Application of response surface methodology to optimize the ultrasound-assisted flavonoid-rich extraction of fish mint (Houttuynia cordata Thunb.)

Abstract

Introduction: Fish mint (Houttuynia cordata Thunb.) has been widely used in both traditional and modern medicine for a long time. Its flavonoid component has a variety of pharmacological effects that have been demonstrated in previous studies. In this research, we optimized the ultrasoundassisted extraction (UAE) of flavonoid-rich content from Houttuynia cordata Thunb. using response surface methodology - central composite design (RSM-CCD). Methods: Based on the results of single-factor test , central composite design (CCD) approach-based response surface methodology (RSM) analysis was utilized to evaluate the effects of ethanol concentration, solid-liquid ratio, extraction time, and temperature on the total flavonoid content expressed as rutin equivalents. Flavonoid component from the extract under optimum conditions was then identified by using UPLC-ESI-MS. Results: The optimum conditions for obtaining the maximum TFC (53.6321 +/- 0.9474 mg RE/g) were found at 80% ethanol concentration, 1/60 g/mL solid-liquid ratio for 38 min at 60 oC. Using UPLC-ESI-MS, we determined six major flavonoid compounds in the extract: rutin, hyperin, isoquercitrin, quercitrin, afzelin, and quercetin. Conclusion: From these results, this study showed that UAE is a fast and efficient technique for flavonoids extraction from the fish mint.