Optimization of the green extraction of polyphenols from the edible flower Clitoria ternatea by high-power ultrasound: A comparative study with conventional extraction techniques

Optimizing the extraction of phytochemicals from medicinal plants is of great importance for several bio-sectors (i.e., food, cosmetic and pharmaceutical industries). The aim of this study was to optimize the time (10-50 min), temperature (25-65 degrees C) and power (250-650 W) of ultrasound-assisted extraction (UAE) in relation to the content of total phenolic compounds (TPC), flavonoids (FVC) and anthocyanins (TAC) from Clitoria ternatea and compare their bioactivity with extracts obtained by conventional extraction techniques (maceration and reflux). The results showed that all evaluated parameters influenced the polyphenol extraction by UAE and the optimal condition (45 oC, 30 min and 350 W) presented contents of 27.42 mg GAE g(-1), 7.24 mg QE g(-1) and 343.18 mg CGE 100 g(-1) for TPC, FVC and TAC, respectively. The optimized extract by UAE showed high antioxidant and antibacterial activity, being higher than the conventional extraction techniques. These results show the efficiency of using UAE to obtain polyphenol-rich extracts from the edible flower C. ternatea.