Phytochemical investigation of the ethyl acetate fraction of Pseudocaryopteris paniculata C.B.Clarke P.D.Cantino resulted in the identification of 26 undescribed iridoid glucosides (paniculosides A-Z), along with 7 known iridoid glucosides. Their structures were elucidated via two-dimensional nuclear-magnetic-resonance (2D-NMR) spectroscopy, high-resolution electrospray ionization mass spectroscopy (HR-ESI-MS), and chemical-hydrolysis methods. All isolated substances were analyzed for their cytoprotective effects against t-BHP-induced toxicity in HepG2 cells. Among the tested compounds, paniculoside A, paniculoside I, paniculoside T, and paniculoside U exhibited moderate cytoprotective activities with IC50 values in the range of 11.72-34.22 μM against t-BHP-induced toxicity.
Keywords: Cytoprotective activity; Iridoid glucosides; Lamiaceae; NMR spectroscopy; Paniculosides a–Z; Pseudocaryopteris paniculata (C.B.Clarke) P.D.Cantino.
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