Triterpenoid Saponins from Clematis graveolens and Evaluation of their Insecticidal Activities

A new hederagenin based triterpenoid saponin, clematograveolenoside A (1), along with three known saponins, tomentoside A (2), huzhangoside D (3) and clematoside S (4), were isolated from the roots and rhizomes of Clematis graveolens. The structure of new compound was elucidated on the basis of detailed analysis of chemical and spectroscopic data including 1D- and 2D NMR spectra. Compound 2 was found the most effective against aphid (Aphis craccivora) with an LC50 of 1.2 and 0.5 mg/mL after treatment for 72 and 96 h, respectively and was followed by compound 4 (LC50 = 2.3 and 1.9 mg/mL) and 1 (LC50 = 3.2 and 2.6 mg/mL). In case of termite (Coptotermis homii), compound 1 was found more toxic with an LC50 of 0.1 mg/L after 24 h of treatment followed by compound 2, 3 and 4 (LC50 = 0.1, 0.2 and 0.2 mg/mL, respectively).