Isolation, Purification and Quantification of Ginsenoside F(5) and F(3) Isomeric Compounds from Crude Extracts of Flower Buds of Panax ginseng

In this paper, the isolation, purification and quantification of ginsenoside F(5) and F(3) isomeric compounds from crude extracts of flower buds of Panax ginseng (CEFBPG) was investigated by reversed-phase high-performance liquid chromatography (RP-HPLC) for the first time. The satisfied separation at analytical scale was achieved using a Zorbax Eclipse XDB C-18 column with a ternary mobile phase of acetonitrile–water–phosphoric acid (28:71:1) at a flow rate of 1.0 mL/min within 40 min. UV detection was set at 203 nm. Ginsenoside F(5) and F(3) was 4.21 mg and 5.13 mg in 1 g flower buds of P. ginseng (FBPG), respectively. The preparation of ginsenoside F(5) and F(3) at semi-preparative scale was performed by using a Daisogel C-18 column and gradient elution system of acetonitrile–water (32:68 → 28:72) at a flow rate of 10 mL/min with a sample load of 20–30 mg, and yielded ginsenosides in purity of more than 96%. Their structures were characterized by NMR and high resolution electrospray ionization mass spectrometry (HRESIMS). All the method validations showed acceptable limits. The results indicate a new source to obtain ginsenoside F(5) and F(3), and show that the method developed here appears to be reliable for simultaneously preparing them from CEFBPG.