Garlic-derived Organosulfur Compounds Research Articles

Naturally occurring organosulfur compounds effectively inhibits PCSK-9 activity and restrict PCSK-9-LDL-receptor interaction via in-silico and in-vitro approach

The present study intended to divulge the potential role of garlic-derived organosulfur compounds (OSCs) in targeting PCSK-9 and averting its interaction with the EGF-A portion of LDL-R via in-vitro and in-silico analysis. Our in-silico screening data showed that 3-(Propylsulfinyl)-L-alanine (PSA), S-Ethyl-L-cysteine (SEC), alliin, and S-Allyl-L-cysteine (SAC) exhibited higher binding energy (−7.05, −7.00, −6.65, and −6.31 Kcal/mol, respectively) against PCSK-9, among other selected OSCs. Further, the protein-protein interaction study of PCSK-9-OSCs-complex with EGF-A demonstrated a similar binding pattern with E-total values ranging from −430.01 to −405.6 Kcal/mol. These results were further validated via in-vitro analysis which showed that SEC, SAC, and diallyl trisulphide (DAT) exhibited the lowest IC50 values of 4.70, 5.26, and 5.29 µg/mL, respectively. In conclusion, the presented data illustrated that SEC, SAC, and DAT were the best inhibitors of PCSK-9 activity and may have the potential to improve the LDL-R function and lower the circulatory LDL-C level.

Garlic-Derived Organosulfur Compounds Regulate Metabolic and Immune Pathways in Macrophages and Attenuate Intestinal Inflammation in Mice.

Scope: Garlic is a source of bioactive phytonutrients that may have anti‐inflammatory or immunomodulatory properties. The mechanism(s) underlying the bioactivity of these compounds and their ability to regulate responses to enteric infections remains unclear. Methods and Results: This study investigates if a garlic‐derived preparation (PTSO‐PTS) containing two organosulfur metabolites, propyl‐propane thiosulfonate (PTSO), and propyl‐propane thiosulfinate (PTS), regulate inflammatory responses in murine macrophages and intestinal epithelial cells (IEC) in vitro, as well as in a model of enteric parasite‐induced inflammation. PTSO‐PTS decreases lipopolysaccharide‐induced secretion of TNFα, IL‐6, and IL‐27 in macrophages. RNA‐sequencing demonstrates that PTSO‐PTS strongly suppresses pathways related to immune and inflammatory signaling. PTSO‐PTS induces the expression of a number of genes involved in antioxidant responses in IEC during exposure to antigens from the parasite Trichuris muris. In vivo, PTSO‐PTS does not affect T. muris establishment or intestinal T‐cell responses but significantly alters cecal transcriptomic responses. Notably, a reduction in T. muris‐induced expression of Tnf, Saa2, and Nos2 is observed. Conclusion: Garlic‐derived organosulfur compounds exert anti‐inflammatory effects in macrophages and IEC, and regulate gene expression during intestinal infection. These compounds and related organic molecules may thus hold potential as functional food components to improve gut health in humans and animals.

The garlic-derived organosulfur compound diallyl trisulphide suppresses tissue factor function.

Tissue factor (TF) is a critical initiator of extrinsic coagulation that sometimes causes thromboembolism. Diallyl trisulphide (DATS) is a secondary metabolite of allicin generated in crushed garlic, with various pharmacological effects. This study aimed to clarify the effect of DATS on the extrinsic coagulation elicited by TF and arteriosclerosis. TF activity was measured using a clotting assay in TF-expressing HL60 cells. DATS inhibited TF activity in a dose-dependent manner. TF expression in TNF-α-stimulated human umbilical vein endothelial cells was examined using real-time PCR and western blotting. DATS inhibited TF mRNA and protein expression induced by TNF-α via inhibition of JNK signalling. The effect of DATS on arteriosclerosis was also examined in apolipoprotein E-deficient mice. DATS administration in these mice tended to decrease atherosclerotic lesion size. These results strongly suggest that DATS prevents thromboembolism triggered by atherosclerosis via the inhibition of plaque formation and TF function.

