Iridoid Glycosides from Underground P arts of Ajuga remota

Fractionation of EtOAc and aqueous MeOH extracts of Ajuga remota underground part has led to the isolation of four new iridoid glycosides identified as 2', 3'-diacetyharpagide (1), 6'-O-rhamnosylharpagide (2), 6'-O-galloyl-7,8-dehydroharpagide (3) and 6-O-xylosylharpagoside-B (4). Together with these were known compounds 8-O-acetylharpagide(5), harpagide (6), cyasterone (7), 20-hydroecdysone (8), sengosterone (9), 3-O-β-glucopyranosylstigmasta-5, 25-diene (10), stigmasterol (11) and ergosterol-5, 8-endoperoxide (12). Their structures were determined using spectroscopic methods as well as comparison with data from known compounds. In the in vitro larvicidal tests using 2 nd instar Aedes aegypti larvae, the EtOAc extract was found to be toxic with LC 50 of 5.30 ± 1.3 µg/mL, while the MeOH extract exhibited weak toxicity with an LC 50 value of 65.94 ± 0.4 µg/mL. Among the pure isolates tested, compound 12 associated with EtOAc extract was the active principal with LC 50 value of 4.40 ± 0.2.