Sulfur-containing Constituents Research Articles

Insecticidal activity of bis(methylthio)methane based volatile extract of Olax zeylanica (L.) against Sitophilus zeamais (L.) and Corcyra cephalonica (Stainton)

Sri Lankan natives traditionally introduce pungently odorized Olax zeylanica (L.) leaves into their grain storages aiming at the efficient control of insect pests associated with stored grains. The headspace components of O. zeylanica leaves were analyzed by GC–MS, subsequently isolated the major compound being responsible for the plant’s protective effect and laboratory bioassays were conducted to test its lethal activities against Sitophilus zeamais (L.) (Coleoptera: Curculionidae) and Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae). A total of 2 headspace sulfur-containing constituents were found consisting the volatilome of O. zeylanica leaves wherein bis(methylthio)methane (BMTM) was identified as the major organosulfur constituent (75.3 %). BMTM provided strong and immediate control against 3–7 days old S. zeamais adults, 1 day old eggs, 15–17 days old larvae and 1 day old adults of C. cephalonica within 24 h of post treatment. In contact and fumigation assays, S. zeamais (LC50(contact) = 0.16 v/v% and LC50(fumigation) = 0.17 v/v%) was more susceptible to BMTM than C. cephalonica (LC50(contact) = 0.19 v/v% and LC50(fumigation) = 0.22 v/v%) in their adult stages. In contact grain assays, adulticidal effects persisted for 84 h. The degree of susceptibility of different C. cephalonica life stages to BMTM was arranged in the order of eggs (LC50 = 0.18 v/v%) > adults (LC50 = 0.19 v/v%) > larvae (LC50 = 0.29 v/v%) producing > 95 % lethal effects at the respective time points of 9, 12, and 24 h. Additionally, it was evidenced that the grain viability and germination were not affected by the uptake of BMTM. BMTM caused substantial toxicities in S. zeamais and C. cephalonica inferring the favorable use of natural BMTM in the successful control of stored grain insect pests, thereby obviating the necessity in sole relying on conventional synthetic insecticides in storage systems.

S-1-propenylcysteine improves TNF-\u03b1-induced vascular endothelial barrier dysfunction by suppressing the GEF-H1/RhoA/Rac pathway

BackgroundVascular endothelial barrier function is maintained by cell-to-cell junctional proteins and contributes to vascular homeostasis. Various risk factors such as inflammation disrupt barrier function through down-regulation of these proteins and promote vascular diseases such as atherosclerosis. Previous studies have demonstrated that aged garlic extract (AGE) and its sulfur-containing constituents exert the protective effects against several vascular diseases such as atherosclerosis. In this study, we examined whether AGE and its sulfur-containing constituents improve the endothelial barrier dysfunction elicited by a pro-inflammatory cytokine, Tumor-necrosis factor-α (TNF-α), and explored their mode of action on TNF-α signaling pathway.MethodsHuman umbilical vein endothelial cells (HUVECs) were treated with test substances in the presence of TNF-α for various time periods. The endothelial permeability was measured by using a transwell permeability assay. The localization of cell-to-cell junctional proteins and actin cytoskeletons were visualized by immunostaining. RhoA and Rac activities were assessed by using GTP-binding protein pulldown assay. Gene and protein expression levels of signaling molecules were analyzed by real-time PCR and western blotting, respectively.ResultsWe found that AGE and its major sulfur-containing constituent, S-1-propenylcysteine (S1PC), reduced hyperpermeability elicited by TNF-α in HUVECs. In addition, S1PC inhibited TNF-α-induced production of myosin light chain (MLC) kinase and inactivation of MLC phosphatase through the suppression of the Rac and RhoA signaling pathways, respectively, which resulted in the dephosphorylation of MLC2, a key factor of actin remodeling. Moreover, S1PC inhibited the phosphorylation and activation of guanine nucleotide exchange factor-H1 (GEF-H1), a common upstream key molecule and activator of Rac and RhoA. These effects of S1PC were accompanied by its ability to prevent the disruption of junctional proteins on the cell–cell contact regions and the increase of actin stress fibers induced by TNF-α.ConclusionsThe present study suggested that AGE and its major constituent, S1PC, improve endothelial barrier disruption through the protection of junctional proteins on plasma membrane.25PWBVc4Kdr4QaTem7i6UUVideo abstract

