Epimedin B(EB)is one of the main flavonoid ingredients present in Epimedium brevicornum Maxim.,a traditional herb widely used in China.Our previous study showed that EB was a stronger inducer of melanogenesis and an a...Epimedin B(EB)is one of the main flavonoid ingredients present in Epimedium brevicornum Maxim.,a traditional herb widely used in China.Our previous study showed that EB was a stronger inducer of melanogenesis and an activator of tyrosinase(TYR).However,the role of EB in melanogenesis and the mechanism underlying the regulation remain unclear.Herein,as an extension to our previous investigation,we provide comprehensive evidence of EB-induced pigmentation in vivo and in vitro and elucidate the melanogenesis mechanism by assessing its effects on the TYR family of proteins(TYRs)in terms of expression,activity,and stability.The results showed that EB increased TYRs expression through microphthalmia-associated transcription factor-mediated p-Akt(referred to as protein kinase B(PKB))/glycogen synthase kinase 3β(GSK3β)/β-catenin,p-p70 S6 kinase cascades,and protein 38(p38)/mitogen-activated protein(MAP)kinase(MAPK)and extracellular regulated protein kinases(ERK)/MAPK pathways,after which EB increased the number of melanosomes and promoted their maturation for melanogenesis in melanoma cells and human primary melanocytes/skin tissues.Furthermore,EB exerted repigmentation by stimulating TYR activity in hydroquinone-and N-phenylthiourea-induced TYR inhibitive models,including melanoma cells,zebrafish,and mice.Finally,EB ameliorated monobenzone-induced depigmentation in vitro and in vivo through the enhancement of TYRs stability by inhibiting TYR misfolding,TYR-related protein 1 formation,and retention in the endoplasmic reticulum and then by downregulating the ubiquitination and proteolysis processes.These data conclude that EB can target TYRs and alter their expression,activity,and stability,thus stimulating their pigmentation function,which might provide a novel rational strategy for hypopigmentation treatment in the pharmaceutical and cosmetic industries.展开更多
Objective:To investigate the suitability of citrus-press cakes,by-products of the juice industry as a source for the whitening agents for cosmetic industry.Methods:Ethylacetate extracts of citrus-press cakes(CCE)were ...Objective:To investigate the suitability of citrus-press cakes,by-products of the juice industry as a source for the whitening agents for cosmetic industry.Methods:Ethylacetate extracts of citrus-press cakes(CCE)were examined for their anti-melanogenic potentials in terms of the inhibition of melanin production and mechanisim of melanogenesis by using Western Blot analysis with tyrosinese,tyrosinase-related protein-1(TRP-1),TRP2,and microphthalmia-associated transcription factor(MITF)proteins.To apply the topical agents,citrus-press cakes was investigated the safety in human skin cell line.Finally flavonoid analysis of CCE was also determined by HPLC analysis.Results:Results indicated that CCE were shown to down-regulate melanin content in a dose-dependent pattern.The CCE inhibited tyrosinase,TRP-2,and MITF expressions in a dose-dependent manner.To test the applicability of CCE to human skin,we used MTT assay to assess the cytotoxic effects of CCE on human keratinocyte HaCaT cells.The CCE exhibited low cytotoxicity at 50μg/mL.Characterization of the citrus-press cakes for flavonoid contents using HPLC showed varied quantity of rutin,narirutin,and hesperidin.Conclusions:Considering the anti-melanogenic activity and human safety,CCE is considered as a potential anti-melanogenic agent and may be effective for topical application for treating hyperpigmentation disorders.展开更多
Aqueous ethanol extracts of powdered stems of Dendrobium loddigesii afforded three new phenolics including threo-7-Oethyl-9-O-(4-hydroxyphenyl)propionyl-guaiacylglycerol(1),(R)-4,5,4ʹ-trihydroxy-3,3ʹ,α-trimethoxybibe...Aqueous ethanol extracts of powdered stems of Dendrobium loddigesii afforded three new phenolics including threo-7-Oethyl-9-O-(4-hydroxyphenyl)propionyl-guaiacylglycerol(1),(R)-4,5,4ʹ-trihydroxy-3,3ʹ,α-trimethoxybibenzyl(2)and(S)-5,5′,7-trihydroxy-3′,4′-dimethoxyflavanone(3),together with eleven known analogues.Their structures were determined by extensive spectroscopic analysis.To identify natural antioxidants,whitening,and anti-aging agents,the abilities of these phenolics were assessed to scavenge the 1,2-diphenyl-2-picrylhydrazyl(DPPH)radical,their abilities to inhibit tyrosinase production,and their abilities to stimulate collagen production by human dermal fibroblasts-adult(HDFa)assay.It was found that compounds 1,4-8,13 and 14 exhibited significant DPPH radical scavenging activities,compound 10 exhibited tyrosinase inhibitory activity(IC_(50)37.904μg/mL),and compound 9 showed significant collagen production with an EC_(50)value of 3.182μg/mL.These results suggest that phenolic constituents from D.loddigesii may be candidate antioxidants,skin-whitening and/or anti-aging agents.展开更多
The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of ty...The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of tyrosinase,the fluorescence of gold nanoparticles was quenched by catechol which can be employed to detect catechol.Under the optimal conditions,a linear range 5.0×10^(-7)-1.0×10^(-3) mol L^(-1) and a detection limit 1.0×10^(-7) mol L^(-1) of catechol were obtained.o-Quinone intermediate produ...展开更多
Objective:To find out and compare the in vitro antioxidant and tyrosinase inhibitory activities of two species of mangrove plants.Methods:Mangrove samples were harvested at the shoreline on the island of Weno,Chuuk St...Objective:To find out and compare the in vitro antioxidant and tyrosinase inhibitory activities of two species of mangrove plants.Methods:Mangrove samples were harvested at the shoreline on the island of Weno,Chuuk State in Micronesia.The phenol content,antioxidant activity(based on DPPH-free radical scavenging)and tyrosinase inhibitory activity in different tissues(leaves,barks and roots)of Rhizophora stylosa(R.stylosa)and Sonneratia alba(S.alba),collected from the island of Weno.Results:Total phenol content ranged from 4.87 to 11.96 mg per g of freeze dried samples.The highest antioxidant activity was observed in R.styiosa bark(85.5%).The highest tyrosinase inhibitory activity was found in S.alba bark.Also,total phenol content and antioxidant activity were higher in methanol extracts than in aqueous extracts.Conclusions:Taken together,the results of this study proved that mangroves can be excellent sources of antioxidant compounds.展开更多
