Monoterpene glycosides from the seeds of Paeonia suffruticosa protect HEK 293 cells from irradiation-induced DNA damage

Three monoterpene glycosides, beta-gentiobiosylpaeoniflorin (1), pyridylpaeoniflorin (2) and (8R)-piperitone-4-en-9-O-beta-D-glucopyranoside (3), together with eight known compounds, which were 6 '-O-beta-glucopyranosylalbiflorin (4), paeoniflorin (5), debenzoyl albiflorin (6), albiflorin (7), oxypaeoniflorin (8), 8-debenzoylpaeoniflorin (9), 8-debenzoylpaeonidanin (10) and 1-O-beta-D-glucopyranosylpaeonisuffrone (11), respectively, were isolated from the seeds of Paeonia suffruticosa. The structures of these compounds were elucidated based on spectral analysis, including 1D, 2D NMR and CD spectrum. In the in vitro cell culture system, compounds 1, 2, 4, 6, 7, 8, 10 and 11 at concentrations of 10 and 20 mu M protected HEK293 cells against Co-60 gamma-rays irradiation induced cell death efficiently, with compounds 2 and 7 showing the greatest potential; Compounds 1, 2, 4, 6, 7 and 11 brought about a significant reduction in the population of apoptotic cells. Furthermore, the irradiation induced formation of gamma-H2AX foci, an important marker of ionizing radiation-induced DNA double-strand breaks (DSBs), was significantly inhibited by compound 2 and 7 too, suggesting a protective effect of these compounds on irradiation-induced cell damage. (C) 2011 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.