Diallyl Sulfide Research Articles

The Effect of Different Extraction Procedures on Antioxidant Activity of Garlic (Allium sativum L.) Essential Oil

This paper studies the effect of different extraction procedures such as soxhlet extraction using n-hexane, distillation method and supercritical extraction (SFE) on the physicochemical properties of garlic essential oil. The yield of garlic essential oil by soxhlet extraction, steam distillation and SFE-CO2 methods was approximately 0.441, 0.124 and 0.465 %, respectively. The results of the oil analysis by gas chromatography/mass spectrometry method show the presence of five major compounds, including diallyl sulfide, diallyl disulfide, 3-vinyl-1,2-dithiacyclohex-4-ene, 3-vinyl-1,2-dithiacyclohex-5-ene and diallyl trisulfide. The antioxidant activity of the essential oil obtained by the SFE-CO2 method was significantly higher than by the distillation method, but was lower than the acid ascorbic one.
 Keywords
 Garlic essential oil, SFE, GC-MS, antioxidant activity, extraction.
 References
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Relaxant effect of diallyl sulfide on nonpregnant rat uterus: Involvement of voltage-dependent calcium channels.

We aimed to determine the effect and mechanism of action of diallyl sulfide (DAS), an active component of sulfur-containing foods such as garlic on rat uterine activity. Isometric tension changes in longitudinal uterine strips obtained from 20 female Sprague-Dawley rats (250-300 g) in estrus stage of estrous cycle were studied in isolated organ baths containing Krebs-Henseleit solution. Diallyl sulfide (10-8 -10-6 M) caused a concentration-dependent relaxation on KCl (60 mM)-induced contractions and inhibited spontaneous peristaltic activity of uterine strips (P < 0.05). None of the following antagonists significantly changed the inhibitory effect of DAS on both KCl-precontracted uterine strips and spontaneous peristaltic activity of the uterus (P > 0.05): nitric oxide synthase inhibitor L-NAME (10-4 M), hydrogen sulfide-producing enzymes cystation β synthase and cystation γ-lyase inhibitors, aminooxyacetic acid (10-4 M) and propargylglycine (10-3 M) and nonselective cyclooxygenase inhibitor indomethacin (10-4 M). However, in calcium-free Krebs solution containing high KCl (30 mM), DAS significantly inhibited CaCl2 (10-5 -10-2 M)-induced uterine contractions in a concentration-dependent manner (P < 0.05). Diallyl sulfide has a relaxing effect on KCl-contracted rat uterus strips and an inhibitory effect on spontaneous uterine activity, possibly by decreasing the calcium influx into the cytoplasm of uterine smooth muscle cells.

Ethanol-Induced Oxidative Stress Modifies Inflammation and Angiogenesis Biomarkers in Retinal Pigment Epithelial Cells (ARPE-19): Role of CYP2E1 and its Inhibition by Antioxidants.

The retinal pigment epithelium (RPE) plays a key role in retinal health, being essential for the protection against reactive oxygen species (ROS). Nevertheless, excessive oxidative stress can induce RPE dysfunction, promoting visual loss. Our aim is to clarify the possible implication of CYP2E1 in ethanol (EtOH)-induced oxidative stress in RPE alterations. Despite the increase in the levels of ROS, measured by fluorescence probes, the RPE cells exposed to the lowest EtOH concentrations were able to maintain cell survival, measured by the Cell Proliferation Kit II (XTT). However, EtOH-induced oxidative stress modified inflammation and angiogenesis biomarkers, analyzed by proteome array, ELISA, qPCR and Western blot. The highest EtOH concentration used stimulated a large increase in ROS levels, upregulating the cytochrome P450-2E1 (CYP2E1) and promoting cell death. The use of antioxidants such as N-acetylcysteine (NAC) and diallyl sulfide (DAS), which is also a CYP2E1 inhibitor, reverted cell death and oxidative stress, modulating also the upstream angiogenesis and inflammation regulators. Because oxidative stress plays a central role in most frequent ocular diseases, the results herein support the proposal that CYP2E1 upregulation could aggravate retinal degeneration, especially in those patients with high baseline oxidative stress levels due to their ocular pathology and should be considered as a risk factor.

