Preparation And Purification Of Ginsenoside Rg5 From Ginseng Fibrous Root Powder

In this paper,the ginsenoside Rg5 was directly prepared from ginseng fibrous root powder,using phosphoric acid and hydrochloric acid as catalyst,water saturated n-butanol solution and ethanol as solvent comparision the influences of conventional heating reflux and microwave-assisted extraction methods on the extraction yield was investigated.A reversed-phase HPLC method was established for the simultaneous determination of ginsenoside Rg5,which provided the basis for the further study.The preparation process was optimized through orthogonal test on the basis of single factor experiment.The Rg5 was extracted in water saturated n-butanol solution using hydrochloric acid as catalyst by heating reflux method.The optimal reaction conditions of 0.06 mol/L HCl concentration,with solid-liquid ratio of 1:40 g/mL,at70 oC for 5 h led to Rg5 in 2.48% yield.The Rg5 was extracted in ethanol using hydrochloric acid as catalyst by conventional heating reflux method.The extraction process of ginsenoside Rg5 was optimized through orthogonal test design.The optimal reaction conditions of 0.06mol/L HCl concentration,with solid-liquid ratio of 1:65 g/mL,at 75 ? for 4 h afforded Rg5 in 3.79% yield.The Rg5 was extracted in ethanol using hydrochloric acid as catalyst by microwave assisted extraction method.The optimal reaction conditions of 0.12 mol/L HCl concentration,with solid-liquid ratio of 1:42 g/m L,at 500 W for 9 min led to Rg5 in 3.14% yield.The Rg5 was extracted in ethanol using phosphoric acid as catalyst by conventional heating reflux method.The extraction process of ginsenoside Rg5 was optimized through RSM.The optimal reaction conditions of 0.15 mol/L H3PO4 concentration,with solid-liquid ratio of 1:40 g/mL,at 100 oC for 6.5 h led to Rg5 in2.17% yield.Ginsenoside Rg5 was separated and purified by using silica gel columnchromatography.The quantitative analysis of Rg5 was carried out through HPLC and characterized by LC-MS,1H-NMR and 13C-NMR.This method can realize the one-step preparation of ginsenoside Rg5 and solve the shortcomings of traditional ways with long extraction time,high extraction temperature and low yield,which is very important to study the pharmacological activities of ginsenoside Rg5 and develop of new anticancer drug.