Two New Isospirostanol-Type Saponins from the Bulbs of Lilium Brownii and Their Anti-Hepatocarcinogenic Activity.

Abstract

Bulbs of Lilium brownii, commonly known as "Bai-he" in China, serve both edible and medicinal purposes in clinical practice. In this study, two new isospirostanol-type saponins were isolated from L. brownii, and their structures were identified by spectroscopic method, and absolute configurations were elucidated by comprehensive analysis of spectral data obtained from combined acid hydrolysis. Two compounds were finally identified as 3-O-[α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside]-(22R,25R)-5α-spirosolane-3β-ol (1) and 3-O-{α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-glucopyranoside}-(22R,25R)-5α-spirosolane-3β-ol (2), respectively. Further, we found that compound 2 significantly suppressed the proliferation of SMMC-7721 and HepG2 cells with IC50 values of 26.3±1.08 μM and 30.9±1.59 μM, whereas compound 1 didn't inhibit both of the two hepatocellular carcinoma. Subsequently, compound 2 effectively decreased the levels of interleukin-1β and tumor necrosis factor-α and the expression of Bcl-2, and increased the expression of Bax and Caspase-3 proteins. Which indicated that the anti-hepatocellular carcinoma effect of compound 2 involves reducing the level of inflammation and inducing apoptosis.