[In vitro evaluation of xanthine oxidase inhibitory activity of aqueous extracts of six medicinal plants]

Overproduction of uric acid by xanthine oxidase [XO] causes gout. XO inhibitors such as allopurinol, are the most important available anti-gout drugs. Medicinal plants are available natural sources that may be useful for the treatment of gout. In this study, the XO inhibitory activity of aqueous extracts of Phaseolus vulgaris, Cinnamomum zeylanicum, Mentha longifolia, Cichorium intybus, Capparis spinosa and Trigonella foenum-graecum that their anti-gout effects have been reported in the literature, were measured. In these experiments, under controlled conditions xanthine turns into uric acid by XO. Uric acid absorbance was measured at 295 nm using a UV spectrophotometer. Adding allopurinol [as positive control] or aqueous extracts to the solution containing XO, can decrease uric acid production by inhibition of this enzyme. At first, XO inhibitory activity of allopurinol and reproducibility of the method were evaluated by conducting three experiments. After that, the XO inhibitory activity of aqueous extracts at 0.1, 0.5, 1, 1.5, 2 and 3 mg/ml were measured. The results showed an EC50= 0.38micro gram/ml for allopurinol. The obtained data showed that Mentha longifolia in compare with its control could inhibit enzyme up to 72% [p< 0.001] at 3 mg/ml. Maximum XO inhibitory activity of Phaseolus vulgaris at 3 mg/ml in compare with its control was 27% [p< 0.001]. Other extracts did not have any significant effect on XO. The results showed that part of the anti-gout effects of Mentha longifolia and Phaseolus vulgaris is due to XO inhibition

In vitro protective effects of Satureja hortensis L. essential oil and ethanolic extract on lymphocytes DNA

DNA damage and oxidative stress are widely recognized as major factors in many degenerative diseases and aging. The protective properties of Satureja hortensis L. on the rat lymphocytes DNA lesions were tested. Lymphocytes were isolated from blood samples taken from healthy rats. DNA breaks and resistance to H[2]O[2]-induced damage were measured with the comet assay. Rat lymphocytes were incubated in S. hortensis ethanolic extract [SHE] [0.05, 0.1, 0.5, 1 and 2.5 mg/ml], essential oil [SHEO] [0.05, 0.1, 0.5, 1 and 2.5 micro l/ml], H[2]O[2] [50, 100 and 200 micro M], a combination of H[2]O[2] [200 micro M] with either SHE [1, 2.5 mg/ml] or SHEO [1, 2.5 micro l/ml] at 4°C for 30 minutes. The extent of DNA migration was measured using a single-cell microgel electrophoresis technique under alkaline conditions. Treatment of rat lymphocytes with SHE or SHEO resulted in significant reduction of H[2]O[2]-induced DNA damage compared to controls. SHE exhibited a significant [p<0.01] inhibitory effect on oxidative DNA damage at 2.5 mg/ml. SHEO [1 and 2.5 micro l/ml] also showed significant inhibitory effects [p <0.01] on H[2]O[2] induced chromosomal damage. Both the ethanolic extract and the essential oil of the plant were able to reverse the oxidative damage on rat lymphocytes induced by hydrogen peroxide