Tyrosinase is an important enzyme in controlling the formation of melanin in melanosome,and plays a key role in the pigmentation of hair and skin.The abnormal expression or activation of tyrosinase is associated with ...Tyrosinase is an important enzyme in controlling the formation of melanin in melanosome,and plays a key role in the pigmentation of hair and skin.The abnormal expression or activation of tyrosinase is associated with several diseases such as albinism,vitiligo,melanoma and Parkinson disease.Excessive deposition of melanin could cause diseases such as freckles and brown spots in the human body,and it is also closely related to browning of fruits and vegetables and insect molting.Detecting and inhibiting the activity of tyrosinase is of extraordinary value in the progress of diagnosis and treatment of these diseases.Therefore,many selective optical detection probes and small molecular inhibitors have been developed,and have made significant contributions to the basic and clinical research on these diseases.In this paper,the detection and inhibition of tyrosinase and their application in whitening products are reviewed,with special emphasis on development of fluorescent probes and inhibitors.Hopefully,this review will help design more efficient and sensitive tyrosinase probes and inhibitors,as well as shed light on novel treatment of diseases such as melanoma.展开更多
Phenolic compounds such as chlorogenic acid,cryptochlorogenic acid,neochlorogenic acid and caffeic acid are widely distributed in fruits,vegetables and traditional Chinese medicines with a wide range of biological act...Phenolic compounds such as chlorogenic acid,cryptochlorogenic acid,neochlorogenic acid and caffeic acid are widely distributed in fruits,vegetables and traditional Chinese medicines with a wide range of biological activities.Tyrosinase plays a critical role in the food industry,but recent studies have proposed unexplored aspects of clinical application.Tyrosinase-catalyzed oxidation of four polyphenols as well as its underlying mechanism remains unclear.In the current work,we investigated the kinetic properties of tyrosinase-catalyzed oxidation of the four polyphenols of interest.To measure the unstable o-quinone products,an analytical method using 3-methyl-2-benzothiazolinone hydrazone(MBTH)was established.The optimal incubation time,buffer pH,temperature and enzyme concentration for the enzyme activity in the presence of each polyphenol of interest were investigated.Under the final optimized conditions,the kinetics and substrate specificity of four polyphenols were examined.K inetic data showed that tyrosinase had the greatest substrate affinity to chlorogenic acid compared with its isomers and caffeic acid.The catalytic efficiency with chlorogenic acid was 8-to 15-fold higher than that with the other 3 polyphenols.Molecular docking study demonstrated that the tight binding of chlorogenic acid at the peripheral site should be the major reason for the specificity to chlorogenic acid.In light of this,the rational design of high-affinity inhibitors against tyrosinase may focus on the binding of both the Cu site and peripheral site.This study will supply a basis for the selection of phenolic acids in food industry and health carc.展开更多
Melanocytes that form stratum basale of skin epidermis express tyrosinase enzyme, which catalyzes initial two rate-limiting steps in the biotransformation of tyrosine into dark pigment called melanin. Even today, Tyro...Melanocytes that form stratum basale of skin epidermis express tyrosinase enzyme, which catalyzes initial two rate-limiting steps in the biotransformation of tyrosine into dark pigment called melanin. Even today, Tyrosinase inhibitors are among the promising candidates in cosmetic industry for skin-lightening formulations. Overexpression of tyrosinase causes excess melanin biosynthesis and deposition resulting in dark skin color. Moreover, localized overexpression of tyrosinase cause variety of hyperpigmentation disorders like melanoma, melasma, chloasma, dark patches, liver patches, etc. There has been a renewed interest in the natural products as main ingredients in the formulation of safe products for skin-whitening and treatment options for hyperpigmentation disorders. In the present communication, the results of our investigations on tyrosinase inhibition, modulation of intracellular tyrosinase and melanin levels in cultured B16F10 melanoma cells by Bacopa monnieri (L.) methanol extract (BME) are presented and discussed as safe option for skin lightening and to treat hyperpigmentation disorders. BME showed 11%, 29%, 54% and 80% inhibition of mushroom tyrosinase activity at an initial 100, 200, 400 and 600 μg of extract. Treatment of α-melanocyte stimulating hormone (α-MSH) stimulated cultured murine melanoma B16F10 cells with 100 μg/ml of the extract showed a decrease in the levels of cellular melanin and cellular tyrosinase content by 22% and 46% respectively. The cytotoxicity studies by MTT assay revealed that the LC50 of the BME is ≥1000 μg/ml in cultured mouse melanoma B16F10 and HEK293 cells.展开更多
Tyrosinase inhibitory activity of the extractives from A. cathartica was examined and their new bioactivity and potent active compounds were identified. Five compounds, glabridin, new lignan, kaempferol, naringenin, a...Tyrosinase inhibitory activity of the extractives from A. cathartica was examined and their new bioactivity and potent active compounds were identified. Five compounds, glabridin, new lignan, kaempferol, naringenin, and allamandicin, were isolated by a series of chromatography, and identified by NMR and LC-MS. Among them, glabridin had the high-est tyrosinase inhibitory activity (IC50:2.93 μM) which is 15 times stronger than that of kojic acid used as positive con-trol (IC50:43.7 μM). Moreover the lignan was indentified as 1-[3-(4-allyl-2,6-dimethoxyphenoxy)-4-methoxyphenyl] propane-1,2,diol which was a novel lignan.展开更多
