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Sulfur-containing compounds contributing to health promotion in Allium species are produced via enzymic and thermochemical reactions. Sulfur-containing amino acids and volatile organosulfur compounds were prepared for an antioxidative assay. The inhibitory activity of S-alk(en)yl-L-cysteines and their sulfoxides, volatile alk(en)yl disulfides and trisulfides, and vinyldithiins in Allium species against lipid hydroperoxide (LOOH) formation in human low-density lipoprotein (LDL) was examined. It was elucidated that the alk(en)yl substituents (methyl, propyl, and allyl) and the number of sulfur atoms in the compounds were important for the antioxidative activity. 3,4-Dihydro-3-vinyl-1,2-dithiin, which is produced by a thermochemical reaction of allyl 2-propenethiosulfinate, exhibited the highest antioxidative activity of human LDL among sulfur-containing compounds.

Organosulfur compounds in onion extracts are formed following the lysis of the S-alk(en)yl-L-cysteine sulfoxides by alliinase. These compounds inhibit the aggregation of human blood platelets and offer the potential for positive cardiovascular health benefits. An experiment was designed to examine temporal and temperature effects on onion-induced antiplatelet activity. Platelet aggregation is induced by various agonists, including ADP, collagen, and thrombin. Unexpectedly, all freshly-juiced onion extracts (ca. 5 minutes post-juicing) appeared to exhibit both an agonist-free aggregation peak (AFP) and a platelet inhibitory peak (PIP) characteristic of inhibition of platelet aggregation. The AFP was minimal by 30 minutes and dissipated in all treatments by 120 minutes, while the PIP increased as onion extracts aged and did not change after 30 minutes at 25 degrees C. This finding confirms the observation that the in vitro platelet inhibitory activity of onion organosulfur compounds is time dependent. Freshly-prepared onion extracts were incubated with the ADP scavenger enzyme apyrase (E.C. 3.6.1.5). AFPs were abolished in apyrase-treated extracts, suggesting that this response may have been due to free ADP in onion extracts, although an amount of ADP required to generate such a response would be unexpected in onion extracts. In addition, platelet aggregates were not observed in the AFP, suggesting this response may be associated with changes in light transmission through platelet rich plasma that are not associated with platelet aggregation. Artifacts of analysis are, therefore, possible when assessing onion-induced antiplatelet activity with freshly-juiced extracts. Temporal formation of platelet-inhibiting organosulfur compounds should be taken into account during both in vitro and in vivo assessment of onion-induced antiplatelet activity.

Two new sulfur-containing compounds, trans-3-methylsulfonyl-2-propenol (1) and trans-3-methylsulfinyl-2-propenol (2) were isolated together with trans-3-methylthioacrylamide (3), entadamide A (4) and entadamide C (5) from the leaves of Clinacanthus siamensis. The structures were established on the basis of the spectroscopic data. The compounds were tested for antimalarial and antimycobacterial activity.

Sulfur-containing compounds contributing to health promotion in Allium species are produced via enzymic and thermochemical reactions. Sulfur-containing amino acids and volatile organosulfur compounds were prepared for an antioxidative assay. The inhibitory activity of S-alk(en)yl-l-cysteines and their sulfoxides, volatile alk(en)yl disulfides and trisulfides, and vinyldithiins in Allium species against lipid hydroperoxide (LOOH) formation in human low-density lipoprotein (LDL) was examined. It was elucidated that the alk(en)yl substituents (methyl, propyl, and allyl) and the number of sulfur atoms in the compounds were important for the antioxidative activity. 3,4-Dihydro-3-vinyl-1,2-dithiin, which is produced by a thermochemical reaction of allyl 2-propenethiosulfinate, exhibited the highest antioxidative activity of human LDL among sulfur-containing compounds.

Botulinum neurotoxin type B causes the inhibition of acetylcholine release at the neuromuscular junction resulting in a flaccid paralysis designated botulism. This occurs through the cleavage of synaptobrevin, an intracellular critical component of neurotransmitter exocytosis, by the zinc-metallopeptidase activity of the smallest subunit of the toxin. Blocking the proteolytic activity may present an attractive approach to treat botulism as to date there is no efficient specific drug therapy available. We have therefore recently described a series of beta-amino-thiol derived pseudotripeptides able of inhibiting the toxin at low (10(-8) M) concentration. In this study, binding characteristics of the protein's active site are explored through various structural modifications of the thiol functionality which was supposed to be a key structural constituent for effective zinc-ion chelation. Surprisingly, sulfanyl-derivatives such as symmetric disulfides were shown to be better inhibitors than their thiol-counterparts, the most potent compound displaying a Ki value of 3.4 nM.

Human LDL were used to study the protective action of four organosulfur compounds (diallyl sulfide, DAS; diallyl disulfide, DADS; S-ethylcysteine, SEC; N-acetylcysteine, NAC) derived from garlic against oxidation and glycation. The four organosulfur compounds significantly inhibited superoxide production by xanthine-xanthine oxidase (P < 0.05) and showed marked copper-chelating capability. DAS and DADS exhibited greater antioxidant activities against copper- and amphotericin B-induced LDL oxidation (P < 0.05) than SEC and NAC. However, SEC and NAC were more effective in sparing LDL alpha-tocopherol (P < 0.05). When oxidation was minimized, SEC was the most powerful agent against LDL glycation (P < 0.05); however, DADS was superior to other agents in suppressing both oxidation and glycation when LDL oxidation occurred simultaneously with glycation. These results suggest that the four organosulfur compounds derived from garlic are potent agents for protecting LDL against oxidation and glycation, and that they may benefit patients with diabetes mellitus or cardiovascular diseases by preventing complications.

The early phase of 3T3 fibroblast interaction with sulfonated styrene copolymer surfaces, of two sulfonic group densities and thus of differing wettability, was studied. The sulfonic groups present on copolymer surfaces affected the behaviour of cells, i.e. they stimulated cell adhesion, activated cell spreading and influenced cytoskeleton reorganization. The relative number of adhering cells correlated, while the number of spreading cells inversely correlated, with the surface density of sulfonic groups. Cell shape and the pattern of distribution of F-actin, alpha-actinin and vinculin in the interacting cells also depend on the surface density of sulfonic groups. On surfaces of high sulfonic group density, highly polarized cells were observed with F-actin bundles. On surfaces of low sulfonic group density, the cells spread with a square-like morphology with F-actin organized in stress fibres. In contrast, the cells spread poorly on nonsulfonated surfaces and cell adhesion was unaffected by surface wettability. The contribution of alpha(5)beta(1), alpha(4), and beta(5)integrins to the cell interaction with fibronectin (FN) and vitronectin (VN) adsorbed from serum-containing medium on polymer surfaces was examined. Our results suggest that surface sulfonic groups influence the conformation of FN and VN adsorbed on polymer surfaces and, in turn, determine the integrins that are involved in cell adhesion., (Copyright 2003 Elsevier Science Ltd.)

