Antioxidant capacity of plant raw material of Scutellaria baicalensis Georgi

Abstract

The aim of this study was to evaluate antioxidant capacity of Scutellaria baicalensis Georgi from two regions of Ukraine: Kyiv city (M. M. Gryshko National Botanical Garden of NAS of Ukraine (NBG)) and Kherson region (Experimental Facility “Novokakhovska” of Rice Research Institute of Ukrainian Academy of Agrarian Sciences (EFN of RRI)). Observation of plants and biochemical analyses conducted with plants collected in the stage of flowering. In study investigated and compared above-ground part of plants and separated organs: inflorescences, stems, leaves. Measured morphometric parameters (height of plants, length, and width of leaves, length, and diameter of inflorescence, the diameter of the stem) showed that the most variable was the length of inflorescence (12.79%) for NBG sample and diameter of the stem (33.33%) for EFN of RRI sample. Ethanolic extracts were screened for the antioxidant capacity. As standards were used gallic acid for polyphenol content (GAE), quercetin for flavonoids (QE), caffeic acid for phenolic acids (CAE), Trolox for antioxidant capacity (TE). The total content of polyphenol compounds was 42.43 – 86.13 mg GAE.g-1 DW (dry weight) (NBG sample) and 28.06 – 96.76 mg GAE.g-1 DW (EFN of RRI sample). The content of flavonoids was 9.39 – 62.97 mg QE.g-1 DW (NBG sample) and 10.64 – 66.07 mg QE.g-1 DW (EFN of RRI sample). The concentration of phenolic acids was 2.60 – 16.13 mg CA.g-1 DW (NBG sample) and 12.02 – 30.12 CA.g-1 DW (EFN of RRI sample). Antioxidant activity of plant extracts was measured by DPPH assay and reducing power method. The first method indicated an antioxidant ability 8.24 – 8.56 mg TE.g-1 DW (NBG sample) and 7.63 – 8.83 mg TE.g-1 DW (EFN of RRI sample). Reducing power of extracts was 51.48 – 306.09 mg TE.g-1 DW (NBG sample) and 63.33 – 260.24 mg TE.g-1 DW (EFN of RRI sample). Very strong positive correlation identified between total polyphenol content, total flavonoid content and reducing power. Scutellaria baicalensis is a rich source of antioxidants and potential raw of further pharmacological study in Ukraine as well as in other regions for improving and enrichment of relevant production.