White mulberry Morus alba and jackfruit Artocarpus heterophyllus are two of seven chosen Vietnamese folk plants which showed the highest tyrosinase inhibition activity. Besides, both of them showed antioxidant and ant...White mulberry Morus alba and jackfruit Artocarpus heterophyllus are two of seven chosen Vietnamese folk plants which showed the highest tyrosinase inhibition activity. Besides, both of them showed antioxidant and antibacterial activities. Especially, the Sulforhodamine B (SRB) assay test result of the root core extract of M. alba figured out its non-toxicity on foreskin fibroblasts.展开更多
The present study modified potato protein and flour with tyrosinase to promote the diversification of potato staple foods.The results indicated that tyrosinase treatment markedly altered the secondary structure of pro...The present study modified potato protein and flour with tyrosinase to promote the diversification of potato staple foods.The results indicated that tyrosinase treatment markedly altered the secondary structure of proteins.After tyrosinase treatment,the maximum decomposition temperature of potato protein and flour increased from 322.32 to 332.40℃ and from 294.24 to 299.61℃,respectively.Tyrosinase treatment remarkably reduced the pasting viscosity of potato flour,that is,the peak viscosity,through reducing viscosity,breakdown,final viscosity,and setback by 32.50,60.98,13.04,68.24,and 74.31%,respectively.In contrast,tyrosinase treatment increased the shear resistance and hardness of the protein and flour gels;the maximum stress values of the protein and flour gels increased from 1.48 to 10.1% and from 6.87 to 14.8%,respectively.Furthermore,tyrosinase treatment promoted viscoelastic properties and structural stability of potato protein and flour.These results may provide an important foundation for the development of novel potato staple foods.展开更多
Hard clam(Meretrix meretrix)has a rich shell color variation among individuals from light yellow to bluish gray,brown red,and black,which may associating with melanin.Tyrosinase(Tyr)is a key rate-limiting enzyme for t...Hard clam(Meretrix meretrix)has a rich shell color variation among individuals from light yellow to bluish gray,brown red,and black,which may associating with melanin.Tyrosinase(Tyr)is a key rate-limiting enzyme for the biosynthesis of melanin,which affects the dark color of animal skin,hair,fur,scales and feathers.Here,we isolated and characterized the full-length cDNA sequence of M.meretrix tyrosinase gene(MmTyr)which encodes a protein with 689 amino acids.Sequence characteristics and phylogenetic analysis showed that there are a variety of Tyr genes in mollusks,which can be divided into different categories.The abundance of MmTyr transcript was detected in six tissues including mantle,adductor muscle,digestive gland,foot,gill and siphon of adult M.meretrix with qRT-PCR.The results showed a higher expression specifically in the mantle,digestive gland and siphon,which was consistent with the phenotypic color difference.In the embryos and larvae at different developmental stages,high expression was found in the trochophore larvae and juvenile clams.Among three M.meretrix strains with different shell colors,the expression level of MmTyr and total melanin content in the mantle edge both showed significant differences,suggesting that MmTyr is involved in the formation of shell color.The results obtained in this study will improve our understanding of molluscan tyrosinase gene function and molecular mechanism of shell color pattern determination.展开更多
The purpose of this study was to develop liposomal formulations of Asparagus racemosus root extract(AR1-6)as well as evaluate the physicochemical properties and in vitro tyrosinase inhibitory activity.Liposomes compos...The purpose of this study was to develop liposomal formulations of Asparagus racemosus root extract(AR1-6)as well as evaluate the physicochemical properties and in vitro tyrosinase inhibitory activity.Liposomes composed of AR1-6 to lipid weight ratio of 1:10 and lecithin(LEC)or Phospholipon90G(PC90G)as structural phospholipid at 7:3 molar ratio to CHOL were prepared by various methods,i.e.chloroform-film(CF),reverse-phase evaporation(REV),polyol dilution(PD),and freeze-drying of monophase solution(MFD)methods.The results revealed that vesicles prepared by CF and MFD were multilamellar whereas those prepared by REV and PD were oligolamellar in nature with particle sizes ranging from 0.26 to 13.83 mm.The zeta potentials were in the range of1.5 to39.3 mV.AR1-6 liposomes with LEC possessed significantly higher entrapment than those with PC90G.The highest entrapment efficiency and in vitro tyrosinase inhibitory activity of 69.08%and 25%,respectively,were obtained from liposomes having LEC and prepared by PD method.The tyrosinase inhibitory activity were in the rank order of LEC>PC90G,and PD>CF>REV>MFD.It could be concluded that the mechanism of vesicle forming in each method of preparation was the key factor influencing physicochemical properties,particularly vesicle type,size,surface charge,and entrapment,which were well correlated with the biological activity.展开更多
