Tubeimoside-1 inhibits proliferation and induces apoptosis by increasing the Bax to Bcl-2 ratio and decreasing COX-2 expression in lung cancer A549 cells.

Plant materials are a great source of cancer chemotherapeutic agents. Tubeimoside-1 (TBMS1) is a triterpenoid saponin extracted from the tubers of Bolbostemma paniculatum (Maxim.) Franquet (Cucurbitaceae), a widely prescribed traditional Chinese medicinal plant that is used for its antiviral and anti-inflammatory properties. The present study was conducted to investigate the effects of TBMS1 on the growth and apoptosis of human lung cancer A549 cells. TBMS1 inhibited the proliferation of the cells in a dose- and time-dependent manner. Apoptosis was confirmed by flow cytometry, fluorescence microscopy and transmission electron microscopy. TBMS1 treatment induced apoptosis by decreasing the expression of Bcl-2 and increasing the expression of Bax in the A549 cells. Inhibition of COX-2 was also observed after treating the cells with TBMS1. TBMS1 may prove to be a useful approach for the chemotherapy of lung cancer.