PHYTOCHEMICAL SCREENING AND ANTIMICROBIAL ACTIVITIES OF LEAF EXTRACTS OF FIVE NEPHELIUM LAPPACEUM CULTIVARS FROM MALAYSIA

Nephelium lappaceum is a tropical tree that is widely distributed in Malaysia and Indonesia. Rambutan fruit is nutritious and rich in vitamins, minerals, and beneficial compounds that offer many health benefits. The research on the potential of N. lappaceum for pharmaceutical use is underestimated. This study aims to determine the phytochemical constituents and unravel the potential of leaf extracts for antibacterial activity. Mature leaves of five cultivars of N. lappaceum (R191, R3, S1, AG28, and GB44) were extracted using two different solvents (methanol and water) and these extracts were subjected to phytochemical screening. The effects of crude leaf extract on antimicrobial activity against the Gram-positive bacteria, Staphylococcus aureus dan the Gram-negative bacteria, Escherichia coli were conducted using the agar well diffusion method. The methanol extraction method recorded a higher yield than the water extraction method in all tested cultivars with AG 28 recording the highest percentage of 28.2%. Phytochemical screening showed the presence of coumarins, flavonoids, phenols, saponins, and tannins in both methanolic and water leaf extracts. Alkaloids were only present in the water extracts except for R191, while no detection of anthocyanin presence in both methanolic and water extracts. Analysis of antibacterial activity based on the zone of inhibition growth for methanolic and water extracts of five different cultivars showed significant antibacterial effects (p<0.05) p <0.05) with methanolic extract being the most effective against S. aureus and E. coli with the highest inhibition zones of 39 (+/- 0.3) mm and 29 (+/- 0.6) mm, respectively. The minimum inhibitory concentration (MIC) value was 1.25 % w/v for R3, AG28, and GB44 in methanolic extracts against E. coli and the lowest MIC (1.25% w/v) was recorded for AG28 in methanolic extracts against S. aureus. . Based on the phytochemicals available in the extracts, flavonoids, phenols, and coumarin may be responsible for the antibacterial activity in this study.