Improved industrial method for extracting alpha yohimbine from plants of genus rauvolfia and extracts thereof

The invention relates to an improved industrial method for extracting alpha yohimbine from a plant of the genus Prauwolfia and an extract of the alpha yohimbine. The invention discloses an improved process for extracting alpha-yohimbine from leaves of rauvolfia plants, and preferably, rauvolfia caraway/rauvolfia tetrafolia. The process involves precipitating a compound of interest using a non-polar alcohol solvent, such as methanol, repeatedly washing with a halogenated solvent, and washing with hexane or petroleum ether to obtain a high purity extract in high yields. Use of organic acids such as tartaric acid and acetic acid and an organic solvent acetic ether is omitted, so that the process is low in time consumption and economical. The yield of the final product is 50-60% higher than that of the prior art, namely 600-670 mg/100 g of dry leaves. Furthermore, the extract obtained by the method of the present invention comprises yohimbine hydrochloride as a labelling compound, whose analytically detectable am