Abstract:

The conditions for ultrasonic-assisted extraction of yohimbine from the roots of Rauvolfia verticillata (Lour.) Baill
grown in Guangxi province was optimized by response surface methodology. The independent variables were raw material
particle size, pH of 50% aqueous ethanol, extraction time and solvent-to-solid ratio and the response was yohimbine yield.
The optimization was carried out using combination of single factor experiments and Box-Behnken experimental design. A
quadratic polynomial regression equation model was established. The results showed that the optimum extraction conditions
for yohimbine from the roots of Rauvolfia verticillata (Lour.) Baill were found to be 120 mesh, 18:1 (mL/g, dry weight),
1 and 59.75 min for powder particle size, solvent-to-solid ratio, pH of acidified ethanol and extraction time, respectively.
Under the optimized conditions, the maximum yield of yohimbine of 3.841 mg/g was obtained which was in good agreement
with the predicted value (3.903 8 mg/g). Therefore, the optimum ultrasonic-assisted extraction conditions are reliable, and
could be used to guide actual production.

Key words: Rauvolfia verticillata (Lour.) Baill, yohimbine, ultrasonic-assisted extraction, response surface methodology