Radical Scavenging Activities of Crude Leaf Extracts from Eupatorium odoratum Linn. and Ageratum conyzoides Linn.

Abstract

     Eupatorium odoratum Linn. (E. odoratum) and Ageratum conyzoides Linn. (A. conyzoides) are a tropical plants found in South East Asia. The leaves are used for bleeding prevention and wound healing. Aims of this study was to investigate the radical scavenging of E. odoratum and A. conyzoides. The dried leaves of E. odoratum and A. conyzoides were extracted by distilled water and 95% ethanol. The levels of total phenolic content and the scavenging of ABTS•+, DPPH, hydroxyl, and superoxide anion radicals were determined. The cytotoxicities were also assessed in human monocytic U937 cell line. The results showed that the highest amount of total phenolic content was found in the aqueous leaf extract of E. odoratum at concentration of 23.01 ± 0.04 mg GAE/g dried weight. The aqueous leaf extract of A. conyzoides had the highest antioxidant activity of ABTS•+ and DPPH radicals with the total antioxidant capacity and the 50% DPPH radical inhibitory concentration (IC50) values of 1.998 ± 0.002 mM Trolox/mg dried weight and 3.25 ± 0.01 mg/mL, respectively. Ethanolic leaf extract of E. odoratum had the highest hydroxyl radical scavenging activity with IC50 value of 0.076 ± 0.001 mg/mL, whereas the ethanolic leaf extract of A. conyzoides had the highest superoxide anion radical scavenging activity with IC50 value of 37.50 ± 2.12 mg/mL. Moreover, E. odoratum and A. conyzoides leaf extracts exhibited a cytotoxic effect on human monocytic U937 cell line. The ethanolic leaf extract of A. conyzoides had the highest cytotoxic effect on human monocytic U937 cell line with the IC50 value of 2.5 mg/mL. In summary, E. odoratum and A. conyzoides crude leaf extracts had the radical scavenging activities. However, A. conyzoides crude leaf extract showed a greater antioxidant activity than that of E. odoratum.