EFFECT OF DIFFERENT DRYING METHODS AND SOLVENTS ON PHENOLIC CONTENT, ANTIOXIDANT AND ANTI-HYPERGLYCEMIC ACTIVITIES OF Melastoma malabathricum LEAVES EXTRACT.

Medicinal plants have been used as anti-diabetic agents due to their excellent antioxidant properties and polyphenolic compounds. This study was carried out to determine the effects of different solvents (ethanol:water ratio of 100:0. 50:50 and 0:100) and drying methods (freeze dry (FD), oven dry (OD) and air dry (AD)) on phenolic content, antioxidant and antihyperglycemic activities of Melastoma malabathricum. The antioxidant activities were determined by DPPH radical scavenging test, ferric reducing antioxidant power (FRAP) test, total phenolic content (TPC) while the anti-hyperglycemic activity were measured by inhibition of α-glucosidase. A trend can be observed whereby M. malabathricum extracted with 100% ethanol showed significantly higher phenolic content and greater antioxidant capacity compared to 50:50 and 100% water extract in all drying techniques which indicates as the best solvent for extracting compound responsible for the activities measured. FD M. malabathricum extracted with 100% ethanol showed lowest IC50 (DPPH) value (21.30 μg/mL), highest antioxidant activity in FRAP (3.85 mg TEAC/g extract) and α-glucosidase inhibition (95.74%). Highest phenolic content (382.19 mg GAE/g extract) also was shown for OD M. malabathricum extracted with 100% ethanol. Positive correlation between TPC with antioxidant and anti-hyperglycemic activities showed that M. malabathricum have potential as a source of natural antioxidant and anti-hyperglycemic agent with the presence of phenolic compounds. [ABSTRACT FROM AUTHOR]