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Concept: Allicin

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BACKGROUND: In ancient times, plants were recognized for their medicinal properties. Later, the arrival of synthetic drugs pushed it to the backstage. However, from being merely used for food, plants are now been widely explored for their therapeutic value. The current study explores the potential of skin and flesh extracts from a hard-necked Rocambole variety of purple garlic in preventing cardiomyocyte hypertrophy and cell death. METHODS: Norepinephrine (NE) was used to induce hypertrophy in adult rat cardiomyocytes pretreated with garlic skin and flesh extracts. Cell death was measured as ratio of rod to round shaped cardiomyocytes. Fluorescent probes were used to measure apoptosis and oxidative stress in cardiomyocytes treated with and without extracts and NE. Pharmacological blockade of nitric oxide (NO) and hydrogen sulfide (H2S) were used to elucidate the mechanism of action of garlic extracts. Garlic extract samples were also tested for alliin and allicin concentrations. RESULTS: Exposure of cardiomyocytes to NE induced an increase in cell size and cell death; this increase was significantly prevented upon treatment with garlic skin and flesh extracts. Norepinephrine increased apoptosis and oxidative stress in cardiomyocytes which was prevented upon pretreatment with skin and flesh extracts; NO, and H2S blockers significantly inhibited this beneficial effect. Allicin and alliin concentration were significantly higher in garlic flesh extract when compared to the skin extract. CONCLUSION: These results suggest that both skin and flesh garlic extracts are effective in preventing NE induced cardiomyocyte hypertrophy and cell death. Reduction in oxidative stress may also play an important role in the anti-hypertrophic and anti-apoptotic properties of garlic extracts. These beneficial effects may in part be mediated by NO and H2S.

Concepts: Nitrogen, Radical, Zinc, Sulfur, Garlic, Hydrogen sulfide, PReVENT, Allicin

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Onion and garlic are renowned for their roles as functional foods. The health benefits of garlic are attributed to di-2-propenyl thiosulfinate (allicin), a sulfur compound found in disrupted garlic but not found in disrupted onion. Recently, onions have been grown with repressed lachrymatory factor synthase (LFS) activity, which causes these onions to produce increased amounts of di-1-propenyl thiosulfinate, an isomer of allicin. This investigation into the key health attributes of LFS-silenced (tearless) onions demonstrates that they have some attributes more similar to garlic and that this is likely due to the production of novel thiosulfinate or metabolites. The key finding was that collagen-induced in vitro platelet aggregation was significantly reduced by tearless onion extract over normal onion extract. Thiosulfinate or derived compounds were shown not to be responsible for the observed changes in the inflammatory response of AGS (stomach adenocarcinoma) cells to tumor necrosis factor alpha (TNFα) when pretreated with model onion juices. A preliminary rat feeding trial indicated that the tearless onions may also play a key role in reducing weight gain.

Concepts: Inflammation, Platelet, Garlic, Allium, Tumor necrosis factor-alpha, Onion, Allicin, Tree onion

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The onion lachrymatory factor (LF) is produced from trans-S-1-propenyl-L-cysteine sulfoxide (PRENCSO) through successive reactions catalyzed by alliinase (EC 4.4.1.4) and lachrymatory factor synthase (LFS), and is responsible for the tear inducing-property and the pungency of fresh onions. We developed tearless, non-pungent onions non-transgenically by irradiating seeds with neon-ion at 20 Gy. The bulbs obtained from the irradiated seeds and their offspring bulbs produced by selfing were screened by organoleptic assessment of tear-inducing property or HPLC analysis of LF production. After repeated screening and seed production by selfing, two tearless, non-pungent bulbs were identified in the third generation (M3) bulbs. Twenty M4 bulbs obtained from each of them showed no tear-inducing property or pungency when evaluated by 20 sensory panelists. The LF production levels in these bulbs were approximately 7.5-fold lower than those of the normal onion. The low LF production levels were due to reduction in alliinase activity, which was a result of low alliinase mRNA expression (less than 1% of that in the normal onion) and consequent low amounts of the alliinase protein. These tearless, non-pungent onions should be welcomed by all who tear while chopping onions and those who work in facilities where fresh onions are processed.

Concepts: Messenger RNA, Garlic, Allium, Tears, Onion, Bulb, Allicin, Tree onion

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In this work, we synthesized internal standards for four garlic organosulfur compounds (OSCs) by reductive amination with (13)C, D2-formaldehyde, and developed an isotope dilution analysis method to quantitate these organosulfur components in garlic samples. Internal standards were synthesized for internal absolute quantification of S-allylcysteine (SAC), S-allylcysteine sulfoxide (alliin), S-methylcysteine (SMC), and S-ethylcysteine (SEC). We used a multiple reaction monitoring (MRM) to detect (13)C, D2-formaldehyde-modified OSCs by ultrahigh-performance liquid phase chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) and obtained MS spectra showing different ratios of (13)C, D2-formaldehyde-modified and H2-formaldehyde-modified compounds. The resulting labeled and unlabeled OSCs were exhibited correlation coefficient (R(2)) ranged from 0.9989 to 0.9994, respectively. The average recoveries for four OSCs at three concentration levels ranged from 89% to 105%. By (13)C, D2-formaldehyde and sodium cyanoborohydride, the reductive amination-based method can be utilized to generate novel internal standard for isotope dilution and to extend the quantitative application.