Organosulfur compounds and sodium bisulfite significantly inhibited (P < 0.05) heterocyclic aromatic amine (HAA) formation in model systems containing phenylalanine, creatinine, and glucose. There was, however, no inhibition by the same compounds in a model system containing only phenylalanine and creatinine. Diallyl disulfide (DAD) and dipropyl disulfide (DPD) concentrations in the model systems were significantly decreased (P < 0.05) after heating for 10 min at 180 degrees C. Only very low concentrations of sulfhydryl groups (4.19 and 4.00 micromol) were produced on heating DAD and DPD for 30 min. Reaction of glucose and DAD produced several sulfur-containing compounds. After 10 min of heating at 180 degrees C, HAA formation in the control model systems was increased significantly, and DAD was an effective inhibitor during this heating period. Tetrahydrothiophene-3-one (THT) and tetrahydrothiophene (THP); two products resulting from the interaction of glucose and DAD, had no direct influence on HAA formation in the model systems.

Dihydrodiols, which are potential proximate carcinogens of phenanthro[4,3-b][1]benzothiophene (3) and phenanthro[3,4-b][1]benzothiophene (4) and possess a "fjord" structure, were synthesized. The dihydrodiols synthesized were trans-3,4-dihydroxy-3,4-dihydrophenanthro[4,3-b][1]benzothiophene (5) and trans-3,4-dihydroxy-3,4-dihydrophenanthro[3,4-b][1]benzothiophene (6). The precursors to the dihydrodiols 5 and 6 were 3-methoxyphenanthro[4,3-b][1]benzothiophene (11) and 3-methoxyphenanthro[3,4-b][1]benzothiophene (16). Compound 11 was obtained via Suzuki cross-coupling reaction of easily accessible starting materials. However, this synthetic strategy utilizing Suzuki reaction for the preparation of 16 was comparatively less productive than that described previously due to time-consuming synthesis of the starting material(s), and extremely poor yield associated with cyclization of the epoxide 15 to 16. The methoxy derivatives 11 and 16 were converted to the corresponding dihydrodiols 5 and 6 by a sequence involving demethylation, oxidation, and reduction. The trans-stereochemistry of the dihydrodiols was established by (1)H NMR, which indicated a large coupling constant between vicinal carbinol protons. The UV spectra of the dihydrodiols 5 and 6 are presented.

The essential oil and several pure sulfur compounds isolated from Scorodophloeus zenkeri were tested for their antibacterial and antifungal activity using a paper disc method, the poisoned food technique, a microatmosphere method and the measurement of cellular ATP content. The essential oil completely inhibited the growth of all fungi tested including yeasts, with the exception of Aspergillus flavus, and was active against the Gram-positive bacteria studied, but not the Gram-negative organisms. 2,4,5,7-Tetrathiaoctane, 2,4,5,6,8-pentathianonane, 2,3,4,6,8-pentathianonane, 2,3,5,6,8,10-hexathiaundecane, 2,3,5-trithiahexane 5-oxide, 2,4,5,7-tetrathiaoctane 2-oxide, 2,3,5,7-tetrathiaoctane 3,3-dioxide and 2,3,5-trithiahexane 3,3-dioxide differed in their effects on the strains studied with respect to both growth and synthesis of cellular ATP. 2,3,5-Trithiahexane, 2,3,4,6-tetrathiaheptane, methyl methanethiosulfonate and bis-methyl-sulfonylmethane exhibited no antimicrobial activity.

The effects of garlic and selected organosulfur compounds (diallyl disulfide, dipropyl disulfide, diallyl sulfide, allyl methyl sulfide, allyl mercaptan, cysteine, and cystine) on the formation of heterocyclic aromatic amines (HAAs) in fried ground beef patties were evaluated. Minced garlic cloves (ca. 4.8 to 16.7%, wt/wt) or organosulfur compounds (0.67 mmol) were added directly to ground beef. Patties (100 g) were fried at 225 degrees C (surface temperature) for 10 min per side. Two patties were fried for each replication, and five replicates were analyzed for each treatment. For each replicate, four subsamples were analyzed (two unspiked subsamples for concentration and two spiked subsamples for the recovery of HAA standards). The volatile sulfur compounds significantly (P < 0.05) reduced concentrations of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine by reductions of 46 to 81%, while average reductions of 35, 22, and 71%, were achieved with cystine, cysteine, and whole garlic, respectively. The volatile sulfur compounds reduced concentrations of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline by 34 to 67%, while reductions of 25, 19, and 63% (P < 0.05) were achieved with cystine, cysteine, and whole garlic, respectively. These studies confirm that garlic and some organosulfur compounds have the potential to reduce HAA formation incooked beef patties.

The nonenzymatic antioxidant activity of diallyl sulfide (DAS), diallyl disulfide (DADS), S-ethyl cysteine (SEC), and N-acetyl cysteine (NAC) in the liposome system was examined. The antioxidant protection from these organosulfur agents was concentration dependent (p < 0.05). SEC and NAC showed significantly lower lipophilicity and greater reducing power than DAS and DADS (p < 0.05). Greater antioxidant protection was presented in the combinations of alpha-tocopherol with four organosulfur agents than alpha-tocopherol treatment alone (p < 0.05), and SEC and NAC showed greater sparing effects on alpha-tocopherol (p < 0.05). Four organosulfur agents lost antioxidant activity when the temperature was 65 degrees C (p < 0.05). At pH 2.5 and 10, DAS and DADS still showed antioxidant activity (p < 0.05). On the basis of the observed nonenzymatic antioxidant protection, these organosulfur compounds are potent agents for enhancing lipid stability.

Synthesis of sulfur derivatives of indane-1,3-dione, VIIb-c, VIIIa-b, IX and X is described. Results of a preliminary pharmacological screening of six compounds [VIIb, VIII, VIIIb, IX, X and XI] are presented.

