The invention discloses a method for extracting and separating
cucurbitacin B, which comprises the following steps: firstly, melon pedicels as a
raw material are crushed and are refluxed and extracted by
ethanol diacolation or
ethanol, an extracting solution is extracted by
ethyl acetate more than three times after being concentrated, and the
ethyl acetate is recovered to obtain a total
cucurbitacin extract; secondly, the total
cucurbitacin extract is taken to be dissolved in a 25 to 45 percent of
ethanol water solution, and the
hydrolysis reaction is carried out in the presence of
acetic acid; the pH value is adjusted to be neutral after full reaction, and the extract is concentrated to dry; and then the obtained extract is treated by purification so as to obtain a
cucurbitacin B product with more than 60 percent of
cucurbitacin B content, and the concentration of the
acetic acid is 0.1 to 0.3 mol / L. Compared with the prior art for extracting and separating
cucurbitacin B, the invention has the following advantages: the analogue (such as cucurbitacin B
glucoside) of the cucurbitacin B is converted into the cucurbitacin B by the
structural transformation in the process of extraction, so that the extraction rate of the cucurbitacin B is improved, the production process is simple, and the operation is simple.