Organosulphur Compounds Induce Apoptosis and Cell Cycle Arrest in Cervical Cancer Cells via Downregulation of HPV E6 and E7 Oncogenes.

The quest for strong, safe and cost-effective natural antiproliferative agents that could reduce cancer has been the focus now a days. In this regard, the organosulfur compounds from garlic (Allium sativum L.), like Diallyl Sulfide (DAS) and Diallyl Disulfide (DADS), have been shown to exhibit potent antiproliferative and anticancer properties in many studies. However, the potential of these compounds against viral oncoproteins in cervical cancer has not been fully elucidated yet. The objective of this study was to analyze the antiproliferative and apoptotic properties of DADS and DAS in HPV16+ human cervical cancer Caski cell line. Caski (cervical cancer cells) were cultured and followed by the treatment of various concentrations of organosulphur compounds (DADS and DAS), cell viability was measured by MTT assay. The apoptotic assay was performed by DAPI and Hoechst3342 staining. Reactive Oxygen Species (ROS) was estimated by DCFDA staining protocol. The distributions of cell cycle and apoptosis (FITC-Annexin V assay) were analyzed by flow cytometry. Finally, gene expression analysis was performed via quantitative real time PCR. Our results showed that DAS and DADS exerted a significant antiproliferative effect on Caski cells by reducing the cell viability and inducing a dose-related increment in intracellular ROS production along with apoptosis in Caski cells. DAS and DADS also induced cell cycle arrest in G0/G1 phase, which was supported by the downregulation of cyclin D1 and CDK4 and upregulation of CDK inhibitors p21WAF1/CIP1 and p27KIP1 in Caski cells. Additionally, DAS and DADS lead to the downregulation of viral oncogene E6 and E7 and restoration of p53 function. Thus, this study confirms the efficacy of both the organosulfur compounds DADS and DAS against cervical cancer cells.

Variety differences in garlic volatile sulfur compounds, by application of selected ion flow tube mass spectrometry (SIFT–MS) with chemometrics

Garlic releases a strong odor after tissue disruption by chewing or other mechanical effects. This odor is strongly associated with the volatile sulfur compounds that can be used for the characterization of garlic. In this study, different varieties of garlic were examined for their volatile sulfur compound concentration, which may be used for purposes of quality control as well as for authentication and classification of garlic varieties. 2- or 3-vinyl-4H-1, 2- or 3-dithiin, allicin, allyl mercaptan, allyl methyl disulfide, allyl methyl sulfide, allyl methyl tetrasulfide, allyl methyl thiosulfide, allyl methyl trisulfide, diallyl disulfide, diallyl sulfide, diallyl tetrasulfide, diallyl trisulfide, dimethyl disulfide, dimethyl thioether, dimethyl thiosulfide, dimethyl trisulfide, and methyl mercaptan were measured in the headspace of garlic for 30 min by selected ion flow tube mass spectrometry (SIFT-MS). German White was determined to be the garlic variety with the highest volatile sulfur compound concentration. Korean Mountain, Music, and Godfathers Italian varieties were discriminated well based on interclass distance (ICD) values. Also, softneck and hardneck garlic were clearly differentiated with chemometrics.

Effect of diallyl disulfide and garlic oil on different human astrocytoma cell lines.

Gliomas are a group of malignant brain tumors. Despite significant efforts to optimize treatment options for patients with high-grade glioma, the prognosis of the overwhelming majority of patients remain poor. This bleak prognosis despite treatment of the glioma, is partly due to the tendency of therapeutics to diffusely penetrate into the neighboring brain tissues, but also due to the innate resistance of these tumors to chemotherapy and radiation. Garlic contains water-soluble and oil-soluble sulfur compounds. The oil-soluble compounds, including diallyl sulfide, diallyl disulfide (DADS), diallyl trisulfide and ajoene, are more effective potential anti-cancer treatments than the water-soluble compounds. There are several studies examining the effects of oil-soluble compounds on various types of cancer cells, although, to the best of our knowledge, there are no studies examining the effects of these compounds on glioma cells. The aim of the present study was to investigate the potential anti-glioma properties of DAD and garlic oil on proliferation and induction of apoptosis in four different types of glioma cell lines representative of different grades of the disease. The results showed that garlic oil exhibits favorable anti-cancer potential towards gliomas of various degrees of differentiation.

