Diallyl Disulfide Treatment Research Articles

Diallyl disulfide attenuates hydrogen peroxide-induced oxidative damage of ovine rumen epithelial cells through the nuclear factor erythroid-2 related factor 2 signaling pathway

Abstract This study investigated the impact of diallyl disulfide (DADS) on oxidative stress induced by hydrogen peroxide (H2O2) in ovine rumen epithelial cells (RECs). Initially, the effects of DADS were evaluated on cellular reactive oxygen species (ROS) levels, antioxidant capacity in RECs were estimated. Then, RNA-seq analysis was conducted in DADS-treated and untreated cells to analyze the differential gene expression, as well as Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Finally, the effects of DADS on Kelch-like ECH associated protein 1/the nuclear factor erythroid 2-related factor 2 (Keap1/Nrf2) signaling pathway in RECs were evaluated. Results showed that DADS remarkably enhanced superoxide dismutase (SOD) activity and total antioxidant capacity (T-AOC) (P < 0.05) while reducing ROS and malonaldehyde production (P < 0.05) in H2O2-treated RECs. Transcriptomic analysis revealed that DADS might influence glutathione synthesis through cysteine and methionine metabolism, thereby affecting the transcription of genes involved in immunity and oxidative stress. The DADS treatment resulted in increased nuclear translocation of Nrf2 and upregulation of mRNA and protein levels of quinone oxidoreductase 1, heme oxygenase 1, and Nrf2. The Nrf2-specific inhibitor nullified the protective effects of DADS on malonaldehyde formation induced by H2O2 and decreased T-AOC and SOD activities. In conclusion, DADS demonstrated the ability to alleviate oxidative stress in RECs by promoting antioxidative capacity through the Keap1/Nrf2 signaling pathway.

Diallyl disulfide inhibits proliferation, epithelial—mesenchymal transition, and invasion through RORα-mediated downregulation of Wnt1/β-catenin pathway in gastric cancer cells

Overactivation of Wnt/β-catenin pathway due to dysfunction of retinoid-related orphan receptor α (RORα) is related to cancer development and progression. Diallyl disulfide (DADS), an active component of garlic, has been reported in our previous study for upregulation of RORα expression in gastric cancer (GC) cells. It remains to be elucidated the role and mechanism of RORα in DADS against GC. This study revealed that DADS treatment resulted in reduced expression levels of Wnt1, β-catenin, TCF-4, intranuclear β-catenin and p-β-catenin in GC cells, concomitant with the compromised expression of β-catenin target genes (Axin, c-Jun, and c-Myc). RORα overexpression augmented DADS-induced downregulation of Wnt1/β-catenin pathway, G2/M phase arrest, and cell growth inhibition in vitro and in vivo. Contrarily, knockdown of RORα attenuated these effects of DADS. Interestingly, DADS induced an increase in the binding of RORα to β-catenin, which may lead to reduction of β-catenin phosphorylation and nuclear translocation. This interplay modulated by DADS may affect β-catenin target gene expression for that the opposite results were observed in DADS-treated RORα knockdown and overexpression cells. DADS caused a decrease in vimentin, snail and MMP-9, as well as an increase in E-cadherin and TIMP3 expression, which restricted epithelial‑mesenchymal transition (EMT), migration, and invasion. The aforementioned effects of DADS were weakened simultaneously when the suppression of DADS on the Wnt1/β-catenin pathway was resisted by knockdown of RORα. In contrast, overexpression of RORα enhanced the effects of DADS. Therefore, RORα-mediated downregulation of Wnt1/β-catenin pathway could undertake an important role in anticancer activity of DADS against GC cell proliferation, EMT, migration, and invasion.

