Effect of diallyldisulphide on an antioxidant enzyme system in Candida species

This study was carried out to show the effect of diallyldisulphide (DADS), an important organosulphur compound found in garlic (Allium sativum), on antioxidant systems in Candida species. Changes in antioxidant metabolites and antioxidant activity in the presence of DADS were found in Candida albicans and Candida tropicalis. Candida cells were treated with sublethal concentrations of DADS. DADS caused a decrease in the activity of all antioxidant enzymes except catalase, resulting in oxidative stress and damaged cells. The amount of oxidative stress generated by DADS was found to be a function of its concentration. A significant decrease in superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase activities but an increase in catalase activity were observed. Increased levels of lipid peroxidation and decreased levels of glutathione were observed in treated cells. Activity of glucose-6-phosphate dehydrogenase decreased significantly following DADS treatment and could be correlated with a decrease in glutathione concentration in both Candida species. These results indicate that diallyl disulphide acts as a pro-oxidant to Candida species and hence may act as a potent antifungal in the management of candidiasis.     

Diallyl disulfide, a chemopreventive agent in garlic, induces multidrug resistance-associated protein 2 expression

The organosulfur compounds (OSCs), present in garlic, are studied for their protective effect against human cancers. P-glycoprotein (P-gp) and multidrug resistance protein 2 (Mrp2) are two transporters involved in the defense of cells and in the development of multidrug resistance. Whereas OSCs increase glutathione S-transferase activity (GST), Mrp2 plays a role in the transport of glutathione (GSH)-conjugates. In this study, we have investigated the effect of two OSCs, diallyl disulfide (DADS) and S-allyl cysteine (SAC), on P-gp and Mrp2 expression in renal brush-border membranes. By Western blot analysis, our results show that DADS induces Mrp2 expression (by 7-fold), which correlates with the rise of GST activity and GSH levels. Surprisingly, a co-administration of OSC with cisplatin, an anticancer drug, significantly increased Mrp2 gene and protein expression (by 30-fold), suggesting that DADS could potentiate the effects of cisplatin. Interestingly, SAC and cisplatin in co-treatment decreased P-gp protein expression and mdr1b isoform mRNA levels. In addition, modulation of the mdr1b isoform and Mrp2 by cisplatin was completely abolished by a glutathione precursor, N-acetyl cysteine. These results indicate that OSCs present in a garlic-rich diet might alter chemotherapeutic treatments using P-gp or Mrp2 substrates.     

Influence of organosulphur compounds from garlic on the secretion of matrix metalloproteinases and their inhibitor TIMP-1 by cultured HUVEC cells

Organosulphur compounds from garlic, especially diallyl disulphide (DADS) at non-toxic concentrations, affected production and secretion of some matrix metalloproteinases (MMPs) and of tissue inhibitor of metalloproteinase-1 (TIMP-1), one of their inhibitors, by human umbilical vein endothelial cells. Addition of DADS to the culture medium resulted in a concentration-dependent reduction of secreted MMP-2 protein and activity as well as TIMP-1 protein. In the presence of inducers (phorbol 12-myristate 13-acetate, forskolin and tumor necrosis factor alpha) addition of DADS caused a distinct concentration-dependent decrease of MMP-9 and TIMP-1 secretion, while not affecting MMP-9 mRNA levels. Intracellular protein levels remained low and were not affected. Other organosulphur compounds like allyl mercaptan and S-allylcysteine showed no or less clear effects on MMP-secretion or TIMP-1-secretion. These results suggest that DADS may mediate some of the biological effects ascribed to garlic preparations through affecting MMP-TIMP balance.     

