4′-O-methylpyridoxine: Preparation from Ginkgo biloba Seeds and Cytotoxicity in GES-1 Cells

Ginkgo biloba seeds are wildly used in the food and medicine industry. It has been found that 4′-O-methylpyridoxine (MPN) is responsible for the poisoning caused by G. biloba seeds. The objective of this study was to explore and optimize the extraction method of MPN from G. biloba seeds, and investigate its toxic effect on human gastric epithelial cells (GES-1) and the potential related mechanisms. The results showed that the extraction amount of MPN was 1.933 μg/mg, when extracted at 40 °C for 100 min, with the solid–liquid ratio at 1:10. MPN inhibited the proliferation of GES-1 cells, for which the inhibition rate was 38.27% when the concentration of MPN was 100 μM, and the IC(50) value was 127.80 μM; meanwhile, the cell cycle was arrested in G2 phase. High concentration of MPN (100 μM) had significant effects on the nucleus of GES-1 cells, and the proportion of apoptotic cells reached 43.80%. Furthermore, the Western blotting analysis showed that MPN could reduce mitochondrial membrane potential by increasing the expression levels of apoptotic proteins Caspase 8 and Bax in GES-1 cells. In conclusion, MPN may induce apoptosis in GES-1 cells, which leads to toxicity in the human body.