Synthesis,cytotoxicity assay,and molecular docking study of hydroxychalcone derivatives as potential tyrosinase inhibitors

In this work,we studied the synthesis,cytotoxicity assay,and molecular docking of hydroxychalcone derivatives as tyrosinase inhibitors.Synthesis of chalcone derivatives was carried out through a Claisen-Schmidt condensation reaction between acetophenone and benzaldehyde derivatives under alkaline conditions for 48 h.The synthesized products were characterized by using Fourier transform infrared(FTIR),gas chromatography-mass spectrometry(GC-MS),proton and carbon nuclear magnetic resonance(1H and 13C NMR)spectrometer.The in vitro inhibitory activity was evaluated against tyrosinase enzyme by employing L-3,4-dihydroxyphenylalanine(L-DOPA)as the substrate.We successfully synthesized 4-hydroxychalcone(HC)and 4-hydroxy-3-methoxychalcone(HMC)with a yield of 60%and 76%,respectively.While the tyrosinase inhibitory test of HC and HMC gave the IC50 value of 64.35 and 21.56μg/mL,respectively,demonstrating that their inhibitory activities against tyrosinase enzyme were better compared with kojic acid and hydroquinone as the positive controls.We also found that HC gave 2025μg/m L as the IC50 value against Vero cells,confirming that it was not toxic to the normal cell line.The molecular docking study gave the root-mean-square deviation value of less than 2?.Furthermore,the binding energies of hydroxychalcone derivatives were found as-30.13 and-31.38 kJ/mol,showing that those compounds could be potentially used as the alternative tyrosinase inhibitors in medical application.

Ferulic Acid in Paper Mulberry and Its Wastewater from Pulps Production

Wastewater from paper mulberry （Broussonetia papyrifera） pulps production was subjected to biological activities evaluations and phenolics characterization. The EtOAc extract was found to be the best antioxidant （IC50 = 0.4408 mg/mL） and tyrosinase inhibitor （IC50 = 1.6340 mg/mL） comparing to vitamin C （1C50 = 0.0011 mg/mL） and kojic acid （IC50 = 0.0244 mg/mL）, respectively, and the highest ferulic acid content （4.450 ±0.0077 ppm）. This fraction was further column chromatographed and antioxidant activity was archived （IC50 = 0.075 mg/mL） as well as tyrosinase inhibitory effect （IC50 = 0.042 mg/mL） in addition to ferulic acid （45.310 ± 0.0115 ppm）. Ferulic acid in paper mulberry was compared. Reflux with H2O gave the highest ferulic acid content （37.848 ± 1.2470 ppm） followed by a mixture of MeOH and H2O （2.002 ± 0.0370 ppm） and MeOH （1.185 ± 0.0320 ppm）, respectively. The reflux H2O was partitioned with EtOAc that extracted most of ferulic acid （256.678 ± 0.3760 ppm） and left less in the aqueous layer （9.408 ± 0.2820 ppm）.

Synthesis,structure and tyrosinase inhibition of natural phenols derivatives

Four series of derivatives of vanillin,anisaldehyde,genistein and aloe emodin were prepared.The single crystal of （E）-1-（5-（4-methoxyphenyl）-3-（4-methoxystyryl）-4,5-dihydro-1H-pyrazol-1-yl）ethanone,which was synthesized from vanillin, was obtained by spontaneous evaporation method.All the compounds were tested for the tyrosinase inhibitory activities.The results demonstrated that the IC_（50）values of vanillin,anisaldehyde,genistein and aloe emodin against mushroom tyrosinase activity are 68,49,343 and 160μM,respectively.Among the twelve derivatives,（E）-1-（5-（4-methoxyphenyl）-3-（4-methoxystyryl）-4,5- dihydro-1H-pyrazol-1-yl）ethanone from vanillin and 4,5-dimethoxy-9,10-dioxo-9,10-dihydroanthracene-2-carboxylic acid from aloe emodin showed good inhibition against the tyrosinase with IC_（50）values of 18μM and 21μM,respectively.

Inhibition of tyrosinase activity and melanine pigmentation by 2-hydroxytyrosol

2-Hydroxytyrosol(2-HT),originally reported as a synthetic compound,was isolated for the first time as a fungal metabolite.2-HT was found to inhibit mushroom tyrosinase with an IC_(50) value of 13.0 mmol/L.Furthermore,2-HT dose-dependently inhibited tyrosinase activity(IC_(50),32.5 mmol/L)in the cell-free extract of B16 melanoma cells andα-melanocyte stimulating hormone(α-MSH)-stimulated melanin formation in intact B16 melanoma cells.

不同来源的芦荟对酪氨酸酶的抑制作用(英文)

In this study, lyophilized and methanolic extracts of aloe gel from different germplasms were evaluated for their potential to inhibit mushroom tyrosinase activity. The results showed potent inhibitory effect of Aloe vera gel extracts on L-dihydroxyphenylalanine(L-DOPA) oxidation catalyzed by tyrosinase in a dose-dependent manner. Significant differences in % inhibition of tyrosinase among the extraction methods and the germplasms were observed. The relative performance of the germplasms was evaluated with the help of posthoc multicomparison test. The methanolic extract was more effective than the lyophilized crude gel in all the germplasms. The inhibitory effect of the lyophilized gel and methanolic extract tested from five germplasms followed the order: RM > TN > S24 > OR > RJN. The germplasm RM showed the highest tyrosinase inhibition, and the maximum % inhibition noted was 26.04% and 41.18%, respectively for the lyophilized and methanolic extracts at 6 mg·mL–1concentration. Lineweaver-Burk plots of the different concentrations of L-DOPA in the absence and presence of lyophilized gel extract showed competitive inhibition of mushroom tyrosinase in all the germplasms. This study suggests that the germplasm RM could potentially be used for the isolation and identification of the effective tyrosinase inhibitory component, and ascertains the critical role of selecting the best source of germplasm for natural product isolation and characterization.

Antimelanogenic effects of Inula britannica flower petal extract fermented by Lactobacillus plantarum KCCM 11613P

The inhibitory effects of Lactobacillus plantarum-fermented and non-fermented Inula britannica extracts on the tyrosinase activity were comparatively investigated to examine whether and how they improve the whitening activity, and the contents of total flavonoids and polyphenolics as bioactive compounds were determined. The skin whitening activity using in vitro or ex vivo tyrosinase and L-3,4-dihydroxyphenylalanine(L-DOPA) staining was examined. The total flavonoid content(TFC) was increased by 13.4% after 72h-fermentation. The viabilities of the B16F10 cells treated with the fermented and non-fermented control extracts were 100.26% and 92.15% at 500μg/ml, respectively. In addition, the inhibition of tyrosinase activity was increased by the fermented samples from 29.33% to 41.74% following fermentation for up to 72h. The tyrosinase activity of the untreated control group was increased to 145.69% in B16F10 cells. The results showed that I. britannica fermented by L. plantarum dose-dependently inhibited tyrosinase activity, which was stimulated by α-melanocyte stimulating hormone. These results suggest that lactic fermented I. britannica extracts can be used as effective skin-whitening materials.