Constituent Of Garlic Oil Research Articles

Anti-obesity effect of garlic oil on obese rats via Shenque point administration

Ethnopharmacological relevanceShenque is an acupoint located in the umbilicus and connected with the meridians. Thus, acupoint herbs applied at Shenque plays a pivotal role in the Chinese traditional medicine due to its sensitivity, permeability, and absorption. Many studies reported the use of Shenque point as a successful therapeutic approach. However, the effect of garlic oil (GO) applied at Shenque point to combat obesity is unmet. Consequently, we investigated the potential benefit of GO applied at Shenque point against obesity. Aim of the studyTo investigate GO effects on obese rats applied at Shenque acupoint and orally administered, and to identify the chemical constituents of GO. Materials and methodsRats were randomly divided into 2 groups: naive and model group. The model group rats were fed with a high fat diet for 7 weeks to induce obesity, and then they were randomly divided into 5 groups: model, GO Shenque point treated groups (25, 50 and 100 mg/kg/day) and oral group (50 mg/kg/day). Biochemical indexes in the serum, weight of adipose tissue and liver histopathology were evaluated after 6 weeks of GO treatment using a Hitachi 7080 analyzer (Hitachi, Japan). Moreover, GO chemical components were detected by gas chromatography-mass spectrometer (GC-MS). ResultsCompared with the naive rats, model rats exhibited higher body and liver weight, increased fat deposition, higher triglyceride concentration and alveolar development. In contrast, GO Shenque point treated groups showed a substantial decrease in body weight (P = 0.358, 0.028, 0.031, respectively), fat mass, cholesterol (P = 0.004, 0.041, 0.001, respectively), triglyceride (P = 0.001, 0.001, 0.001, respectively), and low density lipoprotein concentrations (P = 0.001, 0.000, 0.001, respectively). The effect was more remarkable than the GO orally administered. In addition, twelve GO organosulfur compounds were identified by GC-MS and diallyl trisulfide (DATS) was detected as the main compound, with a 32.08% concentration. ConclusionsThese findings demonstrated that GO had a significant anti-obesity effect on obese rats by reducing the body weight and protecting the liver from damage, and the effect of Shenque point treatment was better than oral administration, suggesting that GO was an effective weight-loss drug and Shenque point administration might be considered as a new anti-obesity approach.

Hypolipidaemic and Antioxidant Activity of Diallyl Disulphide in Rats

The efficacy of diallyl disulphide (DADS), a constituent of garlic oil, as a hypolipidaemic and antioxidant agent was evaluated in rats. In normolipidaemic rats DADS, at doses ranging from 10 to 50 mg kg−1, decreased plasma triglyceride without affecting cholesterolaemia and fast-or noradrenaline-induced lipolysis. DADS proved effective in reducing fructose-induced hypertriglyceridaemia and dietary hypercholesterolaemia in rats, in the latter model DADS significantly raised both the HDL cholesterol and the HDL/VLDL + LDL cholesterol ratio. DADS proved ineffective on triton induced hyperlipidaemia. To gain insight into the antioxidant effect of DADS, hepatic and cardiac antioxidant enzyme activity and glutathione content were studied in rats fed on a high diet and DADS. The antioxidant enzyme activity was significantly enhanced whereas glutathione content was markedly restored in rats fed on a high fat diet simultaneously with DADS. Thus, it appears that DADS exert antioxidant protection by activating the associated antioxidant enzymes.

Diallyl Disulfide Suppresses the Growth of Human Colon Tumor Cell Xenografts in Athymic Nude Mice

The present studies examined the antiproliferative effects of diallyl disulfide (DADS) on the growth of human colon tumor cell line, HCT-15, xenografts in 6-wk-old female NCr nu/nu mice with an initial body weight of 20–22 g. Intraperitoneal injection of 1 mg DADS thrice weekly reduced tumor volume by 69% (P < 0.05) without apparent ill consequences such as altered growth of the host. Providing this quantity of DADS intragastrically also inhibited growth of the HCT-15 tumor. At equivalent DADS dosages, intraperitoneal treatment was proportionately more effective (P < 0.05) in reducing tumor growth than gastric intubation. Tumor inhibition caused by DADS (0.5 mg thrice weekly) was similar to that occurring with 5-fluorouracil (5-FU) treatment (0.5 mg thrice weekly). Combining DADS and 5-FU was no more effective in inhibiting tumor growth than using either compound alone. However, concurrent DADS treatment significantly (P < 0.05) inhibited the depression in leukocyte counts and spleen weight and prevented the elevated plasma urea caused by 5-FU treatment. These data suggest that DADS, a constituent of garlic oil, reduces the toxicity of 5-FU and is an effective antitumorigenic agent against xenografts resulting from an established human colon tumor cell line.