Synthesis, DNA binding, and cytotoxic evaluation of new analogs of diallyldisulfide, an active principle of garlic

Diallyldisulfide (DADS), an active principle of garlic (Allium sativum) is known for its antihyperlipidemic properties. However, its use is limited due to its extreme volatility. In the present study, we have synthesized and characterized a series of six new DADS analogs and investigated their interactions with different DNA duplexes. The spectroscopic and circular dichroism (CD) analyses revealed that DADS analogs bind preferentially with GC rich sequences. Thermodynamic parameters suggest that DADS analogs stabilize the calf thymus (CT) DNA and GC rich duplex by favorable enthalpic gains and follow the hierarchy, d(GC)(7)>CT DNA>d(AT)(10). Further, DADS analogs are less toxic and equally effective as the statins. The analogs therefore have a good potential to provide a new therapeutic approach for the treatment of cardiovascular and related diseases.     

Caralluma fimbriata and metformin protection of rat pancreas from high fat diet induced oxidative stress

A high fat diet promotes oxidative stress, which contributes to the development of pancreatic fibrosis. We compared the protective effects of a hydroalcoholic extract of Caralluma fimbriata (CFE) to metformin (Met) in the pancreas of Wistar rats fed a high fat diet. The experimental animals were divided into five groups: control (C), treated with CFE (C + CFE), treated with high fat diet (HFD), high fat diet treated with CFE (HFD + CFE), and high fat diet treated with metformin (Met) (HFD + Met). CFE was administered orally to groups C + CFE and HFD + CFE rats for 90 days. Met was given to the HFD + Met group. After 90 days, oxidative stress markers in the pancreas including reduced glutathione (GSH), lipid oxidation (LO), protein oxidation (PO), and activities of antioxidant and polyol pathway enzymes, aldose reductase (AR) and sorbitol dehydrogenase (SDH) were assayed and tissue histology was examined. Establishment of oxidative stress in high fat diet fed rats was verified by elevated LO and PO, decreased GSH, decreased activities of antioxidants and increased activities of polyol pathway enzymes. Oxidative stress was prevented in HFD + CFE and HFD + Met groups. Group C + CFE exhibited improved antioxidant status compared to group C. CFE treatment prevented high fat diet induced acinar cell degeneration, necrosis, edema and hemorrhage. CFE could be used as adjuvant therapy for preventing or managing high fat diet induced pancreatic damage.     

Effect of garlic oil extract on glutathione reductase levels in rats fed on high sucrose and alcohol diets: A possible mechanism of the activity of the oil

The effect on glutathione reductase activities of feeding garlic oil to white albino rats maintained on high sucrose and alcohol diets was studied. Whereas high sucrose and alcohol diets resulted in significant increases in the activity of glutathione reductase in liver, kidneys and serum, the presence of garlic oil restored the levels to near normal. It is proposed that the mechanism of this action of garlic oil involves the active principle, diallyl disulphide, which interacts in an exchange reaction with enzymes and substrates such as glutathione reductase and glutathione which contain thiol groups.     

Antihyperlipidemic and antioxidant effects of feather protein hydrolysate in high‐fat diet‐fed mice

The hyperlipidemia is a serious health problem that increases the risk of many complications including cardiovascular disease. This study aims to evaluate the possible antihyperlipidemic effects of the feather protein hydrolysate (FPH) in a mice fed with a high‐fat diet (HFD)‐fed mice during 5 weeks. The FPH administration improved dose‐dependent lipid profile, as well as the liver and renal dysfunction indices in hyperlipidemic mice. The FPH also restored the antioxidant status in liver, kidney, and heart by lowering the lipid peroxidation and enhancing the antioxidant enzymes (catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase [SOD]). Moreover, the histological studies proved that FPH administration prevents hepatic steatosis, glomerular hyperfiltration risk, and cardiac muscle hypertrophy. Accordingly, the FPH is a promising novel medicinal ingredient for possible use in the hyperlipidemic treatment and related complications.     