Inhibitory effects of aqueous garlic extract, garlic oil and four diallyl sulphides against four enteric pathogens

The inhibitory effects of aqueous garlic extract, garlic oil and four diallyl sulphides naturally occurring in this oil against Escherichia coli, Enterobacter cloacae, Enterococcus faecalis, and Citrobacter freundii (total 291 clinical isolates) were studied. The MIC values of four diallyl sulphides against the four enteric pathogens followed the order diallyl monosulphide > diallyl disulphide > diallyl trisulphide > diallyl tetrasulphide (p<0.05). Most interactions of four antibiotics (meropenem, ceftazidime, imipenem and gentamicin) with diallyl polysulphide, determined as FIC index, showed synergistic or additive effects. Garlic oil at 2X MIC reduced original inoculum to ≤ 3 log 10/mL within 8 hr; and 4X MIC reduced original inoculum to < 2log 10/mL in all test enteric pathogens within 6 hr. The intake of aqueous garlic extract in humans provided the antibacterial activity in plasma, determined by inhibitory zone. These results suggested that aqueous garlic extract, garlic oil, and diallyl polysulphide may have potential for the prevention or control of infections caused by enteric pathogens.

Effects of garlic extract on acid production and growth of Streptococcus mutans

Garlic extracts have been used for medicinal purposes for about one thousand years. The antibacterial properties of garlic have been known for more than 60 years. This study was aimed to examine the effects of filtered garlic extracts and diallyl sulfide on the acid production and the growth of Streptococcus mutans 10449 and BHT. Results showed that both garlic extracts and diallyl sulfide could enhance the rate of acid production and inhibit the growth of S. mutans. Strain BHT was highly susceptible, and strain 10449 less sensitive. These data indicate that garlic extracts stimulates the acid production and may thus be harmful to the teeth if eaten with glucose-containing foods, but may inhibit the growth of S. mutans and subsequently reduce the caries incidence.

Chemical composition of the essential oils of Brassica juncea (L.) Coss. grown in different regions, Hebei, Shaanxi and Shandong, of China

The composition of essential oils in the seeds of Brassica juncea (L.) Coss., grown in Hebei, Shaanxi and Shandong Province was determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). We have identified twenty-two compounds constituting 89.6% by weight of the mustard oil from Hebei Province. The main components were allyl isothiocyanate (54.8%), diallyl trisulfide (9.4%), diallyl sulfide (5.5%) and 3-butenyl isothiocyanate (4.8%). Fourteen compounds representing 94.5 % by weight of the mustard oil from Shaanxi Province were identified. They were allyl isothiocyanate (68.8%), diallyl trisulfide (7.8%) and 3-butenyl isothiocyanate (4.9%). Fifteen components were identified accounting for 94.3% by weight of the mustard oil from Shandong Province. Major constituents were allyl isothiocyanate (61.3%), diallyl trisulfide (9.7%) and 3-butenyl isothiocyanate (5.9%).

Incorporation of nanoencapsulated garlic essential oil into edible films: A novel approach for extending shelf life of vacuum-packed sausages

The efficacy of chitosan (CH) and whey protein (WP) films impregnated with garlic essential oil (GEO, 2% v/v) or nanoencapsulated GEO (NGEO, 2% v/v) to extend the shelf life of refrigerated vacuum-packed sausages were assessed and compared during 50 days. The primary evaluation of GEO and NGEO showed that GEO had a considerable amount of active compounds diallyl sulfide derivatives (~67%) and the mean size and zeta potential of NGEO were 101 nm and −7.27 mV, respectively. Based on the microbiological and lipid stability analysis of the sausages, all active films retarded lipid oxidation and the growth of main spoilage bacterial groups compared to the control, and CH film containing NGEO exhibited the best result with the peroxide value, thiobarbituric acid reactive substances and aerobic plate count of 0.37 (meq/kg lipid), 0.47 (mg malondialdehyde/kg) and 3.69 (log CFU/g), respectively, on day 50. The nanoencapsulation of GEO made no significant differences in the sensory properties comparing to free-GEO samples (P < .05).

