Garlic's ability to prevent in vitro Cu2+-induced lipoprotein oxidation in human serum is preserved in heated garlic: effect unrelated to Cu2+-chelation

Advances in the study of vascular related protective effect of garlic (Allium sativum) extract and compounds

Garlic (Allium sativum) is a functional food containing multiple bioactive compounds that find widespread applications in culinary and medicinal practices. It consists of multiple chemical components, including allicin and alliin. This article offers a comprehensive review of the protective effects of garlic extracts and their active constituents on the vascular system. In vitro and in vivo experiments have shown that garlic extracts and their active ingredients possess various bioactive properties. These substances demonstrate beneficial effects on blood vessels by demonstrating anti-inflammatory and antioxidant activities, inhibiting lipid accumulation and migration, preventing lipid peroxidation, promoting angiogenesis, reducing platelet aggregation, enhancing endothelial function, and inhibiting endothelial cell apoptosis. In clinical studies, garlic and its extracts have demonstrated their efficacy in managing vascular system diseases, including atherosclerosis, diabetes, and high cholesterol levels. In summary, these studies highlight the potential therapeutic roles and underlying mechanisms of garlic and its constituents in managing conditions like diabetes, atherosclerosis, ischemic diseases, and other vascular disorders.

Current studies and potential future research directions on biological effects and related mechanisms of allicin

Allicin, a thiosulfonate extract from freshly minced garlic, has been reported to have various biological effects on different organs and systems of animals and human. It can reduce oxidative stress, inhibit inflammatory response, resist pathogen infection and regulate intestinal flora. In addition, dozens of studies also demonstrated allicin could reduce blood glucose level, protect cardiovascular system and nervous system, and fight against cancers. Allicin was widely used in disease prevention and health care. However, more investigations on human cohort study are needed to verify the biological or clinical effects of allicin in the future. In this review, we summarized the biological effects of allicin from previous outstanding and valuable studies and provided useful information for future studies on the health effects of allicin.

Thallium Toxicity in Caenorhabditis elegans: Involvement of the SKN-1 Pathway and Protection by S-Allylcysteine

Monovalent thallium (Tl⁺) is a cation that can exert complex neurotoxic patterns in the brain by mechanisms that have yet to be completely characterized. To learn more about Tl⁺ toxicity, it is necessary to investigate its major effects in vivo and its ability to trigger specific signaling pathways (such as the antioxidant SKN-1 pathway) in different biological models. Caenorhabditis elegans (C. elegans) is a nematode constituting a simple in vivo biological model with a well-characterized nervous system, and high genetic homology to mammalian systems. In this study, both wild-type (N2) and skn-1 knockout (KO) mutant C. elegans strains subjected to acute and chronic exposures to Tl⁺ [2.5-35 μM] were evaluated for physiological stress (survival, longevity, and worm size), motor alterations (body bends), and biochemical changes (glutathione S-transferase regulation in a gst-4 fluorescence strain). While survival was affected by Tl⁺ in N2 and skn-1 KO (worms lacking the orthologue of mammalian Nrf2) strains in a similar manner, the longevity was more prominently decreased in the skn-1 KO strain compared with the wild-type strain. Moreover, chronic exposure led to a greater compromise in the longevity in both strains compared with acute exposure. Tl⁺ also induced motor alterations in both skn-1 KO and wild-type strains, as well as changes in worm size in wild-type worms. In addition, preconditioning nematodes with the well-known antioxidant S-allylcysteine (SAC) reversed the Tl⁺-induced decrease in survival in the N2 strain. GST fluorescent expression was also decreased by the metal in the nematode, and recovered by SAC. Our results describe and validate, for the first time, features of the toxic pattern induced by Tl⁺ in an in vivo biological model established with C. elegans, supporting an altered redox component in Tl⁺ toxicity, as previously described in mammal models. We demonstrate that the presence of the orthologous SKN-1 pathway is required for worms in evoking an efficient antioxidant defense. Therefore, the nematode represents an optimal model to reproduce mammalian Tl⁺ toxicity, where toxic mechanisms and novel therapeutic approaches of clinical value may be successfully pursued.

Herbal Approach for Management of Atherosclerosis: a Review

PURPOSE OF REVIEW

Summarize of the reports on antioxidants especially from herbal sources which battle oxidative stress might be proficient to forestall and repair the free radical-prompted vascular damages in overseeing of atherosclerosis.