Effect of garlic on high fat induced obesity

The present study was performed to examine the effects of garlic on obesity and blood lipid profiles in high-fat induced obesity mice model, and to elucidate the molecular mechanisms responsible for such effect. C57BL/6 mice were fed a standard diet (STD) or high-fat diet (HFD) for 5 weeks to induce obesity. Mice were then randomly divided into four groups with 10 mice per group, and fed experimental diet for 4 weeks; STD group, HFD group, HFD containing 2% or 4% garlic group (HFD + G2 or HFD + G4, respectively). Administration of garlic significantly reduced HFD-induced body weight, epididymal fat accumulation, hyperlipidemia and hypercholesterolemia. Consequently, the atherogenic indexes were reduced by 83% and 91%, respectively, in 2% and 4% garlic supplemented group. Liver steatosis induced by HFD was ameliorated by garlic supplementation. Furthermore, garlic affected the down regulation of expression patterns of epididymal adipose tissue genes such as peroxisome proliferator-activated receptor γ (PPARγ), acetyl CoA carboxylase (ACC), adipose specific fatty acid binding protein (aP2), and glycerol-3-phosphate dehydrogenase (GPDH). These results suggest that garlic may have a potential benefit in preventing obesity.     

Diallyl sulfides in garlic activate both TRPA1 and TRPV1

We searched for novel agonists of TRP receptors especially for TRPA1 and TRPV1 in foods. We focused attention on garlic compounds, diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS). In TRPA1 or TRPV1 heterogeneously expressed CHO cells, all of those compounds increased [Ca²⁺]_i in concentration-dependent manner. The EC₅₀ values of DADS and DATS were similar to that of allyl isothiocyanate (AITC) and that of DAS was 170-fold larger than that of AITC. Maximum responses of these sulfides were equal to that of AITC. The EC₅₀ values of these compounds for TRPV1 were around 100 μM against that of capsaicin (CAP), 25.6 nM and maximum responses of garlic compounds were half to that of CAP. The Ca²⁺ responses were significantly suppressed by co-application of antagonist. We conclude that DAS, DADS, and DATS are agonist of both TRPA1 and TRPV1 but with high affinity for TRPA1.     

The effects of biogenic and abiogenic disulphides on endothelial cells in culture: Comparison of three methods of viability assessment

Effects of biogenic and abiogenic disulfides on viability of human umbilical vein endothelial cells in culture were studied using three methods: inclusion of neutral red (NR) into cells, quantification of intracellular ATP, and modifications of the Mosmann method (1983), the essence of which consists in reduction of tetrazolim salts—MTT and MTS—by cells (Mosmann, 1983). 2,2′-Dithio-bis(N,N-diethyl)dietanamine (DS) was used as an abiogenic sulfide. As for biogenic disulfides, we used oxydized glutathione (GSSG) and garlic oil (GO), the major component of which is diallyl disulfide (DADS). It has been established that DS and GO have a compatible cytotoxic effect (ES₅₀ amounts to ～0.6 mM), whereas GSSG at a concentration up to 1 mM had no effect on the viability of endothelial cells. It has been demonstrated for the first time that DS and GO can serve as mediators of plasma-membrane oxidoreductase activity, with tetrazolium salts being used as the substrate, which may cause a false-negative effect. In this connection, Mosmann’s method has serious limitations in evaluating the effect of disulfides on cell viability, although it can be used when studying the mechanism of their action.     

Garlic allyl derivatives interact with membrane lipids to modify the membrane fluidity

As a novel approach to the mode of medicinal action of garlic, its constituents were comparatively studied with respect to their interactions with membrane lipids to modify the membrane fluidity. Allyl derivatives rigidified tumor cell and platelet model membranes consisting of unsaturated phospholipids and cholesterol at 20–500 μM with the potency being diallyl trisulfide (DATS) > diallyl disulfide (DADS) by preferentially acting on the hydrocarbon cores of lipid bilayers. They were also effective in rigidifying candida cell model membranes prepared with ergosterol and phospholipids at 100–500 μM with the potency being DADS > DATS > diallyl sulfide (DAS), but not bacteria cell model membranes without ergosterol. Alliin, a precursor of these DASs, was not active on any membranes at 500 μM. Both relative intensity and selectivity in membrane effects correlated with those in antiproliferative, antiplatelet and antimicrobial effects. In cell culture experiments, membrane-active DASs inhibited the growth of tumor cells cultured for 24 and 48 h at 20–500 μM to show the potency being DATS > DADS, together with rigidifying cell membranes by acting on their deeper regions more intensively. However, membrane-inactive allyl derivatives were not growth-inhibitory on tumor cells. The membrane lipid interactions of DASs appear to be one of possible mechanisms underlying different effects of garlic.     