Purpose Skin pigmentation disorders,such as vitiligo and melasma,are difficult to diagnose in the early stages,but abnor-mal tyrosinase levels and tyrosinase activity are potential indicators.Some resorufin-based fluo...Purpose Skin pigmentation disorders,such as vitiligo and melasma,are difficult to diagnose in the early stages,but abnor-mal tyrosinase levels and tyrosinase activity are potential indicators.Some resorufin-based fluorescence probes(RBFPs)have been designed to detect tyrosinase in tumors,but they have not been used in skin pigmentation disorders.In this study,one of these RBFPs(synthesized by resorufin salt coupled with 3-(bromomethyl)phenol)was evaluated comprehensively.Methods The RBFP was tested in different kinds of mouse and human skin cells,as well as in in vivo models,including zebrafish,guinea pigs,and Sprague-Dawley rats.In addition,small interfering RNAs(siRNAs),kojic acid,and 1-phenyl-2-thiourea(PTU)were used to inhibit tyrosinase levels or tyrosinase activity.Results This probe successfully detected tyrosinase and emitted red fluorescence in melanoma cells and melanocytes.Fluorescence was also observable in zebrafish and on the skin of guinea pigs when using the RBFP.In mouse and human cells,the RBFP showed good selectivity to tyrosinase.Moreover,in the case of decreased tyrosinase levels or activity caused by siRNAs,kojic acid,or PTU,the probe was sensitive to these changes.Further,the RBFP showed no toxic effects at concentrations of<20μmol/L,both in vitro and in vivo.Conclusions Our findings indicate the value and limitations of the RBFP in tyrosinase detection,but suggest the need for further improvement of fluorescent probes in the diagnosis of skin pigmentation disorders.展开更多
A series of tyrosinase model ligands and complexes containing polyimidazoles wereprepared. 2, 4-Di-tert-butyl-phenol was ortho-hydroxylated by the binuclear copper (?) complex[Cu2(6a)(CH3CN)2](ClO4)2 8a and molecular ...A series of tyrosinase model ligands and complexes containing polyimidazoles wereprepared. 2, 4-Di-tert-butyl-phenol was ortho-hydroxylated by the binuclear copper (?) complex[Cu2(6a)(CH3CN)2](ClO4)2 8a and molecular dioxygen under mild conditions with up to 80.4%yield, 91.4% selectivity and 92.0% conversion.展开更多
Dear Editor,I have carefully read the article entitled 'Homozygosity mapping of a consanguineous Pakistani family affected with oculocutaneous albinism to Tyrosinase gene',published by Shakil et al^([1])in 201...Dear Editor,I have carefully read the article entitled 'Homozygosity mapping of a consanguineous Pakistani family affected with oculocutaneous albinism to Tyrosinase gene',published by Shakil et al^([1])in 2016 and found it very interesting展开更多
Tea, one of the most popular consumed worldwide beverages, is known to be rich in polyphenols, more particularly in catechins. An amperometric biosensor based on tyrosinase was developed in order to monitor the phenol...Tea, one of the most popular consumed worldwide beverages, is known to be rich in polyphenols, more particularly in catechins. An amperometric biosensor based on tyrosinase was developed in order to monitor the phenolic content in black and green teas. The enzyme was immobilised by coreticulation with glutaraldehyde on carbon screen-printed electrodes (CSPE). Initially, the performances of the biosensor were evaluated referring to catechol as a model substrate. This analytical tool exhibits a high sensitivity (217 nA/μM), low limit of detection (LOD) = 0.03 μM, good intra-electrode and inter-electrode reproducibilities with RSD lower than 3% (n = 5 injections) and RSD = 8.14% (n = 12 sensors) respectively. The storage stability was also studied;the biosensor retained successively 85% and 70% of its initial response after 34 and 53 days. Subsequently, several catechin derivatives frequently found in teas were tested and classified relatively to their sensitivities. For tea samples, the results obtained with the biosensors were compared to high performance liquid chromatography (HPLC) analysis. A good correlation between the two methods was obtained. The calculated recovery was between 90% and 96%, proving that the proposed tyrosinase biosensor can be an alternative analytical tool for global determination of catechin derivatives in tea.展开更多
In the present study, olive leaf extract, harvested from four seasons, extracted with solvent (methanol and water), was treated by D101 and Sephadex LH-20, and divided into 10 fractions by TLC detection. The antioxida...In the present study, olive leaf extract, harvested from four seasons, extracted with solvent (methanol and water), was treated by D101 and Sephadex LH-20, and divided into 10 fractions by TLC detection. The antioxidant activity was evaluated using DPPH, superoxide anion scavenging and reducing power assays. Tyrosinase inhibitory activity was also performed with L-DOPA as substrate. On extraction method, there is no significant difference in methanol and water. Among 12 months, autumn showed the best harvest time in whole. OLE showed 90% tyrosinase inhibitory activity and inhibition type was non-competitive competition. By chromagraphy treatment, the ingredients of polysacchmaride and protein showed high bioactivity towards antioxidant and anti-tyrosinase activity, the rest part showed different extent of activity and prove some effect by chromatography treatment indirectly. OLE might be a valuable bioactive source and can be applicable in both the cosmetic and medical use.展开更多
Tyrosinase is encoded by the Tyr (c or albino) locus and is the key enzyme in pigment biosynthesis. Loss of function of this enzyme caused by gene mutation results in albinism. Most cases of albinism are caused by mis...Tyrosinase is encoded by the Tyr (c or albino) locus and is the key enzyme in pigment biosynthesis. Loss of function of this enzyme caused by gene mutation results in albinism. Most cases of albinism are caused by missense mutations of tyrosinase. Albino mutations in Tyr have been identified in various animals, including human, mouse, rat, rabbit, cattle, cat, and ferret, but not in gerbil. We created two new gerbil strains: MON/Num/a (inbred agouti phenotype) and MON/Num/c (albino phenotype). Here, we report that four nucleotide substitutions in the Tyr gene caused two missense mutations in amino acids in the albino gerbil: a G-to-A mutation at position 204 in exon 1 caused R77H, and A-to-G at position 1392 and G-to-T at position 1393 in exon 5 caused Q473R. The substitution at position 1408 in exon 5 was silent. These missense mutations are conserved in all albino phenotypes we tested. Therefore, we suggest that these mutations are responsible for albinism in gerbil.展开更多
基金supported by the Open Project of National Major Science and Technology Infrastructure of Translational Medicine,China(Grant No.:TMSK-2021−404)the SIMM-SHUTCM Joint Innovation Research Program,China(2022)+1 种基金the Youth Innovation Research Foundation,China(Grant No.:A1-U21-205-01010109)the National Natural Science Foundation of China(Grant No.:81972932).
