Simultaneous determination of bioactive compounds in Piper nigrum L. and a species comparison study using HPLC-PDA

Piper nigrum L. is a traditional medicine widely used in India for illnesses such as constipation, diarrhoea, earache, gangrene, heart disease, hernia, hoarseness, indigestion, insect bites, insomnia, joint pain, liver problems, lung disease, oral abscesses, sunburn, tooth decay and toothaches. In this study, six bioactive compounds, namely piperine (1), pellitorine (2), guineensine (3), pipnoohine (4), trichostachine (5) and piperonal (6) were quantified in different extracts of P. nigrum L. and compared with those of P. longum L. and P. chaba Hunter. To evaluate the quality of P. nigrum, a simple, accurate and precise HPLC-PDA method was developed for the simultaneous determination of the above-mentioned six compounds. The separation was achieved by Phenomenex Luna RP C-18 column (150 x 4.6 mm, 5 mu m, Phenomenex Inc, CA, USA) with a binary gradient solvent system of water-acetonitrile, at a flow rate of 1.0 mLmin(-1) and detected at 210, 232, 262 and 343 nm. All six calibration curves showed good linearity (R-2 > 0.9966). The method was reproducible with intra-and inter-day variations of less than 2% and 5%, respectively. The results demonstrated that this method is simple, reliable and suitable for the quality control of these plants.