Iridoid Glycosides and Phenolic Glycosides from Buddleja asiatica with Anti-inflammatory and Cytoprotective Activities

Abstract

Chemical investigation of the methanol extract of the aerial parts of Buddleja asiatica resulted in the isolation of a new iridoid glycoside, buddlejasiaside A (1) and 11 known compounds: 6- O -[α-L-(4-isoferuloyl)-rhamnopyranosylcatalpol (2), specioside (3), verminoside (4), minecoside (5), 6- O -( p -hydroxybenzoyl)-ajugol (6), 6- O -caffeoyl ajugol (7), litanthosalin 8), eurostoside (9), 10- O -caffeoylaucubin (10), phlorizin (11), and garashangin (12). Their chemical structures were identified based on the MS and NMR spectroscopic analyses and comparing with the data reported in the literature. Compounds 1, 2, and 8-10 showed the modest inhibitory effects against nitrite production in LPS-stimulated BV2 microglia, with IC50 values ranging from 43.5-79.6 μM. Compounds 6, 7, and 11 protected HT22 hippocampal cells from glutamate-induced cell death, with EC50 values of 38.9, 14.8, and 27.1 μM, respectively.