Two new terpenoids from the branches and leaves of Rhododendron dauricum L. with neuroprotective activity

Two new terpenoids were isolated from the branches and leaves of Rhododendron dauricum L., named as rhodayritions A (1) and B (2), together with five known compounds which were identified litseachromolaevane A (3), 11-alpha H-dihydrodehydrocostus lactone (4), (+)-9 beta-hydroxyeudesma-4,11(13)-dien-12-al (5), macrostachyoside B (6) and aglaiabbreviatin E (7), respectively. The structures of isolated compounds were determined by UV, HR-ESI-MS, NMR analysis and X-Ray. Their neuroprotective activity was studied on serum deprivation-induced PC12 cells by the MTT method, compounds 1, 6, and 7 exhibited significant neuroprotective activity at 20 mu M.