used in the present study. The parameters of lactate dehydrogenase (LDH), aspartate transaminase (AST), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were determined to address the alterations of cell damage and antioxidant state after quercetin intervention. The toxic insult of ethanol to hepatocytes was challenged by quercetin and these parameters almost returned to the level of control group when hepatocytes were pre-treated with quercetin at the dose of 50muM for 2-4h before ethanol exposure. In conclusion, quercetin pre-treatment provided protection against ethanol-induced oxidative stress in hepatocytes and may be used as a new natural drug for the prevention and/or treatment of ALD.
To investigate the physiological functions of polyphenols from acerola (Malpighia emarginata DC.) fruit, the effects on melanogenesis were studied. The crude polyphenol concentrated extract from acerola (C-AP) was used to examine the skin-lightening effect on brownish guinea pigs which had been subjected to controlled UVB irradiation. The results show that C-AP significantly lightened the UVB-irradiated skin pigmentation. Furthermore, treatment with C-AP reduced the content of melanin in B16 melanoma cells, suggesting that the in vivo skin-lightening effect of C-AP was due to the suppression of melanin biosynthesis in melanocytes. In addition, we found that C-AP could effectively inhibit mushroom tyrosinase activity, the main constituents responsible for this effect being thought to be such anthocyanins as cyanidin-3-alpha-O-rhamnoside (C3R) and pelargonidin-3-alpha-O-rhamnoside (P3R). This result indicates that the skin-lightening effect of C-AP can be partly attributed to the suppression of melanogenesis through the inhibition of tyrosinase activity in melanocytes. An oral ingestion of C-AP may therefore be efficacious for reducing UVB-induced hyper-pigmentation by inhibiting the tyrosinase in melanocytes.
The antioxidant activity, ascorbic acid and phenolic content were studied in 10 exotic fruits from Brazil: abiu, acerola, wax jambu, cashew, mamey sapote, carambola or star fruit, Surinam cherry, longan, sapodilla and jaboticaba. The ascorbic acid was determined by 2,6-dichloroindophenol titrimetic methods and total phenols were measured colorimetrically using the Folin-Ciocalteu reagent. The antioxidant activity was investigated with three different methods: hypochlorous acid scavenging activity, 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization assay, and 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. The highest content of vitamin C (1,525.00 mg/100 g pulp) occurred in acerola. The total phenol content was higher in abiu, acerola, Surinam cherry and sapodilla. In relation to antioxidant activity, acerola has showed the great values in all three different methods tested. It was found that the fruits have a significant antioxidant effect when tested by each method, respectively, and these antioxidant capacities are promising. The sample concentration also influenced its antioxidant power.
The hepatoprotective and antioxidant activity of 50% ethanolic extract of whole plant of Amaranthus spinosus (ASE) was evaluated against carbon tetrachloride (CCl4) induced hepatic damage in rats. The ASE at dose of 100, 200 and 400 mg/kg were administered orally once daily for fourteen days. The substantially elevated serum enzymatic levels of serum glutamate oxaloacetate transaminase (AST), serum glutamate pyruvate transaminase (ALT), serum alkaline phosphatase (SALP) and total bilirubin were restored towards normalization significantly by the ASE in a dose dependent manner. Higher dose exhibited significant hepatoprotective activity against carbon tetrachloride induced hepatotoxicity in rats. The biochemical observations were supplemented with histopathological examination of rat liver sections. Meanwhile, in vivo antioxidant activities as malondialdehyde (MDA), hydroperoxides, reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were also screened which were also found significantly positive in a dose dependent manner. The results of this study strongly indicate that whole plants of A. spinosus have potent hepatoprotective activity against carbon tetrachloride induced hepatic damage in experimental animals. This study suggests that possible mechanism of this activity may be due to the presence of flavonoids and phenolics compound in the ASE which may be responsible to hepatoprotective activity.
The reaction of lipid peroxides in animal tissues with thiobarbituric acid was dependent on pH of the reaction mixture as was the case for linoleic acid hydroperoxide. The optimum pH was found to be 3.5. Taking this fact into consideration, a standard procedure for the assay of lipid peroxide level in animal tissues by their reaction with thiobarbituric acid was developed as follows. Ten percent ( tissue homogenate was mixed with sodium dodecyl sulfate, acetate buffer (pH 3.5), and aqueous solution of thiobarbituric acid. After heating at 95°C for 60 min, the red pigment produced was extracted with n-butanol-pyridine mixture and estimated by the absorbance at 532nm. As an external standard, tetramethoxy-propane was used, and lipid peroxide level was expressed in terms of nmol malondialdehyde. Using this method, the liped peroxide level in the liver of rats suffering from carbon tetrachloride intoxication was investigated. The results were in good agreement with previously reported data obtained by measuring diene content.
