Characterization and HPLC quantification of piperine isolated from piper guineense (fam. piperaceae)

Abstract

Piperine (1 - piperoyl piperidine) is the major alkaloid responsible for the pungent smell of the West African pepper, Piper guineense, a plant whose parts are well known for their traditional indications for various ailments. The amount of piperine in the various parts of Piper guineense are however unknown. This project, seeks to develop a RP-HPLC method to standardize the various parts of Piper guineense using isolated piperine as a biomarker and a secondary reference. All samples of Piper guineense parts were obtained from the Physic garden of KNUST and authenticated by Pharmacognosy Department, KNUST, Kumasi. Piperine was isolated from the dried fruits of Piper guineense with ethanolic KOH and recrystallized from acetone: hexane (3:2). The melting point was determined to be 128oC - 130oC and the crude yield was 2.07%w/w. Thin Layer Chromatography gave Rf values of 0.285 } 0.013 for hexane: ethylactate: glacial acetic acid (3: 1: 0.3) and 0.70 } 0.010 for chloroform: ethylacetate (1: 1). The isolated piperine was characterized by carrying out NMR, UV and mass spectroscopy analyses. A validated reverse phase HPLC with methanol: water (80:20) at a flow rate of 1.40ml/min on a Phenomenex Kromosil 5 C8 (250mm x 4.6mm, 5 micron i.d.) column with detection at 343nm gave a retention time of 3.78 } 0.06 min. Piperine was found to be 0.0054 } 0.00009%w/w in the dried leaves, 0.0437 } 0.000816%w/w for fresh leaves, 0.115 } 0.00228%w/w for dried stem and 3.345 } 0.0339%w/w for dried fruits.