The radioprotective effects of a polyphenolic extract of Olea europaea L. leaves (OL); the flavonoids diosmin and rutin, which are widely used as pharmaceuticals; and the sulfur-containing compounds dimethylsulfoxide (DMSO) and 6-n-propyl-2-thiouracil (PTU) were determined by using the micronucleus test for anticlastogenic activity, evaluating the reduction of the frequency of micronucleated polychromatic erythrocytes (MnPCEs) in bone marrow of mouse before and after X-ray irradiation. With treatment before X-irradiation, the most effective compounds were, in order, rutin > DMSO > OL > PTU > diosmin. These results showed, for the polyphenols studied, a linear correlation (r(2) = 0.965) between anticlastogenic activity and antioxidant capacity. The magnitude of protection with treatment after X-irradiation were lower, and the most effective compounds were, in order, OL > diosmin > rutin; DMSO and PTU lacked radioprotective activity. Therefore, OL is the only substance that showed a significant anticlastogenic activity both before and after X-ray irradiation treatments. Structurally, the free oxygen radicals and lipoperoxyradicals scavenging capacity and, consequently, the anticlastogenic activity of these polyphenolic compounds are based principally on the presence of specific functional groups, mainly catechol groups (rutin, oleuropein, hydroxytyrosol, verbascoside, luteolin), that also increase the stability of the aroxyl-polyphenol radical generated in the above processes.

Excessive nitric oxide (NO) production is involved in cellular injury and possibly in the multistage process of carcinogenesis. In this study, we investigated the effect of organosulfur compounds (S-allyl cysteine, allyl sulfide, diallyl disulfide, allyl isothiocyanate, phenyl isothiocyanate, and benzyl isothiocyanate) that are found in allium or cruciferous vegetables on NO production in J774.1 macrophages activated with lipopolysaccharide (LPS). Diallyl disulfide, allyl, phenyl, and benzyl isothiocyanates inhibited NO production, as evaluated by nitrite formation at 25 microM. Allyl and benzyl isothiocyanates, the most active of the six organosulfur compounds, exhibited dose-dependent inhibition and had IC(50) values of 1.6 and 2.7 microM, respectively. Western blot analysis suggested that suppression of the induction of inducible NO synthase (iNOS) expression is responsible for the inhibition of NO production by allyl and benzyl isothiocyanates. In contrast, these isothiocyanates increased LPS-stimulated tumor necrosis factor alpha (TNF-alpha) release, suggesting their selective action on genes activated by LPS. Our results demonstrate that certain organosulfur compounds inhibit NO synthesis in LPS-activated macrophages, and the inhibitory effect may be a significant component of their anticarcinogenic activity.

Organosulfur compounds present in natural food are generally considered as beneficial for health because of their antioxidant and anticarcinogenic properties. This has led to their excessive and long-term consumption. However, there is also evidence that these compounds demonstrate toxicity and adverse health effects suggesting their potential dual biological roles. Thus, they can act as double-edged biological swords.

The low sulfur amino acid content of legume seeds restricts their nutritive value for animals. We have investigated the limitations to the accumulation of sulfur amino acids in the storage proteins of narrow leaf lupin (Lupinus angustifolius) seeds. Variation in sulfur supply to lupin plants affected the sulfur amino acid accumulation in the mature seed. However, when sulfur was in abundant supply, it accumulated to a large extent in oxidized form, rather than reduced form, in the seeds. At all but severely limiting sulfur supply, addition of a transgenic (Tg) sink for organic sulfur resulted in an increase in seed sulfur amino acid content. We hypothesize that demand, or sink strength for organic sulfur, which is itself responsive to environmental sulfur supply, was the first limit to the methionine (Met) and cysteine (Cys) content of wild-type lupin seed protein under most growing conditions. In Tg, soil-grown seeds expressing a foreign Met- and Cys-rich protein, decreased pools of free Met, free Cys, and glutathione indicated that the rate of synthesis of sulfur amino acids in the cotyledon had become limiting. Homeostatic mechanisms similar to those mediating the responses of plants to environmental sulfur stress resulted in an adjustment of endogenous protein composition in Tg seeds, even when grown at adequate sulfur supply. Uptake of sulfur by lupin cotyledons, as indicated by total seed sulfur at maturity, responded positively to increased sulfur supply, but not to increased demand in the Tg seeds.

The objective of this study was to compare the modulatory effect of garlic oil and its three organosulfur compounds, diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS), on rat hepatic detoxification enzyme activity, and protein and mRNA expression. Rats were orally administered garlic oil (80 or 200 mg/kg bw), DAS (20 or 80 mg/kg bw), DADS (80 mg/kg bw), or DATS (70 mg/kg bw) three times a week for 6 weeks. Control rats received corn oil. According to the results, garlic oil and DAS in dosages of 200 and 80 mg/kg bw, respectively, significantly increased pentoxyresorufin O-dealkylase (PROD) activity as compared with the that of the control rats (P < 0.05). In contrast, N-nitrosodimethylamine demethylase activity in rats that received DADS and DATS was significantly lower than that in the control rats (P < 0.05). Ethoxyresorufin O-deethylase and erythromycin demethylase activities were not influenced by garlic oil, DAS, DADS, or DATS. To the phase II enzyme, garlic oil, DADS, and DATS significantly increased the glutathione S-transferase (GST) activity toward ethacrynic aicd (P < 0.05). Immunoblot assay showed that the protein contents of cytochrome P450 1A1, 2B1, and 3A1 were increased by garlic oil and each of three allyl sulfides, and the change among the allyl sulfides was in the order of DAS > DADS > DATS. The placental form of GST (PGST) level was also increased by garlic oil and the three allyl sulfides, but the increase among the allyl sulfides was DATS congruent with DADS > DAS. P450 2E1, however, was suppressed by each garlic component. Northern blot results indicated that the changes in P450 1A1, 2B1, 3A1, and PGST mRNA levels by garlic components were similar to those noted in the protein levels. These results indicate that the modulatory effect of garlic oil on hepatic drug-metabolizing enzymes can be attributed to its three major allyl sulfide components DAS, DADS, and DATS. These three allyl sulfides vary in modulatory activity, and this variation is related to the number of sulfur atoms in the molecule.

Synthesis of (+/-)-cis-7-hydroxy-3-phenyl-4-(4-(2-piperidinoethanethio)phenyl)chromane (13) and (+/-)-cis-7-hydroxy-3-phenyl-4-(4-(2-pyrrolidinoethanethio)phenyl)chromane (15) is presented. These compounds are representatives of a novel class of compounds with high in vitro binding affinity for the estrogen receptor (IC(50)=7-10 nM), and very low in vitro uterotrophic activity (max stim.=5-17% rel to moxestrol; EC(50)=0.5-1.8 nM).

Cell-based screening for novel tumor-specific drugs has been compromised by the lack of appropriate control cells. We describe a strategy for drug screening based on isogenic human cancer cell lines in which key tumorigenic genes have been deleted by targeted homologous recombination. As a test case, a yellow fluorescent protein (YFP) expression vector was introduced into the colon cancer cell line DLD-1, and a blue fluorescent protein (BFP) expression vector was introduced into an isogenic derivative in which the mutant K-Ras allele had been deleted. Co-culture of both cell lines allowed facile screening for compounds with selective toxicity toward the mutant Ras genotype. Among 30,000 compounds screened, a novel cytidine nucleoside analog was identified that displayed selective activity in vitro and inhibited tumor xenografts containing mutant Ras. The present data demonstrate a broadly applicable approach for mining therapeutic agents targeted to the specific genetic alterations responsible for cancer development.