Is there any still undisclosed biodiversity in Ciauscolo salami? A new glance into the microbiota of an artisan production as revealed by high-throughput sequencing

Ciauscolo is a fermented sausage with the Protected Geographical Indication (PGI) status. To disclose the microbial ecology of a model Ciauscolo salami manufacture during its natural fermentation, viable counting, amplicon-based sequencing and real-time PCR were applied. The volatilome during fermentation was also characterized. The results allowed previously undetected species to be discovered. The core microbiota was composed by Lactobacillus algidus, Leuconostoc carnosum, Lactobacillus sakei, Debaryomyces hansenii, Glomus hyderabadensis, Tilletiopsis washingtonensis, and Kurtzmaniella zeylanoides. Salmonella spp. and Listeria monocytogenes were absent in all the samples; moreover, multiplex real-time PCR revealed the absence of the target genes bont/A, bont/B, bont/E, bont/F, and 4gyrB (CP), encoding botulinic toxins. Volatilome, deeply depending on microbiological metabolism, was characterized by spices-derived components. Limonene, sabinene, α- and β-pinene, 3-carene, and α-thujene were the most represented monoterpene hydrocarbons, whereas β- and α-copaene were the most represented sesquiterpene hydrocarbons. Allyl methyl sulphide and diallyl disulphide were the major aliphatic sulphur compounds, together with diallyl sulphide and allyl methyl disulphide.

Scavenging of Hydrogen Peroxide by Allyl Methyl Sulfide and Diallyl Sulfide, Two Garlic Active Compounds: A Theoretical Study

AbstractWe study potential scavenging of hydrogen peroxide by Allyl Methyl Sulfide and Diallyl Sulfide, two garlic components. The antioxidant properties of garlic are attributed to organosulfide compounds, which react with reactive oxygen species preventing the oxidative stress. We used the B3LYP functional for structure analysis and M06‐2X functional for the reactions employing gaseous, aqueous and non‐polar environments. The conformational analysis and Fukui functions allowed the selection of the initial structures and the region of nucleophilic attack by hydrogen peroxide. The scavenging reactions analyzed are: 1) Sulfoxidation; 2) Epoxidation; and 3) Hydrogenation. Through the intrinsic reaction coordinate, the energy profile, the activation energies, the rate constant and its temperature‐dependence were calculated. The results predict that reactions occur slowly and hydrogenation is not a feasible process. Finally, the sulfoxidation of Allyl Methyl Sulfide and Diallyl Sulfide resulted to be more thermodynamically and kinetically favorable than epoxidation (rate constant values, 10−10 s−1, in comparison with 10−18 s−1 from epoxidation), becoming the most probable pathway for hydrogen peroxide scavenging.

Comparative Therapeutic Effects of Natural Compounds Against Saprolegnia spp. (Oomycota) and Amyloodinium ocellatum (Dinophyceae).

