| Rauvolfia yunnacnsis Tsiang, an important plant as medicine resource, is level III protective plant in Yunnan province, which contains many kinds of alkaloids, such as reserpine and yohimbine. Yohimbine has extensive medical value, which can be applied to cure erectile disfunction, arteriosclerosis and rheumatism. In this paper, the writer had research in the following aspects, the results showed:Research the analysis conditions of hydrochloride acid Yohimbine by HPLC. Experimental results show that the analysis conditions were as follows: chromatographic column:VP-ODS C18, mobile phase:phosphate buffer salt (pH value =5,0.01 mol/L), acetonitrile=80:20, column temperature 30℃, flow velocity 1 mL/ min, detection wavelength 268nm.On the base of research of extracting root powder from Rauvolfia yunnacnsis Tsiang, the best times of extracting were two, and the extraction rate can research 89%.Results of orthogonal optimized experimentation showed that the optimal conditions were rauvolfia root powdered 40 mesh, with pH=2,70% ethanol solvent, at 37 centigrade degrees, solid-liquid ratio 1:10, two times extraction, each time three-hours, oscillator speed 145 r/min. Under these conditions, the quality of yohimbine extracted from Rauvolfia root powder was 1.32×10-4(g yohimbine/g rauvolfia root powder).Filtrate the macroporous adsorptive resin on the base of absorbance and desorption ratio of yohimbine. Study the condition of adsorption and desorption and see about capability of the selected resin. The results shows that the adsorption ratio of resin H-20 can reach 98% in the adsorptive condition which evaporated ethanol from vat liquor of rauvolfia root powder and adjusted pH=3 by using 2mol/L hydrochloride acid. Using methanol (pH=1) as strippant, the desorption ratio up to 85%. Through the adsorption and desorption of resin H-20, the purity of yohimbine can increase by 20 times.Research chromatography process of alumina and silica gel on the base of purity and recovery rate of yohimbine. The experimental results showed:using chloroform and methyl alcohol mixed liquid (chloroform/methyl alcohol=97:3)as mobile phase of alumina column, can wipe off parts of strong polarity impurity, and the purity of production can reach 12.11%, recovery rate was 48.12%. Using chloroform and acetonitrile mixed liquid (chloroform/acetonitrile=97:3) as mobile phase of silica gel column, can wipe off parts of weak polarity impurity, and the purity of production can reach 28.20%, recovery rate was 30.38%. Because of the low content of yohimbine in rauvolfia and the serious interference of impurities, so the purity is still low after two times column chromatography. In order to remove the part of impurities that the nature was similar to yohimbine, in this experiment we use preparative HPLC to wipe off impurities, the purity of yohimbine increased to 68.13%. But the price of preparative liquid chromatography was expensive and it can only fit for treating small quantities samples, so it's difficult in industrial application. So the purification process of yohimbine need further study to reach purpose of the low-cost and high purity.
|
PDF Full Text Request