Acylated iridoid glucosides from Pseudocaryopteris paniculata (C.B.Clarke) P.D.Cantino

Abstract

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.