Tetrahydrofuran lignans from Nectandra megapotamica with trypanocidal activity

The phytochemical investigation of the crude ethanol extract of the leaves of Nectandra megapotamica afforded three new (2d, 3b, and 3c) and eight known (1a-d, 2a-c, and 3a) tetrahydrofuran lignans. Regarding the in vitro trypanocidal activity, the lignan-rich fraction, at a concentration of 2.0 mg/mL, was 100% active. Compound 1a was the most active, showing an IC(50) value of 2.2 microM and lysis of 94% of the parasites at 32 microM. Compounds 1b, 1d, 2a, 2c, and 3a displayed moderate activity, while compound 1c was inactive.