Bioactive enmein-type 6,7- seco - ent -kaurane diterpenoids: natural products, synthetic derivatives and apoptosis related mechanism

Diterpenoids are important and widely distributed natural compounds with various biological effects, including antitumor, anti-inflammatory and so on. Great efforts have been put in phytochemistry research on diterpenoids. A number of structural modified derivatives and pharmacophore incorporated hybrids were also designed and synthesized with promising therapeutic effects. Among the hopefuls, enmein-type 6,7-seco-ent-kaurane diterpenoids with unique ring system and stereogenic centers exhibit attractive activities. Based on their lead-like properties, enmein-type diterpenoids are suitable for further medicinal study. The derivatives were biologically evaluated and showed promising activities, which warranted in-depth research for further understanding. In this review, the natural bioactive enmein-type diterpenoids and the synthetic derivatives were comprehensively summarized.