The fish parasites Saprolegnia spp. (Oomycota) and Amyloodinium ocellatum (Dinophyceae) cause important losses in freshwater and marine aquaculture industry, respectively. The possible adverse effects of compounds used to control these parasites in aquaculture resulted in increased interest on the search for natural products with antiparasitic activity. In this work, eighteen plant-derived compounds (2′,4′-Dihydroxychalcone; 7-Hydroxyflavone; Artemisinin; Camphor (1R); Diallyl sulfide; Esculetin; Eucalyptol; Garlicin 80%; Harmalol hydrochloride dihydrate; Palmatine chloride; Piperine; Plumbagin; Resveratrol; Rosmarinic acid; Sclareolide; Tomatine, Umbelliferone, and Usnic Acid) have been tested in vitro. Sixteen of these were used to determine their effects on the gill cell line G1B (ATCC®CRL-2536™) and on the motility of viable dinospores of Amyloodinium ocellatum, and thirteen were screened for inhibitory activity against Saprolegnia spp. The cytotoxicity results on G1B cells determined that only two compounds (2′,4′-Dihydroxychalcone and Tomatine) exhibited dose-dependent toxic effects. The highest surveyed concentrations (0.1 and 0.01 mM) reduced cell viability by 80%. Upon lowering the compound concentration the percentage of dead cells was lower than 20%. The same two compounds revealed to be potential antiparasitics by reducing in a dose-dependent manner the motility of A. ocellatum dinospores up to 100%. With respect to Saprolegnia, a Minimum Inhibitory Concentration was found for Tomatine (0.1 mM), Piperine and Plumbagin (0.25 mM), while 2′,4′-Dihydroxychalcone considerably slowed down mycelial growth for 24 h at a concentration of 0.1 mM. Therefore, this research allowed to identify two compounds, Tomatine and 2′,4′-Dihydroxychalcone, effective against both parasites. These compounds could represent promising candidates for the treatment of amyloodiniosis and saprolegniosis in aquaculture. Nevertheless, further in vitro and in vivo tests are required in order to determine concentrations that are effective against the considered pathogens but at the same time safe for hosts, environment and consumers.

Diallyl sulfide-induced attenuation of n-hexane-induced peripheral nerve impairment is associated with metabolic inhibition of n-hexane

Chronic exposure to n-hexane could induced serious peripheral nerve impairments. It has been well documented that the metabolic activation from n-hexane to 2,5-hexanedione (2,5-HD) is vital in the pathogenesis. Diallyl sulfide (DAS) is an extract of garlic and able to block the bioactivation of xenobiotic. The current study was designed to investigate whether DAS can attenuate n-hexane induced neuropathy. Male Wistar rats were pretreated with DAS (50 or 100 mg/kg.bw) and then n-hexane (3 g/kg.bw) for 7 weeks. Behavioral performance, biomarker measurement and toxicokinetic studies were performed. Enzymatic methods and western blotting analyses were also conducted to investigate the hepatic phase I enzymes (including cytochrome P450(CYP)2E1, CYP1A1 and CYP2B1) and phase II enzymes (including glutathione S transferase theta 1 (GSTT1) and NA(D)PH dehydrogenase quinone 1 (NQO1)). The results showed that DAS improved the behavioral performance while reducing the toxic metabolite: 2,5-HD and pyrrole adducts. Besides, DAS reduced the expression of CYP2E1 with a proportional decrease in activity, which largely decreased the bioactivation of n-hexane in vivo. The results suggested that DAS decreased the toxic metabolites of n-hexane to attenuate n-hexane-induced peripheral neuropathy.

Modulation of Keap1/Nrf2/ARE Signaling Pathway by Curcuma- and Garlic-Derived Hybrids.

Nrf2 is a basic leucine zipper transcription factor that binds to the promoter region of the antioxidant response element (ARE), inducing the coordinated up-regulation of antioxidant and detoxification genes. We recently synthesized a set of new molecules by combining the functional moieties of curcumin and diallyl sulfide, both known to induce the expression of antioxidant phase II enzymes by activating Nrf2 pathway. The aim of the study is to investigate the ability of such compounds to activate Keap1/Nrf2/ARE cytoprotective pathway, in comparison with two reference Nrf2-activators: curcumin and dimethyl fumarate, a drug approved for the treatment of relapsing-remitting multiple sclerosis. Furthermore, since Nrf2 pathway is known to be regulated also by epigenetic modifications, including key modifications in microRNA (miRNA) expression, the effects of the hybrids on the expression levels of selected miRNAs, associated with Nrf2 signaling pathway have also been investigated. The results show that compounds exert antioxidant effect by activating Nrf2 signaling pathway and inducing the ARE-regulated expression of its downstream target genes, such as HO-1 and NQO1, with two hybrids to a higher extent than curcumin. In addition, some molecules induce changes in the expression levels of miR-125b-5p, even if to a lesser extent than curcumin. However, no changes have been observed in the expression levels of mRNA coding for glutathione synthetase, suggesting that the modulation of this mRNA is not strictly under the control of miR-125b-5p, which could be influenced by other miRNAs.

