engleski

Rhodanine derivatives as potent mushroom tyrosinase inhibitors

Tyrosinases are enzymes belonging to the type-3 copper protein family which contains two copper ions in the active site. These oxidoreductases perform two sequential enzymatic reactions: hydroxylation of monophenols followed by oxidation of diphenols forming quinones which polymerize spontaneously to melanin. Tyrosinases are found in different prokaryotes as well as in plants, fungi, arthropods, and mammals. Besides its positive role in various organisms, like wound healing, sclerotization and pigmentation of insect cuticles, defence against herbivores and pathogens in plants, tyrosinases also can have negative impacts on humans (senile lentigo, melisma, freckles and pigmented ace scars) and plants (browning in fruit and vegetables following cell damage). Therefore, development of new potent tyrosinase inhibitors in medicine and cosmetic industry, as well in the food industry, is of interest. In this research 30 differently substituted rhodanine derivatives as possible mushroom tyrosinase inhibitors were tested with both, L-tyrosine and L-DOPA as substrates. Rhodanine derivatives were synthesized with green method in deep eutectic solvents without usage of organic solvents or harmful catalysts. Synthesised rhodanines inhibited tyrosinase in the range 4.2 - 100.0 % and 1.1 - 100.0 % with L-DOPA and L- tyrosine as substrates, respectively. Compound 3- allyl-5-(3-hydroxy-4-methoxybenzylidene)-2- thioxothiazolidin-4-one showed 100.0 % of tyrosinase inhibition when using both substrates. Tyrosinase inhibition of 100.0 % was also achieved with compounds 3-allyl-5-(4-(benzyloxy)-2- hydroxybenzylidene)-2-thioxothiazolidin-4-one and 3-amino-5-(3-hydroxy-4-methoxybenzylidene)-2- thioxothiazolidin-4-one but with L-tyrosine as substrate. The lowest IC50 values of 0.30 µM in case of L-DOPA and 0.23 µM in case of L-tyrosine were determined for compounds 3-allyl-5-((E)-3- phenylallylidene)-2-thioxothiazolidin-4-one and 3- amino-5-(3-hydroxy-4-methoxybenzylidene)-2- thioxothiazolidin-4-one, respectively.

mushroom tyrosinase ; inhibition ; rhodanine derivatives

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