Diallyl disulfide inhibits the proliferation of human tumor cells in culture

Diallyl disulfide (DADS), an oil-soluble organosulfur compound in processed garlic, was more effective in inhibiting the in vitro growth of human tumor cell lines: HCT-15 (colon), A549 (lung), and SK MEL-2 (skin) than isomolar quantities of the water-soluble compound S-allyl cysteine (SAC). Addition of DADS (100 μM) was cytostatic to all three cell lines. The importance of the allyl and the disulfide groups were revealed by the lack of a comparable depression in the growth of HCT-15 cells exposed to its saturated analogue, dipropyl disulfide (DPDS). Treatment with DADS also resulted in a dose-dependent increase in intracellular free calcium in cells. A dose-dependent decrease in the activity of calcium-dependent ATPase enzyme occurred in HCT-15 cells exposed to increasing quantities of DADS. A correlation ( r = −0.975) was found between the intracellular free calcium levels and the Ca-ATPase activity in DADS-treated cells. These studies document that DADS, a constituent of garlic oil, is an effective inhibitor of the growth of human neoplastic cells. Alterations in calcium homeostasis are likely involved in the growth inhibition/cytotoxicity caused by DADS.

On the involvement of intramolecular protein disulfide in the irreversible inactivation of 3-hydroxy-3-methylglutaryl-CoA reductase by diallyl disulfide

Treatment with diallyl disulfide, a constituent of garlic oil, irreversibly inactivated microsomal and a soluble 50 kDa form of HMG-CoA reductase. No radioactivity was found to be protein-bound on treating the soluble enzyme with [ 35S]diallyl disulfide, indicating the absence of the mixed disulfide of the type allyl-S-S-protein. SDS-PAGE and Western blot analyses of the diallyl-disulfide-treated protein showed no traces of the dimer of the type protein-S-S-protein, but clearly indicated BME-reversible increased mobility, as expected of an intramolecular protein disulfide. The sulfhydryl groups, as measured by alkylation with iodo[2- 14C]acetic acid, were found to decrease in the diallyl-disulfide-treated enzyme protein. Tryptic peptide analysis also gave support for the possible presence of disulfide-containing peptides in such a protein. It appears that diallyl disulfide inactivated HMG-CoA reductase by forming an internal protein disulfide that became inaccessible for reduction by DTT, and thereby retaining the inactive state of the enzyme.

Inhibition of GSH-dependent PGH 2 isomerase in mammary adenocarcinoma cells by allicin.

We have reported tha allicin, a constituent of garlic oil, has no effect on the activities of platelet cyclooxygenase or thromboxane synthase, or vascular PGI 2 synthase. The effect of allicin on glutathione (GSH) dependent PGH 2 to PGE 2 isomerase is unknown. We therefore studied the effect of allicin on PGE 2 biosynthesis in a murine mammary adenocarcinoma cell line (No 4526). Intact or sonicated cells were incubated with either 14C-arachidonic acid (AA) or 14C-PHG 2, respectively. Following metabolism, products were extracted, separated by TLC and analyzed by radiochromatographic scan. PGE 2 was predominantly formed with minimal amounts of PGF 2α and PGD 2. Formation of 6-keto-PGF 1α or TXB 2 was not detected indicating the absence of TXA 2 and PGI 2 synthase activity. Indomethacin and ibuprofen inhibited the PGE 2 formation (p < 0.05). The enzymatic PGE 2 formation in sonicates was blocked by depletion of the cellular non-protein thiols by buthionine sulfoximine and was shown to be dependent on GSH. Allicin, over the range of 10–1000 μM, inhibited the formation of PGE 2 in cells exposed to 2.0 μM 14C-AA for 20 min. and in sonicated cells incubated with 20.0 μM 14C-PGH 2 for 2 min (p < 0.05). Allicin did not alter cyclooexygenase-mediated oxygen utilization in ram seminal vessicle microsomes, suggesting that allicin selectively inhibits the GSH-dependent PGH 2 to PGE 2 isomerase in this adenocarcinoma cell line.

The pharmacological effects of allicin, a constituent of garlic oil.

Garlic has been used in herbal medicine for thousands of years. While garlic oil contains many components and has been widely studied, the pharmacology of pure allicin, a constituent of garlic oil, is not well understood. We report that allicin inhibits human platelet aggregation in vitro without affecting cyclooxygenase or thromboxane synthase activity or cyclic adenosine monophosphate (AMP) levels. Allicin does not alter the activity of vascular prostacyclin synthase. However, it inhibits ionophore A23187-stimulated human neutrophil lysosomal enzyme release. In vivo allicin dilates the mesenteric circulation of the cat independent of prostaglandin release or a beta adrenergic mechanism.

Effects of allyl methyl trisulfide on glutathione S-transferase activity and BP-induced neoplasia in the mouse.

Allyl methyl trisulfide (AMT), a constituent of garlic oil, was studied for its effects on glutathione S-transferase (GST) activity and on benzo[a]pyrene (BP)-induced neoplasia of the forestomach and lungs of female A/J mice. AMT induced increased GST activity in the forestomach, small bowel mucosa, liver, and lung. The forestomach and small bowel mucosa responded to a single low dose of AMT (3.0 mumol) given by oral intubation, whereas liver and lung were less reactive. A dose schedule of two administrations of 15 mumol AMT given 48 hours apart gave close-to-maximum induction in all four tissues and was chosen for investigation of its inhibitory effects. With this dose schedule, AMT produced an inhibition of BP-induced neoplasia of the forestomach as shown by a greater than 70% reduction in the number of tumors found at the completion of the experiment. Inhibition of pulmonary neoplasia did not occur. AMT is a member of a new class of naturally occurring chemicals that have the capacity to inhibit chemical carcinogenesis.