Diallyl disulfide prevents 1,3-dichloro-2-propanol-induced hepatotoxicity through mitogen-activated protein kinases signaling

We investigated whether diallyl disulfide (DADS) has protective effects against 1,3-dichloro-2-propanol (1,3-DCP)-induced hepatotoxicity and oxidative damage in rats and HepG2 cells. DADS was administered to rats once daily for 7 days at doses of 30 and 60 mg/kg/day. One hour after the final DADS treatment, the rats were administered 90 mg/kg 1,3-DCP to induce acute hepatotoxicity. DADS treatment significantly suppressed the increase in serum aminotransferase levels induced by 1,3-DCP administration, and reduced histopathological alterations in the liver. DADS treatment reduced 1-3-DCP-induced apoptotic changes in the liver, as revealed by terminal deoxynucleotidyl transferase dUTP nick end labeling staining and immunohistochemistry for caspase-3. DADS treatment competitively inhibited or reduced cytochrome p450 2E1 (CYP2E1) expression, which is involved in the metabolic activation of 1,3-DCP, and enhanced antioxidant properties. Furthermore, DADS treatment inhibited phosphorylation of mitogen-activated protein kinases (MAPKs) and apoptotic signaling. In in vitro experiments, MAPKs inhibitors reduced the expression of Bax/Bcl-2/Caspase 3 signaling, which effects were more significant in co-treated cells with DADS and MAPKs inhibitors. In conclusion, the protective effect of DADS against 1,3-DCP-induced hepatotoxicity may be related to blocking the metabolic activation of 1,3-DCP by suppressing CYP2E1 expression, inducing antioxidant enzyme activity, and reducing apoptotic activity by inhibiting phosphorylation of MAPKs.

Garlic Volatile Diallyl Disulfide Induced Cucumber Resistance to Downy Mildew

Allicin compositions in garlic are used widely as fungicides in modern agriculture, in which diallyl disulfide (DADS) is a major compound. Downy mildew, caused by Pseudoperonospora cubensis (P. cubensis), is one of the most destructive diseases and causes severe yield losses in cucumbers. To explore the potential mechanism of DADS-induced cucumber resistance to downy mildew, cucumber seedlings were treated with DADS and then inoculated with P. cubensis at a 10-day interval. Symptom observation showed that DADS significantly induced cucumber resistance to downy mildew. Furthermore, both lignin and H2O2 were significantly increased by DADS treatment to responding P. cubensis infection. Simultaneously, the enzyme activities of peroxidase (POD) in DADS-treated seedlings were significantly promoted. Meanwhile, both the auxin (IAA) and salicylic acid (SA) contents were increased, and their related differentially expressed genes (DEGs) were up-regulated when treated with DADS. Transcriptome profiling showed that many DEGs were involved in the biological processes of defense responses, in which DEGs on the pathways of ‘phenylpropanoid biosynthesis’, ‘phenylalanine metabolism’, ‘MAPK signaling’, and ‘plant hormone signal transduction’ were significantly up-regulated in DADS-treated cucumbers uninoculated with the pathogen. Based on the results of several physiological indices and transcriptomes, a potential molecular mechanism of DADS-induced cucumber resistance to downy mildew was proposed and discussed. The results of this study might give new insight into the exploration of the induced resistance mechanism of cucumber to downy mildew and provide useful information for the subsequent mining of resistance genes in cucumber.

Garlic Allelochemical Diallyl Disulfide Alleviates Autotoxicity in the Root Exudates Caused by Long-Term Continuous Cropping of Tomato.

Continuous cropping obstacles seriously affect the sustainable production of tomatoes (Solanum lycopersicum L.). Researchers have found that intercropping with garlic (Allium sativum L.) could alleviate tomato continuous cropping obstacles. Diallyl disulfide (DADS) is the main allelochemical in garlic. However, the mechanism of DADS in alleviating tomato continuous cropping obstacles is still unknown. In this research, aqueous extracts of tomato continuous cropping soil were used to simulate the continuous cropping condition of tomato. Our results showed that DADS increased root activity and chlorophyll content and improved the activity of antioxidant enzymes (superoxide dismutase (SOD), peroxidase (POD), and phenylalanine ammonia-lyase (PAL)) and the metabolism of nonenzymatic antioxidants (glutathione (GSH) and oxidized glutathione (GSSG)) in tomato plants. DADS treatment reduced the content of fatty acid esters in tomato root exudates (e.g., palmitate methyl ester, palmitoleic acid methyl ester, oleic acid methyl ester) and increased the level of substances such as dibutyl phthalate and 2,2'-methylenebis(6-tert-butyl-4-methylphenol). The higher concentrations of palmitate methyl ester inhibited tomato hypocotyl growth, while oleic acid methyl ester inhibited tomato root growth. Moreover, the application of DADS significantly inhibited the secretion of these esters in the root exudates. Therefore, it suggests that DADS may increase tomato resistance and promote tomato plant growth by increasing root activity and photosynthetic capacity and development to reduce autotoxicity of tomato.