Antiviral activity of diallyl trisulfide against H9N2 avian influenza virus infection in vitro and in vivo

BackgroundDiallyl trisulfide (DATS) is a garlic-derived organosulfur compound. As it has been shown to have anti-viral activity, we hypothesized that it may alleviate infections caused by H9N2 avian influenza virus (AIV), which is prevalent in poultry with pandemic potential.MethodsHuman lung A549 epithelial cells were treated with three different concentrations of DATS 24 h before (pre-treatment) or one hour after (post-treatment) H9N2 AIV infection. Culture supernatants were collected 24 h and 48 h post-infection and analyzed for viral titers and levels of inflammatory and anti-viral immune responses. For in vivo experiments, BABL/c mice were administered daily by intraperitoneal injection with DATS (30 mg/kg) for 2 weeks starting 1 day after H9N2 AIV infection. Clinical signs, lung pathology, and inflammatory and anti-viral immune responses were assessed 2, 4, and 6 days after infection.ResultsBoth pre-treatment and post-treatment of A549 cells with DATS resulted in reduced viral loads, increased expression of anti-viral genes (RIG-I, IRF-3, and interferon-β), and decreased expression of inflammatory cytokines (TNF-α and IL-6). These effects were also observed in H9N2 AIV-infected mice treated with DATS. Such treatment also reduced lung edema and inflammation in mice.ConclusionsResults suggest that DATS has anti-viral activity against H9N2 AIV and may be used as an alternative treatment for influenza virus infection.

Acute toxicity of diallyl sulfide derived from Allium sativum (garlic) in mice and its possible mechanisms

BackgroundDiallyl sulfide (DAS) is a garlic-derived organosulfur compound known for its chemotherapeutic properties, as a strong food additive and a potential radiomitigator. Despite its therapeutic potentials, the apparent lack of toxicity data hinders its clinical applications. PurposeThe present study investigated the pre-clinical toxicity of DAS to identify the maximum tolerable and lethal doses and understand its underlying mechanisms at toxic doses. Study designDAS was administered intraperitoneally to C57BL/6 mice at a range of concentrations (160, 1280, 1600, and 1920 mg/kg). Standard toxicological endpoints (survival, body weight changes, hematology, histopathology, and serum biochemistry) were supported with genotoxicity and molecular studies. Findings were correlated with DAS stability by HPLC. ResultsA single dose of DAS up to 1280 mg/kg was well-tolerated without significant changes in standard toxicological parameters. Death was observed at 1600 mg/kg (1/5 male) and 1920 mg/kg (2/5 female and 3/5 male) doses. DAS at 1920 mg/kg dose level also induced marked pathological changes in the lungs, liver, and reproductive organs. This dose increased hepatic enzyme activities and significantly reduced blood cell count. Inflammatory markers like CD68 and NF-κB were upregulated in the lungs. Propidium iodide stained ovarian and testicular germ cells revealed alterations in cell cycle distribution and increased cell death at 1920 mg/kg dose. At the highest dose of DAS, evidence of genotoxicity in terms of the occurrence of a few double minutes, rings, and fragments appeared. HPLC studies revealed a significant and rapid decrease in the DAS peak area following incubation with canola oil or plasma in vitro. ConclusionOur results indicated that lungs, liver, and reproductive organs are affected at higher DAS doses. Based on the findings, we conclude that excessive usage of DAS should be limited owing to the associated toxicities at higher concentrations (1600 mg/kg and above).