Study on the effect of diallyl sulfide on peripheral nerve injury in n-hexane intoxicated rats

Objective: To investigate the antagonistic effect of diallyl sulfide (DAS) against peripheral nerve injury induced by n-hexane in rats. Methods: A total of 68 adult male Wistar rats were selected, among which 50 were randomly selected and divided into blank control group, DAS control group (100 mg/kg·bw) , n-hexane model group, low-dose DAS intervention group (50 mg/kg·bw) , and high-dose DAS intervention group (100 mg/kg·bw) . A rat model of peripheral nerve injury was established by n-hexane exposure, and the rats were treated with DAS at different doses. The changes in pyrrole adducts and behavior were observed, a metabolic analysis was performed for serum pyrrole adducts, and the intervention effect was evaluated. The remaining 18 rats were randomly assigned to the n-hexane model group, the low-dose DAS intervention group, and the high-dose DAS intervention group, with 6 rats in each group, as satellite groups used for the toxicokinetic analysis of serum pyrrole adducts. Results: Compared with the blank control group, the n-hexane model group and low-and high-dose DAS intervention groups had a significant reduction in body weight since week 2 (P<0.01) . Compared with the n-hexane model group at the end of the experiment at week 7, the high-dose DAS intervention group had a significantly higher body weight (P<0.05) , while there was no significant difference in body weight between the n-hexane model group and the low-dose DAS intervention group (P>0.05) . The n-hexane model group developed gait abnormality at week 2 of poisoning, while the low-and high-dose DAS intervention groups developed gait abnormality at weeks 3 and 5 of poisoning, respectively. At the end of the experiment, the n-hexane model group and the low-and high-dose DAS intervention groups had a significantly higher gait score than the blank control group (P<0.01) . At the end of the experiment, the n-hexane model group and the low-dose DAS intervention group had significantly shorter latency in rotarod test than the blank control group (P<0.01) , while there was no significant difference in latency between the DAS control group and the high-dose DAS intervention group (P>0.05) . Compared with the n-hexane model group, the low-and high-dose DAS intervention groups had a significant increase in latency in rotarod test (P<0.01) . Compared with blank control group, the n-hexane model group and the low-dose DAS intervention group had a significant increase in mean nerve conduction velocity (P<0.01) , while there was no significant difference between the blank control group and the DAS control group or high-dose DAS intervention group (P>0.05) , and compared with the n-hexane model group, the low-and high-dose DAS intervention groups had a significant increase in nerve conduction velocity (P<0.01) . Compared with the blank control group at the end of the experiment at week 7, the n-hexane model group and the low-and high-dose DAS intervention groups had significant increases in the concentration of pyrrole adducts in serum, urine, and hair (P<0.01) , while there was no significant difference between the blank control group and the DAS control group (P>0.05) , and the high-dose DAS intervention group had a significantly lower concentration of pyrrole adducts in serum, urine, and hair than the low-dose DAS intervention group (P<0.05) . Serum pyrrole adducts reached the peak level at 9-12 hours and then started to decrease. Compared with the n-hexane model group, the high-and low-dose DAS intervention groups had a significantly shorter half-life period of serum pyrrole adducts (P<0.01) . Compared with the n-hexane model group, the high-and low-dose DAS intervention groups had a significant reduction in the area under the curve of serum pyrrole adducts (P<0.05) . Conclusion: DAS can antagonize peripheral nerve injury induced by n-hexane.

Protective effects of thymoquinone and diallyl sulphide against malathion-induced toxicity in rats.