文摘Epimedin B(EB)is one of the main flavonoid ingredients present in Epimedium brevicornum Maxim.,a traditional herb widely used in China.Our previous study showed that EB was a stronger inducer of melanogenesis and an activator of tyrosinase(TYR).However,the role of EB in melanogenesis and the mechanism underlying the regulation remain unclear.Herein,as an extension to our previous investigation,we provide comprehensive evidence of EB-induced pigmentation in vivo and in vitro and elucidate the melanogenesis mechanism by assessing its effects on the TYR family of proteins(TYRs)in terms of expression,activity,and stability.The results showed that EB increased TYRs expression through microphthalmia-associated transcription factor-mediated p-Akt(referred to as protein kinase B(PKB))/glycogen synthase kinase 3β(GSK3β)/β-catenin,p-p70 S6 kinase cascades,and protein 38(p38)/mitogen-activated protein(MAP)kinase(MAPK)and extracellular regulated protein kinases(ERK)/MAPK pathways,after which EB increased the number of melanosomes and promoted their maturation for melanogenesis in melanoma cells and human primary melanocytes/skin tissues.Furthermore,EB exerted repigmentation by stimulating TYR activity in hydroquinone-and N-phenylthiourea-induced TYR inhibitive models,including melanoma cells,zebrafish,and mice.Finally,EB ameliorated monobenzone-induced depigmentation in vitro and in vivo through the enhancement of TYRs stability by inhibiting TYR misfolding,TYR-related protein 1 formation,and retention in the endoplasmic reticulum and then by downregulating the ubiquitination and proteolysis processes.These data conclude that EB can target TYRs and alter their expression,activity,and stability,thus stimulating their pigmentation function,which might provide a novel rational strategy for hypopigmentation treatment in the pharmaceutical and cosmetic industries.
基金Supported by the Next-Generation BioGreen 21 Program,Rural Development Administration,Republic of Korea,Grant No.PJ009583002013
文摘Objective:To investigate the suitability of citrus-press cakes,by-products of the juice industry as a source for the whitening agents for cosmetic industry.Methods:Ethylacetate extracts of citrus-press cakes(CCE)were examined for their anti-melanogenic potentials in terms of the inhibition of melanin production and mechanisim of melanogenesis by using Western Blot analysis with tyrosinese,tyrosinase-related protein-1(TRP-1),TRP2,and microphthalmia-associated transcription factor(MITF)proteins.To apply the topical agents,citrus-press cakes was investigated the safety in human skin cell line.Finally flavonoid analysis of CCE was also determined by HPLC analysis.Results:Results indicated that CCE were shown to down-regulate melanin content in a dose-dependent pattern.The CCE inhibited tyrosinase,TRP-2,and MITF expressions in a dose-dependent manner.To test the applicability of CCE to human skin,we used MTT assay to assess the cytotoxic effects of CCE on human keratinocyte HaCaT cells.The CCE exhibited low cytotoxicity at 50μg/mL.Characterization of the citrus-press cakes for flavonoid contents using HPLC showed varied quantity of rutin,narirutin,and hesperidin.Conclusions:Considering the anti-melanogenic activity and human safety,CCE is considered as a potential anti-melanogenic agent and may be effective for topical application for treating hyperpigmentation disorders.
基金This project was supported financially by the Yunnan Provincial Science and Technology Department(Nos.2017ZF003-04,2015HB093 and 2019HA001).Authors are grateful to the staff of the analytical group of the State Key Laboratory of Phytochemistry and Plant Resources in West China,Kunming Institute of Botany,Chinese Academy of Sciences,for measurements of all spectra.
文摘Aqueous ethanol extracts of powdered stems of Dendrobium loddigesii afforded three new phenolics including threo-7-Oethyl-9-O-(4-hydroxyphenyl)propionyl-guaiacylglycerol(1),(R)-4,5,4ʹ-trihydroxy-3,3ʹ,α-trimethoxybibenzyl(2)and(S)-5,5′,7-trihydroxy-3′,4′-dimethoxyflavanone(3),together with eleven known analogues.Their structures were determined by extensive spectroscopic analysis.To identify natural antioxidants,whitening,and anti-aging agents,the abilities of these phenolics were assessed to scavenge the 1,2-diphenyl-2-picrylhydrazyl(DPPH)radical,their abilities to inhibit tyrosinase production,and their abilities to stimulate collagen production by human dermal fibroblasts-adult(HDFa)assay.It was found that compounds 1,4-8,13 and 14 exhibited significant DPPH radical scavenging activities,compound 10 exhibited tyrosinase inhibitory activity(IC_(50)37.904μg/mL),and compound 9 showed significant collagen production with an EC_(50)value of 3.182μg/mL.These results suggest that phenolic constituents from D.loddigesii may be candidate antioxidants,skin-whitening and/or anti-aging agents.
基金supported by the National Natural Science Foundation of China(No.20875059)
文摘The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of tyrosinase,the fluorescence of gold nanoparticles was quenched by catechol which can be employed to detect catechol.Under the optimal conditions,a linear range 5.0×10^(-7)-1.0×10^(-3) mol L^(-1) and a detection limit 1.0×10^(-7) mol L^(-1) of catechol were obtained.o-Quinone intermediate produ...
