Phytochemicals contents and antibacterial properties of different solvent extracts from barks and leaves of Ostodes pauciflora Merr

Ostodes pauciflora Merr belongs to the family of Euphorbiaceae, is locally known as ‘buah buantik’ and ‘buah broti’ by the Bidayuh community, and ‘buah merentik’ by the Iban community. Previous biological studies on the genus Ostodes demonstrated its potential to inhibit antibacterial, antiviral, anticancer, and cytotoxicity. Several anti-cancer agents found in O. paniculate have been reported. Besides, a phorbol ester isolated from O. katharinae is reported to inhibit the replication of wild-type HIV-1 and HIV-2. However, there is limited information on this particular genus. In addition, there is a lack of studies done on O. pauciflora, despite being abundant locally in Sarawak. This study investigates the total phenolics and flavonoid contents, antioxidant and antimicrobial activities of different solvent extracts of O. pauciflora leaves and barks based on the standard protocols to reveal their therapeutic potentials. Barks methanol extract recorded the highest phenolics and flavonoids content of 132.48 mg GAE/g of extract and 0.83 mg QE/g of extract, respectively, and scavenged the most 2,2-diphenyl-picrylhydrazyl radicals. All extracts of different solvents, including methanol, chloroform, and hexane, also demonstrated revealed an active inhibitory effect on all the tested pathogens, namely Staphylococcus aureus and Streptococcus pyogenes as Gram-positive bacteria, while Escherichia coli and Pseudomonas aeruginosa as Gram-negative bacteria. This study suggested that the O. pauciflora possessed a substantial amount of phenolics and flavonoid contents, antioxidant, and antimicrobial potentials. Hence, O. pauciflora could be a natural alternative to commercially available antioxidant agents and chemical preservatives used in food products to be utilized to suppress food-borne illnesses such as diarrhea.