Allyl methyl sulfide, a garlic active component mitigates hyperglycemia by restoration of circulatory antioxidant status and attenuating glycoprotein components in streptozotocin-induced experimental rats.

Diabetes is a major noncommunicable life-threatening chronic and pervasive condition that is consuming the world health in a petrifying rate. The circulatory system is one of the major sources of hyperglycemia-induced ROS generation. Historically, garlic has been revered as part of a healthful diet. Organosulfur compounds have been attributed to the medicinal properties and health benefits of garlic. The present study focuses on the ameliorative role of allyl methyl sulfide (AMS) in combating diabetic complications in diabetic rats. Male Wistar rats were randomly divided into four groups. Experimental diabetes was induced by a single intraperitoneal injection (i.p), of streptozotocin (STZ) (40 mg/kg b.w). STZ treated diabetic rats showed significant augment in plasma glucose level, lipidperoxidative (LPO) markers, glycoprotein components (hexose, hexosamine, sialic acid, and fucose), and significant decline in plasma insulin level, nonenzymatic antioxidants and activities of antioxidant enzymes in the circulatory system and tissues. Further, periodic acid-Schiff (PAS) staining of hepatic and renal tissues revealed positive stain accumulation and Western blot investigation of glucose transporter 2 (GLUT 2) in pancreas of STZ-induced hyperglycemic rats. Dietary intervention with AMS (100 mg/kg b.w) for 30 days demonstrated significant protective effects on all the biochemical parameters studied. Besides, biochemical findings were corroborated by histological exertion and Western blot study. The findings of current investigations recommended that AMS can ameliorate the consequences of diabetes due to their antioxidant efficacy and can be used as a potential therapeutic approach. Further studies are warranted to explore the clinical application of AMS.

Activity of Thioallyl Compounds From Garlic Against Giardia duodenalis Trophozoites and in Experimental Giardiasis.

Fresh aqueous extracts (AGEs) and several thioallyl compounds (TACs) from garlic have an important antimicrobial activity that likely involves their interaction with exposed thiol groups at single aminoacids or target proteins. Since these groups are present in Giardia duodenalis trophozoites, in this work we evaluated the anti-giardial activity of AGE and several garlic's TACs. In vitro susceptibility assays showed that AGE affected trophozoite viability initially by a mechanism impairing cell integrity and oxidoreductase activities while diesterase activities were abrogated at higher AGE concentrations. The giardicidal activities of seven TACs were related to the molecular descriptor HOMO (Highest Occupied Molecular Orbital) energy and with their capacity to modify the -SH groups exposed in giardial proteins. Interestingly, the activity of several cysteine proteases in trophozoite lysates was inhibited by representative TACs as well as the cytopathic effect of the virulence factor giardipain-1. Of these, allicin showed the highest anti-giardial activity, the lower HOMO value, the highest thiol-modifying activity and the greatest inhibition of cysteine proteases. Allicin had a cytolytic mechanism in trophozoites with subsequent impairment of diesterase and oxidoreductase activities in a similar way to AGE. In addition, by electron microscopy a marked destruction of plasma membrane and endomembranes was observed in allicin-treated trophozoites while cytoskeletal elements were not affected. In further flow cytometry analyses pro-apoptotic effects of allicin concomitant to partial cell cycle arrest at G2 phase with the absence of oxidative stress were observed. In experimental infections of gerbils, the intragastric administration of AGE or allicin decreased parasite numbers and eliminated trophozoites in experimentally infected animals, respectively. These data suggest a potential use of TACs from garlic against G. duodenalis and in the treatment of giardiasis along with their additional benefits in the host's health.

DEVELOPMENT OF THE FORMULATION AND TECHNOLOGY OF HYDROGEL, CONTAINING ADJARA REGION SULFIDE SILT PELOID.

