Erythroxan diterpenes from Fagonia glutinosa

Further investigation of the ether extract of the aerial parts of Fagonia glutinosa utilizing the brine shrimp bioassay resulted in the isolation of two new cytotoxic erythroxan diterpenes: 1 alpha, 10 alpha-epoxy-2-oxofagonene (1) and 1 beta, 10 beta-epoxy-2-oxofagonene (2). In addition, two inactive diterpenes, 2-oxofagonene (3) and its previously reported isomer 2-oxo-5-epi-fagonene (4), were also isolated.