The Antifungal Effect of Garlic Essential Oil on Phytophthora nicotianae and the Inhibitory Component Involved.

This study explored the chemical compositions of garlic essential oil, the inhibitory activity of garlic essential oil and diallyl disulfide (DADS) against Phytophthora nicotianae, and the effects on mycelial plasma membrane permeability and P. nicotianae inhibition. In total, 29 compounds were detected in garlic essential oil, of which 26 were detected by gas chromatography‒mass spectrometry (GC-MS) and 21 by headspace solid-phase microextraction (HS-SPME) GC-MS. DADS (60.12% and 19.09%) and trisulfide di-2-propenyl (14.18% and 17.98%) were the major components identified by HS-SPME GC-MS and GC-MS analysis, respectively. Half-inhibitory concentration (Ec50, antagonism) and minimum inhibitory concentration (MIC, fumigation) of DADS against P. nicotianae were 150.83 μL/L and 20 μL/L, respectively, while Ec50 of garlic essential oil was 1108.25 μL/L. Mycelial membrane permeability gradually increased in a concentration-dependent manner, and cell death increased at 450 μL/L DADS. Furthermore, DADS treatment significantly reduced the incidence of tobacco black shank and the number of P. nicotianae pathogens in rhizosphere soil. DADS also promoted root development of tobacco seedlings at low concentrations, which was inhibited at high concentrations. Therefore, DADS may play an important role in the antifungal effect against P. nicotianae by destroying mycelial cell membrane integrity, causing an increase in cell membrane permeability, and leading to cell death.

Diallyl Disulfide Induces Apoptosis and Autophagy in Human Osteosarcoma MG-63 Cells through the PI3K/Akt/mTOR Pathway.

Diallyl disulfide (DADs), a natural organic compound, is extracted from garlic and scallion and has anti-tumor effects against various tumors. This study investigated the anti-tumor activity of DADs in human osteosarcoma cells and the mechanisms. MG-63 cells were exposed to DADs (0, 20, 40, 60, 80, and 100 μM) for different lengths of time (24, 48, and 72 h). The CCK8 assay results showed that DADs inhibited osteosarcoma cell viability in a dose-and time-dependent manner. FITC-Annexin V/propidium iodide staining and flow cytometry demonstrated that the apoptotic ratio increased and the cell cycle was arrested at the G2/M phase as the DADs concentration was increased. A Western blot analysis was employed to detect the levels of caspase-3, Bax, Bcl-2, LC3-II/LC3-I, and p62 as well as suppression of the mTOR pathway. High expression of LC3-II protein revealed that DADs induced formation of autophagosome. Furthermore, DADs-induced apoptosis was weakened after adding 3-methyladenine, demonstrating that the DADs treatment resulted in autophagy-mediated death of MG-63 cells. In addition, DADs depressed p-mTOR kinase activity, and the inhibited PI3K/Akt/mTOR pathway increased DADs-induced apoptosis and autophagy. In conclusion, our results reveal that DADs induced G2/M arrest, apoptosis, and autophagic death of human osteosarcoma cells by inhibiting the PI3K/Akt/mTOR signaling pathway.

Diallyl Disulfide From Garlic Oil Inhibits Pseudomonas aeruginosa Quorum Sensing Systems and Corresponding Virulence Factors.

