Antioxidant and Tyrosinase Inhibitory Activities of Unripe and Ripe Fruit and Seed Extracts of Eugenia uniflora

Eugenia uniflora is widely distributed in Java island and used in traditional medicine for the treatment of many ailments. This study aims to compare the bioactivity of the seeds and pericarp of the unripe and ripe fruits of E. uniflora. The plant parts were extracted by maceration in ethanol. Qualitative and quantitative phytochemical analysis of the extracts was carried out according to standard methods. The antioxidant activity was performed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assays. The antiaging potential was assessed using the tyrosinase inhibitory assay. Phytochemical screening show the presence of alkaloids, flavonoids, and terpenoids in the seed and fruit extracts of E. uniflora. The seeds contain more total phenolic and flavonoid contents, as well as a higher antioxidant activity than the fruits. The unripe seeds had the highest antioxidant activity in the DPPH assay with IC₅₀ value of 4.70 µg/mL, which was comparable to that of quercetin (IC₅₀ = 4.76 µg/mL). In the FRAP assay, the ripe fruits exhibited the highest antioxidant activity with a FRAP value of 4245.32 µMFSE/100 g extract. The anti-tyrosinase activity assay showed that the unripe and ripe seeds of E. uniflora have weak tyrosinase inhibitory activity with IC₅₀ of 309.96 and 539.67 µg/mL, respectively compared to kojic acid with IC₅₀ of 27.54 µg/mL. In contrast, the unripe and ripe fruits showed no anti-tyrosinase activity. Therefore, E. uniflora seeds possesses higher potential as antioxidant and antiaging agent than E. uniflora fruits.