The study of free radical reactions is not an isolated and esoteric branch of science. A knowledge of free radical chemistry and biochemistry is relevant to an understanding of all diseases and the mode of action of all toxins, if only because diseased or damaged tissues undergo radical reactions more readily than do normal tissues. However it does not follow that because radical reactions can be demonstrated, they are important in any particular instance. We hope that the careful techniques needed to assess the biological role of free radicals will become more widely used.
A method for the screening of antioxidant activity is reported as a decolorization assay applicable to both lipophilic and hydrophilic antioxidants, including flavonoids, hydroxycinnamates, carotenoids, and plasma antioxidants. The pre-formed radical monocation of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS*+) is generated by oxidation of ABTS with potassium persulfate and is reduced in the presence of such hydrogen-donating antioxidants. The influences of both the concentration of antioxidant and duration of reaction on the inhibition of the radical cation absorption are taken into account when determining the antioxidant activity. This assay clearly improves the original TEAC assay (the ferryl myoglobin/ABTS assay) for the determination of antioxidant activity in a number of ways. First, the chemistry involves the direct generation of the ABTS radical monocation with no involvement of an intermediary radical. Second, it is a decolorization assay; thus the radical cation is pre-formed prior to addition of antioxidant test systems, rather than the generation of the radical taking place continually in the presence of the antioxidant. Hence the results obtained with the improved system may not always be directly comparable with those obtained using the original TEAC assay. Third, it is applicable to both aqueous and lipophilic systems.
The present study was undertaken to estimate the effect of acerola cherry extract (ACE) pretreatment on cell proliferation and the activation of Ras signal pathway at a promotion stage of lung tumorigenesis in mice treated with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Pretreatment with ACE (dose, 70mg/kg body weight and 700 mg/kg body weight) inhibited increases in the levels of proliferating nuclear cell antigen and ornithine decarboxylase at the promotion stage. This treatment of ACE also suppressed the activation of Ras signal pathway at the same stage. These results suggest that ACE regulates abnormal cell growth at the promotion stage of lung tumorigenesis in mice treated with NNK as a result of suppression of the initiation stage.
The extract of Barbados cherry (acerola fruit), a fruit of Malpighia emarginata DC., has been reported to display diverse biological activities such as prevention of age-related diseases. We investigated here the possible effect of Barbados cherry extract on nitric oxide (NO) production by activated macrophages. Barbados cherry was roughly separated into 4 or 5 fractions by two different methods, using various organic solvents such as hexane, acetone, methanol (70% and 100%) and water, and assayed for its ability to inhibit NO production by lipopolysaccharide (LPS)-stimulated mouse macrophage-like Raw 264.7 cells. Among these fractions, AcOEt extracts (AE0) in Method I and acetone extract (A0) in Method II showed the highest inhibitory activity of NO production (SI > 20 and SI = 31, respectively). When these fractions were subjected to silica gel column chromatography, higher inhibitory activity for NO production was concentrated in AcOEt (AE6) (SI = 64) and benzene-AcOEt (1:4) (A10) fractions (SI > 59). Western blot analysis demonstrated that AE6 and A10 fractions reduced the intracellular concentration of inducible NO synthase (iNOS) by approximately one-third. ESR spectroscopy showed that these fractions scavenged various radical species such as superoxide anion (O2-) and NO radicals. These data suggest that the inhibitory effect on NO production by Barbados cherry extracts is partly due to the inhibition of iNOS expression, and scavenging of O2- and NO radicals.
Free radical generation is an important step in the pathogenesis of ethanol-associated liver injury. Administration of ethanol induces an increase in lipid peroxidation both by enhancing the production of oxygen reactive species and by decreasing the levels of endogenous antioxidants. This work focuses on the generation of free radicals provoked by an acute ethanol dose in rats, and the role of different dietary levels of vitamin E. The objective of this investigation was to study the effect of three different dietary levels of vitamin E (deficient, control and supplemented with 20 times higher levels) on plasma and liver lipid peroxidation (assayed by TBARS), vitamin E in plasma and liver, and hepatic glutathione concentration, in rats receiving the different diets. The animals were submitted to an acute dose of ethanol (5 g/kg body weight) administered by gavage at the end of an experimental 4 week period and were sacrificed at 0, 2, 4, 8 and 24 h after ethanol administration. Dietary vitamin E caused a dose-dependent increase in liver and plasma concentration of the vitamin, but ethanol administration decreased hepatic vitamin E in all groups. TBARS concentrations were higher in liver of rats that received the deficient diet, independent of ethanol, however, liver TBARS concentrations were low in control and supplemented groups, but increased with ethanol ingestion. Glutathione levels were lowered by ethanol administration in all groups, in different times, but recovered to this original level in 24 h time. In conclusion, vitamin E deficiency alone induces liver lipid peroxidation in rats, acute administration of ethanol affect vitamin E and GSH level and maintenance of adequate or higher vitamin E levels acts as a protective factor against free radical generation.