Previously, we determined that diallyl disulfide (DADS) from garlic oil can inhibit Pseudomonas aeruginosa PAO1 pathogenic factors by inactivating the transcription of key genes from three quorum sensing (QS) systems (las, rhl, and pqs) based on the effects of DADS on growth, virulence factor production (elastase, pyocyanin, biofilm, and swarming motility), and RNA transcription (real-time q-PCR). To further investigate the mechanisms underlying the inhibition of the three P. aeruginosa QS systems by DADS, high-throughput RNA and proteome sequencing techniques were used to study differences in the transcriptional and proteome expression of P. aeruginosa PAO1 following treatment with DADS. The RNA-seq and proteomic data are available via NCBI Gene Expression Omnibus database with accession number GSE118801 and ProteomeXchange with identifier PXD011144, respectively. The experimental results indicated that all key genes of the three QS systems (las, rhl, and pqs) of P. aeruginosa PAO1 as well as the virulence factors (including exoprotease LasA, elastase LasB, lectin LecA and LecB, pyocyanin biosynthesis, and biofilm formation) regulated by these three QS systems were inhibited. This is consistent with our previous studies on the physiology, biochemistry, and RNA expression of P. aeruginosa treated with DADS. Additionally, our results also indicated that bacterial motility, chemotaxis, and two-component systems were inhibited by DADS treatment. All these changes abolish the sensitivity of P. aeruginosa PAO1 to environmental stimuli and cause the cells to be in a state of passivation. Further research is needed to determine how QS systems regulate these functions. Our findings could potentially contribute to the treatment and control of P. aeruginosa infection, virulence, and pathogenicity.

Diallyl disulfide suppresses FOXM1-mediated proliferation and invasion in osteosarcoma by upregulating miR-134.

Diallyl disulfide (DADS), a volatile component of garlic oil, exerts anticancer activity in various types of cancers, while its anticancer effects against osteosarcoma (OS) have not been previously explored. This study aimed to investigate the anticancer potential of DADS in OS and to explore the underlying mechanisms. DADS reduced the cell viability and increased the expression of miR-134 in OS cell lines, and this effect was in a time- and concentration-dependent manner. Furthermore, in vitro functional assays revealed that DADS significantly inhibited the proliferation and invasion of human OS U2OS and MG-63 cells, which was partially reversed by miR-134 inhibitor transfection. DADS exhibited in vivo antitumor activity and upregulated miR-134 expression in xenograft tumors. Downregulation of miR-134 attenuated DADS-induced antitumor capacity. Further bioinformatics prediction analysis revealed that the 3'-untranslated region (3'-UTR) of Forkhead Box M1 (FOXM1) harbored miR-134-binding sites, and overexpression of miR-134 repressed the luciferase activity of the reporting vector containing FOXM1 3'-UTR. Both miR-134 overexpression and DADS inhibited FOXM1 expression in U2OS cells, while enforced expression of FOXM1 suppressed DADS-induced antiproliferation and anti-invasion capacity in U2OS cells. Furthermore, DADS treatment led to significant downregulation of cyclin D1, c-myc, and lymphoid enhancer-binding factor 1 expression, but the remarkably upregulated p21 level in U2OS cells. Collectively, DADS could be a promising anticancer agent for OS, and the underlying mechanisms might be associated with the antiproliferation and anti-invasion properties through upregulating miR-134 expression.

Diallyl disulfide, a garlic-rich compound ameliorates trichloromethane-induced renal oxidative stress, NFkB activation and apoptosis in rats

Summary The renal-protective effect of diallyl disulfide (DADS) on tricholoromethane (CHCl3)-induced renal toxicity was investigated. Twenty five rats, divided into five groups of five animals each were used. CHCl3 at the dose of 200 mg/kg was orally administered, and concomitantly treated with DADS (50 mg/kg), 5 days/week for a period of 3 weeks. Compared with control, there was no significant increase in kidney malondialdehyde (MDA), but a significant increase in levels of nuclear factor kappa B (NFkB) expressions, TUNEL positive cells (apoptosis), as well as hydrogen peroxide (H2O2), nitric oxide (NO) and reduced glutathione (GSH) concentrations. In addition, a significant decrease in expressions of kidney p53 and catalase (CAT) activity, and a non-significant decrease in glutathione peroxidase (GPx) activity were recorded following CHCl3 administration. Conversely, following DADS treatment, there was a significant increase in the expressions of p53, and a significant and non-significant decrease in apoptotic positive cells and NFkB expressions respectively. Administration of DADS significantly reduced the levels of H2O2 and NO, but did not have effect on the level of GSH, while CAT and GPx activities were significant improved. Protection by DADS against TCM-induced renal-toxicity may therefore be via suppressions of NFkB activation, oxidative stress and apoptosis in rats.

