EVALUATION OF STABILITY, TANNIN CONTENT, ANTIOXIDANT ACTIVITY, AND ANTIMICROBIAL PROPERTIES OF Melastoma Malabathricum Linn. LEAF EXTRACT IN A WATER-BASED EMULSION

Melastoma malabathricum (Linn.) (MML) is a small tree native to Southeast Asia, traditionally used in folk medicine to treat a variety of ailments, including hemorrhoids and wounds from childbirth. The leaves of MML contain several phytochemical constituents, including tannins, which are known for their antimicrobial and antioxidant properties. These properties position MML as a promising alternative to traditional antibiotics, especially in combating drug-resistant pathogens like Staphylococcus aureus. Traditionally, MML leaves are applied as a paste to wounds to serve as a topical antibiotic. However, this approach has proven to be impractical, prompting interest in more conventional formulations such as lotions and emulsions. To keep pace with the increasing reliance on herbal medicine, this study evaluates the potential of MML leaf extract in water-based emulsions, focusing on tannin content, antimicrobial and antioxidant activities, and emulsion stability. The crude extract was obtained using two methods—Soxhlet Extraction Method (SEM) and Cold Extraction Method (CEM)—to determine which method has the higher potential to produce the most effective antimicrobial agent. Both methods used a solvent mixture of ethanol, methanol, and water in a 70:20:10 ratio. After rotary evaporation, the yields of crude extract were 4.98 grams (SEM) and 3.62 grams (CEM), respectively. The extraction efficiency of CEM was higher in terms of tannin yield (31.63% more than SEM), while SEM exhibited superior antioxidant activity (66.94% higher than CEM). In addition, the stability tests indicated that the emulsions should be stored at 30ºC to prevent dissociation, suggesting a temperature-dependent stability factor. For antimicrobial activity, the study tested emulsions containing 3%, 5%, and 7% crude leaf extract, with the 7% concentration exhibiting the most promising antimicrobial properties. Based on the results of both the extraction methods and emulsion testing, the 7% emulsion could serve as an effective formulation for developing alternative topical treatments.