Antioxidant and Anti-Inflammatory Effects of Diallyl Disulfide on Hepatotoxicity Induced by Cyclophosphamide in Rats

Diallyl disulfide (DADS) is a garlic-derived organo-sulfur compound. This study was carried out to investigate the protective potential, antioxidant, and anti-inflammatory effects of this compound against cyclophosphamide (CP)-induced hepatotoxicity in rats. A single intraperitoneal dose of CP (200 mg/kg) resulted in a significant disturbance in hepatic function and oxidative stress, as well as inflammatory biomarkers. In addition, histopathological examination showed distinct changes and increased expression of proliferating cell nuclear antigen in hepatocytes. On the other hand, daily oral preadministration of DADS (200 mg/kg) for 10 days before the CP dose effectively attenuated the hepatotoxicity caused by CP administration as confirmed by significant amelioration of the aforementioned parameters in rat’s liver. It could be concluded that administration of DADS can diminish CP-induced hepatotoxicity through concurrent upregulation of antioxidant and anti-inflammatory responses that denote its possible potential clinical application against side effects of the CP drug.

The effects of storage and hop extract on aroma and flavour compounds in Balkan-style sausages packed under a CO2-containing anaerobic atmosphere

Changes in the levels of pH, lactic acid, acetic acid, headspace volatile compounds, and spoilage odour intensity during a 35 day refrigerated storage period in two sets of a Balkan-style fresh sausage, a control sausage (CON) and a sausage containing an aqueous hop extract (HOP), packaged under a 20% CO2 and 80% N2 atmosphere were evaluated. Storage resulted in progressive sausage acidification and increased the levels of acetic acid, 1-methylbutanol, ethyl acetate, ethyl hexanoate, and 2-ethylhexanol; all of which are associated with anaerobic microbial metabolism under sugar restricted conditions. Storage decreased the levels of hexanal, heptanal, pentanol, and garlic-derived organosulfur compounds. Hop extract showed oxygen scavenging abilities, and decreased the levels of the volatile compounds derived from lipid auto-oxidation while contributing to the presence of specific terpene compounds. The use of hop extract did not improve the shelf life of sausages packed under anaerobic atmosphere. The spoilage odour appeared in both types of sausages on the 14th day, and it was considered strong from day 21 onwards.

S-allylmercaptocysteine ameliorates lipopolysaccharide-induced acute lung injury in mice by inhibiting inflammation and oxidative stress via nuclear factor kappa B and Keap1/Nrf2 pathways

The garlic-derived organosulfur compound S-allylmercaptocysteine (SAMC) has been reported to exhibit anti-inflammatory and anti-oxidative activities, whereas its potential therapeutic effect on lipopolysaccharide (LPS)-induced acute lung injury (ALI) is unknown. In this study, we focused on exploring the therapeutic effects of SAMC on LPS-induced ALI mice and the involvement of underlying molecular mechanisms. BalB/c mice were treated with SAMC (10, 30 and 60 mg/kg) or positive control N-acetylcysteine (NAC, 500 mg/kg) by gavage after intratracheal instillation of LPS for 30 min and were sacrificed 24 h after LPS administration. Our results indicate that the treatment with SAMC not only ameliorated the histological changes but also decreased LPS-triggered lung edema. Moreover, SAMC displayed an anti-inflammatory effect through reducing inflammatory cells infiltration, myeloperoxidase (MPO) formation and inhibiting pro-inflammatory cytokines/mediator production including tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) via suppressing the activation of nuclear factor-kappaB (NF-κB) signaling pathway. Furthermore, SAMC attenuated oxidative stress evoked by LPS via diminishing malondialdehyde (MDA) formation and reversing glutathione (GSH) and superoxide dismutase (SOD) depletion. Meanwhile, SAMC up-regulated expressions of endogenous antioxidant/detoxifying proteins including heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase 1(NQO1) through reversing the suppression of Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid-2 related factor 2 (Nrf2) signaling pathway. Our results demonstrate that SAMC effectively attenuated LPS-induced ALI which was largely dependent upon inhibition of inflammation and oxidative stress via NF-κB and Keap1/Nrf2 signaling pathways.

