Phytochemical content, thin layer chromatographic profile, and pharmacologic activities of the Philippine native Melastoma malabathricum Linn. from Benguet

Abstract

Melastoma malabathricum Linn. is a traditional medicinal plant used to treat wounds, infections, and diabetes. We investigated the phytochemical content, thin–layer chromatography (TLC) profile, and pharmacological properties of M. malabathricum. An ethanolic extract of M. malabathricum was prepared and subjected to phytochemical screening and analysis of the total phenolic content (TPC) and total flavonoid content (TFC). TLC was performed to characterize the constituents. Antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Antibacterial activities against antibiotic-resistant bacterial pathogens (Staphylococcus aureus, Enterobacter cloacae, Enterococcus faecium, and Klebsiella pneumoniae) were determined using a resazurin-based assay. Hypoglycemic activity was determined using the alpha-glucosidase inhibition assay. Phytochemical analysis revealed the presence of tannins, polyphenols, flavonoids, triterpenoids, and saponins. TPC was 298.68±7.79 mg GAE/g, and TFC was 37.34±1.87 mg QE/g. The ethanolic extract inhibited DPPH free radical formation by 82.59% (IC50, 57.98±2.80 μg/mL) and was active against the gram-positive pathogens E. faecium and MRSA (MICs, 4 mg/mL and 8 mg/mL, respectively). In addition, the extract inhibited alpha-glucosidase activity more potently (99.35%) than the positive control, acarbose (93.57% inhibition). Overall, this study demonstrates M. malabathricum contains bioactive compounds with antioxidant, antibacterial, and potent hypoglycemic activities. These pharmacologic activities support the traditional use of this plant in the management of infections and diabetes.