基金supported by Korea Institute of Ocean Science&Technology research project:E99161
文摘Objective:To find out and compare the in vitro antioxidant and tyrosinase inhibitory activities of two species of mangrove plants.Methods:Mangrove samples were harvested at the shoreline on the island of Weno,Chuuk State in Micronesia.The phenol content,antioxidant activity(based on DPPH-free radical scavenging)and tyrosinase inhibitory activity in different tissues(leaves,barks and roots)of Rhizophora stylosa(R.stylosa)and Sonneratia alba(S.alba),collected from the island of Weno.Results:Total phenol content ranged from 4.87 to 11.96 mg per g of freeze dried samples.The highest antioxidant activity was observed in R.styiosa bark(85.5%).The highest tyrosinase inhibitory activity was found in S.alba bark.Also,total phenol content and antioxidant activity were higher in methanol extracts than in aqueous extracts.Conclusions:Taken together,the results of this study proved that mangroves can be excellent sources of antioxidant compounds.
基金This work was financially supported by the National Natural Science Foundation of China(81672508,21675085)Jiangsu Provincial Foundation for Distinguished Young Scholars(BK20170041,BK20170042)+5 种基金the Joint Research Funds of Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University(2020GXLH-Z-008,2020GXLH-Z-023)the Natural Science Basic Research Programof Shaanxi(Program No.2019JM-016)Key Research and Development Program of Shaanxi(2020ZDLGY13-04)Open Research Fund of Anhui Key Laboratory of Tobacco Chemistry(20181140)China-Sweden Joint Mobility Project(51811530018)Fundamental Research Funds for the Central Universities.
文摘Tyrosinase is an important enzyme in controlling the formation of melanin in melanosome,and plays a key role in the pigmentation of hair and skin.The abnormal expression or activation of tyrosinase is associated with several diseases such as albinism,vitiligo,melanoma and Parkinson disease.Excessive deposition of melanin could cause diseases such as freckles and brown spots in the human body,and it is also closely related to browning of fruits and vegetables and insect molting.Detecting and inhibiting the activity of tyrosinase is of extraordinary value in the progress of diagnosis and treatment of these diseases.Therefore,many selective optical detection probes and small molecular inhibitors have been developed,and have made significant contributions to the basic and clinical research on these diseases.In this paper,the detection and inhibition of tyrosinase and their application in whitening products are reviewed,with special emphasis on development of fluorescent probes and inhibitors.Hopefully,this review will help design more efficient and sensitive tyrosinase probes and inhibitors,as well as shed light on novel treatment of diseases such as melanoma.
基金The study was supported by grants from the National Natural Science Foundation of China(No.81773811)Yunnan Applied Basic Research Project(No.2017FB074)+1 种基金the Yunnan Provincial Tobacco Monopoly Bureau Grants(No.2017YN09)the Fundamental Research Funds for the Central Universities(No.2020kfyXGYJ061).
文摘Phenolic compounds such as chlorogenic acid,cryptochlorogenic acid,neochlorogenic acid and caffeic acid are widely distributed in fruits,vegetables and traditional Chinese medicines with a wide range of biological activities.Tyrosinase plays a critical role in the food industry,but recent studies have proposed unexplored aspects of clinical application.Tyrosinase-catalyzed oxidation of four polyphenols as well as its underlying mechanism remains unclear.In the current work,we investigated the kinetic properties of tyrosinase-catalyzed oxidation of the four polyphenols of interest.To measure the unstable o-quinone products,an analytical method using 3-methyl-2-benzothiazolinone hydrazone(MBTH)was established.The optimal incubation time,buffer pH,temperature and enzyme concentration for the enzyme activity in the presence of each polyphenol of interest were investigated.Under the final optimized conditions,the kinetics and substrate specificity of four polyphenols were examined.K inetic data showed that tyrosinase had the greatest substrate affinity to chlorogenic acid compared with its isomers and caffeic acid.The catalytic efficiency with chlorogenic acid was 8-to 15-fold higher than that with the other 3 polyphenols.Molecular docking study demonstrated that the tight binding of chlorogenic acid at the peripheral site should be the major reason for the specificity to chlorogenic acid.In light of this,the rational design of high-affinity inhibitors against tyrosinase may focus on the binding of both the Cu site and peripheral site.This study will supply a basis for the selection of phenolic acids in food industry and health carc.
文摘Melanocytes that form stratum basale of skin epidermis express tyrosinase enzyme, which catalyzes initial two rate-limiting steps in the biotransformation of tyrosine into dark pigment called melanin. Even today, Tyrosinase inhibitors are among the promising candidates in cosmetic industry for skin-lightening formulations. Overexpression of tyrosinase causes excess melanin biosynthesis and deposition resulting in dark skin color. Moreover, localized overexpression of tyrosinase cause variety of hyperpigmentation disorders like melanoma, melasma, chloasma, dark patches, liver patches, etc. There has been a renewed interest in the natural products as main ingredients in the formulation of safe products for skin-whitening and treatment options for hyperpigmentation disorders. In the present communication, the results of our investigations on tyrosinase inhibition, modulation of intracellular tyrosinase and melanin levels in cultured B16F10 melanoma cells by Bacopa monnieri (L.) methanol extract (BME) are presented and discussed as safe option for skin lightening and to treat hyperpigmentation disorders. BME showed 11%, 29%, 54% and 80% inhibition of mushroom tyrosinase activity at an initial 100, 200, 400 and 600 μg of extract. Treatment of α-melanocyte stimulating hormone (α-MSH) stimulated cultured murine melanoma B16F10 cells with 100 μg/ml of the extract showed a decrease in the levels of cellular melanin and cellular tyrosinase content by 22% and 46% respectively. The cytotoxicity studies by MTT assay revealed that the LC50 of the BME is ≥1000 μg/ml in cultured mouse melanoma B16F10 and HEK293 cells.
