Phytochemical, antioxidant and antibacterial evaluation of Melastoma malabathricum L.: An indonesian traditional medicinal plant

Abstract

Antibiotic resistance has become a worldwide threat to public health and traditional medicinal plants may provide a simple solution to overcome this problem. Many plants are known to contain antioxidants such as polyphenols and flavonoids which are active agents against pathogens. To find phytochemicals to boost the immune system naturally, it is essential to investigate new plant sources of antioxidants and antimicrobials. Melastoma malabathricum L. belongs to the Melastomataceae family and is traditionally used to treat several ailments related to infectious diseases, i.e. wounds, dysentery, diarrhea, stomachache, and toothaches. This study aimed to evaluate the phytochemical, antibacterial and antioxidant activities of extracts and fractions of M. malabathricum leaves. Antibacterial effect was tested against selected strains from the American Type Culture Collection (ATCC) including Staphylococcus aureus, Escherichia coli, and methicillin-resistant Staphylococcus aureus (MRSA) using microdilution assay while antioxidant activity was analyzed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method. Ethyl acetate extract showed the highest antibacterial activity against S. aureus and MRSA with MIC 1 mg/mL (0.1% b/v) and the highest antioxidant activity with IC50 of 43.30 µg/mL with DPPH free radical scavenging assay. Ethyl acetate fraction exhibited the presence of the flavonoid contents by citroboric reagent. Extracts and fractions of M. malabathricum leaves revealed that the potential activity against selected bacterial and DPPH assay might be due to the presence of phenolic substances. These findings support the usage of these plants as a traditional medicine for wound healing and further investigations are needed to identify the active constituents.