Characterisation of antioxidative activities of various extracts of Centella asiatica (L) Urban

Antioxidative activity of various extracts from different parts of Centella asiatica, including leaves, petioles (stolons) and roots, using three types of solvents (ethanol, water and light petroleum), were evaluated using a linoleic acid model system and the thiobarbituric acid test. Results showed that the ethanol extract of all parts of C. asiatica exhibited significantly (P<0.05) higher antioxidative activity than the water extract, while the light petroleum ether showed negligible activity. Increasing the concentration of the extract (1000–3000 ppm) resulted in increase in antioxidative activity of both the ethanol and the water extract. From 3000 ppm upward, antioxidative activity of the ethanol extract was not significantly different (P<0.05) from that of α-tocopherol. Roots showed the highest activity of the parts tested. The antioxidative activities of the ethanol extracts were found to be stable up to 50 °C and exhibited optimum activity at neutral pH.