| abstract |
Disclosed is a novel compound derived from the culture of an actinomycete and having an anti-tumor activity. Specifically disclosed is a compound represented by formula (I), (II), or (III), an optical isomer thereof, or a pharmaceutically acceptable salt thereof. The compound can be isolated from the culture broth of an actinomycete belonging to the genus Streptomyces. In formulae (I), (II), and (III), R 1 , R 2 , R 5 , and R 6 each independently represent a hydrogen atom, a methyl group, a hydroxymethyl group, or a hydroxyl group, or R 1 and R 2 or R 5 and R 6 are joined together to form a double bond; R 3 , R 4 , R 7 , and R 8 each independently represent a methyl group or a hydroxymethyl group; and R 9 represents a hydrogen atom or a hydroxyl group. |