Diallyl Disulfide (DADS), a Constituent of Garlic, Inactivates NF-κB and Prevents Colitis-Induced Colorectal Cancer by Inhibiting GSK-3β.

There is a strong belief that garlic has medicinal properties and may even reduce the risk of developing certain cancers including those of the gastrointestinal tract. The chemopreventive effects of garlic may be attributed to the anti-inflammatory properties of the sulfur-containing constituents of garlic, which includes diallyl disulfide (DADS). Here, we demonstrate that DADS prevented colorectal tumorigenesis in a mouse model of colitis-induced colorectal cancer. Supplementation with 85 ppm of DADS (60 mg daily human equivalent dose) in the diet of FVB/N mice treated with chemical carcinogen azoxymethane (AOM) and colonic irritant dextran sodium sulfate (DSS) resulted in the reduction in tumor incidence, tumor number, and tumor burden by 21.54%, 47.3%, and 66.4%, respectively. Further analysis revealed that mice fed the DADS-supplemented diet resolved the initial DSS-induced inflammation faster than those on the control diet, preventing prolonged inflammation and cellular transformation. Subsequent mechanistic studies in vitro suggest that DADS chemopreventive effects are mediated through NF-κB signaling. When SW480 colorectal cancer cells were treated with DADS, NF-κB nuclear localization and activity were diminished. Interestingly, NF-κB suppression was found to be dependent on DADS inhibition of GSK-3β, a positive regulator of NF-κB. Inhibition of GSK-3β and loss of nuclear NF-κB activity were also observed in vivo in AOM/DSS-treated mice fed a diet supplemented with 85 ppm DADS. Our results indicate that DADS can prevent tumorigenesis by suppressing inflammation, a process largely involving GSK-3β inhibition and consequential reduction in NF-κB nuclear localization. Cancer Prev Res; 9(7); 607-15. ©2016 AACR.

Sulfur-containing constituents and one 1H-pyrrole-2-carboxylic acid derivative from pineapple [ Ananas comosus (L.) Merr.] fruit

Two sulfur-containing compounds, ( S)-2-amino-5-(( R)-1-carboxy-2-(( E)-3-(4-hydroxy-3-methoxyphenyl)allylthio)ethyl-amino)-5-oxopentanoic acid ( 1) and ( S)-2-amino-5-(( R)-1-(carboxymethylamino)-3-(( E)-3-(4-hydroxyphenyl)allylthio)-1-oxopropan-2-ylamino)-5-oxopentanoic acid ( 2), and one 1H-pyrrole-2-carboxylic acid derivative, 6-(3-(1H-pyrrole-2-carbonyloxy)-2-hydroxypropoxy)-3,4,5-trihydroxy-tetrahydro-2H-pyran-2-carboxylic acid ( 3), together with eighteen known phenolic compounds, were isolated from the fruits of pineapple. Their structures were elucidated by a combination of spectroscopic analyses. Some of these compounds showed inhibitory activities against tyrosinase. The half maximal inhibitory concentration values of compounds 1, 4, 5, 6, 7 are lower than 1 mM. These compounds may contribute to the well-known anti-browning effect of pineapple juice and be potential skin whitening agents in cosmetic applications.

