Constituents with tyrosinase inhibitory activities from branches of Ficus erecta var. sieboldii King

Abstract

Phytochemical investigation of the branches of Ficus erecta var. sieboldii King resulted in the isolation of eight constituents: p-hydroxybenzoic acid (1), methyl p-hydroxybenzoate (2), vanillic acid (3), methyl vanillate (4), syringic acid (5), β-sitosterol (6), α-amyrin acetate (7), and ethyl linoleate (8). Their chemical structures were identified via spectroscopic means as well as by comparing their data with literature values. Studies on tyrosinase inhibition activities were conducted for the isolated compounds. Among them, p-hydroxybenzoic acid (1) and methyl p-hydroxybenzoate (2) were identified as active tyrosinase inhibitors with IC₅₀ values of 0.98 ± 0.042 and 0.66 ± 0.025 mM, respectively, showing comparable activities to that of arbutin (IC₅₀ = 0.32 ± 0.015 mM), a standard control. Inhibition kinetics, as analyzed by Lineweaver-Burk plots, indicated that compounds 1 and 2 were competitive inhibitors of diphenolase of mushroom tyrosinase. Notably, isolated compounds 1–8 were reported for the first time as constituents of F. erecta.

Keywords::

• Ficus erecta
• tyrosinase inhibition
• p-hydroxybenzoic acid
• methyl p-hydroxybenzoate
• competitive inhibitor

Acknowledgment

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0007254).

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.