Optimization of the extraction process of anthocyanins and polyphenols from Hibiscus rosa-sinensis L. flowers.

Abstract

Hibiscus rosa-sinensis L. flowers present several chemical compounds with therapeutic activity. The objective of this work was to optimize the extraction process of polyphenols and anthocyanins. The influence of ethanol percentage, extraction time, drug/solvent ratio and temperature. Besides this, physical, chemical and toxicological characterization of the optimum extract obtained were evaluated. The optimum extraction conditions were: 50 % ethanol, 24 h, drug/solvent ratio of 1 g:20 mL and 60 ºC; these last two significantly influenced the response variables. The optimized hydroalcoholic extract showed total anthocyanin and polyphenol contents of 18 and 1297 mg/L  respectively,  pH of 5.3, total  solids  content  of  2.42 %  and  density of 1.0227 g/mL. It did not show acute oral  toxicity at  doses of 2 g/kg in experimental animals. The extract obtained can be used in the preparation of new phytopharmaceuticals and in obtaining natural dyes in powder form.