Cytotoxic ent-kaurane diterpenoids from Isodon eriocalyx

Abstract

Five new ent-kaurane diterpenoids, epi-maoecrystal N (1), eriocalyxin G (2), maoecrystal W (3), maoecrystal X (4), and maoecrystal Y (5), along with 22 known ones, were isolated from Isodon eriocalyx (Dunn.) Hara., and their structures were determined by spectroscopic methods. All diterpenoids, except for 3 and 13, were evaluated for inhibition of the K562, T-24, Me180, QGY-7701, and BIU87 cell lines (Table 2).