In the world today, the demand for the preparations and cosmetics, made of peloids is increasing significantly, which is explained by the increased interest of the community to the ecologically clean raw materials of natural origin, it often replaces expensive chemical preparations, which are often accompanied by some contraindications. The increased interest in peloids in the world put on the agenda the question of rational use of acting mud mines as well as the problem of cosmetic and medicinal preparations, developed on their basis. It is noteworthy that the development of ready-made, soft drug forms from the Adjara region sulfide silt peloids is one of the most topical and important issues, as at present there is not available the form of ready-made drugs containing the sulfide silt peloids of this region. Therefore, the aim of the research was to develop the formulation and technology of the hydrogel, containing the Adjara region sulfide silt peloid. The sulfide silt peloid of the Ardagani lake have been used for preparing the hydrogel compositions, as it is distinguished by its advantageous physical-chemical properties and content of biologically active ingredients compared with other studied peloids. The main physical-chemical and technological characteristics of hydrogels compositions have been studied using the following methods: uniformity, pH, the colloidal stability, thermal stability , osmotic activity - by dialysis method using semiconductor membrane (Kruvichinski method), release of active ingredient was studied by using Franz diffusion cells, viscosity was determined by Viscometer RVDV-1 T (Dongguan Zhongli Instrument Technology Co., China), the structure of hydrogel composition - by microscopic (ROW Rathenow, Germany) examination. Based on the conducted studies have been established, that the hydrogel composition N6 is distinguished by its best properties compared to other hydrogel compositions, in which the carboxymethylcellulose was used as a base.The conducted studies became the basis for the development of the formula and technological scheme of production for the hydrogel of Ardagani lake sulfide silt peloid of Adjara region. The results of determining the main characteristics of the given gel provide the desired quality and efficiency of the product.

A review of cinnabar (HgS) and/or realgar (As4S4)-containing traditional medicines.

ETHNOPHARMOCOLOGICAL RELEVANCE: Herbo-metallic preparations have a long history in the treatment of diseases, and are still used today for refractory diseases, as adjuncts to standard therapy, or for economic reasons in developing countries. AIM OF THE REVIEW: This review uses cinnabar (HgS) and realgar (As4S4) as mineral examples to discuss their occurrence, therapeutic use, pharmacology, toxicity in traditional medicine mixtures, and research perspectives. MATERIALS AND METHODS: A literature search on cinnabar and realgar from PubMed, Chinese pharmacopeia, Google and other sources was carried out. Traditional medicines containing both cinnabar and realgar (An-Gong-Niu-Huang Wan, Hua-Feng-Dan); mainly cinnabar (Zhu-Sha-An-Shen Wan; Zuotai and Dangzuo), and mainly realgar (Huang-Dai Pian; Liu-Shen Wan; Niu-Huang-Jie-Du) are discussed. RESULTS: Both cinnabar and realgar used in traditional medicines are subjected to special preparation procedures to remove impurities. Metals in these traditional medicines are in the sulfide forms which are different from environmental mercurials (HgCl2, MeHg) or arsenicals (NaAsO2, NaH2AsO4). Cinnabar and/or realgar are seldom used alone, but rather as mixtures with herbs and/or animal products in traditional medicines. Advanced technologies are now used to characterize these preparations. The bioaccessibility, absorption, distribution, metabolism and elimination of these herbo-metallic preparations are different from environmental metals. The rationale of including metals in traditional remedies and their interactions with drugs need to be justified. At higher therapeutic doses, balance of the benefits and risks is critical. Surveillance of patients using these herbo-metallic preparations is desired. CONCLUSION: Chemical forms of mercury and arsenic are a major determinant of their disposition, efficacy and toxicity, and the use of total Hg and As alone for risk assessment of metals in traditional medicines is insufficient.

Optimisation of steam distillation extraction oil from onion by response surface methodology and its chemical composition.

