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

Electromagnetic induction heating (EMIH) assisted extraction of phenolic compounds from Rosmarinus officinalis L, and the antioxidant and antimicrobial activities of the plant extract were 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 ± 2.1 mg Gallic acid equivalents per g dry weight and total flavonoids contents 14.48 ± 1.5 mg quercetin equivalents per g dry weight, under optimum extraction conditions (extraction time 2 h, 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 EMIH showed a strong antioxidant ability (89.25%; EC50 of 0.0148 µg/mL). Besides, the antimicrobial bioassay demonstrated that the extract possessed a good antimicrobial activity against all tested fungi and bacteria.