In the late 20(th) century, the treatment of cancer began to include its prevention. Today, compounds exist that will lower the risk of developing certain types of cancer. This has been demonstrated in studies where chemically induced tumor growth has been slowed or reversed. Anti-inflammatory compounds having chemopreventive activity are piroxicam, sulindac, aspirin, celecoxib and curcumin. The selective estrogen receptor modulators, tamoxifen and raloxifene, are beneficial in the prevention of estrogen dependent tumors. Retinoids, vitamin A derivatives, such as targretin and fenretinide are useful in the prevention of tumors. Compounds containing sulfur, such as sulforaphane and oltipraz, are even useful as radioprotective agents. The steroid dehydroepiandosterone can inhibit experimental carcinogenesis. All of these chemical classes provide a start for the medicinal chemist to design more effective chemopreventive agents. The biomarkers used to determine the chemopreventive activity of new compounds are quite often activities of enzymes. The identification of those individuals at high risk is still in its infancy and presents a troubling dilemma.

Allium vegetables have been shown to have beneficial effects against several diseases, including cancer. Garlic, onions, leeks, and chives have been reported to protect against stomach and colorectal cancers, although evidence for a protective effect against cancer at other sites, including the breast, is still insufficient. The protective effect appears to be related to the presence of organosulfur compounds and mainly allyl derivatives, which inhibit carcinogenesis in the forestomach, esophagus, colon, mammary gland, and lung of experimental animals. The exact mechanisms of the cancer-preventive effects are not clear, although several hypotheses have been proposed. Organosulfur compounds modulate the activity of several metabolizing enzymes that activate (cytochrome P450s) or detoxify (glutathione S-transferases) carcinogens and inhibit the formation of DNA adducts in several target tissues. Antiproliferative activity has been described in several tumor cell lines, which is possibly mediated by induction of apoptosis and alterations of the cell cycle. Allium vegetables and organosulfur compounds are thus possible cancer-preventive agents. Clinical trials will be required to define the effective dose that has no toxicity in humans.

Further chemical modification to identify more chemically stabilized EP4-receptor selective agonists was continued. As a result, a further two EP4-receptor selective agonists 5-thiaPGE(1) 2a, 10 and 9beta-chloroPGF(2) analogue 11 were discovered.

Background: Proinflammatory cytokines play key roles in atherogenesis and disease progression. Because hyperhomocysteinemia is an independent risk factor for cardiovascular disease, we hypothesized that homocysteine could be atherogenic by altering the expression of specific cytokines in vascular endothelial cells., Methods and Results: Northern blot and RNase protection assays showed that DL-homocysteine induced mRNA expression of the proinflammatory cytokines monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) in cultured human aortic endothelial cells (HAECs). Homocysteine had no effect on expression of other cytokines, namely tumor necrosis factor-alpha, granulocyte-macrophage colony-stimulating factor, interleukin-1beta, and transforming growth factor-beta. MCP-1 mRNA expression increased 1 hour after homocysteine treatment, reached a maximum within 2 to 4 hours, and declined to basal levels over the next 24 hours. Induction of mRNA expression for both chemokines was observed with as little as 10 micromol/L DL-homocysteine, and maximal expression was achieved with 50 micromol/L DL-homocysteine. Homocysteine also triggered the release of MCP-1 and IL-8 protein from HAECs into the culture medium. The induction was specific for homocysteine, because equimolar concentrations of L-homocystine, L-cysteine, and L-methionine had no effect on mRNA levels and protein release. Furthermore, L-homocysteine induced chemokine expression, but D-homocysteine did not, thus demonstrating enantiomeric specificity. The culture medium from homocysteine-treated HAECs promoted chemotaxis in human peripheral blood monocytes and U937 cells. Anti-human recombinant MCP-1 antibody blocked the migration., Conclusions: Pathophysiological levels of L-homocysteine alter endothelial cell function by upregulating MCP-1 and IL-8 expression and secretion. This suggests that L-homocysteine may contribute to the initiation and progression of vascular disease by promoting leukocyte recruitment.

The putative hypolipidemic effect of garlic remains controversial. To gain further insight into the effect of garlic on lipid metabolism, the present study determined the inhibitory effects of water-soluble organosulfur compounds present in garlic on triglyceride (TG) and fatty acid synthesis in cultured rat hepatocytes. When incubated at 0.05 to 4.0 mmol/L with cultured hepatocytes, S-allyl cysteine (SAC) and S-propyl cysteine (SPC) decreased [2-14C]acetate incorporation into triglyceride in a concentration-dependent fashion achieving a maximal inhibition at 4.0 mmol/L of 43 and 51%, respectively. The rate of [2-14C]acetate incorporation into phosphlipids was depressed to a similar extent by SAC and SPC. SPC, SAC, S-ethyl cysteine (SEC), and gamma-glutamyl-S-methyl cysteine decreased [2-14C]acetate incorporation into fatty acid synthesis by 81, 59, 35, and 40%, respectively, at 2.0-4.0 mmol/L concentrations. Alliin, gamma-glutamyl-S-allyl cysteine, gamma-glutamyl-S-propyl cysteine S-allyl-N-acetyl cysteine, S-allylsulfonyl alanine, and S-methyl cysteine had no effect on fatty acid synthesis. The activities of lipogenic enzymes, fatty acid synthase (FAS), and glucose-6-phosphate dehydrogenase (G6PDH) were measured in cultured hepatocytes treated with the inhibitors. The activity of FAS in cells treated with 4.0 mmol/L SAC and SPC, respectively, was 32 and 27% lower than that of nontreated cells. Neither SAC nor SPC affected G6PDH activity. The results indicate that SAC, SEC, and SPC inhibit lipid biosynthesis in cultured rat hepatocytes, and further suggest that these S-alk(en)yl cysteines of garlic impair triglyceride synthesis in part due to decreased de novo fatty acid synthesis resulting from inhibition on FAS. Whether tissue concentrations of active garlic components can achieve levels required to inhibit TG synthesis in vivo warrants further investigation.

