Antioxidant and tyrosinase inhibition activities of Eurycoma longifolia and Swietenia macrophylla.

ABSTRACT

Extract from plants have been reported to contain valuable bioactive compounds that have potential in promoting antioxidant activity. The present study was aimed to investigate the extracts of two plants available in Southeast Asia, Eurycoma longifolia and Swietenia macrophylla for their primary metabolite contents, phenolic contents, antioxidant and anti- tyrosinase activity. Two types of solvents were utilised in the extraction process of both plants. Ethyl acetate found to be a better solvent for isolation of primary metabolite compound compared to methanol. For Folin-Ciocalteu assay, methanol extract of Swietenia macrophylla possed higher phenolic content while for Eurycoma longifolia, ethyl acetate extract had higher phenolic content. In DPPH assay, the radical scavenging activity of extracts were strongly correlated to the total phenolic content based on the percentage of DPPH radical scavenging of each extracts (p<0.05). In tyrosinase inhibition assay, the activity of each extracts were very low compared to standard Kojic acid. It was assumed that, the ability of plant extracts to inhibit tyrosinase are partly contributed by antioxidant potential of the extracts (p<0.01).