New antiplasmodial diterpenes from gutierrezia sarothrae

Abstract

Bioassay guided fractionation of the MeOH extract of the plant Gutierrezia sarothrae (Asteraceae) using an assay for antiplasmodial activity against the drugresistant Dd2 strain of Plasmodium falciparum led to the isolation of the two new diterpenes 3α-angeloyloxy-15-hydroxylabda-7, 13-dien-16, 15-olid-18-oic acid (1) and 3α-angeloyloxy-15-methoxylabda-7, 13-dien-16, 15-olid-18-oic acid (2). The structures of 1 and 2 were elucidated by interpretation of 1D and 2D NMR spectroscopic data, mass spectrometry, and comparison with the data of related compounds reported in the literature. Compound 1 exhibited moderate antiplasmodial activity with an IC50 values of 10.4 ± 4.3 μM.