Abstract:

Based on the adsorption-desorption tests of total flavonoids and amentoflavone from leaves of Nageia nagi(Thunberg) Kuntze on different resins, AB-8 resin with the preferable adsorption and desorption performances was selected from four kinds of resins, which were AB-8 and D101 resins, and polyamide resins(PLA-1 and PLA-2). The optimum process was recommended as follows: for the adsorption tests, the mass concentration of total flavonoids was 1.5-3.0 g/L, the load rate was 22 mL/h and volume of loading solution was 220 mL; desorption tests was sequentially operated with 140 mL 80% ethanol-water solution as eluent at the wash rate of 44 mL/h. As a result, with the optimized processes, the content of total flavonoid and amentoflavone was significantly increased from 13.6% to 52.8% and 0.1% to 2.37%, respectively. Varieties of chromatographic techniques were used to separate and purify the extract fromleaves of N. nagi. The structures of the compounds were identified by UV, FT-IR, MS, 1D NMR and 2D NMR. Eight compounds were isolated from the n-butanol extract from branches and leaves of N. nagi alcohol extract. They were catechin(1), apigenin(2), epi-catechin(3), vitexin(4), vitexin rhamnoside(5), amentoflavone(6), podocarpus flavone A(7), and bilobetin(8). Among them, compounds4, 5 and 8 were isolated from genus Nageia for the first time.

Key words: Nageia nagi leaves, flavonoids, biflavones, flavone glycosides, purification with macroporous resin