Bioactivity of Extractives from Stachytarpheta urticaefolia

Abstract

The n-hexane and methanol extracts of Stachytarpheta urticaefolia leaves exhibited significant antinociceptive effects (p < 0.01) in acetic acid-induced writhing model at a dose of 250 mg/kg b.w. Two compounds isolated from the plant, ipolamiide (1) and α-spinasterol (2), were also found to be potent inhibitors of acetic acid-induced writhing on mice at 50 mg/kg b.w. (p < 0.01). Abortifacient activity was demonstrated within 20 h of administration of a methanolic leaf extract at 200 mg/kg b.w. The methanolic leaf extract and compounds 1 and 2 were also tested for in vitro antibacterial activities against 18 bacterial strains. The extract showed mean zones of inhibition ranging from 17 to 30 mm at 500 µg/disk, but the compounds demonstrated only mild or no in vitro antibacterial activity even at 400 µg/disk. Finally, in a cytotoxicity study, the n-hexane and methanol extracts of leaves and root bark of the plant and the purified compounds (1, 2) exhibited LC₅₀ values of 5.42, 4.42, 17.15, 5.38, 3.93, and 13.65 µg/ml, respectively, against the brine shrimp nauplii, whereas the positive control, vincristine sulfate, showed an LC₅₀ of 0.583 µg/ml.

Keywords: :

• Abortifacient
• Antibacterial Activity
• Analgesic
• Cytotoxicity
• Stachytarpheta Urticaefolia
• Verbenaceae