dihydrotanshinone i (di) is a naturally occurring compound extracted from "salvia miltiorrhiza" bunge, also known as chinese sage, red sage root, and the chinese herbal dan shen. it belongs to a class of lipophilic abietane biterpenoids and has been reported to have cytotoxicity to a variety of tumor cells. since they were first discovered, over 40 related compounds and over 50 hydrophilic compounds have been isolated from dan shen.