HPTLC ASSAY OF THYMOQUINONE IN BLACK SEED AND BLACK SEED OIL (NIGELLA SATIVA LINN) AND IDENTIFICATION OF THYMOQUINONE CONVERSION WITH UV-VIS

Abstract

A reliable and simplified quantitative high performance thin-layer chromatography (HPTLC) method for the determination of the bioactive constituent of the commercially available black seed and black seed oil using a scanning densitometer is described. The identification of thymoquinone spot obtained from 80% aq. MeOH extract of the seed is confirmed by Nuclear Magnetic Spectroscopy (NMR). The solvent system consisted of hexane and dichloromethane (1:1) were used and all the spot visualised and quantitated at 254 nm. The thymoquinone content of freshly pressed black seed oil was 1.3%, while that of the seed was 1%. Furthermore UV-Vis measurement is significantly used for swift relative comparison of thymoquinone levels in black seed oils and to follow the transformation of thymoquinone when the oil is exposed to sunlight. Keywords: Nigella sativa; black seed; black cumin; black cumin oil; thymoquinone.