Oil extraction from onion was performed by steam distillation. Response surface methodology was applied to evaluate the effects of ratio of water to raw material, extraction time, zymolysis temperature and distillation times on yield of onion oil. The maximum extraction yield (1.779%) was obtained as following conditions: ratio of water to raw material was 1, extraction time was 2.5 h, zymolysis temperature was 36° and distillation time was 2.6 h. The experimental values agreed well with those predicted by regression model. The chemical composition of extracted onion oil under the optimum conditions was analysed by gas chromatography-mass spectrometry technology. The results showed that sulphur compounds, like alkanes, sulphide, alkenes, ester and alcohol, were the major components of onion oil.

Garlic Organosulfur Compounds Reduce Inflammation and Oxidative Stress during Dengue Virus Infection.

Dengue virus (DENV) is a mosquito-borne flavivirus that causes significant global human disease and mortality. One approach to develop treatments for DENV infection and the prevention of severe disease is through investigation of natural medicines. Inflammation plays both beneficial and harmful roles during DENV infection. Studies have proposed that the oxidative stress response may be one mechanism responsible for triggering inflammation during DENV infection. Thus, blocking the oxidative stress response could reduce inflammation and the development of severe disease. Garlic has been shown to both reduce inflammation and affect the oxidative stress response. Here, we show that the garlic active compounds diallyl disulfide (DADS), diallyl sulfide (DAS) and alliin reduced inflammation during DENV infection and show that this reduction is due to the effects on the oxidative stress response. These results suggest that garlic could be used as an alternative treatment for DENV infection and for the prevention of severe disease development.

Antitumor Allium Sulfides.

We examined the sulfides in onion (Allium cepa L.), Welsh onion (A. fistulosum L.), and garlic (A. sativum L.), and obtained three new thiolane-type sulfides (onionins A1-A3) from onion; two new thiabicyclic-type sulfides (welsonins A1, A2), together with onionins A1-A3, from Welsh onion; and six new acyclic-type sulfides (garlicnins L-1-L-4, E, and F), ten new thiolane-type sulfides (garlicnins A, B1-B4, C1-C3, K1, and K2), and three new atypical cyclic-type sulfides (garlicnins G, I, and J) from garlic. Acetone extracts showed the potential of these sulfides in inhibiting the polarization of M2 activated macrophages that are capable of suppressing tumor-cell proliferation. The effect of the thiolane-type sulfide of a major component, onionin A1, on tumor progression and metastasis in both osteosarcoma and ovarian cancer-bearing mouse models was then examined. Tumor proliferation was depressed, and tumor metastasis was controlled by regulating macrophage activation. These results showed that onionin A1 is an effective agent for controlling tumors in both in vitro and in vivo models, and that the antitumor effects observed in vivo are likely caused by reversing the antitumor immune system. Activation of the antitumor immune system by onionin A1 might be an effective adjuvant therapy for patients with osteosarcoma, ovarian cancer and other malignant tumors. Based on these findings, pharmacological investigations will be conducted in the future to develop natural and healthy foods and anti-cancer agents that can prevent or combat disease.

Atypical Cyclic Sulfides, Garlicnins G, I, and J, Extracted from Allium sativum.

Newly characterized, atypical sulfides, garlicnins G (1), I (2), and J (3), were isolated from the acetone extracts of garlic bulbs, Allium sativum. Their production pathways are regarded as different from those of cyclic sulfoxides, 3,4-dimethyltetrahydrothiophene-S-oxide derivatives such as onionins A1-A3, garlicnins B1-B4 and C1-C3.

Diallyl Sulfide and Its Role in Chronic Diseases Prevention.

Diallyl sulfide (C6H10S, DAS) is one of the novel natural organosulfur compounds, which is mostly obtained from the genus Allium plants. Numerous studies have revealed several unique properties of DAS in terms of its health-promoting effects. DAS has proved to be anticancer, antimicrobial, anti-angiogenic, and immunomodulatory like unique functions as demonstrated by the multiple investigations. Diallyl sulfide can also impede oxidative stress and chronic inflammation as suggested by the literature. Studies also explored that DAS could thwart the development of chronic diseases like cancer, neuronal, cardiovascular disease through modulating mechanistic pathways involved in pathogenesis. In this book chapter, we have attempted to give the comprehensive view on DAS about the physiochemical and biological properties, and its preventive role in chronic diseases with a mechanistic overview.