文摘Tyrosinase inhibitory activity of the extractives from A. cathartica was examined and their new bioactivity and potent active compounds were identified. Five compounds, glabridin, new lignan, kaempferol, naringenin, and allamandicin, were isolated by a series of chromatography, and identified by NMR and LC-MS. Among them, glabridin had the high-est tyrosinase inhibitory activity (IC50:2.93 μM) which is 15 times stronger than that of kojic acid used as positive con-trol (IC50:43.7 μM). Moreover the lignan was indentified as 1-[3-(4-allyl-2,6-dimethoxyphenoxy)-4-methoxyphenyl] propane-1,2,diol which was a novel lignan.
文摘White mulberry Morus alba and jackfruit Artocarpus heterophyllus are two of seven chosen Vietnamese folk plants which showed the highest tyrosinase inhibition activity. Besides, both of them showed antioxidant and antibacterial activities. Especially, the Sulforhodamine B (SRB) assay test result of the root core extract of M. alba figured out its non-toxicity on foreskin fibroblasts.
基金supported by the National Natural Science Foundation of China(31771933 and 31471700)the Shandong Key Research and Development Plan(Public Welfare Projects),China(2019GSF109035)+2 种基金the International Cooperation Foundation of Qilu University of Technology(Shandong Academy of Sciences),China(QLUTGJUZ014)the Special Funds for Taishan Scholars Project,China(ts201712060)the Independent Training Innovation Team Project of China(2018GXRC004)。
文摘The present study modified potato protein and flour with tyrosinase to promote the diversification of potato staple foods.The results indicated that tyrosinase treatment markedly altered the secondary structure of proteins.After tyrosinase treatment,the maximum decomposition temperature of potato protein and flour increased from 322.32 to 332.40℃ and from 294.24 to 299.61℃,respectively.Tyrosinase treatment remarkably reduced the pasting viscosity of potato flour,that is,the peak viscosity,through reducing viscosity,breakdown,final viscosity,and setback by 32.50,60.98,13.04,68.24,and 74.31%,respectively.In contrast,tyrosinase treatment increased the shear resistance and hardness of the protein and flour gels;the maximum stress values of the protein and flour gels increased from 1.48 to 10.1% and from 6.87 to 14.8%,respectively.Furthermore,tyrosinase treatment promoted viscoelastic properties and structural stability of potato protein and flour.These results may provide an important foundation for the development of novel potato staple foods.
基金supported financially by the National Key Research and Development Program of China (No. 2018YFD0901404)the National Natural Science Foundation of China (No. 31772846)+3 种基金the Zhejiang Provincial Natural Science Foundation (No. LY16C190004)the General project of Zhejiang Provincial Educational Department (No. Y201329410)the Open-End Funds of Jiangsu Key Laboratory of Marine Biotechnology (No. HS16001)the Modern Agro-Industry Technology Research System (No. CARS-49)
文摘Hard clam(Meretrix meretrix)has a rich shell color variation among individuals from light yellow to bluish gray,brown red,and black,which may associating with melanin.Tyrosinase(Tyr)is a key rate-limiting enzyme for the biosynthesis of melanin,which affects the dark color of animal skin,hair,fur,scales and feathers.Here,we isolated and characterized the full-length cDNA sequence of M.meretrix tyrosinase gene(MmTyr)which encodes a protein with 689 amino acids.Sequence characteristics and phylogenetic analysis showed that there are a variety of Tyr genes in mollusks,which can be divided into different categories.The abundance of MmTyr transcript was detected in six tissues including mantle,adductor muscle,digestive gland,foot,gill and siphon of adult M.meretrix with qRT-PCR.The results showed a higher expression specifically in the mantle,digestive gland and siphon,which was consistent with the phenotypic color difference.In the embryos and larvae at different developmental stages,high expression was found in the trochophore larvae and juvenile clams.Among three M.meretrix strains with different shell colors,the expression level of MmTyr and total melanin content in the mantle edge both showed significant differences,suggesting that MmTyr is involved in the formation of shell color.The results obtained in this study will improve our understanding of molluscan tyrosinase gene function and molecular mechanism of shell color pattern determination.
基金The financial support from the Thai Herbal NanoCosmeceuticals Coordinated Research Program,National Nanotechnology Center,National Science and Technology Development Agency,Thailand is gratefully acknowledged.
文摘The purpose of this study was to develop liposomal formulations of Asparagus racemosus root extract(AR1-6)as well as evaluate the physicochemical properties and in vitro tyrosinase inhibitory activity.Liposomes composed of AR1-6 to lipid weight ratio of 1:10 and lecithin(LEC)or Phospholipon90G(PC90G)as structural phospholipid at 7:3 molar ratio to CHOL were prepared by various methods,i.e.chloroform-film(CF),reverse-phase evaporation(REV),polyol dilution(PD),and freeze-drying of monophase solution(MFD)methods.The results revealed that vesicles prepared by CF and MFD were multilamellar whereas those prepared by REV and PD were oligolamellar in nature with particle sizes ranging from 0.26 to 13.83 mm.The zeta potentials were in the range of1.5 to39.3 mV.AR1-6 liposomes with LEC possessed significantly higher entrapment than those with PC90G.The highest entrapment efficiency and in vitro tyrosinase inhibitory activity of 69.08%and 25%,respectively,were obtained from liposomes having LEC and prepared by PD method.The tyrosinase inhibitory activity were in the rank order of LEC>PC90G,and PD>CF>REV>MFD.It could be concluded that the mechanism of vesicle forming in each method of preparation was the key factor influencing physicochemical properties,particularly vesicle type,size,surface charge,and entrapment,which were well correlated with the biological activity.
