Tyrosinase inhibitory activity
A Comparative Study of Tyrosinase Activity
| Compound IC₅₀(muM) | % inhibition (at 100 µM) | IC₅₀(muM) |
|---|---|---|
|
Kojic acid 133.4 |
41.1 |
133.4 |
|
Licorice extract |
71 |
62 |
|
Oxyresveratrol 12.7 |
83.5 |
12.7 |
|
Dihydrooxyresveratrol 1.6 |
96.3 |
1.6 |
Dose‑dependent inhibitory effect on tyrosinase by Dihydrooxyresveratrol, Oxyresveratrol and Kojic acid.
Samples shown are Oxyresveratrol (Circle), Tetrahydroxy bibenzyl (triangle) and Kojic acid (diamond). Effects on tyrosinase activity by the samples as a function of concentration are represented as inhibition % , means ± S.E of three independent tests.
Kinetic studies conducted on Dihydrooxyresveratrol in comparison with oxyresveratrol to measure the ability to inhibit mushroom tyrosinase with L‑Dopa as substrate.
Data were obtained as mean values of I/V, inverse of the increase of absorbance at the wave length 490 nm per minute (∆A490/ min) , with different concentrations of L Dopa as substrate. Inhibitors of the enzyme were tetrahydro bibenzyl with 2.4 mM (triangle ∆) , 1.2 mM (circle O) and No bibenzyl (circle O)
The observed Km value and V max establish the product as a non‑competitive inhibitor of tyrosinase on L Dopa. The Ki value obtained in the study establishes the compound Dihydrooxyresveratrol has 5‑fold higher affinity to the enzyme than oxyresveratrol.
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