The redox-active drug metronidazole and thiol-depleting garlic compounds act synergistically in the protist parasite Spironucleus vortens.

Spironucleus vortens is a protozoan parasite associated with significant mortalities in the freshwater angelfish, Pterophyllum scalare. Control of this parasite is especially problematic due to restrictions on the use of the drug of choice, metronidazole (MTZ), on fish farms. Use of garlic (Allium sativum) is undergoing a renaissance following experimental validations of its antimicrobial efficiency. Ajoene ((E,Z)-4,5,9-trithiadodeca-1,6,11-triene 9-oxide), is a stable transformation product of allicin, the primary biologically active component of garlic. In the current study, an ajoene oil crude extract had a minimum inhibitory concentration (MIC) of 40µg/ml against S. vortens. GC-MS and NMR spectroscopy revealed this ajoene extract contained a mixture of the (E) and (Z)-ajoene isomers along with diallyl disulphide (DADS) and diallyl trisulphide (DATS). The only component of the ajoene crude oil found to substantially inhibit S. vortens growth by optical density monitoring (Bioscreen C Reader) was (Z)-ajoene (MIC 16µg/ml). Ajoene oil acted in synergy with MTZ in vitro, reducing the individual MIC of this drug (4µg/ml) by 16-fold, and that of ajoene oil by 200-fold with a fractional inhibitory concentration (FIC) index of 0.263. This synergistic interaction was confirmed in vivo. S. vortens-infected Pterophyllum scalare angelfish dosed orally with 0.5% (v/w) MTZ combined with 0.05% (v/w) ajoene displayed a significant reduction in faecal trophozoite count, whilst those fed on 0.5% MTZ flakes (half the recommended oral dose) alone did not. This study demonstrates for the first time the synergistic interaction between the synthetic drug MTZ and natural ajoene oil both in vitro and in vivo. Future work should evaluate the potential synergy of ajoene and MTZ against MTZ-resistant bacteria and protists.

Chemical composition and biological activities of Eruca vesicaria subsp. longirostris essential oils.

Context To date, there are no reports to validate the Tunisian traditional and folklore claims of Eruca vesicaria (L) Cav. subsp. longirostris (Brassicaceae) for the treatment of disease. Objective Investigation of the chemical composition antimicrobial and antioxidant activity of essential oils from Eruca longirostris leaves, stems, roots and fruits. Materials and methods The essential oils of E. longirostris from leaves, stems, roots and fruits were obtained after 4 h of hydrodistillation. Chemical compositions were determined using a combination of GC/FID and GC/MS. The in vitro antimicrobial activity of the volatile constituents of E. longirostris was performed in sterile 96-well microplates against three Gram-positive, four Gram-negative bacteria and one strain as yeast. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values were reported. Furthermore, the antioxidant activity was evaluated by DPPH and ABTS assays. Results The main compound for fruits, stems and roots was the erucin (96.6%, 85.3% and 83.7%, respectively), while ß-elemene (35.7%), hexahydrofarnesylacetone (23.9%), (E)-ß-damascone (15.4%), erucin (10.6%) and α-longipinene (9.6%) constituted the major compounds in the essential oil of the leaves. The experimental results showed that in all tests, essential oil of fruits showed the better antioxidant activity than the others. On the other hand, the oils of stems, fruits and roots showed significant antimicrobial activity with MIC values ranging from 0.125 to 0.31 mg/mL against Candida species, Gram-positive and Gram-negative bacteria, mainly Salmonella enterica. Conclusions The present results indicate that essential oils of E. longirostris can be used as a source of erucin.

