Original Articles
Narendra Kumar Singh and Viren
Abstract
Ipomoea sepiaria Koenig in Roxb. Hort. Beng., commonly known as Lakshmana, is an important medicinal plant used for the treatment of burning sensation, general debility & sterility in women, hyperdypsia, constipation, diabetes and leucorrhea by the ethnic groups in India. In the present study two compounds ISPE–2 and ISPE–5 were isolated from the methanol extract of the whole plant (MEIS). Isolated compound (ISPE–2) was quantified in MEIS by high performance thin layer chromatography (HPTLC). Both MEIS and ISPE–2 were screened for in–vitro antioxidant activity by measuring DPPH (1, 1‒diphenyl‒2‒picryl‒hydrazil) radical, superoxide radical and H2O2 (hydrogen peroxide) scavenging capacity. Chloroform: methanol (98: 2) fraction yielded a white crystalline compound ISPE–2 (250 mg) and chloroform: methanol (95: 5) fraction yielded a white amorphous powder, ISPE–5 (20 mg). Quantity of ISPE–2 in MEIS was found to be 9.25 %. Both MEIS and ISPE–2 were found to have antioxidant activity, but activity of ISPE–2 (IC50 >100) was found significantly low as compared to MEIS (IC50 <100). On the basis of spectroscopic data and physical properties, structure of ISPE–2 and ISPE–5 were confirmed as dodecyl–p–coumarate and β–sitosterol respectively. Since antioxidant activity of isolated compound ISPE–2 is low as compared to the activity of extract from which it is isolated, hence antioxidant activity of MEIS is not only due to the presence of ISPE–2 but might be due to the presence of several other compounds.