Ent-kaurane and ent-abietane diterpenoids from Isodon phyllostachys

6,7-Seco-ent-Kauranoids Derived from Oridonin as Potential Anticancer Agents

“…The genus Isodon is well-known for producing bioactive diterpenoids with diverse carbon skeletons. − More than 700 ent -kauranoids have been identified from the genus Isodon thus far, including mainly ent -kaurenes, 6,7-seco- ent -kaurenes, and 8,9-seco- ent -kaurenes . Several ent -kaurenes such as oridonin ( 1 , Scheme ) and its analogues have been studied extensively for the development of novel anticancer agents. − Recently, there has been a growing interest in further investigating 6,7-seco- ent -kaurene derivatives, which may be classified into the spiro-lactone and enmein types (Figure ), because of their broad range of bioactivities. − In particular, spiro-lactone-type ent -kaurenes bearing diverse chemical skeletons have exhibited promising antitumor activities. , …”