Estimation of phenolic compounds content and antioxidant activity of leaves extracts of some selected non-traditional plants

The aim of the research is the determination of the total antioxidant activity and the content of phenolic compounds of the leaves of 12 species of non-traditional plants, namely, Amelanchier alnifolia (Nutt.) Nutt. ex M. Roem., Aronia mitschurinii A.K. Skvortsov & Maitul., Castanea sativa Mill., Chaenomeles japonica (Thunb.) Lindl., Cornus mas L., Diospyros kaki L., Diospyros lotus L., Diospyros virginiana L., Lycium barbarum L., Lycium сhinense Mill., Pseudocydonia sinensis (Thouin) C.K. Schneid., Ziziphus jujuba Mill. Total phenolic content was evaluated using the Folin-Ciocalteu reagent assay. Antioxidant activity was measured using two different methods (DPPH – 2,2-diphenyl-1-picrylhydrazyl, MRAP – molybdenum reducing antioxidant power). Significant variability was observed in phenolic compounds content and total antioxidant activity. Total polyphenol content ranged from 38.02 (Z. jujuba) to 80.58 (C. sativa) mg GAE.g-1 DM, total flavonoid content from 22.47 (P. sinensis) to 54.61 (L. barbarum) mg QE.g-1 DM and phenolic acids content from 3.51 (A. mitschurinii) to 24.67 (Ch. japonica) mg CAE.g-1 DM. All tested samples exhibited DPPH• radical scavenging activities with values from 6.92 (A. mitschurinii) to 9.0 (C. mas) mg TEAC.g-1 DM. Antioxidant activity by molybdenum reducing antioxidant power method ranged from 109.43 (A. mitschurinii) to 322.95 (C. mas) mg TEAC.g-1 DM. Differences between the species of non-traditional plants were significant in all observed parameters. Obtained results of phytochemical composition demonstrated the possibility of leaves' use of non-traditional plants as sources of valuable bioactive compounds with health-promoting and disease-preventing properties.