Diterpenes from the stem bark of Euphorbia neriifolia and their in vitro anti-HIV activity.

ABSTRACT

Six previously undescribed diterpenoids, named euphorantins S-T and euphorneroids A-D, including ingol and ent-atisane types, along with eleven known diterpenoids, were isolated from Euphorbia neriifolia. Their structures were elucidated on the basis of extensive NMR analysis and high resolution mass spectrometry. Euphorneroid D and ent-3-oxoatisan-16α,17-acetonide exhibited moderate anti-HIV-1 activities, with EC50 values of 34 µM (SI = 2.3) and 24 µM (SI = 1.9), respectively.