Antiproliferative effect of Momordica cochinchinensis seeds on human lung cancer cells and isolation of the major constituents

Gac, Momordica cochinchinensis (Lour.) Spreng., Cucurbitaceae, is an indigenous South Asian edible fruit and has been used therapeutically in Traditional Chinese Medicine. Previous studies have shown that M. cochinchinensis seed (Momordicae Semen) has various pharmaceutical properties such as antioxidant and anti-ulcer effects as well as contains secondary metabolites with potential anticancer activities such as triterpenoids and saponins. However, its biological activities in cancer have not yet been investigated. In this study, we found that its ethanol extract reduced cell proliferation in four human lung cancer cell lines, A549, H1264, H1299 and Calu-6. Phytochemical investigation of the ethanol extract was carried out, and resulted in isolation of two major saponins, which were identified as gypsogenin 3-O-β-d-galactopyranosyl(1 → 2)-[α-l-rhamnopyranosyl(1 → 3)]-β-d-glucuronopyranoside (1) and quillaic acid 3-O-β-d-galactopyranosyl(1 → 2)-[α-l-rhamnopyranosyl(1 → 3)]-β-d-glucuronopyranoside (2). Treatment with these isolated compounds (1 and 2) decreased cel1 proliferation in all human lung cancer cell lines tested. In addition, the compounds attenuated primary lung endothelial cell proliferation. Taken together, these findings suggest M. cochinchinensis seeds have antiproliferative activity on human lung cancer cells as well as angiostatic effect on lung endothelial cells