Involvement of calcium in the cardiac depressant actions of a garlic dialysate

Treatment of Saos-2 osteosarcoma cells with diallyl trisulfide is associated with an increase in calreticulin expression

Diallyl trisulfide (DATS) is a natural organic sulfur compound that may be isolated from garlic and has strong anticancer activity. DATS has been demonstrated to upregulate the expression of calreticulin (CRT) in various types of human cancers, which is associated with the prognosis of cancer and its response to therapy. However, whether DATS has the same effect on human osteosarcoma cells is not known. Therefore, in the present study, Saos-2 human osteosarcoma cells were cultured with different concentrations of DATS (0, 25, 50 and 100 µmol/l) for 24 h, or with 50 µmol/l DATS for different time periods (0, 12, 24 and 36 h). Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blotting and immunofluorescent staining were used to detect CRT mRNA and protein in the Saos-2 cells. Exposure to DATS changed the morphology and inhibited the growth of the Saos-2 cells, and its effects appeared to be concentration- and exposure time-dependent. The optimum concentration and exposure time of DATS were 50 µmol/l and 24 h, respectively. The levels of CRT mRNA and protein in the Saos-2 cells were significantly upregulated following exposure to DATS. The upregulation of CRT expression by DATS may be a mechanism underlying the ability of DATS to inhibit the growth of human osteosarcoma Saos-2 cells.

Involvement of adenosine and standardization of aqueous extract of garlic (Allium sativum Linn.) on cardioprotective and cardiodepressant properties in ischemic preconditioning and myocardial ischemia-reperfusion induced cardiac injury

The present study investigated the effect of garlic (Allium sativum Linn.) aqueous extracts on ischemic preconditioning and ischemia-reperfusion induced cardiac injury, as well as adenosine involvement in ischemic preconditioning and garlic extract induced cardioprotection. A model of ischemia-reperfusion injury was established using Langendorff apparatus. Aqueous extract of garlic dose was standardized (0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.07%, 0.05%, 0.03%, 0.01%), and the 0.05% dose was found to be the most effective. Higher doses (more than 0.05%) were highly toxic, causing arrhythmia and cardiodepression, whereas the lower doses were ineffective. Garlic exaggerated the cardioprotective effect of ischemic preconditioning. The cardioprotective effect of ischemic preconditioning and garlic cardioprotection was significantly attenuated by theophylline (1,000 µmol/L) and 8-SPT (10 mg/kg, i.p.) and expressed by increased myocardial infarct size, increased LDH level, and reduced nitrite and adenosine levels. These findings suggest that adenosine is involved in the pharmacological and molecular mechanism of garlic induced cardioprotection and mediated by the modulation of nitric oxide.

Pharmacodynamic interaction of captopril with garlic in isoproterenol-induced myocardial damage in rat

It is known that various preparations of garlic and angiotensin-converting enzyme (ACE) inhibitor such as captopril (CAP) have beneficial effects on the left ventricular function and cardiovascular events after myocardial infarction (MI) when used individually. There is no reported interaction between garlic homogenate (GH) and CAP during and after acute MI. Thus the purpose of the current study was to evaluate the possible pharmacodynamic interaction of GH with CAP on isoproterenol (ISO)-induced myocardial damage in rat. Female Wistar albino rats were treated with GH at three different doses of 125; 250 and 500 mg/kg orally for 30 days and CAP (30 mg/kg, p.o.) was incorporated in the interactive groups during the last seven days of GH treatment. Myocardial damage was induced by administration of ISO (150 mg/kg, s.c.) for two consecutive days. Biochemical parameters were studied in serum and heart tissue homogenate of all animals. The GH 250 mg/kg was found to dislodge the effect of ISO on superoxide dismutase and catalase and retained the activities of LDH and CK-MB. Incorporation of CAP during GH treatment provided further protection to myocardium from injury. However, higher dose of GH alone or with CAP failed to prevent damaging effect of ISO. Histopathological determinations confirmed biochemical findings. Thus it is concluded that the combination needs to be used carefully when garlic is consumed at high doses.

Purification and bioassays of a diuretic and natriuretic fraction from garlic (Allium sativum)

The intravenous administration of a purified fraction (6 microg/kg) to anaesthesized dogs was followed by a significant biphasic diuretic and natriuretic response which reached a maximum at 180 min after injection. Chloride, but not potassium ions, followed the natriuretic profile. No changes were observed in arterial blood pressure or in the electrocardiogram. The purified garlic fraction also induced an inhibitory dose-dependent effect on kidney Na, K-ATPase.