RECENT FINDINGS

Atherosclerosis is the one of the fundamental reason for hypertension, stroke, myocardial localized necrosis, and numerous other cardiovascular illnesses. Atherosclerosis associated path physiological factors like hypercholesterolemia, hypertension, diabetes mellitus, and smoking actuates oxidative stress which are characterized by excessive oxidation and improper exclusion. The herbal plant-based antioxidant agents are effective towards the management/treatment of atherosclerosis by different ways like, by diminishing the oxidation of low-density lipoproteins, diminishing the cell proliferation, restraining the foam cell arrangement, and advancing the reverse cholesterol transport, down regulation of pro-atherogenic genes, and inflammatory mediators. This review is a critical analysis about the role of oxidative stress in atherogenesis and furthermore outlines the ongoing study/examination done on the management of atherosclerosis by utilizing herbal antioxidant agents.

Investigation of antioxidant activities of Pleurotus ostreatus stored at different temperatures

In this study, the antioxidant capacity of oyster mushroom (Pleurotus ostreatus) stored in five different temperature environments was investigated by DPPH (1,1 diphenyl-2-picryl hydrazyl) radical scavenging method. The antioxidant capacity results of oyster mushroom extracts were examined by spectroscopic measurements and expressed as percent of inhibition. The IC50 values of mushroom samples were calculated with DPPH method using calibration equations, and change in antioxidant properties was also tried to decipher by SEM images. The IC50 values of Pleurotus ostreatus for four different concentrations were also found in h+20°C > inh+4°C> inh-10°C> inh-20°C> inh-40°C, respectively. As a conclusion, the temperature factor of oyster mushroom in the range of -40°C to +20°C storage conditions is directly proportional to the change of antioxidant properties. The results have shown the importance of logistics and storage conditions in preserving the antioxidant properties of oyster mushroom and similar food samples.

Detoxification effects of phytonutrients against environmental toxicants and sharing of clinical experience on practical applications

According to the Food and Health Bureau and Trade and Industry Department of the Hong Kong Government, 90 % of the total food supply in Hong Kong was imported from the Mainland China. In addition, the hidden or illegal use of prohibited pesticides, food adulteration (e.g., using industrial salt in food processing, using gutter oil as cooking oil), and pollutions were periodically reported by the media. Excessive exposure to toxic heavy metals or persistent organic pollutants (POPs) from diet or environmental is inevitable amid industrialization and pollution. Understanding of the detoxification ability among nutrients in plant-based food (i.e., phytonutrients in green tea, onion, garlic, coriander, and turmeric) offers therapeutic and preventive effects against the poisoning effects due to these pollutants. Oxidative stress and pro-inflammatory actions are the common mechanisms for heavy metals or POPs toxicities, while phytonutrients counteracts these cellular insults by anti-oxidation, upregulation of anti-inflammatory pathways, and chelation.

Role of oxidative and nitrosative stress in cisplatin-induced nephrotoxicity

cis-Diamminedichloroplatinum (II) (cisplatin) is an important chemotherapeutic agent useful in the treatment of several cancers; however, it has several side effects such as nephrotoxicity. The role of the oxidative and nitrosative stress in cisplatin-induced nephrotoxicity is additionally supported by the protective effect of several free radical scavengers and antioxidants. Furthermore, in in vitro experiments, antioxidants or reactive oxygen species (ROS) scavengers have a cytoprotective effect on cells exposed to cisplatin. Recently, the participation of nitrosative stress has been more explored in cisplatin-induced renal damage. The use of a water-soluble Fe(III) porphyrin complex able to metabolize peroxynitrite (ONOO(-)) has demonstrated that this anion contributes to both in vivo and in vitro cisplatin-induced toxicity. ONOO(-) is produced when nitric oxide (NO*) reacts with superoxide anion (O(2)(*-)); currently, there are evidences suggesting alterations in NO* production after cisplatin treatment and the evidence appear to NO* has a toxic effect. This article goes through current evidence of the mechanism by more than a few compounds have beneficial effects on cisplatin-induced nephrotoxicity, contribute to understanding the role of oxidative and nitrosative stress and suggest several points as part of the mechanism of cisplatin toxicity.

