The seasonal variation of antioxidant activity of Nigella spp. in Ukraine

Abstract

This study aimed to evaluate the antioxidant potential of ethanol extracts of Nigella L. species from the Kherson Oblast of Ukraine. The extracts of seeds and above-ground parts of N. damascena L., N. hispanica L., N. orientalis L., and N. sativa L. cv. Diana were used to determine the total phenolic content (TPC), total flavonoid content (TFC), total phenolic acid content (TPAC), free radical scavenging activity (FRSA), and molybdenum reducing power (MRP). The plant raw material taken for the experiment in sprouting, budding, flowering, and ripening. The TPC of seed extracts was from 8.11 to 35.12 mg GAE.g^-1, TFC from 3.21 to 12.65 mg QE.g^-1, TPAC from 2.1 to 8.21 mg CAE.g^-1, FRSA from 3.56 to 7.32 mg TE.g^-1, and MRP from 23.47 to 68.34 mg TE.g^-1. The study of TPC investigated Nigella spp. during vegetation showed accumulation of them from 33.65 to 54.11 mg GAE.g^-1 in the sprouting, from 54.89 to 65.76 mg GAE.g^-1 in the budding, from 43.18 to 88.43 mg GAE.g^-1 in the flowering, and from 49.21 to 71.45 mg GAE.g^-1 in the ripening depending on species. The TFC was from 17.87 to 27.18 mg QE.g^-1 at the sprouting, from 31.87 to 43.54 mg QE.g^-1 in the budding, from 29.11 to 57.34 mg QE.g^-1 in the flowering, and from 23.98 to 50.32 mg QE.g^-1 in the ripening, depending on species. The TPAC was 12.11–17.32 mg CAE.g^-1 in the sprouting, 11.17–18.43 mg CAE.g^-1 in the budding, 10.09–28.45 mg CAE.g^-1 in the flowering, and 17.86–22.43 mg CAE.g^-1 in the ripening. FRSA was in the sprouting 4.56–7.77 mg TE.g^-1, in the budding 6.38–8.11 mg TE.g^-1, in the flowering 7.12–9.67 mg TE.g^-1, and in the ripening 5.12–9.54 tmg TE.g^-1 depending on species. The MRP in the sprouting was 27.14–65.29 mg TE.g^-1, in the budding 45.48–77.5 mg TE.g^-1, in the flowering 77.89–94.32 mg TE.g^-1, and in the ripening 96.11–110.87 mg TE.g^-1. A strong correlation found between MRP and TPC, TFC, TPAC (r = 0.824–0.965) in the seed extracts. The results obtained in this study can be used for further biochemical and farmaceutical research.