The garlic allelochemical DADS influences cucumber root growth involved in regulating hormone levels and modulating cell cycling

Most allelochemicals are phytotoxic to the receiver plants and may influence the cell micro- and ultrastructure, cell division, phytohormone levels, and ultimately growth. In order to understand the allelopathic potential of garlic, the effects of its main bioactive allelochemical diallyl disulfide (DADS), experiments were carried out to observe the seed germination, root growth, and developmental responses in cucumber seedlings treated with various concentrations of DADS. The obtained data suggested active influence of DADS on cucumber root growth and development. Significant responses were observed in early root growth and elongation, mitotic cell division and elongation, and root architecture modulation. The effect, however, was dose dependent, and lower concentrations of DADS proved to be promotional whereas higher concentrations of DADS inhibited cucumber root growth and development. Relative root elongation (RRE) revealed that DADS could increase growth of cucumber roots in the early developmental days. Moreover, DADS application significantly influenced mitosis-related gene expression. Observed genes CYCA and CDKB were initially downregulated in the first 24 h but significantly upregulated after 48 h, while gene CDKA was upregulated in the first 24 h. Similarly, DADS application significantly altered primary plant hormones, such as IAA, ABA, GA3, and ZR, in the cucumber roots. Taken together, low concentrations of DADS treatment could promote cucumber root growth and induce main root elongation by upregulating CDKA and CDKB gene expression and regulating hormone balance in root. The current findings offer insight into the allelopathic potential of garlic allelochemical DADS and can be considered vital for establishing plant allelopathic studies.

Tristetraprolin: A novel target of diallyl disulfide that inhibits the progression of breast cancer.

Diallyl disulfide (DADS), a volatile component of garlic oil, has various biological properties, including antioxidant, antiangiogenic and anticancer effects. The present study aimed to explore novel targets of DADS that may slow or stop the progression of breast cancer. First, xenograft tumor models were created by subcutaneously injecting MCF-7 and MDA-MB-231 breast cancer cells into nude mice. Subsequently, western blot analysis was performed to investigate the expression of tristetraprolin (TTP), urokinase-type plasminogen activator (uPA) and matrix metalloproteinase-9 (MMP-9) in the xenograft tumors, and cell cultures. Tablet cloning, Transwell and wound healing assays revealed that DADS treatment significantly inhibited the proliferation, invasion and migration of breast cancer cells. In addition, DADS treatment led to significant downregulation of uPA and MMP-9 protein expression, but significantly upregulated TTP expression in vivo and in vitro. Knocking down TTP expression using small interfering RNA reversed the aforementioned effects of DADS, which suggests TTP is a key target of DADS in inhibiting the progression of breast cancer.

Diallyl disulfide effect on the invasion and migration ability of HL-60 cells with a high expression of DJ-1 in the nucleus through the suppression of the Src signaling pathway.

