Phytochemical screening and antibacterial properties of “duro” leaves (Nephelium ramboutan-ake (Labill.) Leenh. 1986) against Escherichia coli and Staphylococcus aureus

From the hinterlands of southern Palawan, Philippines, resides one of the oldest tribes in the country, the Palaw’an tribe. As mountain dwellers, they have developed unique healing practices, including the use of the “duro” Nephelium ramboutan-ake (Labill.) Leenh. 1986 plant to treat diarrhea. This study aimed to characterize the leaf morphology of “duro,” screen for the phytochemicals present, and assess the antibacterial properties of the “duro” leaf extract using the Kirby-Bauer test. Leaves of “duro” were collected from Sitio Sumurum, Brgy. Ransang, Rizal, Palawan. Samples were verified, dried, and extracted before being subjected to phytochemical screening and antibacterial susceptibility test. The morphological characteristics of “duro” leaves include smooth, green-colored, paripinnate compound leaves with an oblanceolate shape arranged oppositely. They have entire margins and pinnate venation, are attached through a petiolate, with the leaf base decurrent at the petiole, and have a mean size of 10.33 cm by 5.77 cm. Only alkaloids, flavonoids, saponins, and tannins were detected among the secondary metabolites tested, while cardiac glycosides and terpenoids were absent. The "duro" leaves extract exhibited moderate antibacterial properties against Escherichia coli (Migula, 1895) Castellani and Chalmers, 1919 and Staphylococcus aureus Rosenbach, 1884, with mean inhibition zones of 12 mm and 10.67 mm, respectively. The antibacterial properties and presence of phytochemicals suggest the therapeutic potential of "duro" leaves for treating diarrhea. This study addresses knowledge gaps regarding "duro," its medicinal use among the Palaw'an tribe, and promotes further research on indigenous plants.