جستجوی مقالات مرتبط با کلیدواژه « anti-tyrosinase activity » در نشریات گروه « پزشکی »

Tyrosinase enzyme has a key role in melanin biosynthesis by converting tyrosine into dopaquinone. It also participates in the enzymatic browning of vegetables by polyphenol oxidation. Therefore, tyrosinase inhibitors are useful in the fields of medicine, cosmetics, and agriculture. Many tyrosinase inhibitors having drawbacks have been reported to date; so, finding new inhibitors is a great need.

A variety of 6-hydroxy-3,4-dihydronaphthalenone chalcone-like analogs (C1-C10) have been synthesized by aldol condensation of 6-hydroxy tetralone and differently substituted benzaldehydes. The compounds were evaluated for their inhibitory effect on mushroom tyrosinase by a spectrophotometric method. Moreover, the inhibition manner of the most active compound was determined by Lineweaver-Burk plots. Docking study was done using AutoDock 4.2. The drug-likeness scores and ADME features of the active derivatives were also predicted.

Most of the compounds showed remarkable inhibitory activity against the tyrosinase enzyme. 6-Hydroxy-2-(3,4,5-trimethoxybenzylidene)-3,4-dihydronaphthalen-1(2H)-one (C2) was the most potent derivative amongst the series with an IC50 value of 8.8 μM which was slightly more favorable to that of the reference kojic acid (IC50 = 9.7 μM). Inhibitory kinetic studies revealed that C2 behaves as a competitive inhibitor. According to the docking results, compound C2 formed the most stable enzyme-inhibitor complex, mainly via establishing interactions with the two copper ions in the active site. In silico drug-likeness and pharmacokinetics predictions for the proposed tyrosinase inhibitors revealed that most of the compounds including C2 have proper drug-likeness scores and pharmacokinetic properties.

Therefore, C2 could be suggested as a promising tyrosinase inhibitor that might be a good lead compound in medicine, cosmetics, and the food industry, and further drug development of this compound might be of great interest.

In this study,five oximes were synthesized,characterized,and their antioxidant activity investigatedexperimentally,theoretically. Labeled OX1–OX5,our oximes were subjected to three antioxidantactivity assays (1,1-diphenyl-2-picrylhydrazyl,cupric reducing antioxidant capacity test [CUPRAC],and ferric reducing antioxidant power test). The related results were very fulfilling presenting certainantioxidant properties for the majority of the studied compounds,especially with CUPRAC test whereOX1,OX2 presented a better result than the used standard antioxidants. Besides,the thermodynamicmolecular descriptors (bond dissociation enthalpy,ionization potential,and proton affinity) of ourmolecules were calculated with the density functional theory to elucidate the experimental results. Theresulting values were in a good agreement with the experimental results. The second part of this workconsisted of an anti-tyrosinase activity evaluation of the five oximes where three of them displayed aninhibitory effect against this enzyme. To analyze this result,a molecular docking was conducted andthe obtained values were in accordance with the experience. Absorption,distribution,metabolism,andexcretion properties were also assessed via Molinspiration software,all our molecules satisfied therelated conditions. Thus,the conducted theoretical,experimental studies were in excellent harmony,together supporting the antioxidant power of our compounds,which could permit their use in cosmetic,pharmaceutical,or food industry domains,after further clinical tests.

Sideritis species have been known as medicinal plants since ancient times, and used as tea in Mediterranean countries such as Turkey, Greece and Spain. They are also used for the treatment of several ailments such as a cough, common cold and gastrointestinal disorders. The aim of the present study was to perform the chemical composition, antioxidant, anticholinesterase and anti-tyrosinase activities of the essential oils of Sideritis albiflora and S. leptoclada. β-caryophyllene (21.2%) and Germacrene D (17.9%) were identified as the major compounds in S. albiflora and S. leptoclada essential oils, respectively. The essential oil of S. albiflora showed the highest lipid peroxidation inhibitory (IC50:73.8±0.8 µg/mL), DPPH free radical scavenging (28.3±0.1%), ABTS cation radical scavenging (IC50:50.6±1.0 µg/mL), reducing power (A0.05: 181.7±0.6 µg/mL), acetylcholinesterase (22.1±0.4%), butyrylcholinesterase (IC50:157.2±0.9 µg/mL) and tyrosinase (15.2±0.4%) inhibitory activities. Moreover, S. albiflora essential oil had rich total phenolic and flavonoid contents indicating 41.5±0.8 µg PEs/mg extract and 21.4±1.0 µg QEs/mg extract, respectively. This study suggests that consumption of Sideritis species as tea may protect one against melanogenesis, amnesia, and oxidative stress without any observable side effect.