Synthesis of novel heterocyclic ring-fused 18β-glycyrrhetinic acid derivatives with antitumor and antimetastatic activity.

Glycyrrhetinic acid (GA) is one of the most important triterpenoic acids shows many pharmacological effects, especially antitumor activity. GA triggers apoptosis in various tumor cell lines. However, the antitumor activity of GA is weak, thus the synthesis of new synthetic analogs with enhanced potency is needed.