Concepts: Scientific method, Mass spectrometry, Analytical chemistry, Tandem mass spectrometry, Alliin, Allicin, Reductive amination, Sodium cyanoborohydride

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Alliin is a garlic organosulfur compound that possesses various pharmacological properties. In the present study, the protective effects and molecular mechanism of alliin on Lipopolysaccharides (LPS)-induced acute lung injury (ALI) were analyzed. LPS-induced ALI was induced in BALB/c mice by intranasal instillation of LPS. Alliin was administered intraperitoneally to mice 1 h after LPS treatment. The results showed that alliin markedly inhibited lung myeloperoxidase (MPO) activity and wet/dry (W/D) ratio induced by LPS. Alliin also inhibited TNF-α and IL-1β in the bronchoalveolar lavage fluid (BALF) induced by LPS. Furthermore, LPS-induced lung pathological injury was attenuated by treatment of alliin. LPS-induced NF-κB activation was significantly inhibited by alliin. In addition, the expression of peroxisome proliferator-activated receptor γ (PPARγ) was up-regulated by treatment of alliin. Taken together, these results suggested that alliin protected against LPS-induced ALI by activating PPARγ, which subsequently inhibited LPS-induced NF-κB activation and inflammatory response. Alliin might be used as an anti-inflammatory agent in the treatment of ALI.

Concepts: Inflammation, Pulmonology, Peroxisome proliferator-activated receptor, Pneumonia, Anti-inflammatory, Bronchoalveolar lavage, Lavage, Allicin

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Garlic, a widely cultivated global vegetable crop, is threatened by the underground pest Bradysia odoriphaga in China. Previous reports indicated that garlic essential oil, of which the dominant components are sulfides or thiosulfinates, exhibits insecticidal activity against pests. However, it is unclear whether the resistance of garlic to B. odoriphaga is related to thiosulfinates. Here, we compared the resistance of 10 garlic cultivars at various growth stages to B. odoriphaga by field investigation and indoor life-table data collection. Furthermore, the relationship between thiosulfinates content and resistance, as well as the toxicity of garlic oil and allicin against B. odoriphaga larvae was determined. Field surveys demonstrated that the garlic cultivars Qixian and Cangshan possessed the highest resistance, while Siliuban and Yishui were the most sensitive. When reared on Qixian, B. odoriphaga larval survival and fecundity declined by 26.2% and 17.7% respectively, but the development time was prolonged by 2.8 d compared with Siliuban. A positive correlation was detected between thiosulfinates content and resistance. Furthermore, garlic oil and allicin exhibited strong insecticidal activity. We screened out 2 pest-resistant cultivars, for which thiosulfinate content was highest. Additionally, the insecticidal activity displayed by sulfides and allcin suggests their potential for exploitation as botanical insecticides.

Concepts: Garlic, Allicin

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We evaluated organosulphur compounds in Allium vegetables, including garlic, elephant garlic and onion, using high-performance liquid chromatography. Among organosulphur compounds, elephant garlic had considerable γ-glutamyl peptides, and garlic had the highest alliin content. Onion had low level of organosulphur compounds than did elephant garlic and garlic. In addition, antioxidant capacities were evaluated by oxygen radical absorbance capacity (ORAC) values and 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay. The results showed that garlic had the highest antioxidant capacity, followed by elephant garlic and onion. Furthermore, a positive correlation was observed between antioxidant activities and organosulphur compounds (R > 0.77). Therefore, our results indicate that there was a close relationship between antioxidant capacity and organosulphur compounds in Allium vegetables.

Concepts: Chromatography, Garlic, Allium, Oxygen radical absorbance capacity, Onion, Alliaceae, Shallot, Allicin

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Garlic contains the organosulfur compound allicin which exhibits potent antifungal activity. Here we demonstrate the use of a highly simplified yeast chemical genetic screen to characterize its mode of action. By screening 24 validated yeast gene deletion “signature” strains for which hypersensitivity is characteristic for common antifungal modes of action, yeast lacking the high affinity Cu2+ transporter Ctr1 was found to be hypersensitive to allicin. Focusing on transition metal related genes identified two more hypersensitive strains lacking the Cu2+ and Zn2+ transcription factors Mac1 and Zap1. Hypersensitivity in these strains was reversed by the addition of Cu2+ and Zn2+ ions respectively. The results suggest the antifungal activity of allicin is mediated through restricted Cu2+ and Zn2+ uptake or inhibition of Cu2+ and Zn2+ metalloproteins. As certain antimicrobial modes of action are much more common than others, the approach taken here provides a useful way to identify them early on.

Concepts: DNA, Gene, Genetics, Transcription, Chromosome, Garlic, Organosulfur compounds, Allicin

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In this study, the anti-inflammatory effects and the molecular mechanism of alliin were analyzed in dextran sulfate sodium (DSS)-induced colitis mice and lipopolysaccharide-stimulated RAW264.7 cell model.

Concepts: Matter, Chemistry, Ion, Anti-inflammatory, Garlic, Organosulfur compounds, Allicin, Dextran

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Organosulphur compounds (OSCs) present in garlic (Allium sativum L.) are responsible of several biological properties. Functional foods researches indicate the importance of quantifying these compounds in food matrices and biological fluids. For this purpose, this paper introduces a novel methodology based on dispersive liquid-liquid microextraction (DLLME) coupled to high performance liquid chromatography with ultraviolet detector (HPLC-UV) for the extraction and determination of organosulphur compounds in different matrices. The target analytes were allicin, (E)- and (Z)-ajoene, 2-vinyl-4H-1,2-dithiin (2-VD), diallyl sulphide (DAS) and diallyl disulphide (DADS). The microextraction technique was optimized using an experimental design, and the analytical performance was evaluated under optimum conditions. The desirability function presented an optimal value for 600μL of chloroform as extraction solvent using acetonitrile as dispersant. The method proved to be reliable, precise and accurate. It was successfully applied to determine OSCs in cooked garlic samples as well as blood plasma and digestive fluids.

Concepts: Blood, High performance liquid chromatography, Viscosity, Liquid, Garlic, Allium, Diallyl disulfide, Allicin