Ultrasonic approach in Clitoria ternatea (butterfly pea) extraction in water and extract sterilization by ultrafiltration for eye drop active ingredient

The aim of this study is to evaluate butterfly pea ultrasound-assisted extraction (UAE) in water and sterilize the extract using ultrafiltration (UF) membrane for use as an active ingredient in phytopharmaceutical eye drops. The effect of petal-to-leaf (PTL) ratio and extraction time on anthocyanin concentration and antibacterial activity has been studied. The result showed that the optimum configuration was PTL ratio of 1:0 and extraction time of 30 minutes, which significantly yielded anthocyanin concentration of 35.41 +/- 0.62 mg/l and exhibited the highest antibacterial activity in terms of inhibition zone against S.aureus of 14.75 +/- 1.06 mm. Subsequently, feasibility of using UF membrane to sterilize the butterfly pea extract was also studied. Number of bacteria in the extract was varied to check whether UF was able to sterilize the extract regardless of the degree of bacterial contamination. The results showed no presence of bacteria in the permeate during 21 days of observation and an increase in anthocyanin concentration as well as antibacterial activity of the extract. In conclusion, UF was very effective to sterilize butterfly pea extract without the application of heat, thus, preserve the heat-sensitive compounds such as anthocyanins. (C) 2015 Published by Elsevier B.V.