Malathion is a potent organophosphate insecticide that inhibits acetylcholinesterase (AChE) enzyme. Our experimental objective was to investigate the beneficial effects of diallyl sulphide (DAS) and thymoquinone (TQ) against malathion-induced oxidative stress in rat cerebral, hepatic, and renal tissues. For 30days, rats received corn oil alone (negative control) or malathion by intragastric gavage (200mg/kg daily), either alone (positive control) or combined with oral DAS (200mg/kg daily) or TQ (10mg/kg daily) (treatment groups). Later, blood samples were collected via direct cardiac puncture and tissue samples were obtained for biochemical analysis. Malathion administration was associated with significant increases (p < 0.05) in the serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, γ-glutamyl transferase, cholesterol, urea, creatinine, and 8-OHdG (DNA damage biomarker), as well as significant (p < 0.05) decreases in theserum levels of total proteins, albumin, triglycerides, and AChE. Moreover, it significantly increased thetissue concentrations of malondialdehyde and nitric oxide and reduced tissue glutathione concentration and activities of antioxidant enzymes (glutathione peroxidase, superoxide dismutase, and catalase). Treatment of malathion-intoxicated rats with DAS or TQ significantly minimized these biochemical and oxidative effects with more frequent reversal to normal ranges of serum biomarkers, tissue oxidative markers, and antioxidant enzymes in the TQ group. In conclusion, treatment with DAS or TQ ameliorated the biochemical and oxidative effects of malathion, probably through reducing the generation of reactive oxygen and nitrogen radicals, as well as enhancing the antioxidant defense mechanisms.

Impact of harvest date on the content of volatile components in garlic

The aim of this study was to define optimal harvesting date of garlic cv. 'Istarski crveni' by comparing the amount of volatile compounds as one of quality indicators. In total 17 volatile compounds were determined in tested garlic samples by headspace solid-phase microextraction coupled to gas chromatography with flame ionization and mass spectrometric detection (HS-SPME-GC-FID-MS) regardless of harvesting date. Major volatiles diallyl trisulfide, diallyl sulfide, methyl allyl disulfide and diallyl disulfide representing 98.5 % of all the determined compounds have shown no significant difference between harvest dates. Significantly higher content of the two minor volatiles, allyl mercaptane and thieno[2,3-b]thiophene, was found in the last and second when compared to the first harvest date. Principal components PC1 and PC2 explained 78% of the total variance and pointed to certain relations between harvest dates and volatiles. The technological maturity had probably been reached at the first harvesting date since similar amounts of volatiles were found during the observed period.

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.

Antitumour Effect of a Mixture of N-Propyl Polysulfides In Vitro

Abstract Copper serves as a limiting factor for multiple steps of tumour progression, including angiogenesis, growth and metastasis. High levels of copper have been found in a wide spectrum of human cancers. Antitumour activities of copper-chelating drugs have been reported in animal models. Organosulfur compounds (diallyl sulfide, DAS; diallyl disulfide, DADS; S-ethylcysteine, SEC; N-acetylcysteine, NAC) derived from garlic exhibit marked copper-chelating activity. We analysed a mixture of fifteen n-propyl polysulfides (DPPS) for potential antitumour activity against several murine tumour cell lines, including colon carcinoma (CT26), mammary carcinoma (4T1) and melanoma cell lines (B16F10), and compared the effects with the antiproliferative effect in highly proliferative murine mesenchymal stem cells (mMSCs). The effects of the mixture of n-propyl polysulfides (100%) on cell viability were determined using MTT assays. Cell apoptosis was analysed using Annexin V-FITC/PI assays. The results of the MTT assays indicate that this standardized mixture of n-propyl polysulfides has a strong, dose-dependent cytotoxic effect against all three of the tested tumour cell lines (CT26, 4T1, B16F10). The cytotoxic effect of the n-propyl polysulfide mixture against the CT26 and B16F10 cell lines was much stronger than that of cisplatin and was significantly weaker in mMSCs, which are non-cancerous and highly proliferative cells, than in cancer cells. Flow cytometric analysis of CT26 and 4T1 cells revealed that apoptosis was not the dominant mechanism of cell death induced by the n-propyl polysulfide mixture. The n-propyl polysulfide mixture exerted highly cytotoxic activity against murine colon carcinoma and melanoma cell lines, but its antiproliferative activity against mMSCs was significantly lower than that of cisplatin.