title: High-performance liquid chromatography quantification of principal antioxidants in black seed (Nigella sativa L.) phytopharmaceuticals.
abstract: A new, simple, sensitive, rapid, and accurate isocratic RP-HPLC method was developed and validated for simultaneous analysis of the principal antioxidants of Nigella sativa, i.e., thymoquinone (TQ), carvacrol (CR), and its isomer thymol (THY), in different phytopharmaceuticals. The mobile phase was water-methanol (40 + 60, v/v) at a flow rate of 1.5 mL/min. Quantification was achieved with UV detection at 254 nm, based on peak area. The method was validated for linearity, accuracy, precision, selectivity, and robustness. The proposed method is stability-indicating for determination of TQ in the presence of its degradants. The LOD and LOQ (microg/mL) were, respectively, 0.006 and 0.021 for TQ, 0.002 and 0.006 for CR, and 0.027 and 0.090 for THY. The mean recoveries measured at three concentrations were higher than 99%, with RSD <2%. This analytical method is suitable for quality control of the marker substances in this widely used natural protective and curative remedy.
authors.affiliation: Suez Canal University, Faculty of Pharmacy, Department of Pharmaceutical Analytical Chemistry, Ismailia, Egypt.
authors.forename: Ghada M
authors.initials: GM
authors.lastname: Hadad
authors.forename: Randa A Abdel
authors.initials: RA
authors.lastname: Salam
authors.forename: Rabab M
authors.initials: RM
authors.lastname: Soliman
authors.forename: Mostafa K
authors.initials: MK
authors.lastname: Mesbah
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D016227:Benzoquinones / Q000032:analysis; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D000081007:Cymenes; D000432:Methanol / Q000737:chemistry; D008956:Models, Chemical; D039821:Monoterpenes / Q000032:analysis; D031881:Nigella sativa / Q000378:metabolism*; D004364:Pharmaceutical Preparations / Q000032:analysis*; D008517:Phytotherapy / Q000379:methods*; D010936:Plant Extracts / Q000032:analysis*; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013943:Thymol / Q000032:analysis; D013997:Time Factors
chemical_list: D000975:Antioxidants; D016227:Benzoquinones; D000081007:Cymenes; D039821:Monoterpenes; D004364:Pharmaceutical Preparations; D010936:Plant Extracts; D013943:Thymol; C073316:carvacrol; C003466:thymoquinone; D000432:Methanol