• YAKHAK HOEJI
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• v.41 no.4
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• pp.439-443
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• 1997

From the root bark of Broussonetia kazinoki (Moraceae) two antioxidant components were identified. Their structures were determined as kazinol A (1) and kazinol E (2) (is oprenylated flavan and isoprenylated 1,3-diphenyl propan derivatives) by comparing NMR data with those of the reported compounds from relative plants. The antioxidant activity of 1 and 2 were monitored by the method of DPPH radical scavenging activity, whose $SC_{50}$ values were $41.4{\mu}M\;and\;33.4{\mu}M$, respectively. These compounds also exhibited inhibitory activity against tyrosinase, which is the sole key enzyme for the melanin biosynthesis and play a role in conversion of tyrosine to dopa, and dopa to dopaquinone. The antioxidant effect and the suppression of melanin biosynthesis are useful for anti-aging, increasing vitality in the incidence of major degenerative diseases, and cosmetic products in relation to hyperpigmentation.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1409-1413
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• 2000

The seeds of Coix lachryma-jobi L. var. ma-yuen(yullmoo) were investigated for the free radical scavenging and mushroom tyrosinase inhibitory activities. Brown yullmoo, which contains bran in the seed, has also been evaluated for comparison. After partitioning of the total methanol extracts of yullmoo and brown yullmoo, each organic layer exhibited mild or potent dose-dependent inhibition(about 20-80%) on 1,1-diphenyl picryl hydrazyl(DPPH) free radical with the concentration of $300\;{\mu}g/ml$ to $800\;{\mu}g/ml$. n-Butanol fraction of yullmoo showed the most potent scavenging effect on DPPH free radical. $IC_{50}$ of n-butanol fraction was $423\;{\mu}g/ml$, about six to seven fold higher concentration than standard BHT at the same inhibition rate. As for the tyrosinase inhibitory activity, all of the fractions including the methanol extract exhibited the similar activities even after partitioning. The chloroform fraction of brown yullmoo was found to show the most potent inhibitory activity with an $IC_{50}$ of $321.5\;{\mu}g/ml$.