Inhibition of growth and induction of apoptosis in A549 cells by compounds from oxheart cabbage extract.

BACKGROUND: Oxheart cabbage (Brassica oleracea var. capitata) is a member of the Brassica genus. Although some studies on the anticancer effects of extracts from oxheart cabbage have been reported, comprehensive information on the bioactive fractions and components from oxheart cabbage extracts is still lacking. The aim of this study was to isolate and identify the bioactive fractions and components from oxheart cabbage seeds using activity-guided isolation methods. RESULTS: The cytotoxicity and apoptotic effects of fraction II, fraction III, iberverin, sulforaphane and iberin from oxheart cabbage seed extract were investigated. The results showed that all five components had inhibitory effects on the in vitro growth of A549 cells which were dose-dependent. These compounds also changed the morphology of A549 cells, and their inhibitory activity on A549 cells was as follows: sulforaphane > iberin > iberverin > fraction III > fraction II. The IC50 values were 3.53 ± 0.63, 4.93 ± 1.02, 7.07 ± 0.51, 15.56 ± 0.24 and 27.32 ± 0.63 µg mL(-1) respectively. Fraction II, fraction III, iberverin, sulforaphane and iberin induced cell apoptosis by increasing early apoptosis and late apoptosis/necrosis, and activation of caspase-3, -8 and -9. CONCLUSION: These results indicated that the decrease in A549 cell viability by active compounds from oxheart cabbage seed extract was due to the induction of apoptosis. © 2015 Society of Chemical Industry.

Composition of the Essential Oil of Allium neapolitanum Cirillo Growing Wild in Sicily and its Activity on Microorganisms Affecting Historical Art Crafts.

Essential oil of the aerial parts of Allium neapolitanum Cirillo collected in Sicily were analyzed by gas-chromatography-flame-ionization detection and gas-chromatography-mass spectrometry. Nineteen compounds were identified in the oil and the main components were found to be (E)-chrysanthenyl acetate (28.1%), (Z)-chrysanthenyl acetate (23.8%), (E)-ß-farnesene (9.6%), dimethyl trisulfide (9.6%), camphor (7.4%), methyl allyl disulfide (6.8%) and 1-methyl-3-allyl trisulfide (5.8%). The essential oil showed good antimicrobial activity against 11 strains of test microorganisms, including several species infesting historical material.

Experimental study on the optimization of extraction process of garlic oil and its antibacterial effects.

BACKGROUND: Garlic oil which is the main active constituent of garlic has a wide range of pharmacological activities, and a broad antibacterial spectrum. It also has a strong anti-cancer activity, and can significantly inhibit a variety of tumors such as liver cancer, gastric cancer and colon cancer. The objective is to study the extraction process of garlic oil and its antibacterial effects. MATERIALS AND METHODS: CO2 Supercritical extraction was used to investigate the optimal processing conditions for garlic oil extraction; filter paper test and suspension dilution test were applied to determine the bacteriostatic action of garlic oil. RESULTS: In the CO2 supercritical extraction experiment, factors influencing the yield of garlic oil were: extraction pressure > extraction temperature > extraction time in descending order. Range analysis showed that the optimal experimental conditions for CO2 supercritical extraction of garlic oil were extraction pressure of 15 Mpa, temperature of 40 °C, and duration of 1 h. Different concentrations of garlic oil could all inhibit the growth of Staphylococcus aureus, Escherichia coli and Bacillus subtilis, suggesting that garlic oil has an antibacterial effect. CONCLUSION: The optimal experimental conditions for CO2 supercritical extraction of garlic oil were: extraction pressure of 15 Mpa, temperature of 40 °C, and duration of 1 h; garlic oil has an antibacterial effect.

Garlic-derived allyl sulfides in cancer therapy.

