High performance liquid chromatographic analysis of the pharmacologically active quinones and related compounds in the oil of the black seed (Nigellasativa L.)

An HPLC method for quantifying the putative pharmacologically active consti tuents: thymoquinone (TQ), dithymoquinone (DTQ), thymohydroquinone (THQ), a nd thymol (THY), In the oil of Nigella sativa seed is described. Extraction of the constituents from the oil was carried out using C-18 PrepSep mini c olumns followed by quantification of the recovered constituents by HPLC on a reversed-phase mu Bondapak C-18 analytical column, using an isocratic mob ile phase of water:methanol:2-propanol (50:45:5% v/v) at a flow rate of 2 m i min(-1). UV detection was at 254 nm for TQ, DTQ, and THY, and at 294 nm f or THQ. The above four compounds were separated with good resolution, repro ducibility, and sensitivity under these conditions. This analytical method was used to quantify the above four constituents in a commercial sample of N. sativa seed oil, and provides a goad quality control methodology for the pharmacologically active components in this widely used natural remedy. (C ) 1999 Elsevier Science Ltd. All rights reserved.