In Vitro Studies On Antioxidant And Anti-Parasitic Activities Of Compounds Isolated Fromrauvolfia Caffrasond

As part of an ongoing study of natural products from local medicinal plants, the methanol extract of stem bark ofRauvolfia caffraSond was investigated for biological activity. Column chromatography and preparative thin-layer chromatography were used to isolate lupeol (1), raucaffricine (2),N-methylsarpagine (3), and spegatrine (4). The crude extract, fractions and isolated compounds were tested for anti-oxidant, antitrypanosomal and anti-proliferation activities. Two fractions displayed high DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and reducing power with IC50(The half maximal inhibitory concentration) and IC(0.5)values of 0.022 +/- 0.003 mg/mL and 0.036 +/- 0.007 mg/mL, and 0.518 +/- 0.044 mg/mL and 1.076 +/- 0.136 mg/mL, respectively. Spegatrine (4) was identified as the main antioxidant compound inR. caffrawith IC(50)and IC(0.5)values of 0.119 +/- 0.067 mg/mL and 0.712 +/- 0 mg/mL, respectively. One fraction displayed high antitrypanosomal activity with an IC(50)value of 18.50 mu g/mL. However, the major constituent of this fraction, raucaffricine (2), was not active. The crude extract, fractions and pure compounds did not display any cytotoxic effect at a concentration of 50 mu g/mL against HeLa cells. This study shows directions for further in vitro studies on the antioxidant and antitrypanosomal activities ofRauvolfia caffraSond.