A new sesquiterpene lactone from the leaves of Ha et Grushv. (Vietnamese ginseng).

(Vietnamese ginseng, Ngoc Linh ginseng) is an endemic species of Vietnam. From the methanol extract of the leaves of , five compounds (-) were isolated, including one new sesquiterpene lactone such as panaxolide () and four known compounds. The structures of the compounds (-) were elucidated by spectral techniques such as 1 D NMR (H NMR, C NMR), 2 D NMR (COSY, HSQC, HMBC, NOESY) and mass spectrometry. The absolute configuration of was determined based on the Cotton effects in the CD spectrum. All of the five compounds were screened for their growth inhibitory activities against cancerous cells (HepG2) and normal cells (fibroblast) using the SRB assay. Panaxolide () showed the highest potential for the growth inhibition of cancerous cells HepG2 with the IC values of 63.8 μM.