Ultrasound-assisted extraction of medicinal plants and evaluation of their biological activity

Abstract

Nowadays, medicinal plants used in folk medicine are being increasingly studied and used in pharmaceutical, food and nutraceutical fields. Ultrasound-assisted procedure is extensively used recently for the extraction of valuable molecules. The study objective was to investigate total phenolic content using Folin-Ciocalteu’s method and determine the antioxidant capacity in Centaurium erythraea Pers., Glycyrrhiza glabra L., Polygonum hydropiper L., Silene vulgaris L., Aspalathus linearis L., Helichrysum arenarium (L.) Moench., Sambucus nigra L. and Echinacea purpurea M. In order to evaluate the antioxidant activity various in vitro methods such as Fe3+ reducing power by FRAP method, 2,2-diphenyl-1-picryl-hydrazyl free radical (DPPH· ) scavenging activity, 2,2´-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS∙+ ) scavenging activity and Cupric reducing antioxidant capacity (CUPRAC) were performed separately. Total phenolic content ranged from 4.08±0.03 to 20.48±0.13 mg GAE/g DW. The established antioxidant potential of the studied plant extracts correlated significantly with total phenolic content. Both S. nigra flowers and A. linearis leaves extracts revealed to be the most potential. The results demonstrated the investigated ultrasound extracts as potential sources of useful properties and could contribute to different benefits in fields like pharmacy, food preparation and cosmetics.