Microwave-assisted extraction for Hibiscus sabdariffa bioactive compounds.

H. sabdariffa has demonstrated positive results against chronic diseases due to the presence of phytochemicals, mainly phenolic compounds. The extraction process of bioactive compounds increases the efficient collection of extracts with high bioactivity. Microwave-Assisted Extraction (MAE) constituted a "green technology" widely employed for plant matrix. In this work, the impact of temperature (50-150 °C), composition of extraction solvent (15-75% EtOH) and extraction time (5-20 min) on the extraction yield and individual compounds concentrations were evaluated. Furthermore, the characterization of 16 extracts obtained was performed by HPLC-ESI-TOF-MS. The results showed that 164 °C, 12.5 min, 45% ethanol was the best extraction condition, although glycoside flavonoids were degraded. Besides that, the optimal conditions for extraction yield were 164 °C, 60% ethanol and 22 min. Thus, temperature and solvent concentration have demonstrated to be potential factors in MAE for obtaining bioactive compounds from H. sabdariffa.