• Journal of Applied Biological Chemistry
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• v.60 no.1
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• pp.49-54
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• 2017

In the course of screening tyrosinase inhibitory activity, EtOAc-soluble fraction of Coix lachryma-jobi var. mayuen Stapf. (Gramineae) roots showed significant inhibition. Further fractionation of the EtOAc-soluble fraction resulted in six compounds, which were identified as (+)-icariol $A_2$ (1), zhepiresionol (2), 4-hydroxybenzaldehyde (3), trans-${\rho}$-coumaric acid (4), N-(2-hydroxy-4-methoxyphenyl)-2-hydroxyacetamide (5), and coixol (6). The chemical structures of these compounds were identified on the basis of spectroscopic methods (MS, 1D and 2D NMR) and comparison with literature values. Compound 1 was first reported from this plant. Also, this is the first time that the isolation of compound 5 has been reported from nature source. Among the isolated compounds, compounds 4 and 6 showed enzyme inhibitory activity, with $IC_{50}$ values of 6.5 and $62.4{\mu}M$, respectively, in comparison with these of positive control, arbutin.