The present study examined the effect of diallyl disulfide (DADS) on the invasion and migration ability of HL-60 cells with a high expression of parkinsonism associated deglycase (DJ-1) in the nucleus (HHDN), and its molecular mechanism. A western blot assay was used to measure the effects of DADS and an Src inhibitor on the expression of DJ-1 and the Src signal pathway in HHDN. The effects of DADS and Src inhibitors on the invasion and migration ability of HHDN was detected using Transwell migration and invasion chamber experiments. The experiments were divided into three groups: A control group (HL-60 cells), an empty vector group and a high expression group (HHDN cells). Western blot assays revealed that the expression of DJ-1 in HHDN was inhibited in a time-dependent manner following treatment with DADS for 24, 48 and 72 h. Following DADS treatment, the expression of phosphorylated Src (p-Src) and phosphorylated Fak (p-Fak) were significantly decreased in all groups compared with the untreated groups, however the expression level of Src, Fak and integrin did not change significantly. Western blot analysis results revealed that following treatment with DADS and Src inhibitor, the expression levels of p-Src and p-Fak significantly decreased in all three groups compared with untreated groups, whereas the expression levels of Src, Fak and integrin did not change significantly. The expression of DJ-1 in HHND was inhibited in time-dependent manner following treatment with DADS and Src inhibitor for 24, 48 and 72 h. Transwell migration and invasion assay results revealed that DADS and Src inhibitors may suppress migration and invasion in leukemic cells, and a combination of the two treatments may result in more efficient suppression. DADS may downregulate DJ-1-mediated invasion and migration in leukemic cells through suppressing the Src-Fak-Integrin signaling pathway, and the Src inhibitor may enhance the antitumor effect of DADS.

Antiarthritic Activity of Diallyl Disulfide against Freund's Adjuvant-Induced Arthritic Rat Model.

Diallyl disulfide (DADS) is an organosulfur compound derived mainly from garlic and genus Allium plants, which possess diverse biological properties. The aim of the present study was to evaluate the antiarthritic activity of DADS in rats with arthritis induced using complete Freund's adjuvant (CFA). DADS (20 mg/kg and 50 mg/kg) was administered and tested against CFA-induced arthritic rats by assessing various parameters: body weight, paw volume, arthritic score, organ indices (spleen and thymus), hematological and biochemical parameters, and proinflammatory cytokines. Histopathological analyses were also performed. The treatment of rats with DADS provoked significant reductions in paw volume, edema formation, arthritic score, and organ indices, together with significant improvement in body weight. DADS treatment also improved joint destruction and reduced inflammation, which was supported by histopathological studies. DADS significantly reduced the white blood cell count and improved red blood cell count in CFA-induced rats. The anti-arthritic activity in the CFA-induced rats was further confirmed by biochemical analysis. These findings suggest that DADS prevented cartilage destruction, improved health status, and reduced inflammation by decreasing the expression of proinflammatory cytokines in arthritis-induced rats. Hence, DADS may be a potential therapeutic candidate for the treatment of rheumatoid arthritis.

Expression of heat-shock protein genes in Apis mellifera meda (Hymenoptera: Apidae) after exposure to monoterpenoids and infestation by Varroa destructor mites (Acari: Varroidae)

Heat shock proteins (hsps) protect proteins in eukaryotic cells from damage. Expression of hsps in insects subject to different environmental stimuli is poorly characterized. Here, levels of expression of the hsps genes (hsp40, hsp70, and hsp90) were recorded in Apis mellifera Linnaeus (Hymenoptera: Apidae) workers after exposure to sublethal concentrations of thymol, eucalyptol, α-pinene, trans-anethole, diallyl disulfide and infestation with Varroa mites. Our results show a dose-dependent up-regulation in the levels of all the hsps tested after the bees were treated with thymol, eucalyptol and α-pinene. Although these up-regulated expressions were statistically significant for hsp70 and hsp90 when the bees were treated with thymol and eucalyptol, they were not significant when treated with α-pinene. In addition, significant down-regulated expressions of the hsp genes were recorded in the diallyl disulfide treatment. The transcriptions of all the hsps tested were significantly down-regulated when pupae were infested with different numbers (0-5) of Varroa mites. Thus, it is likely that hsps can be used as biomarkers of survival when honey bees are under toxic and pathogenic stress, but this needs to be confirmed.

Transcriptomic insights into the allelopathic effects of the garlic allelochemical diallyl disulfide on tomato roots.

