Clerodane Diterpenoids with Anti-hyperglycemic Activity from Tinospora crispa

Four new clerodane diterpenoids,tinosporols A–C(2–4)and tinosporoside A(5),together with six known analogues were isolated from the vines of Tinospora crispa.Their structures were established by extensive spectroscopic analysis.The relative configuration at C-12 in the known diterpenoid borapetoside E(1),the major component of the plant,was firstly established with the aid of molecular model.Compound 1 significantly reduced serum glucose levels at dosedependent manners in alloxan-induced hyperglycemic mice and db/db type 2 diabetic mice.