The Extraction and Purification of Piperine

Ground black pepper fruit (10 g, 60 mesh powder) was dissolved in 100 mL of ethanol absolute, refluxing under 80°C for 2 h. The filtrate and residue were collected separately by vacuum filtration, standing for further use. The residue was dissolved in 100 mL of ethanol absolute, refluxing under the same condition. The filtrate was collected and mixed with the obtained filtrate. The mixture of these two filtrates was concentrated to 10–15 mL by reduced pressure distillation and the pH value was adjusted to pH 4 by 6 mol/L HCl, standing for 4 h. After centrifugation at 1,200 rpm for 10 min and filtration, the precipitate (piperic acid undissolved in acid) was removed and the filtrate was adjusted by 10% NaOH solution to pH 11, standing for 2 h, and then immersed in the hot water bath. The deionized water was slowly added until the solution became turbid and a yellow solid precipitated out from the solution. The mixture was placed in an ice-bath for 4 h and then centrifuged at 1,200 rpm for 10 min. A yellow powdered solid was obtained as the crude piperine.

Acetone (25 mL) was added into the obtained crude piperine, dissolved by gentle heating with or without the precipitate from the solution. Either the solution with precipitate was filtered by heating to obtain the solid or the solution without precipitate was added deionized water (25 mL) until the precipitate come out from the solution and then centrifuged and filtered, repeating 3 times to obtain the solid. The liposoluble compounds in the obtained solid were removed by diethyl ether. The yellow powder was obtained as piperine.