Diallyl disulphide and lovastatin: effects on energy and protein utilisation in, as well as methane emission from, sheep

Currently research on feed supplementation with natural compounds to improve energy and protein utilisation and to mitigate the greenhouse gas methane in ruminants is intensively pursued. Two compounds, diallyl disulphide (DADS), an important component of garlic oil, and lovastatin, an inhibitor of a key enzyme of methanogenic Archaea, were selected on the basis of their in vitro anti-methanogenic potential. In three 23-day experimental runs, six sheep received hay and concentrate in a duplicate 3 x 3 Latin square design. The concentrate was either not supplemented or supplemented with either 4 g DADS or 80 mg lovastatin per kg of total dietary dry matter. There were no refusals of concentrate for any treatment. Respiratory measurements were conducted on experimental days 7/8 (Period 1) and days 17/18 (Period 2). Relative to the control, digestibility of neutral detergent fibre (NDF) tended to increase (p = 0.09) with DADS by 14%. This was associated with an increased (p = 0.07) body energy retention of the animals. Effects on nitrogen balance and ruminal fermentation traits were never significant. No influence of supplements or period was found on total daily CH4 production which averaged at 28.6 g per sheep. However, across both periods the amount of CH4 produced per kg NDF digested was lower (-8%; p = 0.02) with DADS than without supplementation, and the lovastatin treatment ranged in between. In conclusion, the study demonstrated a certain potential of DADS to improve fibre digestion and body energy retention and to limit CH4 formation in relation to digestible fibre intake, while lovastatin remained ineffective.     

Diallyl sulfide, diallyl disulfide and diallyl trisulfide affect drug resistant gene expression in colo 205 human colon cancer cells in vitro and in vivo

To elevate chemo-resistance of human cancer cells is a major obstacle in the treatment and management of malignant cancers. Diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS) are presented in the Alliaceae family particularly in garlic. Although DAS, DADS and DATS have been shown to exhibit anticancer activities, there is little information on effects of these compounds on drug resistant genes in human colon cancer cells in vitro and in vivo. Herein, we are the first to show that DAS, DADS and DATS at 25 μM for 24-h and 48-h incubations promoted expression of drug resistant genes in colo 205 human colon cancer cells. In vitro experiments indicated that DATS promoted gene expression of multidrug resistant 1 (Mdr1) (p<0.05), and DAS and DADS promoted MRP3 gene expression and DATS alone stimulated gene expression of multidrug resistance-associated protein-1 (MRP1) (p<0.05) in colo 205 cells. In vivo studies demonstrated that DADS and DATS induced Mdr1 and MRP1 gene expression (p<0.05). DADS promoted MRP3 gene expression (p<0.05) as well as DADS and DATS increased MRP4 and MRP6 gene expression (p<0.05) in the colo 205 xenograft mice. Based on our in vitro and in vivo results, diallyl polysulfides (DAS, DADS and DATS) affected the gene expression of the multidrug resistance in colo 205 human colon cancer cells in vitro and in vivo.     