Garlic is an allelopathic crop that can alleviate the obstacles to continuous cropping of vegetable crops. Diallyl disulfide (DADS), one of the most important allelochemicals in garlic, promotes tomato root growth. Therefore, the global transcriptome profiles of DADS-treated tomato roots over time were investigated to reveal the potential growth-promoting mechanisms. We detected 1828, 1296 and 1190 differentially expressed genes (DEGs) in the 4, 24 and 48 h samples, respectively. Most DEGs involved in assimilatory sulfate reduction and glutathione metabolism were up-regulated after short-term (4 h) DADS treatment. In addition, increased activity of defensive enzymes and up-regulation of six peroxidase genes were observed, suggesting that DADS could induce tomato resistance. In plant-pathogen interactions, DEGs related to calcium signaling were primarily inhibited, while those encoding pathogenesis-related proteins were primarily up-regulated. Although plant hormone synthesis and signal transduction were both significantly affected by DADS, the expression trends of the genes in these two pathways were conflicting. This research provides comprehensive information concerning the changes in the tomato root transcriptome affected by DADS and may help direct further studies on DADS-responsive genes to enhance the current understanding of the mechanisms by which DADS alleviates the obstacles to continuous cropping.

Mechanism of protection by diallyl disulfide against cyclophosphamide-induced spermatotoxicity and oxidative stress in rats

The present study investigated the protective effects and the mechanism of action of diallyl disulfide (DADS) against cyclophosphamide (CP)-induced spermatotoxicity and oxidative damage in rats. DADS (50 mg/kg/day) was administered orally to rats once daily for 10 days. On the first 2 days, CP (150 mg/kg/day) was injected intraperitoneally to rats 1 h after DADS treatment. CP caused decreases in body weight, food consumption, epididymal sperm motility, and the number of spermatogenic germ cells and increases in the testes and epididymides weights, spermatogenic cell apoptosis, and histopathologic alterations in the testis. The significant decreases in glutathione content and catalase, glutathione S-transferase, and glutathione reductase activities and the significant increase in malondialdehyde content indicated that CP-induced testicular toxicity was mediated through oxidative stress. In contrast, DADS administration significantly attenuated the spermatotoxicity of CP, including attenuating the decreases in sperm motility and the number of spermatogenic germ cells and the increases in reproductive organ weights, oxidative stress, apoptotic changes, and histopathologic alterations. DADS also significantly increased CYP2B1/2 and CYP3A1 expression and significantly decreased CYP2C11 expression. The results show that the protective effects of DADS against CP-induced spermatotoxicity may be mediated by its ability to decrease metabolic activation of CP by inhibiting CYP2C11 and inducing CYP3A1, and by its potent antioxidant and antiapoptotic effects.

The Garlic Allelochemical Diallyl Disulfide Affects Tomato Root Growth by Influencing Cell Division, Phytohormone Balance and Expansin Gene Expression.

Diallyl disulfide (DADS) is a volatile organosulfur compound derived from garlic (Allium sativum L.), and it is known as an allelochemical responsible for the strong allelopathic potential of garlic. The anticancer properties of DADS have been studied in experimental animals and various types of cancer cells, but to date, little is known about its mode of action as an allelochemical at the cytological level. The current research presents further studies on the effects of DADS on tomato (Solanum lycopersicum L.) seed germination, root growth, mitotic index, and cell size in root meristem, as well as the phytohormone levels and expression profile of auxin biosynthesis genes (FZYs), auxin transport genes (SlPINs), and expansin genes (EXPs) in tomato root. The results showed a biphasic, dose-dependent effect on tomato seed germination and root growth under different DADS concentrations. Lower concentrations (0.01–0.62 mM) of DADS significantly promoted root growth, whereas higher levels (6.20–20.67 mM) showed inhibitory effects. Cytological observations showed that the cell length of root meristem was increased and that the mitotic activity of meristematic cells in seedling root tips was enhanced at lower concentrations of DADS. In contrast, DADS at higher concentrations inhibited root growth by affecting both the length and division activity of meristematic cells. However, the cell width of the root meristem was not affected. Additionally, DADS increased the IAA and ZR contents of seedling roots in a dose-dependent manner. The influence on IAA content may be mediated by the up-regulation of FZYs and PINs. Further investigation into the underlying mechanism revealed that the expression levels of tomato EXPs were significantly affected by DADS. The expression levels of EXPB2 and beta-expansin precursor were increased after 3 d, and those of EXP1, EXPB3 and EXLB1 were increased after 5 d of DADS treatment (0.41 mM). This result suggests that tomato root growth may be regulated by multiple expansin genes at different developmental stages. Therefore, we conclude that the effects of DADS on the root growth of tomato seedlings are likely caused by changes associated with cell division, phytohormones, and the expression levels of expansin genes.

