Inhibitory effects of the water extracts of Lavendula sp. on mushroom tyrosinase activity

This study aimed to evaluate the inhibition properties of six lavender species, including Lavendula angustifolia, Lavandula angustifolia “Vera”, Lavendula X allardii, Lavendula stoechas, Lavendula viridis and Lavendula X heterophylla, toward the activity of mushroom tyrosinase. When using l-3,4-dihydroxyphenylalanine (l-Dopa) as the substrate for mushroom tyrosinase, the water extracts of leaves and stems from L. stoechas and L. angustifolia “Vera” showed strong inhibitory effects against the activity of mushroom tyrosinase (70% and 66.4% inhibition, respectively). Oven-drying the leaves and stems or free-drying the water extracts significantly decreased the inhibitory abilities of the water extracts from all lavender species. The water extract from L. stoechas decreased the Vmax values when using l-Dopa, catechol and 3,4-dihydroxyphenylacetic acid (DHPAA) as the substrates. It increased the value of Km when l-Dopa and catechol were the substrates but it decreased the Km when DHPAA was used. It behaved as a mixed-type inhibitor toward mushroom tyrosinase.