Abstract
Ultrasound-assisted extraction (UAE) or ultrasonic extraction technology has been used for the isolation of bioactive compounds from Argyreia speciosa (Linn. f.) Sweet plant (family: Convolvulaceae). Argyreia speciosa is an Indian traditional medicinal plant having strong evidence of various properties widely used in Ayurveda. Dried flowers were used for extraction and the response surface methodology (RSM) was used to optimize the conditions of extraction for the yield of total phenolics and antioxidants from A. speciosa flowers (ASF) in respect of three variables: temperature, power, and time. Damage and structural changes of the bioactive compounds were studied by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy techniques. The optimum UAE conditions obtained by RSM for the yield of total phenolic content from ASF were 42.41 degrees C temperature, 43.62 % power, and 26.51 min process time and conditions for the maximum antioxidant activity by DPPH radical scavenging were 41.36 degrees C temperature, 57.02 % power, and 26.63 min. These findings showed that the UAE under optimum conditions increased the percentage yield of bioactive compounds. SEM results showed that there was no relevant damage to the cells, and FTIR spectroscopy verified that there were no changes in chemical structure. It has been concluded that UAE method is an effective technique for enhancing the yields of major phenolic compounds from A. speciosa flowers.