The antioxidant activity of phytochemicals and of the methanolic extract of Lavandula stoechas was evaluated by β-carotene-linoleate bleaching, DPPH radical scavenging, ferric reducing/antioxidant power (FRAP). The obtained results were compared with antioxidant activities of synthetic antioxidants, such as BHT and BHA. The highest antioxidant activity of the extract was observed by DPPH radical scavenging assay, which was 84.45 ± 5.1% at 1 mg ml −1 . Rutin, rosmarinic acid, and caffeic acid were main phenolics in the extract. The total phenolic content of the methanolic extract of Lavandula stoechas was found to be 105.5 ± 2.7 mg gallic acid equivalent (GAE). Electron spin resonance (ESR) measurements were also performed on the samples. Free radicals were determined by ESR method. g value was found to be 2.0034 for the Lavandula stoechas; 2.0052 for quercetin.

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A study of the binding of niclosamide (NC) to serum proteins such as human serum albumin, hemoglobin, and globulin was carried out using fluorescence and UV-visible spectroscopy. Interactions between NC and these proteins were estimated by Stern-Volmer and van't Hoff equations. The binding constants and the thermodynamic parameters, ΔH, ΔS, and ΔG at different temperatures were also determined by using these equations. Data showed that NC may exhibit a static quenching mechanism with all proteins. The thermodynamic parameters were calculated. Data showed that van der Waals interactions and hydrogen bonds are the main forces for human serum albumin and hemoglobin. Globulin, however, bound to NC via hydrophobic interaction. The spectral changes of synchronous fluorescence suggested that both the microenvironment of NC and the conformation of the proteins changed in relation to their concentrations during NC's binding.

Secondary metabolites (flavonoids and phenolics) in the methanolic extracts of Brassica napus genotypes, spring and winter canola were evaluated. Antioxidant activity of the extracts was evaluated by b-carotene linoleic acid model system, scavenging ability of hydrogen peroxide (H 2 O 2 ) assay and cupric reducing antioxidant capacity (CUPRAC) assay. Also, total flavonoid contents of the extracts were determined by aluminum chelating method. Results showed that naringin and eriodictyol were found to be in both species. Data showed that winter canola exihibited high antioxidant capacity with 60.6 Ϯ 0.4% in b-carotene linoleic acid model system and also CUPRAC value (4.18 Ϯ 0.11 mM TEAC/g) and scavenging ability of H 2 O 2 (57.12 Ϯ 1.13%) was higher than spring canola. However, total flavonoid content of spring canola was higher than that of winter canola. Both canola species may be of importance in variety improvement, nutraceuticals, bio-pharmaceuticals and food additives as natural antioxidants. PRACTICAL APPLICATIONSThis study reveals antioxidant activity of the methanolic extracts of Brassica napus genotypes, spring and winter canola seeds growing in Turkey, measured by various assays including by b-carotene linoleic acid model system, scavenging ability of hydrogen peroxide assay and cupric reducing antioxidant capacity (CUPRAC) assay. Total flavonoid contents of the extracts were also measured as quercetin equivalent by aluminum chelating method. Secondary metabolites of the extracts of Brassica napus genotypes were analyzed by high-performance liquid chromatography.

In this study, we investigated the antioxidant capacity and total phenolic content of the extracts Ginkgo biloba from Turkey. The antioxidant activity of the methanolic and acetone extracts from G. biloba leaves was measured by various assays, including ferric reducing antioxidant power assay, cupric reducing antioxidant capacity assay and metal chelating capacity. Total phenolic content of the extracts was measured as gallic acid equivalents (GAE) by Folin–Ciocalteu reagent. The methanolic extract showed higher antioxidant activity related to high phenolic content with 76.0 ± 5.2 mg GAE/g dry weight. Fatty acid compositions of the methanolic and acetone extracts of G. biloba were analyzed. Data suggested that G. biloba grown in Turkey may be an important source of natural antioxidant. PRACTICAL APPLICATIONS This study reveals antioxidant activity of the methanolic and acetone extracts of Ginkgo biloba leaves growing in Turkey measured by various assays, including ferric reducing antioxidant power assay, cupric reducing antioxidant capacity assay and metal chelating capacity. Total phenolic content of the extracts was also measured as gallic acid equivalents by Folin–Ciocalteu reagent. Fatty acid compositions of the extracts of G. biloba were analyzed by gas chromatography.