Hypochlorous acid scavenging capacity of garlic

The ability of the following aqueous garlic extracts to scavenge hypochlorous acid (HOCl) was studied: (a) unheated extract of raw garlic (RG), (b) heated extract of raw garlic (HRG), (c) extract of boiled garlic cloves (BG) and (d) extract of microwave-treated garlic cloves (MG). The HOCl scavenging activity was evaluated following changes in the absorption spectrum of catalase (370-450 nm). RG, HRG and BG scavenged HOCl in a concentration-dependent way: the IC(50) (mg/mL) values for RG, HRG and BG were 0.339 +/- 0.028, 0.632 +/- 0.030 and 0.690 +/- 0.031, respectively. The HOCl scavenging ability of garlic was significantly decreased when garlic cloves or the extract of raw garlic were heated (BG and HRG, respectively); this scavenging ability was eliminated when garlic was subjected to microwave heating (MG). The IC(50) value for the reference compound, ascorbic acid, was 0.500 +/- 0.049 mg/mL. In summary, raw garlic concentration-dependently scavenged HOCl; this ability was eliminated in extracts of microwave-treated garlic cloves but not in heated extracts of raw garlic or extracts of boiled garlic cloves.

Protective effects of garlic powder against potassium dichromate-induced oxidative stress and nephrotoxicity

Potassium dichromate (K(2)Cr(2)O(7))-induced nephrotoxicity is associated with oxidative stress. In the present work the effect of garlic powder, a recognized antioxidant, on K(2)Cr(2)O(7)-induced nephrotoxicity and oxidative stress was studied. Rats were fed a 2% garlic powder diet for 1 month. A single injection of K(2)Cr(2)O(7) (15 mg/kg) to rats induced tubule interstitial damage and an increase in the following markers of renal injury 2 days later: blood urea nitrogen (4.6-fold), serum creatinine (9.7-fold), proteinuria (35.9-fold), urinary excretion of N-acetyl-beta-d-glucosaminidase (12.9-fold) and glutathione-S-transferase (2.3-fold) and a decrease of 65% in serum glutathione peroxidase activity. In addition, K(2)Cr(2)O(7) injection increased the following nitrosative and oxidative stress markers in kidney: 3-nitrotyrosine (1.9-fold), 4-hydroxy-2-nonenal (2.1-fold), malondialdehyde (1.8-fold) and protein carbonyl content (1.7-fold). It was found that garlic powder feeding was able to prevent by 44-71% the alterations in the markers of renal injury studied, by 55% the histological damage, and by 47-100% the increase in markers of oxidative and nitrosative stress. It is concluded that the ability of garlic powder to ameliorate K(2)Cr(2)O(7)-induced renal injury is associated with its antioxidant properties. Our data support the use of garlic powder as a renoprotective agent.

Effect of heating on peroxynitrite scavenging capacity of garlic

The ability to scavenge peroxynitrite (ONOO(-)) was studied in the following aqueous garlic extracts: (a) unheated extract of garlic powder (GP), (b) heated extract of garlic powder (HGP), (c) unheated extract of raw garlic (RG), (d) heated extract of raw garlic (HRG), (e) extract of boiled garlic cloves (BG), (f) extract of microwave-treated garlic cloves (MG), and (g) extract of pickled garlic (PG). All the extracts scavenged ONOO(-) in a concentration-dependent way. IC(50) (mg/mL) values for each extract were 0.30+/-0.02 and 0.35+/-0.04 for GP and HGP, respectively; and 0.84+/-0.08, 0.59+/-0.04, 0.76+/-0.09, 1.71+/-0.19, and 1.45+/-0.07 for RG, HRG, BG, MG, and PG, respectively. The ONOO(-) scavenging capacity (IC(50) values) was not decreased in HGP (vs. GP, p>0.05) and in HRG and BG (p>0.05 vs. RG). In contrast, the ONOO(-) scavenging capacity decreased in MG and PG (vs. RG, p<0.001). The IC(50) values for the reference compounds nordihydroguiaretic acid and penicillamine were 1.1 and 4.5mug/mL. The heating before or after garlic cutting was unable to eliminate the capacity of the extracts to scavenge ONOO(-); this capacity was significantly decreased in PG and MG.

