HPTLC assay Of Thymoquinone In Black Seed And Black Seed Oil (Nigella Sativa Linn) And Identification Of Thymoquinone Conversion With Uv-Vis.

  • Yehualashet Belete Mengestu African Laboratory for Natural Products (ALNAP), Department of Chemistry, Addis Ababa University, Addis Ababa, Ethiopia.
  • Ermias Dagne


A reliable and simplified quantitative high performance thin-layer chromatography(HPTLC) method for the determination of the bioactive constituent of the commerciallyavailable black seed and black seed oil by using a scanning densitometer is described. Theidentification of bioactive thymoquinone spot obtained from 80% aq. MeOH extract of the seedis confirmed by Nuclear Magnetic Spectroscopy (NMR). A solvent system consisting of hexaneand dichloromethane (1:1) was used and all spots were visualised and quantitated at 254 nm. Thethymoquinone content of freshly pressed black seed oil was 1.3%, while that of the seed was 1%.Furthermore UV-Vis measurement was mainly used for quick relative comparison ofthymoquinone levels in black seed oils and to follow the transformation of thymoquinone whenthe oil is exposed to sunlight. Considering the close values of thymoquinone levels in the seeds(1.0%) versus in the pressed oil (1.3%) obtained in this study, it can be concluded that ingestingin turn comparable amounts of the seeds and oil for therapeutic purposes may confer similarbenefits.