Garlic (Allium sativam L.) is widely used in traditional herbal remedies and alternative medicine. The potential health benefits of garlic are largely attributed to its metabolic byproducts. Extensive in vivo and in vitro studies has demonstrated that the garlic derivatives possess anti-cancer effects, but the underlying mechanisms are not completely understood. In this mini-review, we aim to summarize the reported biological effects of garlic products as anti-tumor agents, and present the possible molecular mechanisms responsible for the anti-carcinogenesis effects of garlic and its derivatives.

Acyclic sulfides, garlicnins L-1-L-4, E, and F, from Allium sativum.

Six novel acyclic sulfides, named garlicnins L-1-L-4 (1-4), E (5), and F (6), were isolated from the acetone extracts, with the ability to suppress M2 macrophage activation, of the bulbs of garlic (Allium sativum L.), and their chemical structures were characterized.

Investigating the responses of Cronobacter sakazakii to garlic-drived organosulfur compounds: a systematic study of pathogenic-bacterium injury by use of high-throughput whole-transcriptome sequencing and confocal micro-raman spectroscopy.

We present the results of a study using high-throughput whole-transcriptome sequencing (RNA-seq) and vibrational spectroscopy to characterize and fingerprint pathogenic-bacterium injury under conditions of unfavorable stress. Two garlic-derived organosulfur compounds were found to be highly effective antimicrobial compounds against Cronobacter sakazakii, a leading pathogen associated with invasive infection of infants and causing meningitis, necrotizing entercolitis, and bacteremia. RNA-seq shows changes in gene expression patterns and transcriptomic response, while confocal micro-Raman spectroscopy characterizes macromolecular changes in the bacterial cell resulting from this chemical stress. RNA-seq analyses showed that the bacterial response to ajoene differed from the response to diallyl sulfide. Specifically, ajoene caused downregulation of motility-related genes, while diallyl sulfide treatment caused an increased expression of cell wall synthesis genes. Confocal micro-Raman spectroscopy revealed that the two compounds appear to have the same phase I antimicrobial mechanism of binding to thiol-containing proteins/enzymes in bacterial cells generating a disulfide stretching band but different phase II antimicrobial mechanisms, showing alterations in the secondary structures of proteins in two different ways. Diallyl sulfide primarily altered the α-helix and ß-sheet, as reflected in changes in amide I, while ajoene altered the structures containing phenylalanine and tyrosine. Bayesian probability analysis validated the ability of principal component analysis to differentiate treated and control C. sakazakii cells. Scanning electron microscopy confirmed cell injury, showing significant morphological variations in cells following treatments by these two compounds. Findings from this study aid in the development of effective intervention strategies to reduce the risk of C. sakazakii contamination in the food production environment and on food contact surfaces, reducing the risks to susceptible consumers.

Effect of Allium sativum and Allium cepa oils on different stages of Boophilus annulatus.

The study is aimed to investigate the acaricidal effect of Allium sativum (garlic) and Allium cepa (onion) oils on different stages of Boophilus annulatus hard tick. Engorged B. annulatus females were collected from naturally infected cattle. A number of engorged ticks were incubated at 28 °C and 85 % relative humidity to lay eggs, which were incubated to obtain larvae that were used in the study. The used garlic and onion oils were prepared by steam distillation and were analyzed by gas chromatography. These oils were dissolved in ethanol, methanol alcohols, and, partially, in water. The oils were tested in different concentrations; 1, 2, 5, 10, and 20 %. These concentrations were applied on adult ticks by adult immersion test; on larvae by larval immersion technique and on eggs. The 20, 10, and 5 % of garlic oil dilutions in ethanol and methanol killed all adult ticks and larvae within 24 h. Similar results were obtained for 10 and 20 % garlic oil dissolved in water. The effect of 10 % aqueous solution of garlic oil on embryonated eggs was clear as its addition to these eggs led to their in ability to hatch, deformity in shape, and change in color. The 10 and 20 % onion oil in ethanol and methanol alcohols killed 76-86 % of the adult ticks within 72 h post-application. While, all larvae died within 24 h postsubjected to these two concentrations. These concentrations (10 and 20 %) of onion oil in water killed 56-80 % of the treated ticks. Moreover, 10 % aqueous solution of onion oil prevented hatching of embyonated eggs. We concluded that garlic and onion oils have acaricidal effect on all stages of B. annulatus at concentrations higher than 5 %. Only garlic oil could kill 100 % of adult ticks at concentrations from 5 % in alcohols.

