Phenolic glycosides and indole alkaloids isolated from the roots and rhizomes of Clematis chinensis and their anti-inflammatory activity

Six undescribed compounds, including three phenolic glycosides (1-3) and three indole alkaloids (4-6), together with ten known alkaloids (7-16) and three known phenolic glycosides (17-19), were isolated from 70% EtOH aqueous extracts of the roots and rhizomes of Clematis chinensis Osbeck. The structures were elucidated by NMR, HRESIMS and X-ray diffraction spectroscopies. The anti-inflammatory activity of these compounds was evaluated, and twelve compounds showed significant inhibitory activity against TNF-alpha with an inhibition ratio from 47.87% to 94.70% at a dose of 10 mu M. Compound 7 exhibited significant inhibitory activity against TNF-alpha and IL-6 with IC50 values of 3.99 mu M and 2.24 mu M, respectively. Compound 8 displayed potent anti-inflammatory activity against mouse ear edema induced by croton oil. A mechanistic study suggested that compounds 7 and 8 decreased the activation of the NF-kappa B signaling pathway to reduce the secretion of inflammatory factors in LPS-induced RAW 264.7 cells.