title: Determination of oxygen radical absorbance capacity of black cumin (Nigella sativa) seed quinone compounds.
abstract: In this study, the antioxidant capacities of main quinone constituents of Nigella sativa seeds, namely dithymoquinone (1), thymohydroquinone (2) and thymoquinone (3), were compared using DPPH and ORAC methods. The best scavenging activity was produced by 2, which showed a remarkable activity of 2.60 Trolox equivalents (TE) in a concentration range between 1.6 and 6.4 microg/mL and IC50 value of 2.4 microg/mL in ORAC and DPPH assays, respectively. Contrastingly, 3 possessed only weak DPPH scavenging efficacy (IC50 = 170 microg/mL) but significant antioxidative action of 1.91 TE in ORAC assay. No effect has been observed for 1. Additionally, modified protocol for synthesis of 2 has been developed with aim to enhance its availability for further studies as well as for its future potential use. Based on the results of this study, we conclude that 2 could be considered as a compound with prospective antioxidative properties.
authors.affiliation: Department of Crop Sciences and Agroforestry, Institute of Tropics and Subtropics, Czech University of Life Sciences Prague, Kamycka 129, 165 21, Prague 6-Suchdol, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Tesarova
authors.forename: Blanka
authors.initials: B
authors.lastname: Svobodova
authors.forename: Ladislav
authors.initials: L
authors.lastname: Kokoska
authors.forename: Petr
authors.initials: P
authors.lastname: Marsik
authors.forename: Marie
authors.initials: M
authors.lastname: Pribylova
authors.forename: Premysl
authors.initials: P
authors.lastname: Landa
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Vadlejch
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D016227:Benzoquinones / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D031881:Nigella sativa / Q000737:chemistry*; D011809:Quinones / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry; D013943:Thymol / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D016227:Benzoquinones; D016166:Free Radical Scavengers; D011809:Quinones; C003465:thymohydroquinone; D013943:Thymol; C003466:thymoquinone