Involvement of calreticulin in cell proliferation, invasion and differentiation in diallyl disulfide-treated HL-60 cells.

Diallyl disulfide (DADS) has shown potential as a therapeutic agent in various cancers. Previously, calreticulin (CRT) was found to be downregulated in differentiated HL-60 cells treated with DADS. The present study investigated the role of CRT proteins in DADS-induced proliferation, invasion and differentiation in HL-60 cells. The present study demonstrated that DADS treatment significantly changed the morphology of HL-60 cells and caused the significant time-dependent downregulation of CRT. Small interfering RNA (siRNA)-mediated knockdown of CRT expression significantly inhibited proliferation, decreased invasion ability, increased the expression of cluster of differentiation (CD)11b and reduced the expression of CD33 in DADS-treated HL-60 cells. DADS also significantly affected cell proliferation, invasion and differentiation in CRT-overexpressed HL-60 cells. Nitroblue tetrazolium (NBT) reduction assays showed decreased NBT reduction activity in the CRT overexpression group and increased NBT reduction in the CRT siRNA group. Following treatment with DADS, the NBT reduction abilities in all groups were increased. In conclusion, the present study clearly demonstrates the downregulation of CRT during DADS-induced differentiation in HL-60 cells and indicates that CRT is involved in cell proliferation, invasion and differentiation in DADS-treated HL-60 cells.

The Effect of Garlic Derivatives (S-Allylmercaptocysteine, Diallyl Disulfide, and S-Allylcysteine) on Gentamicin Induced Ototoxicity: An Experimental Study.

ObjectivesGentamicin is a potent aminoglycoside antibiotic. Ototoxicity and nephrotoxicity are the main side effects which restrict the use of gentamicin. Garlic with its intrinsic antioxidant activity may prove beneficial in prevention from ototoxicity. S-allylmercaptocysteine (SAMC), diallyl disulfide (DD), and S-allylcysteine (SAC) are three active compounds found in garlic. In this study, we investigated the effect of SAMC, DD, and SAC on the ototoxicity induced by gentamicin in rats, by using brainstem evoked response audiometry (BERA).MethodsThirty male Wistar rats with intact Preyer’s reflex initially weighing 220–260 g were randomly assigned to either the gentamicin injection with SAMC treatment group (Genta-w SAMC), DD treatment group (Genta-w DD), SAC treatment group (Genta-w SAC), gentamicin injection without any active compounds (AC) treatment groups (Genta-w/o AC), or control group (n=6 rats each group). Gentamicin was given 120-mg/kg body weight, intraperitoneally once daily for 25 days to subjects in all groups except the control group. SAMC 100-mg/kg, and DD 50-mg/kg body weight were given intragastrically, and SAC 250-mg/kg body weight was given intraperitoneally once daily to subjects in Genta-w SAMC, and Genta-w DD, and Genta-w SAC groups, respectively during the study. After 25 days hearing thresholds were evaluated by using BERA test.ResultsThe mean amplitude of auditory thresholds (sensation level [SL]) measured by using BERA for the Genta-w SAMC, Genta-w DD, Genta-w SAC, Genta-w/o AC, and control groups were 22±8, 25±5, 30±9, 54±11, and 10±7 dB SL, respectively (mean±SD). The differences between every active compound group (Genta-w SAMC, Genta-w DD, and Genta-w SAC) and Genta-w/o AC were statistically significant (P<0.016).ConclusionSAMC, DD, and SAC are derivative of garlic seems to attenuate aminoglycoside-induced hearing loss. The effect of SAMC and DD seems to be more prominent than that of SAC.