Two anthocyanins, cyanidin-3-alpha-O-rhamnoside (C3R) and pelargonidin-3-alpha-O-rhamnoside (P3R), and quercitrin (quercetin-3-alpha-O-rhamnoside), were isolated from acerola (Malpighia emarginata DC.) fruit. These polyphenols were evaluated based on the functional properties associated with diabetes mellitus or its complications, that is, on the radical scavenging activity and the inhibitory effect on both alpha-glucosidase and advanced glycation end product (AGE) formation. C3R and quercitrin revealed strong radical scavenging activity. While the inhibitory profiles of isolated polyphenols except quercitrin towards alpha-glucosidase activity were low, all polyphenols strongly inhibited AGE formation.
Reactive oxygen species (ROS) have been associated with acute ethanol-induced liver damage. N-acetylcysteine (NAC) is a glutathione (GSH) precursor and direct antioxidant. In this study, we investigated the effects of NAC on acute ethanol-induced liver damage. Female ICR mice were administered by gavage with a single dose of ethanol (6g/kg). NAC was administered in two different modes. In mode A, mice were injected with different doses of NAC at 30min before ethanol. In mode B, mice were injected with different doses of NAC at 4h after ethanol. Acute ethanol-induced liver damage was estimated by measuring serum alanine aminotransferase (ALT) activity and histopathological changes. Result showed that a single dose of ethanol (6g/kg) caused a significant increase in serum ALT activity, followed by microvesicular steatosis and necrosis in mouse liver. Pretreatment with NAC significantly protected against acute ethanol-induced liver damage in a dose-independent manner. Correspondingly, pretreatment with NAC significantly attenuated acute ethanol-induced lipid peroxidation and GSH depletion and inhibited hepatic TNF-alpha mRNA expression. By contrast, post-treatment with NAC aggravated ethanol-induced hepatic lipid peroxidation and worsened acute ethanol-induced liver damage in a dose-dependent manner. Taken together, NAC has a dual effect on acute ethanol-induced liver damage. Pretreatment with NAC prevent from acute ethanol-induced liver damage via counteracting ethanol-induced oxidative stress. When administered after ethanol, NAC might behave as a pro-oxidant and aggravate acute ethanol-induced liver damage.
Acute and chronic ethanol treatment has been shown to increase the production of reactive oxygen species, lower cellular antioxidant levels, and enhance oxidative stress in many tissues, especially the liver. Ethanol-induced oxidative stress plays a major role in the mechanisms by which ethanol produces liver injury. Many pathways play a key role in how ethanol induces oxidative stress. This review summarizes some of the leading pathways and discusses the evidence for their contribution to alcohol-induced liver injury. Many of the seminal reports in this topic have been published in Hepatology , and it is fitting to review this research area for the 25th Anniversary Issue of the Journal.
Shoots, roots, and seeds of corn (Zea mays L., cv. Michigan 500), oats (Avena sativa L., cv. Au Sable), and peas (Pisum sativum L., cv. Wando) were analyzed for their superoxide dismutase content using a photochemical assay system consisting of methionine, riboflavin, and p-nitro blue tetrazolium. The enzyme is present in the shoots, roots, and seeds of the three species. On a dry weight basis, shoots contain more enzyme than roots. In seeds, the enzyme is present in both the embryo and the storage tissue. Electrophoresis indicated a total of 10 distinct forms of the enzyme. Corn contained seven of these forms and oats three. Peas contained one of the corn and two of the oat enzymes. Nine of the enzyme activities were eliminated with cyanide treatment suggesting that they may be cupro-zinc enzymes, whereas one was cyanide-resistant and may be a manganese enzyme. Some of the leaf superoxide dismutases were found primarily in mitochondria or chloroplasts. Peroxidases at high concentrations interfere with the assay. In test tube assays of crude extracts from seedlings, the interference was negligible. On gels, however, peroxidases may account for two of the 10 superoxide dismutase forms.