Analysis of volatile components in a Chinese fish sauce, Fuzhou Yulu, by gas chromatography-mass spectrometry

Volatile components of Fuzhou Yulu, a Chinese fish sauce, were analyzed by gas chromatography-mass spectrometry (GC-MS), and two pretreatment methods, i.e., purge and trap (P&T) GC-MS and ethyl acetate extraction followed by GC-MS, were compared. P&T-GC-MS method determined 12 components, including sulfur-containing constituents (such as dimethyl disulfide), nitrogen-containing constituents (such as pyrazine derivatives), aldehydes and ketones. Ethyl acetate extraction followed by GC-MS method detected 10 components, which were mainly volatile organic acids (such as benzenepropanoic acid) and esters. Neither of the two methods detected alcohols or trimethylamine. This study offers an important reference to determine volatile flavor components of traditional fish sauce through modern analysis methods.

Volatile Organic Sulfur-Containing Constituents in Poncirus trifoliata (L.) Raf. (Rutaceae)

During our screening of plant materials to find new natural fragrance and flavor ingredients, we discovered two series of 3-sulfanylalkyl alkanoates in a peel extract of fruits of wild-growing Poncirus trifoliata (L.) Raf. (Rutaceae), a species closely related to Citrus. The two series belong to alkanoates of 3-methyl-3-sulfanylbutan-1-ol and 3-sulfanylhexan-1-ol, respectively, and thus are members of a family of natural molecules having in common a 1,3-positioned O,S moiety. The alkanoate residues comprise all even-numbered saturated fatty acids from C2 (acetate) to C18 (octadecanoate). Among the 20 sulfur-containing compounds identified, 14 are described for the first time as naturally occurring in a botanical species. Several cysteine-S-conjugates were synthesized as hypothetical precursors of the new volatile sulfur-containing constituents, where after S-(3-hydroxy-1,1-dimethylpropyl)-L-cysteine, S-[3-(acetyloxy)-1,1-dimethylpropyl]-L-cysteine, and S-[1-(2-hydroxyethyl)butyl]-L-cysteine were identified in the fruit peel. No cysteine-S-conjugates were detected in the fruit juice.

Combinatorial Synthesis by Nature: Volatile Organic Sulfur-Containing Constituents ofRuta chalepensis L.

Ongoing interest in discovering new natural fragrance and flavor ingredients prompted us to examine a solvent extract of sulfurous-sweaty smelling Ruta chalepensis L. (Rutaceae) plant material more closely. Twenty-one sulfur-containing constituents of similar structures were identified by GC/MS techniques. Amongst them, 14 have never been described to occur in nature. The compounds 1-18 belong to a family of natural flavor and fragrance molecules having a 1,3-positioned O,S moiety in common. The identities of the natural constituents were confirmed by comparison with synthetic reference samples, and the organoleptic properties of the latter were studied. The relative and absolute configurations of the four stereoisomers of 4-methyl-3-sulfanylhexan-1-ol (5) were established by stereoselective synthesis. The natural isomers consisted of a 65 : 35 mixture of (3R,4S)-5 and (3S,4S)-5.

The Production of Reactive Oxygen Species and the Mitochondrial Membrane Potential Are Modulated during Onion Oil–Induced Cell Cycle Arrest and Apoptosis in A549 Cells

Protective effects of Allium vegetables against cancers have been shown extensively in experimental animals and epidemiologic studies. We investigated cell proliferation and the induction of apoptosis by onion oil extracted from Allium cepa, a widely consumed Allium vegetable, in human lung cancer A549 cells. GC/MS analysis suggested that propyl sulfides but not allyl sulfides are major sulfur-containing constituents of onion oil. Onion oil at 12.5 mg/L significantly induced apoptosis (13% increase of apoptotic cells) as indicated by sub-G1 DNA content. It also caused cell cycle arrest at the G2/M phase; 25 mg/L onion oil increased the percentage of G2/M cells almost 6-fold compared with the dimethyl sulfoxide control. The action of onion oil may occur via a reactive oxygen species-dependent pathway because cell cycle arrest and apoptosis were blocked by the antioxidants N-acetylcysteine and exogenous glutathione. Marked collapse of the mitochondrial membrane potential suggested that dysfunction of the mitochondria may be involved in the oxidative burst and apoptosis induced by onion oil. Expression of phospho-cdc2 and phospho-cyclin B1 were downregulated by onion oil, perhaps accounting for the G2/M arrest. Overall, these results suggest that onion oil may exert chemopreventive action by inducing cell cycle arrest and apoptosis in tumor cells.

