Cyclopentanoid monoterpene glycosides from the aerial parts of Paederia foetida L.

Eight previously undescribed cyclopentanoid monoterpene glycosides, paedosides A-H (1-8), and 19 known analogues were isolated from the aerial parts of Paederia foetida L. The structures of these compounds, especially their absolute configurations, were unequivocally established by comprehensive spectroscopic analysis, various quantum chemical calculations, and single-crystal X-ray diffraction analysis. Compound 1 contains a thiocarbonate group, with the aglycone C-1 linked via O-glycosidic bonds to both sugar C-1' and C-6', thereby forming a 7-membered ring. Compounds 2-4 feature a skeleton with three ortho-fused five-membered rings. Proposed biosynthetic pathways for compounds 1-4 are shown in Scheme 1. Compounds 1-27 were tested for cytotoxicity, hepatoprotective activity, and inhibitory effects on NO production in LPS-activated microglia, but all were inactive (IC50 > 10 μM or the compounds showed no significant cell protection at 10 μM).