The hepatoprotective activity of the aqueous extract of the roots of Decalepis hamiltonii was investigated against ethanol-induced oxidative stress and liver damage. Pretreatment of rats with aqueous extract of the roots of D. hamiltonii, single (50, 100 and 200mg/kg b.w.) and multiple doses (50 and 100mg/kg b.w. for 7 days) significantly prevented the ethanol (5g/kg b.w.) induced increases in the activities of the serum enzymes, aspartate and alanine transaminases, alkaline phosphatase and lactate dehydrogenase in a dose dependent manner. Parallel to these changes, the root extract inhibited the ethanol-induced oxidative stress in the liver by suppressing lipid peroxidation and protein carbonylation and maintaining the levels of antioxidant enzymes and glutathione. The biochemical changes were consistent with histopathological observations suggesting marked hepatoprotective effect of the root extract. The protective effect of the root extract against hepatotoxicity of alcohol was more pronounced by the multiple dose pretreatment. Hepatoprotective activity of the aqueous extract of the roots of D. hamiltonii could be attributed to the antioxidant effect of the constituents and enhanced antioxidant defenses.
The involvement of free radical mechanisms in the pathogenesis of alcoholic liver disease (ALD) is demonstrated by the detection of lipid peroxidation markers in the liver and the serum of patients with alcoholism, as well as by experiments in alcohol-feed rodents that show a relationship between alcohol-induced oxidative stress and the development of liver pathology. Ethanol-induced oxidative stress is the result of the combined impairment of antioxidant defences and the production of reactive oxygen species by the mitochondrial electron transport chain, the alcohol-inducible cytochrome P450 (CYP) 2E1 and activated phagocytes. Furthermore, hydroxyethyl free radicals (HER) are also generated during ethanol metabolism by CYP2E1. The mechanisms by which oxidative stress contributes to alcohol toxicity are still not completely understood. The available evidence indicates that, by favouring mitochondrial permeability transition, oxidative stress promotes hepatocyte necrosis and/or apoptosis and is implicated in the alcohol-induced sensitization of hepatocytes to the pro-apoptotic action of TNF-alpha. Moreover, oxidative mechanisms can contribute to liver fibrosis, by triggering the release of pro-fibrotic cytokines and collagen gene expression in hepatic stellate cells. Finally, the reactions of HER and lipid peroxidation products with hepatic proteins stimulate both humoral and cellular immune reactions and favour the breaking of self-tolerance during ALD. Thus, immune responses might represent the mechanism by which alcohol-induced oxidative stress contributes to the perpetuation of chronic hepatic inflammation. Together these observations provide a rationale for the possible clinical application of antioxidants in the therapy for ALD.
A crude acerola polyphenol fraction (C-AP) was prepared by subjecting an acerola extract to a C18 cartridge column, and eluting the adsorbed fraction with ethanol containing 10% of acetic acid. C-AP appeared in a previous study to have an inhibitory effect on alpha-glucosidase and particularly on maltase activities. To elucidate the antihyperglycemic effect of C-AP further, we examined the regulation by C-AP of glucose uptake in Caco-2 cell; this resulted in the inhibition of glucose uptake. We next conducted single administration tests of glucose and maltose to ICR mice to investigate whether C-AP really controlled the intestinal glucose absorption in an animal body. The results showed that C-AP significantly suppressed the plasma glucose level after administering both glucose and maltose, suggesting that C-AP had a preventive effect on hyperglycemia in the postprandial state. The mechanism for this effect is considered to have been both suppression of the intestinal glucose transport and the inhibition of alpha-glucosidase. Despite such a preventive effect, the therapeutic effect of C-AP on hyperglycemia appeared to be low from the experiment with KKAy mice.
The involvement of oxidative stress in the pathogenesis of alcoholic diseases in the liver has been repeatedly confirmed. Resveratrol, a natural phytoalexin present in grape skin and red wine possesses a variety of biological activities including antioxidant. This study was conducted to evaluate whether resveratrol has a preventive effect on the main indicators of hepatic oxidative status as an expression of the cellular damage caused by free radicals, and on antioxidant defence mechanism during chronic ethanol treatment. Wistar rats were treated daily with 35% ethanol solution (3 g/kg/day i.p.) during 6 weeks and fed basal diet or basal diet containing 5 g/kg resveratrol. Control rats were treated with i.p. saline and fed basal diet. Experimentally, chronic ethanol administration leads to hepatotoxicity as monitored by the increase in the level of hepatic marker enzymes and the appearance of fatty change, necrosis, fibrosis and inflammation in liver sections. Ethanol also enhanced the formation of MDA in the liver indicating an increase in lipid peroxidation, a major end-point of oxidative damage, and caused drastic alterations in antioxidant defence systems. Particularly the activities of hepatic superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) were found reduced by ethanol treatment while glutathione reductase (GR) activity was unchanged. Dietary supplementation with resveratrol during ethanol treatment inhibited hepatic lipid peroxidation and ameliorated SOD, GPx and CAT activities in the liver. Conclusively, we can suggest that resveratrol could have a beneficial effect in inhibiting the oxidative damage induced by chronic ethanol administration, which was proved by the experiments that we conducted on rats.