Allicin, an extremely active constituent of freshly crushed garlic, is produced upon reaction of alliin with the enzyme alliinase (EC 4.4.1.4). A bacterium Cupriavidus necator with the ability of alliinase production was isolated from a soil sample and was identified by morphological, biochemical and 16S rRNA sequence. Alliinase production was optimised and it was further purified to apparent homogeneity with 103-fold purification and specific activity of 209 U/mg of protein by using DEAE Cellulose and Sephadex G-100 chromatography. The enzyme is a homodimer of molecular weight 110 kDa with two subunits of molecular weight 55 kDa each. The optimum activity of the purified enzyme was found at pH 7 and the optimum temperature was 35 °C. The enzyme exhibited maximum reaction rate (Vmax) at 74.65 U/mg and Michaelis-Menten constant (Km) was determined to be 0.83 mM when alliin was used as a substrate. The cytotoxic activity of in-situ generated allicin using purified alliinase and alliin was assessed on MIA PaCa-2 cell line using MTT assay and Acridine orange-ethidium bromide staining. This approach of in-situ allicin generation suggests a novel therapeutic strategy wherein alliin and alliinase work together synergistically to produce cytotoxic agent allicin.

Extraction of volatile organic compounds (VOCs) into a condensed phase requires maximizing the surface-to-volume ratio of the extracting medium. In the case of the solid-phase extracting media, the surface-to-volume ratio can be increased by implementing porous monoliths or particles with different size. In the case of the liquid-phase extracting media, the surface-to-volume ratio can be increased by generating microbubbles or aerosol microdroplets. Here, we propose dry ice fog extraction (DIFE) approach. Briefly, aerosol microdroplets are generated by inserting dry ice into the extraction solvent. The produced fog, containing high-density microdroplets, is directed toward the sample headspace, where the gas-liquid extraction occurs. The microdroplets, containing the extracted VOCs, subsequently coalesce on a cold surface. The movement of the microdroplets is facilitated by a small pressure difference between the fog generator and the extract collector. Within several minutes, a few hundred microliters of the extract are collected, which is sufficient for chromatographic and mass spectrometric analyses. In this proof-of-concept study, the DIFE approach was characterized by using gas chromatography coupled with electron ionization mass spectrometry (MS), as well as direct infusion atmospheric pressure chemical ionization MS. The limits of detection for linalool and menthol were 2.0 × 10-6 and 4.7 × 10-5 M, respectively. The method was further applied in analyses of VOCs emanating from a variety of liquid and solid matrices (e-cigarette "vapor", cinnamon branch, curly spearmint leaves, lily petal, garlic bulb, ginger root, mouthwash, shampoo, spoiled seafood, toothpaste, and red wine). DIFE effectively isolated the VOCs associated with these complex matrices.

Globally, non-small cell lung cancer is a leading cause of cancer-related mortality and about 40% of these cancers are detected in the metastatic stage. Epithelial mesenchymal transition (EMT) plays a critical role during malignant transformation, and the extracellular matrix component, fibronectin (FN), is a known inducer of invasion and metastasis. Diallyl disulphide (DADS), a bioactive component of garlic, exhibits a wide spectrum of biological activities including the inhibition of cancer cell migration and invasion. The present study was aimed at deciphering the effect of DADS on the regulation of FN-induced EMT in A549 lung cancer cells. DADS suppressed the FN-induced invasion and migration potential of A549 cells which may be attributed to the reduced activity of gelatinases. DADS suppressed the FN-aggravated EMT of A549 cells by the upregulation of the epithelial markers, E-cadherin and cytokeratin-18, and the downregulation of the mesenchymal markers, N-cadherin and vimentin, and the transcription factors, snail, slug and twist. DADS was effective in inhibiting the nuclear translocation of β-catenin and the phosphorylation of glycogen synthase kinase-3β and in suppressing the activity of dishevelled homolog 2 and T-cell-factor/lymphoid enhancer factor in FN-induced A549 cells. Cumulatively, this study indicated that DADS might be able to reverse FN-induced EMT in A549 cells via the suppression of Wnt signaling.

Allicin, one of the main biologically active compounds derived from garlic, was previously reported to possess multiple pharmacological activities. Whether allicin protected against chronic social defeat stress (CSDS) induced depressive-like behaviors remained unknown. Thus, our present study for the first time investigated the potential antidepressant effects and the mechanisms of allicin on the CSDS mice model. Thirty minutes before social defeat stress, allicin (2, 10, 50 mg/kg) was treated by intraperitoneal injection. The duration times of CSDS model establishment and allicin intervene were 10 days. Subsequently, the force swimming test (FST), social interaction test (SIT), and sucrose preference test (SPT) were applied for behavioral assessments. The levels of inflammation mediators were determined by commercial ELISA kits. The concentration of iron was tested, and relative protein expressions were measured by western blot. Oxidative stress and apoptosis markers were also detected by commercial kits and western blot. The behavioral defects induced by social defeat stress were obviously improved by allicin. Microglia activation, as well as inflammatory cytokines elevation in the hippocampus of CSDS also down-regulated by administration of allicin. Furthermore, content of iron and protein expressions of key components in iron metabolism were remarkably aberrant changed in the CSDS mice hippocampus, meanwhile, allicin ameliorated this phenomenon. Allicin decreased the production of reactive oxygen species (ROS), malondialdehyde (MDA), and protein carbonyl, and the protein expression of NOX4, as well as up-regulated the activities of superoxide dismutase (SOD) and Nrf2/HO-1 pathway. In addition, allicin attenuated the enhanced neuronal apoptosis. Finally, allicin supplementation inhibited the Nucleotide-binding oligomerization domain containing 3 (NLRP3) inflammasome hyperactivity, and the expressions of inflammasome components, such as ACS, caspase-1, and IL-1β in the hippocampus of CSDS mice. Allicin attenuated depressive-like behaviors of CSDS mice through reducing neuroinflammation, ameliorating iron abnromal accumulation, balacing oxidative stress, and attenuation neuronal apoptosis in the hippocampus via suppression of NLRP3 inflammasome.