Recent studies have shown that point mutations in the dihydropteroate synthase (DHPS) gene of human-derived Pneumocystis carinii are related to exposure to sulfa drugs and possibly represent the emergence of sulfa resistance. We developed a simple single-strand conformation polymorphism (SSCP) method to permit rapid detection of these mutations. With plasmid constructs, SSCP was able to detect as little as 10% of a minority population. The SSCP assay was compared to direct sequencing for typing the DHPS gene by examining 37 clinical isolates with known DHPS sequences and 41 clinical isolates with unknown DHPS sequences. The typing results were consistent between these two methods for all isolates except 11 in which mutations were detected by SSCP but not by direct sequencing. Sequencing of individual clones after subcloning confirmed the presence of mutations in a minority population as determined by SSCP. SSCP is a very simple and sensitive method for rapid identification of P. camii DHPS mutations.

The medicinal use of garlic dates back thousands of years, but there was little scientific support of its therapeutic and pharmacologic properties until recently. In the past decade, the cancer-protective effects of garlic have been well established by epidemiologic studies and animal experiments. However, the cardiovascular-protective properties of garlic are less well understood. In particular, despite the reported hypocholesterolemic effect of garlic, the mechanism of the effect is unclear. In a recent randomized, double-blind, placebo-controlled intervention study, we showed that aged garlic extract (AGE) supplementation was effective in lowering plasma concentration of total cholesterol by 7% and LDL cholesterol by 10% in hypercholesterolemic men compared with subjects consuming a placebo. Supplementation of AGE in animal diets similarly reduced plasma concentrations of total cholesterol and triacylglycerol by 15 and 30%, respectively. In subsequent experiments using cultured rat hepatocytes, we found 44--87% inhibition of cholesterol synthesis by the water-extractable fraction (WEF), methanol-extractable fraction (MEF) and petroleum ether-extractable fraction (PEF) of fresh garlic, and Kyolic (liquid form of AGE). These observations suggested that hydrophilic and hydrophobic compounds of garlic are inhibitory to cholesterol synthesis. Because S-allylcysteine (SAC) alone was less potent than Kyolic, which contains SAC and other sulfur compounds, a maximal inhibition appears to require a concerted action of multiple compounds of garlic. In a series of experiments, we further characterized the inhibitory potency of individual water-soluble and lipid-soluble compounds of garlic. Among water-soluble compounds, SAC, S-ethylcysteine (SEC), and S-propylcysteine (SPC) inhibited cholesterol synthesis by 40--60% compared with 20--35% by gamma-glutamyl-S-allylcysteine (GSAC), gamma-glutamyl-S-methylcysteine (GSMC) and gamma-glutamyl-S-propylcysteine (GSPC). Lipid-soluble sulfur compounds (i.e., diallyl sulfide, diallyl disulfide, diallyl trisulfide, dipropyl sulfide and dipropyl trisulfide) at low concentrations (0.05--0.5 mol/L) slightly (10--15%) inhibited cholesterol synthesis but became highly cytotoxic at high concentrations (1.0--4.0 mol/L). All water-soluble compounds, except S-allylmercaptocysteine, were not cytotoxic, judging from the release of cellular lactate dehydrogenase into the culture medium. Taken together, the results of our studies indicate that the cholesterol-lowering effects of garlic extract, such as AGE, stem in part from inhibition of hepatic cholesterol synthesis by water-soluble sulfur compounds, especially SAC.

A series of phosphonothioic acid derivatives of (S)-2-hydroxyglutarate with various alkyl or aryl ligands to the central phosphorus atom was examined for stereoselective inhibition of the glutamate carboxypeptidase, carboxypeptidase G. The inhibitory potencies of these stereoisomers were compared to corresponding synthetic phosphonic acid analogues in order to reveal the significance of the sulfur ligand of the phosphonothioic acid motif upon the inhibition of this metallopeptidase. The acquisition of the individual phosphonothioic acid diastereomers was achieved through the resolution of the respective phosphonate ester precursors. In all cases, the (+)p-diastereomers of these phosphonothioic acid derivatives of (S)-2-hydroxyglutarate were found to be more potent inhibitors of glutamate carboxypeptidase than the corresponding (-)p antipodes with the most dramatic difference observed for the butyl isomers (13.6-fold). Based upon Ki values obtained, the most potent inhibitor of the series by nearly an order of magnitude was the (+)p-n-butylphosphonothioic acid derivative, revealing specific structural and stereochemical requirements by this glutamate carboxypeptidase. With the exception of the (+)p-n-butyl analogue, the isosteric replacement of oxygen with sulfur of the phosphonic acid moiety did not enhance inhibitory potency.

There is evidence that onions and garlic protect against cancer in humans. It has been suggested that this effect is due to the organosulfur compounds in these vegetables and that these substances act through induction of phase II detoxification enzymes. In the present studies, we have compared the ability of diallyl sulfide, dially disulfide, and diallyl trisulfide, compounds that are derived from garlic, to increase the activity of the phase II enzymes quinone reductase and glutathione transferase in a variety of rat tissues. We have also examined the onion-derived substances, dipropyl sulfide, dipropyl disulfide, dipropenyl sulfide, and dipropenyl disulfide, under identical conditions. Diallyl trisulfide and diallyl disulfide were potent inducers of the phase II enzymes. Dipropenyl disulfide was much less active, while little effect on enzyme activity was seen in animals dosed with dipropyl disulfide. Diallyl sulfide and dipropyl sulfide were weak inducers of quinone reductase and glutathione transferase, but dipropenyl sulfide was very active, with an effect similar to that of diallyl disulfide. It is possible that diallyl disulfide and diallyl trisulfide are important in the anticancer action of garlic, while dipropenyl sulfide could be involved in the beneficial action of onions.

Hydroponically grown spinach plants were deprived of an external source of sulphate after an initial period when the S-supply was sufficient. The time-course of events following this treatment was monitored. The first responses were found in the uptake and translocation of NO(3)(-) and the uptake of SO(4)(2-). The former declined by approximately 50%, the effect being most significant at higher [NO(3)(-)](ext.) while the latter increased 6-fold over a 4 d period. Growth in the absence of external SO(4)(2-) resulted in exhaustion of internal SO(4)(2-) pools, the effect being seen first in roots, then in young leaves and, after a marked delay, in mature leaves. In young leaves, there were dramatic increases in the [NO(3)(-)] and the content of arginine in the first 2 d of S-deprivation. The concentration of glutamine, the most abundant amino acid in S-sufficient conditions, also more than doubled in S-deficient young leaves. The changes in arginine levels were also found in older leaves, but the change in glutamine level was not seen. Assays of nitrate reductase activity (NRA) and nitrate reductase (NR) mRNA from young leaves of S-replete and S-deprived plants revealed a divergence in activity and content only late in the experiments (between days 4 and 8) when results were expressed on a unit leaf basis. However, there were also time-dependent changes in the protein content that kept the specific activities (NRA:protein and RNA:protein) more or less unchanged. The results imply that the impact of S-deficiency on N-utilization are more sensitively monitored by simple measurements of the chemical composition of young leaves than by measurements of NRA or NR transcript abundance. They also suggest that protein synthesis in young leaves is strongly dependent on a continuous supply of SO(4)(2-) from outside the plant.

