Tyrosinase Inhibitory and Antioxidant Activity of Paederia foetida L.

Paederia foetida L. is a tropical Asian plant containing bioactive compounds and often used as functional foods. The aim of this study was to determine the antioxidant capacity and inhibitory activity of P. foetida leaves extract on tyrosinase activity. In addition, the total phenolic content (TPC) and total flavonoid content (TFC) were determined. TPC and TFC was evaluated by the Folin-Ciocalteu and the aluminum chloride (AlCl3) colorimetric method, respectively. The antioxidant capacity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) method. The antioxidant capacity was expressed as trolox equivalent antioxidant capacity (TEAC) dan ascorbic acid equivalent capacity (AAEC). The tyrosinase inhibitory activity was conducted by enzyme-linked immunosorbent assay (ELISA) using L-tyrosine as a substrate and measured at 490 nm by ELISA reader. TPC in the crude extract, fraction A, and fraction B was 173.18 ± 3.99, 553.95 ± 5.70 and 405.37 ± 33.90, respectively. TFC in the crude extract, fraction A, and fraction B was 12.79 ± 0,25, 143.16 ± 9.27, 143.50 ± 6.90, respectively. The best antioxidant capacity of the extract was shown in the DPPH method (15.71 ± 1.6 mg TEAC/g and 100.77 ± 8.5 mg AAEC/g). Meanwhile, fraction B showed the best antioxidant capacity by the FRAP (11.48 ± 1.5 TEAC/g and 8.39 ± 1.2 mg AAEC/g ) and CUPRAC (116.34 ± 1.9 mg TEAC/g and  66.11 ± 1.3 mg AAEC/g) methods. Tyrosinase inhibitory activity exhibited that the IC50 of fraction A and B was 13.67 μg/mL and 13.37 μg/mL, respectively.