Evaluation of the Process of Flavoring Olive Oil with Garlic

Garlic-flavored olive oil, containing the garlic-derived organosulfur compound diallyl disulfide (DADS), has become popular and is widely available in markets because of its pleasant aroma. However, few studies have evaluated the process of flavoring olive oil with garlic. This study aimed to investigate the amount of DADS transferred from garlic into olive oil under different flavoring conditions. The effects of time and temperature of heating, duration for which the garlic was left standing after slicing, and amount of sliced garlic added were determined as independent variables. The results indicated that the heating temperature and duration for which the garlic was left standing strongly influenced the amount of DADS transferred. Moreover, increases in the quantity of sliced garlic resulted in improved quality and enhanced antioxidant capacity of the oil and increased the amount of DADS transferred. We determined the optimal conditions for garlic-flavored olive oil preparation by a heating process, based on the amount of DADS transferred and hence its aroma intensity.

Diallyl sulfide alleviates cyclophosphamide-induced nephropathic encephalopathy in rats

Diallyl sulfide (DAS) is a garlic-derived organosulfur compound. The current study was planned to evaluate the protecting effects of DAS against cyclophosphamide (CP)-induced nephropathic encephalopathy. DAS (100 mg/kg) was orally administered for 4 days, 60 min after the last dose, rats were injected with CP (150 mg/kg). DAS treatment before CP significantly decreased serum urea, creatinine, sodium, potassium, calcium, blood urea nitrogen (BUN), C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-1β (IL-1ß) and tumor necrosis factor-alpha (TNF-α) compared with CP-treated rats. DAS treatment decreased malondialdehyde (MDA) and increased superoxide dismutase (SOD) and reduced glutathione (GSH) levels in the renal tissues and significantly attenuated the elevated neurotransmitters N-methyl-D-aspartate/adenosine triphosphate (NMDA), γ-aminobutyric acid (GABA) levels and remarkably restored neuronal nitric oxide (NO) level and nitric oxide synthase (nNOS) activity in the brain compared to CP-treated rats. DAS for 4 consecutive days before CP showed moderate positive immunohistochemically expression of the glial fibrillary acidic protein (GFAP) in the brain and kidney tissues comparable to CP-treated rats. DAS afforded renal and neuroprotection against CP-induced nephropathic encephalopathy due to its capacity to ameliorates the afore-mentioned biochemical parameters which were supported by histopathological and immunohistochemically examination.

Modulation of hydrogen sulfide gasotransmitter limits the proven benefits of garlic

Garlic has been used as a medicinal food for centuries. The biological activity of garlic relies on the presence of highly reactive sulfur compounds. Widespread in vitro and in vivo studies have reported the mechanism of action of the anticancer activity of garlic-derived organosulfur compounds (OSCs) in a wide range of cancer types. Moreover, epidemiological studies support an inverse correlation between garlic intake and cancer risk. More recently, several studies have reported the ability of garlic-derived OSCs to release hydrogen sulfide (H2S) and to affect H2S biosynthesis by altering specific H2S enzyme activity, such as cystathionine-beta-synthase or cystathionine-gamma-lyase. Paradoxically, some studies have reported that overexpression of H2S-producing enzymes is associated with ovarian and colon cancer progression. In this review, we aimed to provide a critical analysis of garlic anticancer activity by documenting our current understanding of the anticancer activity of garlic-derived OSCs. We propose here to raise a mechanistic gap in garlic-mediated anticancer activity by documenting our current knowledge of the role of H2S in cancer biology.

Relationship between consumption of raw garlic and handgrip strength in a large-scale adult population