Overall, a host of studies provides compelling evidence that garlic and its organic allyl sulfur components are effective inhibitors of the cancer process. These studies reveal that the benefits of garlic are not limited to a specific species, to a particular tissue, or to a specific carcinogen. Several mechanisms are likely to account for this protection. Notable among these is a depression in nitrosamine formation and a reduction in carcinogen bioactivation. The benefits provided by garlic must be viewed as part of the entire diet, since several dietary constituents can influence the degree of protection. More than one compound is responsible for the anticancer properties associated with garlic. Future research should focus on how genetic variability and daily environmental factors influence the anticancer benefits attributed to garlic and its allyl sulfur components.

Several anionic sulfur compounds are recognized as efficacious pretreatments for sulfur mustard (HD) poisoning. Our intent was to see if pretreatment compounds had a direct effect on DNA, a site where HD damage is thought to occur. A modification of the method of Szinicz et al. (Arzneim.-Forsch. 1981; 31: 1,713-1,717) was used to analyze the UV/VIS spectrum (205-400 nm) (n = 6) of calf thymus DNA (10-15 x 10(3) kDa) in the absence or presence of increasing concentrations of sodium thiosulfate, sodium 2-aminoethanethiosulfonate (thiotaurine), sodium metabisulfite or sodium sulfate. All compounds produced concentration-dependent absorbance decreases primarily at 212 nm, but also at 259 nm, with the exception of sodium sulfate. For example, 8.36 x 10(-4) M sodium thiosulfate reduced the absorbance of DNA at 212 nm by >60%. The kinetics of sulfur compounds on native DNA need further study. We propose that these anionic sulfur compounds interact with DNA possibly by changing the topology of this macromolecule. Effects may be due to interactions of these sulfur compounds at higher concentrations with DNA, with resulting ligand-DNA supercoiling. This process could protect against HD intoxication, which is caused in part by the uncoiling of DNA.

New sulfur-containing amides, cassipoureamide-A (1) and -B (2), have been isolated from the stem wood of Cassipourea guianensis, and their structures were determined to be cis-N-(2-hydroxyethyl)-4-hydroxy-1,2-dithiolane-3-carboxamide and cis-N-(2-hydroxyethyl)-5-hydroxy-1,2,3-trithiane-4-carboxamide, respectively, by MS and NMR studies.

The activity of the superoxide-sensitive enzyme aconitase was monitored to evaluate the generation of superoxide in neuronal cell lines treated with beta-amyloid (Abeta) peptide 1-42. Treatment of differentiated and undifferentiated rat PC12 and human neuroblastoma SK-N-SH cells with soluble Abeta1-42 (Abeta-derived diffusible ligands) or fibrillar Abeta1-42 caused a 35% reversible inactivation of aconitase, which preceded loss of viability and was correlated with altered cellular function. Aconitase was reactivated upon incubation of cellular extracts with iron and sulfur, suggesting that Abeta causes the release of iron from 4Fe-4S clusters. Abeta neurotoxicity was partially blocked by the iron chelator deferoxamine. These data suggest that increased superoxide generation and the release of iron from 4Fe-4S clusters are early events in Abeta1-42 neurotoxicity.

The 190-kDa multidrug resistance protein MRP1 is an ATP-binding cassette protein that confers resistance to multiple antineoplastic agents and actively transports conjugated organic anions. We have previously shown that MRP1-mediated GSH transport is stimulated by verapamil but transport of verapamil in the presence or absence of GSH is not observed. We have now examined 20 sulfur-containing verapamil analogs for their ability to inhibit MRP1-mediated leukotriene C(4) (LTC(4)) transport and stimulate GSH uptake into inside-out membrane vesicles. All of the derivatives were poor inhibitors of LTC(4) uptake. However, the inhibitory potency of the more lipophilic dithiane compounds could be enhanced by coincubation with GSH whereas this was not the case for the more hydrophilic dithiane tetraoxides. The dithiane derivatives stimulated GSH transport whereas, with one exception, the dithiane tetraoxides did not. One pair of dithiane stereoisomers differed significantly in their ability to stimulate GSH transport although their ability to inhibit LTC(4) uptake in the presence of GSH was comparable. Our findings indicate that the GSH transport activity of MRP1 can be dissociated from its conjugated organic anion transport activity., (Copyright 2000 Academic Press.)

The immunomodulatory effects of naturally occurring sulphur compounds such as diallyl sulphide (DAS), diallyl disulphide (DADS) and allyl methyl sulphide (AMS) were studied in BALB/c mice. After treatment with five doses (20 mg/dose) of sulphur-containing compounds, the total white blood cell (WBC) count was enhanced significantly in mice. Among the sulphur compounds studied, DADS showed the maximum number of WBC (17,900 cells/mm(3)) on the 6th day, and highest antibody titre of 516 on the 12th day. Administration of DAS and DADS enhanced the weight of vital organs such as the spleen and thymus. DADS, AMS, and DAS administration could enhance the number of plaque forming cells (PFC) in the spleen of the animals. Maximum numbers of PFC (1,409 PFC/10(6) spleen cells) were observed in DADS-treated animals. Bone-marrow cellularity was also increased significantly (P<0.001) in DADS (19.3 x 10(6) cells/femur) and AMS (24.7 x 10(6) cells/femur) treated animals. The number of alpha-esterase positive cells was enhanced in DAS (1,315/4,000 cells), DADS (1,748/4,000 cells), and AMS (1,648/4,000 cells) treated animals, compared to normal animals (1,065/4,000 cells). These results are suggestive of an immunostimulating effect of sulphur compounds.

It has been well documented that natural organosulfur compounds (OSCs) derived from plants such as garlic, onions and mahogany trees possess antiproliferative properties; however, the essential chemical features of the active OSC compounds remain unclear. To investigate the association between OSC structure and growth inhibitory activity, we synthesized novel relatives of dysoxysulfone, a natural OSC derived from the Fijian medicinal plant, Dysoxylum richii. In this study, we have examined the antiproliferative effects of these novel OSCs on a model human leukemic cell system and show that the compounds segregate into three groups. Group I, consisting of compounds A, B, G and J, did not affect either cell proliferation or the cell cycle profile of the leukemic cell lines. Group II, consisting of compounds F and H, induced the cells to undergo apoptosis from the G2/M phase of the cell cycle. Group III, consisting of compounds C, D, E and I, decreased cell proliferation and induced apoptosis throughout the cell cycle. The apoptotic agonists of Group II and III shared a common disulfide moiety, essential for leukemic cell cytotoxicity. Interestingly, Group II compounds did not affect cell viability of normal human diploid cells, suggesting the regions flanking the disulfide group contributes to the specificity of cell killing. Thus, we provide evidence that structure-activity analysis of natural products can identify novel compounds for the development of new therapeutics that can trigger apoptosis in a tumor-specific manner.

