Biochemical characterization of orthosiphon aristatus and evaluation of pharmacological activities

Abstract

This study investigated the phytochemicals, protein and cellulose profiles, and the antiradical, antibacterial and cytotoxicity activities of Orthosiphon aristatus. The cellulose profile of the herb had functional groups of C-H and C-O stretching, C = O ester, CH2 bending and scissoring using alkaline treatment and bleaching process. Rosmarinic acid was the most dominant compound in the plant extract and its fractions prepared from reflux extraction followed by column chromatography for sample clean-up. At least 8 protein bands could be seen from the polyacrylamide gel and transketolase with the molecular size, 73 kDa was identified. The antiradical activity of the protein fraction increased after trypsin hydrolysis. The antiradical activities of crude extract and fraction 2 achieved up to 90% inhibition at 80 and 40 µg mL-1, respectively. Fractionation increased the rosmarinic acid concentration, thus increasing the antioxidant capacity of fraction. Rosmarinic acid was the main contributor inhibiting the growth of Pseudomonas aeruginosa. Both crude extract and its fraction were non-cytotoxic as the 50% cell viability was 565.6 and 150.5 µg mL-1, respectively, using human fibroblasts.