Obesity is a major problem in developed countries and a burden on social health care systems. Several epidemiological studies showed the protective effects of green tea against obesity-related diseases. Cyclic guanosine monophosphate (cGMP) acts as a mediator for the physiological effects of (-)-epigallocatechin-3-O-gallate, the major constituent of green tea. Here, we showed that the level of phosphodiesterase 5, a negative regulator of cGMP, was up-regulated in adipose tissues of high-fat/high-sucrose (HF/HS) diet-fed mice and that this up-regulation was ameliorated by diallyl disulfide (DADS), the major organosulfur in garlic. A green tea extract (GT) and DADS in combination attenuated HF/HS diet-induced adipose increase and triglyceride accumulation in the liver. In these mechanisms, the combination regimen suppressed the HF/HS diet-induced up-regulation of fatty acid synthesis-related enzymes including sterol regulatory element-binding protein-1 (SREBP-1), fatty acid synthase, and stearoyl-CoA desaturase-1. Moreover, this combination diet up-regulated thermogenesis-related genes including peroxisome proliferator-activated receptor (PPAR) gamma coactivator 1 alpha and uncoupling proteins in both white and brown adipose tissues. In conclusion, we identified DADS as an enhancer of the anti-obesity effect of GT accompanied by the suppression of SREBP-1 and activation of PPAR axis. The combination diet is a novel and easily applicable approach against obesity-related diseases.

A single clove of edible garlic (Allium sativum L.) of about 10g produces up to 5mg of allicin (diallylthiosulfinate), a thiol-reactive sulfur-containing defence substance that gives injured garlic tissue its characteristic smell. Allicin induces apoptosis or necrosis in a dose-dependent manner but biocompatible doses influence cellular metabolism and signalling cascades. Oxidation of protein thiols and depletion of the glutathione pool are thought to be responsible for allicin's physiological effects. Here, we studied the effect of allicin on post-translational thiol-modification in human Jurkat T-cells using shotgun LC-MS/MS analyses. We identified 332 proteins that were modified by S-thioallylation in the Jurkat cell proteome which causes a mass shift of 72 Da on cysteines. Many S-thioallylated proteins are highly abundant proteins, including cytoskeletal proteins tubulin, actin, cofilin, filamin and plastin-2, the heat shock chaperones HSP90 and HSPA4, the glycolytic enzymes GAPDH, ALDOA, PKM as well the protein translation factor EEF2. Allicin disrupted the actin cytoskeleton in murine L929 fibroblasts. Allicin stimulated the immune response by causing Zn2+ release from proteins and increasing the Zn2+-dependent IL-1-triggered production of IL-2 in murine EL-4 T-cells. Furthermore, allicin caused inhibition of enolase activity, an enzyme considered a cancer therapy target. In conclusion, our study revealed the widespread extent of S-thioallylation in the human Jurkat cell proteome and showed effects of allicin exposure on essential cellular functions of selected targets, many of which are targets for cancer therapy.

Cancer is one of the leading causes of morbidity and mortality worldwide, which increases health-care costs. It has been reported that some dietary components such as aged garlic, one of the garlic preparations with no strong odor and harsh irritating taste, exhibits anticancer effects. This review summarizes the potential beneficial effects of aged garlic on cancer incidences as well as prevention and improvement of factors related to malignancy. Electronic databases, including MEDLINE, Web of Science, the Cochrane Library, and Google Scholar were searched. All study designs which were focused on cancer incidence, or indices related to malignancy as outcomes in human, animal, and human cells studies, and aged garlic and its ingredients as exposures were reviewed in accordance to the items for systematic reviews (PRISMA) guidelines. Initially, 304 articles were identified. Then, 25 articles which met the inclusion criteria were selected. Based on the evaluation, overall quality score of human studies was well. Although there were inconsistent evidence from human studies, results of the animal and laboratory results were mostly consistent. The overall findings may suggest that intakes of aged garlic are inversely associated with cancer. In this regard, the studies have shortcomings. Therefore, more precise investigations will be necessary to decide whether aged garlic consumption is recommendable as a part of cancer prevention or control programs. However, due to anticancer properties of aged garlic, its consumption along with healthy diet may have beneficial effects on cancer.