The study was undertaken to test the inhibitory potential on cholesterogenesis of organosulfur compounds derived from garlic. The primary rat hepatocytes maintained in Dulbecco's modified Eagle's medium were treated with [2-14C]acetate as substrate for cholesterol synthesis in the presence or absence of test compounds at 0.05 to 4.0 mmol/L. Eleven water-soluble and six lipid-soluble compounds of garlic were tested. Among water-soluble compounds, S-allyl cysteine (SAC), S-ethyl cysteine (SEC), and S-propyl cysteine (SPC) inhibited [2-14C]acetate incorporation into cholesterol in a concentration-dependent manner, achieving 42 to 55% maximal inhibition. Gamma-glutamyl-S-allyl cysteine, gamma-glutamyl-S-methyl cysteine, and gamma-glutamyl-S-propyl cysteine were less potent, exerting only 16 to 29% maximal inhibitions. Alliin, S-allyl-N-acetyl cysteine, S-allylsulfonyl alanine, and S-methyl cysteine had no effect on cholesterol synthesis. Of the lipid-soluble compounds, diallyl disulfide (DADS), diallyl trisulfide (DATS), and dipropyl disulfide (DPDS) depressed cholesterol synthesis by 10 to 25% at low concentrations (< or =0.5 mmol/L), and abolished the synthesis at high concentrations (> or =1.0 mmol/L). Diallyl sulfide, dipropyl sulfide, and methyl allyl sulfide slightly inhibited [2-14C]acetate incorporation into cholesterol only at high concentrations. The complete depression of cholesterol synthesis by DADS, DATS, and DPDS was associated with cytotoxicity as indicated by marked increase in cellular LDH release. There was no apparent increase in LDH secretion by water-soluble compounds except S-allyl mercaptocysteine, which also abolished cholesterol synthesis. Judging from maximal inhibition and IC50 (concentration required for 50% of maximal inhibition), SAC, SEC, and SPC are equally potent in inhibiting cholesterol synthesis.

To determine the role of nonsulfur vs. sulfur amino acids in regulation of cysteine metabolism, rats were fed a basal diet or diets supplemented with a mixture of nonsulfur amino acids (AA), sulfur amino acids (SAA), or both for 3 wk. Hepatic cysteine-sulfinate decarboxylase (CSDC), cysteine dioxygenase (CDO), and gamma-glutamylcysteine synthetase (GCS) activity, concentration, and mRNA abundance were measured. Supplementation with AA alone had no effect on any of these measures. Supplementation of the basal diet with SAA, with or without AA, resulted in a higher CDO concentration (32-45 times basal), a lower CSDC mRNA level (49-64% of basal), and a lower GCS-heavy subunit mRNA level (70-76%). The presence of excess SAA and AA together resulted in an additional type of regulation: a lower specific activity of all three enzymes was observed in rats fed diets with an excess of AA and SAA. Both SAA and AA played a role in regulation of these three enzymes of cysteine metabolism, but SAA had the dominant effects, and effects of AA were not observed in the absence of SAA.

Basic fibroblast growth factor (FGF-2) interacts with high-affinity tyrosine-kinase fibroblast growth factor receptors (FGFRs) and low-affinity heparan sulfate proteoglycans (HSPGs) in target cells. Both interactions are required for FGF-2-mediated biological responses. Here we report the FGF-2 antagonist activity of novel synthetic sulfonic acid polymers with distinct chemical structures and molecular masses (MMs). PAMPS [poly(2-acrylamido-2-methyl-1-propanesulfonic acid)], (MM approximately 7,000-10,000), PAS [poly(anetholesulfonic acid)], (MM approximately 9,000-11,000), PSS [poly(4-styrenesulfonic acid)], (MM = 70,000), and poly(vinylsulfonic acid) (MM = 2,000), inhibited FGF-2 binding to HSPGs and FGFRs in fetal bovine aortic endothelial GM 7373 cells. They also abrogated the formation of the HSPG/FGF-2/FGFR ternary complex, as evidenced by their capacity to prevent FGF-2-mediated cell-cell attachment of FGFR-1-overexpressing, HSPG-deficient Chinese hamster ovary cells to wild-type HSPG-bearing cells. Direct interaction of the polysulfonates with FGF-2 was demonstrated by their ability to protect the growth factor from proteolytic cleavage. Accordingly, molecular modeling, based on the crystal structure of the interaction of FGF-2 with a heparin hexamer, showed the feasibility of docking PAMPS into the heparin-binding domain of FGF-2. In agreement with their FGF-2-binding capacity, PSS, PAS, and PAMPS inhibited FGF-2-induced cell proliferation in GM 7373 cells and murine brain microvascular endothelial cells. The antiproliferative activity of these compounds was associated with the abrogation of FGF-2-induced tyrosine phosphorylation of FGFR-1. Moreover, the polysulfonates PSS and PAS inhibited FGF-2-induced activation of mitogen-activated protein kinase-1/2, involved in FGF-2 signal transduction. In conclusion, sulfonic acid polymers bind FGF-2 by mimicking heparin interaction. These compounds may provide a tool to inhibit FGF-2-induced endothelial cell proliferation in angiogenesis and tumor growth.

Antidotes for cyanide (CN) intoxication include the use of sulfane sulfur donors (SSDs), such as thiosulfate, which increase the conversion of CN to thiocyanate by the enzyme rhodanese. To develop pretreatments that might be useful against CN, SSDs with greater lipophilicity than thiosulfate were synthesized and assessed. The ability of SSDs to protect mice against 2LD50 of sodium cyanide (NaCN) administered either 15 or 60 min following administration of an SSD was assessed. To study the mechanism of action of the SSD, the candidate compounds were examined in vitro for their effect on rhodanese and 3-mercaptopyruvate sulfurtransferase (MST) activity under increasing SSD concentrations. Tests were conducted on nine candidate SSDs: ICD1021 (3-hydroxypyridin-2-yl N-[(N-methyl-3-aminopropyl)]-2-aminoethyl disulfide dihydrochloride), ICD1022, (3-hydroxypyridin-2-yl N-[(N-methyl-3-aminopropyl)]-2-aminoethyl disulfide trihydrochloride), ICD1584 (diethyl tetrasulfide), ICD1585 (diallyl tetrasulfide), ICD1587 (diisopropyl tetrasulfide); ICD1738 (N-(3-aminopropyl)-2-aminoethyl 2-oxopropyl disulfide dihydrochloride), ICD1816 (3,3'-tetrathiobis-N-acctyl-L-alanine), ICD2214 (2-aminoethyl 4-methoxyphenyl disulfide hydrochloride) and ICD2467 (bis(4-methoxyphenyl) disulfide). These tests demonstrated that altering the chemical substituent of the longer chain sulfide modified the ability of the candidate SSD to protect against CN toxicity. At least two of the SSDs at selected doses provided 100% protection against 2LD50 of NaCN, normally an LD99. All compounds were evaluated using locomotor activity as a measure of potential adverse behavioral effects. Positive hypoactivity relationships were found with several disulfides but none was found with ICD1584, a tetrasulfide. Separate studies suggest that the chemical reaction of potassium cyanide (KCN) and cystine forms the toxic metabolite 2-iminothiazolidine-4-carboxylic acid. An alternative detoxification pathway, one not primarily involving the sulfur transferases. may be important in pretreatment for CN intoxication. Although studies to elucidate the precise mechanisms are needed. it is clear that these newly synthesized compounds provide a new rationale for anti-CN drugs, with fewer side-effects than the methemoglobin formers.