Garlic-derived organosulfur compounds have numerous potential benefits (e.g. antioxidant and anti-inflammatory effects) on human health. Although these functions might be related to the onset and progression of muscle strength decline, no studies have explored the relationship between garlic consumption and muscle strength in the general population. The aim of this study was to investigate whether raw garlic consumption is related to handgrip strength in a large-scale adult population. A cross-sectional study (n=28,958) was performed in Tianjin, China. Frequency of raw garlic consumption was assessed using a valid self-administered food frequency questionnaire. Handgrip strength was measured using a handheld digital dynamometer. Analysis of covariance and multiple logistic regression were used to evaluate the relationship between raw garlic consumption and handgrip strength. In males, after adjusted potential confounding factors, the least square means (95% confidence intervals) of handgrip strength across raw garlic consumption categories were 42.5 (40.2-44.9) for almost never; 43.0 (40.7-45.5) for <1time/week; 43.4 (41.0-45.8) for 1time/week; and 43.8 (41.5-46.3) for ≥2-3times/week (P for trend <0.0001). The adjusted odds ratios (95% confidence intervals) of low handgrip strength (<20th percentile of handgrip strength) across the categories of raw garlic consumption in males were 1.00, 0.86 (0.76, 0.98), 0.76 (0.67, 0.87), and 0.66 (0.58, 0.74) (P for trend <0.0001). Similar results were also observed in females. The study firstly revealed a positive correlation between raw garlic consumption and handgrip strength in both males and females. Further studies are needed to explore the casual relationship.

Diallyl Trisulfide Enhances Benzo[a]pyrene-induced CYP1A1 Expression and Metabolic Activation in Hepatic HepG2 Cells.

Benzo[a]pyrene (BaP), an environmental pollutant produced by combustion processes, induces expression of cytochrome P450 (CYP) 1A1 via the activation of aryl hydrocarbon receptor (AHR). Induced CYP1A1 is involved in BaP metabolism, resulting in either detoxification or metabolic activation in a context-dependent manner. The effect of diallyl trisulfide (DATS), a garlic-derived organosulfur compound, on BaP metabolism has not been investigated. The combined effect of DATS and BaP on BaP metabolism in hepatocyte-derived HepG2 cells was examined. DATS enhanced BaP-induced CYP1A1 and CYP1B1 mRNA expression, BaP hydroxylation and BaP-DNA adduct formation. Combined treatment of BaP and DATS also increased reactive oxygen species levels. DATS enhanced BaP-induced AHR recruitment and histone H3 acetylation on the CYP1A1 promoter. DATS combined treatment enhances BaP metabolic activation through an AHR-modulating mechanism.

Converting organosulfur compounds to inorganic polysulfides against resistant bacterial infections

The use of natural substance to ward off microbial infections has a long history. However, the large-scale production of natural extracts often reduces antibacterial potency, thus limiting practical applications. Here we present a strategy for converting natural organosulfur compounds into nano-iron sulfides that exhibit enhanced antibacterial activity. We show that compared to garlic-derived organosulfur compounds nano-iron sulfides exhibit an over 500-fold increase in antibacterial efficacy to kill several pathogenic and drug-resistant bacteria. Furthermore, our analysis reveals that hydrogen polysulfanes released from nano-iron sulfides possess potent bactericidal activity and the release of polysulfanes can be accelerated by the enzyme-like activity of nano-iron sulfides. Finally, we demonstrate that topical applications of nano-iron sulfides can effectively disrupt pathogenic biofilms on human teeth and accelerate infected-wound healing. Together, our approach to convert organosulfur compounds into inorganic polysulfides potentially provides an antibacterial alternative to combat bacterial infections.

Whole Transcriptome Sequencing Analysis of the Synergistic Antimicrobial Effect of Metal Oxide Nanoparticles and Ajoene on Campylobacter jejuni.

Two metal oxide (i.e., Al2O3 and TiO2) nanoparticles and ajoene, a garlic-derived organosulfur compound, were identified to be effective antimicrobials against Campylobacter jejuni, a leading cause of human gastrointestinal diseases worldwide. A significant synergistic antimicrobial effect was observed using ajoene and Al2O3/TiO2 nanoparticles in a combined manner to cause at least 8 log10 CFU/mL reduction of C. jejuni cells. Whole transcriptome sequencing (RNA-seq) and confocal micro-Raman spectroscopic analyses revealed the antimicrobial mechanism and identified the roles of ajoene and metal oxide nanoparticles in the synergistic treatment. Ajoene and metal oxide nanoparticles mediated a two-phase antimicrobial mechanism. Ajoene served as the inducing factor at the first phase that caused injury of cell membranes and increased the susceptibility of C. jejuni to stress. Metal oxide nanoparticles served as the active factor at the second phase that targeted sensitive cells and physically disrupted cell structure. This synergistic antimicrobial treatment demonstrates a potential to reduce the prevalence of C. jejuni and other pathogens on food contact surfaces and in the food chain.