Reactive oxygen species scavenging capacity of different cooked garlic preparations

It was studied if the ability of aqueous garlic extracts to scavenge superoxide anion (O(2)(*-)), hydrogen peroxide (H(2)O(2)), and hydroxyl radical (OH(*)) is altered in the following aqueous preparations: (a) extracts of boiled garlic cloves (BG), (b) extracts of microwave-treated garlic cloves (MG), and (c) extracts of pickled garlic (PG), and heated extracts of (a) garlic powder (HGP) and (b) raw garlic (HRG). The data were compared with the unheated raw garlic (RG) or with the unheated garlic powder (GP). Extracts of GP and RG scavenged O(2)(*-), H(2)O(2), and OH(*) in a concentration-dependent way. The reactive oxygen species scavenging capacity was not decreased in the aqueous garlic extracts except in MG and HRG (for O(2)(*-)) and in HGP and PG (for H(2)O(2)). The heating before or after garlic cutting was unable to eliminate the capacity of the extracts to scavenge H(2)O(2), O(2)(*-), and OH(*).

Modulation of selenite cataract by the flavonoid fraction ofEmilia sonchifolia in experimental animal models

The purpose of the study was to investigate the role of flavonoids from Emilia sonchifolia (ES) on the progression of selenite-induced cataract. The antioxidant property of the flavonoids isolated from ES was assessed by measuring its capacity to inhibit superoxide production and serum oxidation in vitro in comparison with quercetin. Based on these experiments, an in vivo study was conducted to evaluate the modulatory effects of the flavonoids against selenite cataract. Cataract was induced by a single subcutaneous injection of sodium selenite (4 mg/kg body weight). The treatment group received flavonoids from ES (1 mg/kg) and this was compared with the quercetin treated group. Lens opacification was monitored by a slit lamp microscope and classified into six stages. Activity of the antioxidant enzymes - superoxide dismutase and catalase - and the level of lipid peroxidation products thiobarbituric acid reacting substances and reduced glutathione were studied. Slit lamp examination showed that the flavonoid fraction from ES could modulate the progression of cataract. Activities of superoxide dismutase, catalase and reduced glutathione were found to be increased in the ES treated groups, while thiobarbituric acid reacting substances were decreased compared with the selenite-induced group. The results suggest that flavonoids from ES can modulate lens opacification and oxidative stress in selenite-induced cataract.

Raw and boiled garlic enhances plasma antioxidant activity and improves plasma lipid metabolism in cholesterol-fed rats

In the present study the effect of garlic, in a form more similar to how most people eat garlic, on lipid and antioxidant metabolism in rats was investigated. The antioxidant activity was determined by the efficacy to scavenge 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) derived radicals in garlic samples. The highest results were estimated in aqueous fraction in comparison with other extracts divided on the basis of polarity. Wistar male rats were randomly divided into 10 diet groups, each with seven animals. The groups were named: Control, RG (raw garlic), BG (boiled garlic for 20 min), AERG (aqueous extract of raw garlic), AEBG (aqueous extract of boiled garlic), Ch (Cholesterol), Ch/RG, Ch/BG, Ch/AERG and Ch/AEBG. All experimental diets were supplemented with 25 mg of lyophilized garlic/kg body weight obtained from raw, boiled and their aqueous extracts over a period of 30 days. Serum lipid (total cholesterol, LDL-cholesterol and triglycerides) concentrations were higher in all groups fed cholesterol (Ch); however, the increase was significant only in Ch group, without garlic supplementation. In groups of rats fed diets with cholesterol, garlic samples significantly hindered the rise of TC and LDL-C (P < 0.05). A significant increase (P < 0.05) in the plasma antioxidant activity was registered in experimental groups of rats fed cholesterol-free diets supplemented with garlic; oppositely, a significant decrease was only in group of rats given food containing cholesterol without garlic. The protein spectra has shown that during short boiling some proteins change their functional properties such as solubility and mobility, resulting in a number of protein bands in SDS-electrophoresis.

CONCLUSIONS

Raw and boiled garlic improved plasma lipid metabolism and plasma antioxidant activity in an experiment on rats. Thus, dietary hypolipidemic garlic was effective in reducing the oxidant stress, which was indicated by an increase of antioxidant activity and a decrease of lipids in the rats' blood. It was found that garlic boiled for 20 min has the same bioactivity as raw garlic in its antioxidant and protein spectra. Therefore it should be added at this time to foods. The selenium and copper content of raw garlic is not altered by boiling. The protein electrophoretic pattern of raw garlic is altered by boiling.