Chemical characterization of interspecific hybrids between Allium cepa L. and Allium kermesinum Rchb.

Interspecific hybridization between wild and cultivated species of the genus Allium has been performed to generate plant material possessing biochemical properties of both parental plants. These cross-breeding experiments should lead to Allium plants with higher amounts of valuable constituents. The chemical characterization of interspecific hybrids between A. cepa and A. kermesinum is described on the basis of their sulfur-containing constituents and secondary metabolites. In addition, the hybrid character has been proven by random amplified polymorphic DNA (RAPD) analysis of the progenies obtained from the crosses. It has been shown that the distribution of the cysteine sulfoxides as well as the volatile secondary metabolites in the hybrids is not uniform. The profiles are mainly determined by the paternal wild species A. kermesinum. It has been ascertained that the gas chromatography profiles of the hybrids show increasing amounts of unsymmetrical substituted oligosulfides, which are known to be physiologically active substances. On the basis of statistical calculations, three different types of hybrids can be separated. The chemical analysis of cysteine sulfoxides and volatile sulfur-containing substances is shown to be a useful tool for breeding purposes as it allows an effective selection with regard to optimal distribution and amount of valuable constituents.

Biodegradation of crude oil into nonvolatile organic acids in a contaminated aquifer near Bemidji, Minnesota

As the result of a pipeline burst, a body of light aliphatic crude oil floats atop the groundwater in a shallow sand and gravel aquifer in a remote area outside Bemidji, Minnesota. Biodegradation has resulted in the formation of a plume of DOC downgradient from the oil body. Groundwater has also been contaminated in an area known as the spray zone, from vertical infiltration of DOC resulting from biodegradation of crude oil in the overlying unsaturated zone. The majority of DOC in the contaminated groundwater is in the form of nonvolatile organic acids (NVOA's) which represent the partial oxidation products of the crude oil constituents. The NVOA's have been classified into three fractions according to their isolation on XAD resins: hydrophobic neutrals (HPO-N), hydrophobic acids (HPO-A) and hydrophilic acids (HPI-A). These fractions of NVOA's were isolated from a well downgradient from the oil body (well 530; DOC=21 mg C/l), from a well in the spray zone (well 603; DOC=15 mg C/l) and from an uncontaminated well upgradient of the oil body where the naturally occurring DOC is 2.9 mg C/l (well 310). The three sets of NVOA's were characterized by elemental analyses, molecular weight determinations, 14C ages and liquid phase 1H and 13C NMR. The crude oil and the saturate, aromatic, resin and asphaltene fractions of the crude oil were similarly analyzed by elemental analysis and NMR. The NVOA's from the contaminated wells were clearly distinguishable from the naturally occurring groundwater DOC. Based upon molecular weights, sulfur contents, aromaticities and the presence of methyl groups bonded to aromatic rings, the characterization data suggests that the NVOA's originate from the C 18 or greater alkylaromatic, naphthenoaromatic and sulfur-containing constituents of the crude oil, including possibly the resins and asphaltenes.

Isolation and Identification of Homologues of Ajoene and Alliin from Bulb-Extracts ofAllium ursinum

From the chloroform extract of ALLIUM URSINUM L. (Liliaceae) bulbs, in addition to other sulfur-containing constituents ( E/Z)-4,5,9-trithiadeca-1,6,11-dien-9-oxide [= methylajoene) and ( E/Z)-4,5,9-trithiaocta-1,6-dien-9-oxide (= dimethylajoene) were isolated and identified by NMR and mass spectroscopy. These two compounds were also found in A. SATIVUM but in lower amounts. The higher contents of the corresponding precursors (+)- S-methyl- L-cysteine sulfoxide (MCSO) and methylallyl/allylmethy] thiosulfmate in A. URSINUM water/methanol extracts correspond with the higher amounts of ajoene homologues.