Activities of garlic oil, garlic powder, and their diallyl constituents against Helicobacter pylori

Chronic Helicobacter pylori disease is reduced with Allium vegetable intake. This study was designed to assess the in vivo anti-H. pylori potential of a variety of garlic substances. The garlic materials all showed substantial but widely differing anti-H. pylori effects against all strains and isolates tested. The MICs (range, 8 to 32 microg/ml) and minimum bactericidal concentrations (MBCs) (range, 16 to 32 microg/ml) of undiluted garlic oil (GO) were smaller than those of garlic powder (GP) (MIC range, 250 to 500 microg/ml; MBC range, 250 to 500 microg/ml) but greater than the MIC of allicin (4. 0 microg/ml) (Table 2) present in GP. Allicin (MIC, 6 microg/ml; MBC, 6 microg/ml) was more potent than diallyl disulfide (MIC range, 100 to 200 microg/ml; MBC range, 100 to 200 microg/ml), its corresponding sulfide, but of a strength similar to that of diallyl tetrasulfide (MIC range, 3 to 6 microg/ml; MBC range, 3 to 6 microg/ml). Antimicrobial activity of the diallyl sulfides increased with the number of sulfur atoms. Time course viability studies and microscopy showed dose-dependent anti-H. pylori effects with undiluted GO, GP, allicin, and diallyl trisulfide after a lag phase of ca. 1 to 2 h. Substantial in vitro anti-H. pylori effects of pure GO and GP and their diallyl sulfur components exist, suggesting their potential for in vivo clinical use against H. pylori infections.     

Effects of allyl sulfides on the growth of predominant gut anaerobes

At a small supplied concentration (3–5 mM), diallyl disulfide (DADS) and diallyl monosulfide (DAMS), compounds previously shown to have both tumoricidal and protective effects against carcinogenesis, affected the growth of components of the normal anaerobic gut microflora. Organisms that were affected by DAMS and DADS includedBacteroides ruminicola, Bacteroides succinogenes, Butyrivibrio fibrisolvens, Ruminococcus albus, Ruminococcus flavefaciens, Ruminococcus bromii, andPeptostreptococcus productus. Organisms found unaffected, over the same supplied concentration range, includedBacteroides fragilis, Bacteroides vulgatus, Fusobacterium necrophorum, Fusobacterium nucleatum, andSelenomonas ruminantium. In addition to their direct effects upon host cell physiology, the active components of garlic oil may exert modifying effects on the nature and function of the predominant gut microflora of warm-blooded animals.     

Chemoprotective effect of diallyl trisulfide from garlic against carbon tetrachloride-induced acute liver injury of rats

Diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS) are principal constituents of garlic oil. We studied the effect of these sulfides on the phase II drug-metabolizing enzymes, and on the rat model of acute liver injury induced by carbon tetrachloride (CCl4). A highly purified form of each sulfide (more than 99% purity) was administered i.p. to rats at a concentration of 10 or 100 micromol/kg body weight for 14 consecutive days. DATS (10 micromol/kg) and DADS at a 10-fold higher dose (100 micromol/kg) significantly increased the activities of glutathione S-transferase (GST) and quinone reductase (QR); whereas DAS did not. In the CCl4-induced acute liver injury model of rats, DATS (10 micromol/kg) significantly suppressed the increase in plasma lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) activities. In conclusion, hepatic phase II enzymes were induced strongly by the trisulfide and weakly by the disulfide, but not by DAS. DATS significantly reduced the liver injury caused by CCl4. DATS may be one of the important factors in garlic oil that protects our body against the injury caused by radical molecules.     

Efficacy of piperine, an alkaloidal constituent from Piper nigrum on erythrocyte antioxidant status in high fat diet and antithyroid drug induced hyperlipidemic rats