Allyl methyl sulfide, an organosulfur compound alleviates hyperglycemia mediated hepatic oxidative stress and inflammation in streptozotocin - induced experimental rats

Therapeutic approaches based on dietary compounds obtained from food products to handle diabetes involving oxidative stress and inflammation. Garlic is a common spice and has a long history as a folk remedy. Allyl methyl sulfide (AMS) is a potential garlic-derived organosulfur compound displaying a substantial range of optimistic actions in various diseases. Herein, we investigated the potential role of AMS in ameliorating the effects of oxidative stress and inflammation in the liver of streptozotocin (STZ)-induced experimental rats. Diabetes was induced by single intraperitoneal (i.p.) injection of STZ (40 mg/kg/b.w). STZ-induced hyperglycemic rats received daily intragastric doses of 50, 100 and 200 mg/kg/b.w of the AMS for 30 days. Dietary intervention of AMS (100 mg/kg b.w) resulted in significant attenuation in blood glucose and expression of pro-inflammatory markers TNF-α, IL-6, NF-κB p65 unit and significant elevation in the plasma insulin level. Moreover, AMS instigated a marked enhance in the levels of hepatic tissue non enzymatic antioxidants and the activities enzymatic antioxidants of diabetic rats with significant decline in lipid peroxides and hydroperoxides formation, serum biomarkers of liver damage, thus representing the protecting efficacy of AMS in hyperglycemic state. The pathological abnormalities in hepatic tissues of diabetic rats were significantly ameliorated by AMS supplementation and offered great support to the biochemical findings. These conclusions explicate the prospective use of AMS as a promising compound against glucotoxicity mediated hepatic oxidative dysfunction in rats. Clinical trials in validating this benefit for optimizing the AMS nutrition are however warranted.

Anticancer effects of garlic and garlic-derived bioactive compounds and its potential status as functional food

Background: Garlic, or Allium savitum, has long been used to treat various diseases, including cancer. The anticancer effects of garlic are linked to the several garlic-derived organosulfur compounds, such as allicin, ajoene, DAS, DADS, DATS, and SAMC. Animal and in vitro studies have demonstrated that garlic bioactive compounds may prevent cancer through mechanisms such as inducing cell cycle arrest, promoting apoptosis, and inhibiting angiogenesis in different cancer cells. Observational studies, including case-control and cohort studies, have been conducted to confirm the protective effect against colorectal, gastric, and other cancers associated with garlic-derived bioactive compounds and raw garlic consumption, but results have been mixed. Analysis of cell and animal model studies and epidemiological studies using the FDA’s evidence-based review system for health claims and FFC’s proposed standard for evaluating and developing functional food, it has been concluded that garlic cannot yet be considered as a functional food primarily due to the inconclusive data from observational studies and insufficient evidence from randomized clinical trials. Keywords: Garlic, cancer, allicin, bioactive compound, functional food

Wnt/β-catenin signaling mediates the suppressive effects of diallyl trisulfide on colorectal cancer stem cells.