Three 1,3-dithiolanes and four 1,3-dithianes have been synthesised from 1-(1,3-dithiolan-2-yl)-2-propanone and 1-(1,3-dithian-2-yl)-2-propanone, respectively. Asymmetric reductions of these ketones using baker's yeast gave the corresponding enantiopure (S)-alcohols. Baker's yeast also reduced the double bond in 3-(1,3-dithian-2-yl)-3-buten-2-one enantioselectively to give (S)-3-(1,3-dithian-2-yl)-2-butanone. 3-(1,3-Dithian-2-yl)-3-buten-2-one was also reduced chemo-selectively and the resulting 3-(1,3-dithian-2-yl)-3-buten-2-ol was resolved by transesterification in organic solvent using lipase B from Candida antarctica to yield the (S)-alcohol and the (R)-acetate with very high enantiomeric ratio, E. Racemic 1-(1,3-dithiolan-2-yl)-2-propanol and 1-(1,3-dithian-2-yl)-2-propanol were also resolved under similar conditions to give the (S)-alcohols and the corresponding (R)-acetates.

N-Aroyl-, N-Arylsulfonyl-, and N-Aryl-S,S-dimethyliminosulfuranes have been synthesized and evaluated as potential dermal penetration enhancers. The title compound and Azone exhibit similar activities for permeation of hydrocortisone through hairless mouse skin.

The inhibitory effects of three pure compounds isolated from wood garlic, 2,4,5-trithiahexane (I), 2,4,5,7-tetrathiaoctane (II), and 2,4,5,7-tetrathiaoctane 2,2-dioxide (III), on rabbit platelet aggregation induced by collagen, arachidonic acid, U46619, ADP (adenosine 5'-diphosphate), PAF (platelet aggregating factor), and thrombin were studied in vitro. The anti-aggregating activity of 2,4,5,7-tetrathiaoctane 4,4-dioxide (IV) was also measured with collagen and arachidonic acid. I, II, III, and IV inhibited the platelet aggregation induced by all tested agonists. I, II, and III exhibited a stronger inhibitory effect against the thrombin-induced aggregation of GFP (gel-filtered platelets) than against the aggregation induced by the other agonists. Notably, the IC50 value for III was 4 microM, which is approximately 2.5 times stronger than MATS (methyl allyl trisulfide), a major anti-platelet compound isolated from garlic. In inhibiting collagen-induced aggregation, II was as potent as MATS and aspirin, with a marked disaggregation effect on the secondary aggregation by arachidonic acid, at the rate of 47.05%/min at a concentration of 10(-4) M. I, II, and III also suppressed U46619-induced aggregation. These results suggest that sulfur-containing compounds in wood garlic not only inhibit arachidonic acid metabolism but also suppress aggregation in association with the function of the platelet plasma membrane.

The static adhesion of living L1210 cells to sulfonated copolymer surfaces of different sulfonic group content and the actin cytoskeleton organization in the adhering cells were studied. The strength of the cell-substratum interaction was estimated by determining the relative number of cells remaining adherent despite experiencing a shearing force equal to 1.25 x 10(-11) N caused by the laminar flow of the medium. The cell-substratum interaction took place in a medium with or without serum. The distribution of F-actin and alpha-actinin in the adhering cells was determined in sequences of fluorescent images of cell optical slices with the use of a computer method of cell image analysis. It was shown that the surface sulfonic groups affect not only the rate and strength of cell-substratum adhesion but also the F-actin and alpha-actinin distribution (in the cell regions near the substratum surface) in cells adhering in the medium containing serum. These proteins, concentrated in the tips of microvilli, were observed as dots. The distinctness (discernibleness) and sizes of these dots depend on the surface content of sulfonic groups. F-actin is located at the periphery of the cells in cells adhering in the medium without serum and alpha-actinin is concentrated in small dots at the periphery and in the central part of the cells., (Copyright 1999 Academic Press.)

The naturally occurring organosulfur compounds (OSCs) diallyl sulfide (DAS), diallyl disulfide (DADS), dipropyl sulfide (DPS), and dipropyl disulfide (DPDS) were studied with respect to their effects on hepatic, intestinal, renal, and pulmonary phase II drug metabolizing enzymes, i.e., glutathione S-transferase (GST), microsomal epoxide hydrolase (mEH), quinone reductase (QR), and UDP-glucuronosyltransferase (UGT). OSCs were administered po to male SPF Wistar rats. In addition to assays of total enzyme activity, the ability of OSCs to modify the levels of mEH and rGSTA1/A2, A3/A5, M1, M2, and P1 was assessed by Western blotting. Remarkably, DADS significantly increased all Phase II enzyme activities, except the pulmonary mEH. It was noteworthy that only DADS induced QR activity. DAS, DPS, and DPDS induced mEH, GST, and UGT activities in the liver. Interestingly, DAS, DPS, and DPDS significantly decreased renal GST activity. In the same manner, DAS, DPS, and DPDS decreased rGSTA1/A2 and A3/A5 levels in the kidney. Conversely, all OSCs were able to induce GST of alpha and mu classes in the liver. In the intestine, DADS and DAS increased rGSTA1/A2, M2, and P1, while rGSTA3/A5 and M2 were only increased by DADS. In addition, DADS induced rGSTP1 dramatically in the four tissues analyzed. DADS also increased the mEH levels in the liver, intestine, and kidney, while DAS and DPS moderately induced mEH level in the liver. This study brings additional insights into the effects of OSCs on Phase II enzymes and suggests that DADS could be a promising chemopreventive agent considering its pleiotropic capacity of induction., (Copyright 1999 Academic Press.)