The main aim of this study was to investigate the effect of piperine on erythrocyte antioxidant status in high fat diet (HFD) and antithyroid drug induced hyperlipidemic rats. Male Wistar rats were divided into eight groups. The first four groups were fed a control diet and in addition were given respectively 1% carboxymethyl cellulose (CMC); 10 mg/kg body weight carbimazole (CM); 10 mg CM + 40 mg/kg body weight piperine and 10 mg CM + 2 mg/kg body weight atorvastatin (ATV). A similar pattern was followed for the next four groups except that they were all fed HFD instead of the control diet. Erythrocyte osmotic fragility, total cholesterol, phospholipids, lipid peroxidation products, enzymic and non-enzymic antioxidant status were studied in all experimental groups. Significantly increased osmotic fragility, total cholesterol/phospholipid ratio, thiobarbituric acid reactive substances and lipid hydroperoxides were observed in the plasma and erythrocytes of HFD fed and CM treated rats compared to the control. Superoxide dismutase, catalase, glutathione peroxidase, vitamin E and reduced glutathione in erythrocytes and vitamin C in the plasma were also significantly lowered in HFD fed, antithyroid drug treated rats compared to control animals. Concurrent piperine supplementation along with HFD and antithyroid drug administration normalized erythrocyte osmotic fragility, reduced lipid peroxidation, and improved the enzymic and non-enzymic antioxidant status compared to those rats that did not receive piperine. Thus, our results indicate that piperine supplementation markedly protects erythrocytes from oxidative stress by improving the antioxidant status in HFD fed antithyroid drug treated rats.     

Effect of Garlic Supplementation on Erythrocytes Antioxidant Parameters, Lipid Peroxidation, and Atherosclerotic Plaque Formation Process in Oxidized Oil-Fed Rabbits

Effect of garlic supplementation on blood antioxidant status, lipid peroxidation, and coronary plaque formation process was investigated in oxidized oil-fed rabbits. Eighteen adult male mixed European rabbits were given a balanced diet (21 g% protein, 34 g% fat, 45 g% carbohydrate), which contained isocaloristic addition of nonoxidized or oxidized rapeseed oil in the presence and absence of garlic. The experiment lasted 24 weeks. At the beginning and every 6 weeks, rabbits were weighed, and blood was taken. To evaluate the antioxidant status of the rabbits, erythrocytes malondialdehyde (MDA) concentration, total superoxide dismutase (t-SOD), and glutathione peroxidase (GPX) activations were determined. After the experiment was completed, aortas were dissected for histological examinations. Changes in the contents of the above parameters and histological examinations showed that oxidized rapeseed, oil administered to rabbits, caused the development of atherosclerotic changes and disturbed antioxidant status. The addition of garlic in such diets inhibited atherosclerotic changes in the aorta wall, and it is related to the homeostatic activity of antioxidative enzymes and lipid peroxidation.     

Promising role of ferulic acid,atorvastatin and their combination in ameliorating high fat diet-induced stress in mice

AimsThe present study evaluated a comparative and combined hepatoprotective effect of atorvastatin (AS) and ferulic acid (F) against high fat diet (HFD) induced oxidative stress in terms of hyperlipidemia, anti-oxidative status, lipid peroxidation and inflammation.Main methodsMale Swiss albino mice were given a diet containing high fat (H) (23.9% wt/wt), supplemented with AS (10 mg/kg) or F (100 mg/kg) and both (10 and 100 mg/kg) for 8 weeks. The control mice (C) were fed with normal diet.Key findingsThe H mice exhibited increased body weight; hyperlipidemia; serum level of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6); hepatic lipid profile; lipid accumulation; reactive oxygen species (ROS) of hepatocytes, lipid peroxidation and liver antioxidant capacity was decreased. Immunofluorescent and Western blot assay revealed activation of nuclear factor kappa B (NF-κB) signaling pathway. The addition of F or AS and both in the diet significantly counteracted HFD induced body weight gain; hyperlipidemia; TNF-α, IL-6; hepatic lipid profile; fatty infiltration; NF-κB signaling pathway; ROS; lipid peroxidation and moreover elevated levels of hepatic antioxidant enzymes activity were observed.SignificanceSimultaneous treatment with AS, F and their combination protected against HFD induced weight gain and oxidative stress. The protection may be attributed to the hypolipidemic and free radical scavenging activity of AS or F and their combination. This study illustrates that AS and F have relatively similar hypolipidemic, antioxidative, anti-inflammatory actions and the AS + F combination along with HFD has shown outstanding effects as compared to other treated groups.