Determination and Comparison of 4 '-O-Methylpyridoxine Analogues in Ginkgo biloba Seeds at Different Growth Stages

The antivitamin B-6, 4'-O-methylpyridoxine (MPN); its glucoside, 4'-O-methylpyridoxine-5'-glucoside (MPNG); and vitamin B-6 compounds, including pyridoxal (PL), pyridoxamine, pyridoxine, pyridoxal-5'-phosphate (PLP), and pyridoxamine-5'-phosphate, exist in Ginkgo biloba seeds, which are widely used as food and medicine. This work aimed to determine the MPN analogues in G. biloba seeds at different growth stages in terms of cultivars and ages of trees. The highest total MPN contents of 249.30, 295.62, and 267.85 mu g/g were obtained in the mature stages of three selected G. biloba samples. The total contents of vitamin B-6 compounds decreased significantly in the entire growth period of the three samples. Principal-component analysis revealed that MPN and MPNG were important contributors in the MPN-analogue metabolism of G. biloba seeds. The influence of the cultivar on the content and composition of MPN analogues was greater than that of the age of the G. biloba tree.