Allium sativum-derived allitridin inhibits Treg amplification in cytomegalovirus infection.

This study investigated the effects of allitridin compound on murine cytomegalovirus (MCMV)-induced regulatory T cell (Treg; CD4(+) CD25(+) Foxp3(+) ) amplification in vivo and in vitro. One hundred twenty MCMV-infected mice were allocated at random into two groups for treatment with allitridin or placebo. Another 120 mock-infected mice were randomly allocated as controls for the allitridin treatment and placebo treatment groups. The mice were euthanized at various time points after infection (out to 120 days) to evaluate the effects of treatment on Treg presence and function, as well as MCMV infective load. Co-culture with mouse embryo fibroblasts (MEF) and MCMV was performed to evaluate allitridin-mediated Treg and anti-CMV effects. The maximum tolerance concentration (MTC) of allitridin was used to treat cells for 3 days. Changes in Foxp3 mRNA and protein levels, percentages of T cell subsets, and Treg-related cytokines (IL-10 and TGF-ß) were measured. Allitridin treatment did not influence Foxp3 expression and Treg proportion in uninfected mice, but did down-regulate each in infected mice during the chronic infection period. Additionally, allitridin treatment reduced the MCMV load in salivary glands. MTC allitridin treatment of co-cultures partially blocked MCMV induction of Foxp3 mRNA and protein expression. In vitro treatment with allitridin also increased significantly the percentages of Tc1, Tc2, and Th1, reduced the secreted levels of IL-10 and TGF-ß1, and significantly suppressed viral loads. In conclusion, allitridin can promote MCMV-induced Treg expansion and Treg-mediated anti-MCMV immunosuppression. Therefore, allitridin may be useful as a therapeutic agent to enhance the specific cellular immune responses against CMV.

Effect of allyl sulfides from garlic essential oil on intracellular ca2+ levels in renal tubular cells.

Diallyl sulfide (1), diallyl disulfide (2), and diallyl trisulfide (3), which are major organosulfur compounds of garlic (Allium sativum), are recognized as a group of potential chemopreventive compounds. In this study, the early signaling effects of 3 were examined on Madin-Darby canine kidney (MDCK) cells loaded with the Ca(2+)-sensitive dye fura-2. It was found that 3 caused an immediate and sustained increase of [Ca(2+)](i) in a concentration-dependent manner (EC(50) = 40 µM). Compound 3 also induced a [Ca(2+)](i) elevation when extracellular Ca(2+) was removed, but the magnitude was reduced by 45%. In Ca(2+)-free medium, the 3-induced [Ca(2+)](i) level was abolished by depleting stored Ca(2+) with 1 µM thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor). Elevation of [Ca(2+)](i) caused by 3 in the Ca(2+)-containing medium was not affected by modulation of protein kinase C activity. The 3-induced Ca(2+) influx was inhibited by nifedipine and nicardipine (1 µM). U73122, an inhibitor of phospholipase C, abolished ATP (but not the 3-induced [Ca(2+)](i) level). These findings suggest that 3 induced a significant [Ca(2+)](i) elevation in MDCK renal tubular cells by stimulating both extracellular Ca(2+) influx and thapsigargin-sensitive intracellular Ca(2+) release via as yet unidentified mechanisms. Furthermore, the order of the allyl sulfide-induced [Ca(2+)](i) elevation and cell viability was 1 < 2 < 3. The differential effect of allyl sulfides on Ca(2+) signaling and cell death appears to correlate with the number of sulfur atoms in the structure of these allyl sulfides.