基金supported by the National Natural Science Foundation of China(No.82073420)the Project of Health and Family Planning Commission of Hunan Province(No.C2019173)+2 种基金the Wisdom Accumulation and Talent Cultivation Project of the Third Xiangya Hospital of Central South University(No.YX202007)the New Xiangya Talent Project of the Third Xiangya Hospital of Central South University(No.20170301)the Fundamental Research Funds for the Central Universities of Central South University(No.2020zzts294),China.
文摘Purpose Skin pigmentation disorders,such as vitiligo and melasma,are difficult to diagnose in the early stages,but abnor-mal tyrosinase levels and tyrosinase activity are potential indicators.Some resorufin-based fluorescence probes(RBFPs)have been designed to detect tyrosinase in tumors,but they have not been used in skin pigmentation disorders.In this study,one of these RBFPs(synthesized by resorufin salt coupled with 3-(bromomethyl)phenol)was evaluated comprehensively.Methods The RBFP was tested in different kinds of mouse and human skin cells,as well as in in vivo models,including zebrafish,guinea pigs,and Sprague-Dawley rats.In addition,small interfering RNAs(siRNAs),kojic acid,and 1-phenyl-2-thiourea(PTU)were used to inhibit tyrosinase levels or tyrosinase activity.Results This probe successfully detected tyrosinase and emitted red fluorescence in melanoma cells and melanocytes.Fluorescence was also observable in zebrafish and on the skin of guinea pigs when using the RBFP.In mouse and human cells,the RBFP showed good selectivity to tyrosinase.Moreover,in the case of decreased tyrosinase levels or activity caused by siRNAs,kojic acid,or PTU,the probe was sensitive to these changes.Further,the RBFP showed no toxic effects at concentrations of<20μmol/L,both in vitro and in vivo.Conclusions Our findings indicate the value and limitations of the RBFP in tyrosinase detection,but suggest the need for further improvement of fluorescent probes in the diagnosis of skin pigmentation disorders.
基金supported by the National Natural Science Foundation of China.(No.20172038)
文摘A series of tyrosinase model ligands and complexes containing polyimidazoles wereprepared. 2, 4-Di-tert-butyl-phenol was ortho-hydroxylated by the binuclear copper (?) complex[Cu2(6a)(CH3CN)2](ClO4)2 8a and molecular dioxygen under mild conditions with up to 80.4%yield, 91.4% selectivity and 92.0% conversion.
文摘Dear Editor,I have carefully read the article entitled 'Homozygosity mapping of a consanguineous Pakistani family affected with oculocutaneous albinism to Tyrosinase gene',published by Shakil et al^([1])in 2016 and found it very interesting
文摘Tea, one of the most popular consumed worldwide beverages, is known to be rich in polyphenols, more particularly in catechins. An amperometric biosensor based on tyrosinase was developed in order to monitor the phenolic content in black and green teas. The enzyme was immobilised by coreticulation with glutaraldehyde on carbon screen-printed electrodes (CSPE). Initially, the performances of the biosensor were evaluated referring to catechol as a model substrate. This analytical tool exhibits a high sensitivity (217 nA/μM), low limit of detection (LOD) = 0.03 μM, good intra-electrode and inter-electrode reproducibilities with RSD lower than 3% (n = 5 injections) and RSD = 8.14% (n = 12 sensors) respectively. The storage stability was also studied;the biosensor retained successively 85% and 70% of its initial response after 34 and 53 days. Subsequently, several catechin derivatives frequently found in teas were tested and classified relatively to their sensitivities. For tea samples, the results obtained with the biosensors were compared to high performance liquid chromatography (HPLC) analysis. A good correlation between the two methods was obtained. The calculated recovery was between 90% and 96%, proving that the proposed tyrosinase biosensor can be an alternative analytical tool for global determination of catechin derivatives in tea.
文摘In the present study, olive leaf extract, harvested from four seasons, extracted with solvent (methanol and water), was treated by D101 and Sephadex LH-20, and divided into 10 fractions by TLC detection. The antioxidant activity was evaluated using DPPH, superoxide anion scavenging and reducing power assays. Tyrosinase inhibitory activity was also performed with L-DOPA as substrate. On extraction method, there is no significant difference in methanol and water. Among 12 months, autumn showed the best harvest time in whole. OLE showed 90% tyrosinase inhibitory activity and inhibition type was non-competitive competition. By chromagraphy treatment, the ingredients of polysacchmaride and protein showed high bioactivity towards antioxidant and anti-tyrosinase activity, the rest part showed different extent of activity and prove some effect by chromatography treatment indirectly. OLE might be a valuable bioactive source and can be applicable in both the cosmetic and medical use.
文摘Tyrosinase is encoded by the Tyr (c or albino) locus and is the key enzyme in pigment biosynthesis. Loss of function of this enzyme caused by gene mutation results in albinism. Most cases of albinism are caused by missense mutations of tyrosinase. Albino mutations in Tyr have been identified in various animals, including human, mouse, rat, rabbit, cattle, cat, and ferret, but not in gerbil. We created two new gerbil strains: MON/Num/a (inbred agouti phenotype) and MON/Num/c (albino phenotype). Here, we report that four nucleotide substitutions in the Tyr gene caused two missense mutations in amino acids in the albino gerbil: a G-to-A mutation at position 204 in exon 1 caused R77H, and A-to-G at position 1392 and G-to-T at position 1393 in exon 5 caused Q473R. The substitution at position 1408 in exon 5 was silent. These missense mutations are conserved in all albino phenotypes we tested. Therefore, we suggest that these mutations are responsible for albinism in gerbil.
