Isolation, Purification and Quantification of Ginsenoside F₅ and F₃ Isomeric Compounds from Crude Extracts of Flower Buds of Panax ginseng

In this paper, the isolation, purification and quantification of ginsenoside F₅ and F₃ 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 F₅ and F₃ was 4.21 mg and 5.13 mg in 1 g flower buds of P. ginseng (FBPG), respectively. The preparation of ginsenoside F₅ and F₃ 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 F₅ and F₃, and show that the method developed here appears to be reliable for simultaneously preparing them from CEFBPG.