Five previously undescribed compounds from Ajuga lupulina Maxim. and their in vitro activities

A new biflavone (philonotisflavone-3'''-methyl ether), three diterpenes (lupulin G, lupulin H, lupulin I), a new ecdysteroid (ajugasterone E), and four known compounds were isolated from the whole plant of Ajuga lupulina Maxim. Their structures were determined by spectroscopic analysis, including MS, NMR and ECD spectral data. Compounds 1-3 has DPPH radical scavenging ability, and compound 1 has stronger activity than vitamin C. Compounds 2, 3, 7 and 8 have potential cytotoxic activity against Hela, with IC₅₀ values less than 20.0 μM. Abietane diterpenes 2, 3, 7 and 8 are also found to have NO inhibitory effects with IC₅₀ values less than 40.0 μM.