Identification and formation of some selected sulfur-containing flavor compounds in various meat model systems

The volatiles of various meat model systems containing thiamin, cysteine, cystine and various carbohydrates were isolated by simultaneous steam distilllation-extraction. The fraction were analysed by GC-MS. Identifications were focused on sulfur-containing constituents. Individual components were isolated by GC and characterized by MS, IR and NMR spectroscopies. Formation pathways, sensory properties and spectroscopic data of various compounds are described.

Hypercysteinemia and delayed sulfur excretion in cirrhotics after oral cysteine loads

Biosynthesis of cysteine from methionine via the hepatic transsulfuration pathway is impaired in some cirrhotic patients, who therefore might require cysteine in the diet. However, because further metabolism of cysteine also occurs primarily in the liver, the metabolic clearance of this amino acid could be impaired in cirrhosis. We administered oral loads of L-cysteine to cirrhotic patients and healthy volunteers. Plasma cyst(e)ine (free and protein-bound cysteine, and 1/2 cystine) and urinary sulfur-containing constituents were measured at various times postload. Cirrhotic subjects exhibited a greater maximal plasma cyst(e)ine concentration and plasma elimination half-life (t1/2) and a delayed excretion of metabolic end products after an oral L-cysteine load. The postload increase in total plasma cyst(e)ine was accounted for primarily by an increase in the disulfide form (cystine). These studies show that cirrhotics have an impaired ability to clear cyst(e)ine from the plasma.

Microbial Metabolism of Inorganic Sulfur Compounds

Abstract Inorganic sulfur compounds are used by microorganisms (bacteria, fungi, algae) and plants for assimilation, i.e. biosynthesis of sulfur-containing cell constituents. Quantitatively, within the biogeochemical cycle of sulfur the utilization of inorganic sulfur compounds in bacterial energy metabolism, i.e. dissimilatory sulfur utilization, is of far higher importance. Reduced sulfur compounds serve as electron donors for photosynthesis and respiration, whereas inorganic sulfur compounds of oxidation levels above sulfide serve as electron donors in anaerobic respiration as well as in fermentation. In still other bacteria reduced sulfur compounds act as protective agents against hydrogen peroxide.

Gamma Irradiation Effect on the Sulfhydryls Content of Skimmilk Powder

Abstract The effect of gamma-irradiation of skimmilk powder on the sulfur-containing constituents that may contribute to flavor defects when the powder is recombined with water, was investigated. Before irradiation no free –SH groups were detected in the laboratory prepared powders but they were present (18.5 mm/ lOOg) in the commercial high heat powder studied. After the application of irradiation doses of 0.4, 0.8, 1.2 and 1.6 Mrads the percentage increase in the –SH groups of the laboratory produced powder was 15.3 to 69.2 for free, 6.4 to 9.3 for masked and 6.4 to 29.3 for total sulfhydryl groups. The corresponding results for the commercial powder were 2 to 20 for free, 7.3 to 9.4 for masked and 12.8 to 32.3 for total –SH groups. The addition of ascorbic acid to the liquid skimmilk which after drying, amounted to 2.7 to 23.8 mm/100 of powder was reflected in a 2.4 to 16.5% decrease in total –SH groups when an irradiation dose of 0.4 Mrads was applied. Ascorbyl palmitate added under the same conditions and concentrations decreased the total –SH groups by 3.5 to 29.9%. Similar protection of the powder was obtained when the irradiation dose was 1.6 Mrads. The irradiation of skimmilk powder containing labelled 14 Ci-ascorbic acid revealed degradation products which could be recovered as carbonyls.