Diterpenes from the roots of Euphorbia kansui and their in vitro effects on the cell division of Xenopus

Twelve polycyclic diterpenes have been isolated from the roots of Euphorbia kansui. Nine were assigned with an ingenol skeleton, 20-O-(2'E,4'E-decadienoyl)ingenol (1), 20-O-(2'E,4'Z-decadienoyl)ingenol (2), 3-O-(2'E,4'Z-decadienoyl)ingenol (3), 3-O-(2'E,4'E-decadienoyl)ingenol (4), 3-O-(2'E,4'Z-decadienoyl)-5-O-acetylingenol (5), 3-O-(2'E,4'Z-decadienoyl)-20-O-acetylingenol (6), 3-O-(2'E,4'E-decadienoyl)-20-O-acetylingenol (7), 20-O-(decanoyl)ingenol (8), and 5-O-(2'E,4'E-decadienoyl)ingenol (9), and three with a jatrophane skeleton, kansuinins A (12), B (11), and C (10). Compounds 1, 2, 5, 9, and 12 are new compounds, while 4 and 7 were assigned with new geometric configurations. Their structures were elucidated by spectroscopic and chemical analysis. In vitro treatment of cultured individual Xenopus cells at the blastular stage with 1-9 arrested cleavage significantly (0.5 microg/mL of each compound resulted in >75% cleavage arrest). Of the three jatrophane diterpenes (10-12), only kansuinin B (11) showed any activity, resulting in 87% cleavage arrest at 50 microg/mL.