Cancer stem cells (CSCs) are responsible for colorectal cancer (CRC) initiation, growth, and metastasis. Garlic-derived organosulfur compound diallyl trisulfide (DATS) possesses cancer suppressive properties. Wnt/β-catenin signaling is a key target for CSCs inhibition. However, the interventional effect of DATS on colorectal CSCs has not been clarified. We aimed to illustrate the regulation of Wnt/β-catenin in DATS-induced colorectal CSCs inhibition. Serum-free medium culture was used to enrich colorectal CSCs. SW480 and DLD-1 sphere-forming cells were treated with different concentrations of DATS for 5 days; LiCl and β-catenin plasmids were used to stimulate the activity of Wnt/β-catenin pathway. The size and number of colonspheres were detected by tumorsphere formation assay; the expression of colorectal CSCs-related genes was detected by Western blotting and qRT-PCR; the capacities of colorectal CSCs proliferation and apoptosis were detected by Cell Counting Kit-8, Hoechst 33258 cell staining and flow cytometry, respectively. The levels of colorectal CSCs markers were elevated in the tumorspheres cells. DATS efficiently suppressed the activity of colorectal CSCs, as evidenced by reducing the size and number of colonspheres, decreasing the expression of colorectal CSCs markers, promoting apoptosis and inhibiting the proliferation of colorectal CSCs. Moreover, DATS suppressed the activity of Wnt/β-catenin pathway, while upregulation of Wnt/β-catenin diminished the inhibitory effect of DATS on colorectal CSCs. Wnt/β-catenin pathway mediates DATS-induced colorectal CSCs suppression. These findings support the use of DATS for targeting colorectal CSCs.

A possible mechanism of inhibition of U87MG and SH-SY5Y cancer cell proliferation by diallyl trisulfide and other aspects of its activity

The study was conducted to elucidate the mechanism of antiproliferative and antioxidative action of diallyl trisulfide (DATS), a garlic-derived organosulfur compound. Changes in the l-cysteine desulfuration, and the levels of cystathionine and non-protein thiols in DATS-treated human glioblastoma (U87MG) and neuroblastoma (SH-SY5Y) cells were investigated. The inhibition of proliferation of the investigated cells by DATS was correlated with an increase in the inactivated form of Bcl-2. In U87MG cells, an increased level of sulfane sulfur and an increased activity of 3-mercaptopyruvate sulfurtransferase (MPST) and rhodanese, the enzymes involved in sulfane sulfur generation and transfer, suggest that DATS can function as a donor of sulfane sulfur atom, transferred by sulfurtransferases, to sulfhydryl groups of cysteine residues of Bcl-2 and in this way lower the level of active form of Bcl-2 by S-sulfuration. Diallyl trisulfide antioxidative effects result from an increased level of cystathionine, a precursor of cysteine, and an increased glutathione level. MPST and rhodanese, the level of which is increased in the presence of DATS, can serve as antioxidant proteins.

P4 Diallyl Trisulfides, a garlic-derived organosulfur compound, attenuates vascular metastasis of hypoxic breast cancer cells by targeting the thioredoxin system

Metastasis is the leading cause of high mortality in breast cancer patients. As is shown by numerous clinical studies and research data, intra-tumor hypoxia is closely related to the fatality rate of breast cancer patients, which may suggest that HIF-1α expression plays a contributory role in breast cancer metastasis. DATS was screened out from the garlic fat-soluble components on the basis of HIF-1α transcriptional activity. DATS not only demonstrated that it could effectively inhibit HIF-1α transcriptional activity, but that it also affected the mRNA levels of its direct target genes LOX, ANGPTL4 and LOXL-4 to varying degrees. DATS attenuated the metastatic potential of MDA-MB-231 cells in hypoxia-induced embryonic zebrafish assays, xenograft and orthotopic tumor assays. Those results also showed that DATS could dose-dependently inhibit the migration and angiogenesis of MDA-MB-231 cells using EC-cancer cell adhesion, wound-healing, transwell and tube formation in vitro experiments. Inhibition of L1CAM, EMT-related proteins (Slug, Snail, MMP-2) and VEGF-A protein expression was also induced by DATS. DATS modulates HIF-1α not only at the protein level but also via direct inhibition of its activity through its effects on upstream Trx-1 protein level. DATS also inhibits the enzyme activity of Trx reductase in breast cancer cells. In keeping with reduced Trx-1 nuclear translocation from cytoplasm by DATS, the production of the reduced form of Trx-1 was dramatically decreased. Collectively, this present study indicates that targeting the Trx system with DATS may provide a promising strategy for treating metastasis in breast cancer.