Antioxidant and antibacterial activities of M. malabathricum L. in aqueous, chloroform and methanol leaf extracts using various assays / Nor Hafiza Husain

Melastoma malabathricum Lamk (M. malabathricum L.) leaves crude was tested for antioxidant activity antimicrobial activity which consists of aqueous extract (MMAE), chloroform extract (MMCE) and methanol extract (MMME). Total phenolic compounds in samples was investigated using total phenolics content (TPC) assay based on Gallic acid equivalence (GAE). The results showed all the extracts contain high phenolic contents (TPC) except for MMCE where MMAE contains 3344.2 ± 19.09 mg/ lOOg GAE; MMCE had 92.46 ± 7.25mg/ lOOg GAE and MMME had 3055.1 ± 8.68 mg/ lOOg GAE. Antioxidant assay consists of DPPH assay, Xanthine/xanthine oxidase (X/XOD) superoxide scavenging assay and Tyrosinase inhibitory activity (%).The assays were run in order to get IC50 value which showed the minimum concentration of sample needed in order to obtain 50 percent of activity in antioxidant assay. IC50 of 273.842 µg/ml and 122.321 µg/ml for MMAE and MMME, respectively were recorded from DPPH assay. In (X/XOD) superoxide scavenging assay, MMAE and MMME give a significantly maximum scavenging activity which is 95.60 % and 98.50 %, respectively but only MMCE give the reading of IC50 at 199.526 µg/ml whereas in Tyrosinase inhibitory activity(%), the ICso for MMCE and MMME are 183.021 µg/ml and 273.842 µg/ml. This showed that MMME have potent antioxidant activity at DPPH but perform less activity in thyrosinase inhibitory activity. Antimicrobial activity of M malabathricum L. was done on various bacteria which are staphylococcus aures, escherichia coli, pseudomonas aeruginosa, candida albicans and microsporum canis. However, no activities were detected in all antimicrobial assays. The overall findings indicate that M malabathricum L. crude extracts possess high antioxidant properties but no antimicrobial activity were observed at 5.0 µg/ µlit thus further investigates are needed to purify bioactive compounds in order to obtain more conclusive results.