Enhancement of total phenolic and flavonoids extraction from Rosmarinus officinalis L using electromagnetic induction heating (EMIH) process.

Abstract

Electromagnetic induction heating (EMIH) assisted extraction of phenolic compounds from Rosmarinus officinalis L,and theantioxidant and antimicrobial activities of the plant extractwere examined in this study. The extraction yield acquired with this process was found to be 25.1 ± 2%, with maximum amounts of phenolic compounds: 127.87 ± 2.1mg Gallic acid equivalents per g dry weight and total flavonoids contents 14.48 ± 1.5mg quercetin equivalents per g dry weight, under optimum extraction conditions (extraction time 2h, ratio of raw material to liquid 1:2 and 0% of NaCl). The antioxidant activity was assessed by the 1,1-diphenyl-2-picrylhydrazyl (DPPH); 2, 2'-azinobis (3-ethylbenzothiazoline-6- sulfonic acid) radical cation (ABTS+) and ferric reducing power (FRAP) methods. The results indicate the extract derived through EMIHshowed a strong antioxidant ability (89.25%; EC50 of 0.0148µg/mL). Besides, the antimicrobial bioassay demonstrated that theextract possessed a good antimicrobial activity against all tested fungi and bacteria.