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-α with an inhibition ratio from 47.87% to 94.70% at a dose of 10 μM. Compound 7 exhibited significant inhibitory activity against TNF-α and IL-6 with IC50 values of 3.99 μM and 2.24 μM, 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-κB signaling pathway to reduce the secretion of inflammatory factors in LPS-induced RAW 264.7 cells.