Evaluation of the chemopreventive effects of Hypericum perforatum L on DMBA-applied rat oral mucosa.

OBJECTIVE: Hypericum perforatum L also known as St. John's wort is known to have many beneficial properties for the organism including its antioxidant and anticancer activities. It is also known to have shown antiproliferative and cytotoxic effects against various cancer cell lines. The purpose of this study was to investigate the effects of Hypericum perforatum L on 7,12-dimethylbenz(a)anthracene-induced rat oral squamous cell carcinoma model. DESIGN: The in vitro antioxidant properties of Hypericum perforatum L was determined and an extract was prepared. Thirty Wistar male rats were divided randomly into 4 groups (Control group, DMBA group, HP + DMBA group, HP group). The antioxidant defense mechanisms in tissue and blood samples were evaluated biochemically and immunohistochemically, the carcinomatous changes in connective tissue were investigated immunohistochemically and epithelial changes in the tissue samples were evaluated histopathologically. RESULTS: The extract revealed inhibitory effects on some antioxidant enzymes (catalase, glutathione peroxidase). Immunohistochemical evaluations revealed no invasive changes in the connective tissue. Hypericum perforatum L demonstrated chemopreventive effects although it did not prevent carcinomatous changes altogether. CONCLUSIONS: Hypericum perforatum L is a promising chemopreventive agent and further studies are needed in order to evaluate the full potential of this plant.

Effects of garlic extract consumption on blood lipid and oxidant/antioxidant parameters in humans with high blood cholesterol.

Effects of garlic extract supplementation on blood lipid profile and oxidant/antioxidant status were investigated in volunteer subjects with high blood cholesterol. A total of 23 volunteer subjects with high blood cholesterol (>5.98 mmol/L) participated in the study. Of them, 13 patients were evaluated as a hypertensive group and the others a normotensive group. Before (first sample) and after (second sample) garlic extract consumption for 4 months, routine blood analyses including lipid parameters and liver and kidney function tests were performed. Additionally, blood oxidant (malondialdehyde [MDA], oxidation resistance [OR]), and antioxidant (antioxidant potential [AOP], nonenzymatic superoxide radical scavenger activity [NSSA]) parameters were measured. Serum total cholesterol, low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) cholesterols, and triglyceride levels were found to be significantly lowered, but HDL high-density lipoprotein cholesterol level increased after the extract use. The total:HDL cholesterol ratio was also found to be significantly decreased after the extract use. There were no meaningful differences with regard to other routine biochemical parameters. Additionally, blood AOP, OR, and NSSA values were found increased and MDA level decreased in the second samples relative to the first ones. Systolic and diastolic blood pressure values were also found to be significantly lowered after extract supplementation in the hypertensive group, but no similar changes were observed in the normotensive group. We conclude that garlic extract supplementation improves blood lipid profile, strengthens blood antioxidant potential, and causes significant reductions in systolic and diastolic blood pressures. It also leads to a decrease in the level of oxidation product (MDA) in the blood samples, which demonstrates reduced oxidation reactions in the body.