ascorbic-acid and kojic-acid

So-called darkened age spots encompass distinct pathological processes. The efficacy of topical depigmenting agents is difficult to objectivate.. To assess the hypopigmenting effect of three cosmetic formulations using objective biometrological methods.. 50 women of South-East Asian ancestry were enrolled in this pilot study. They had solar lentigines according to dermoscopic criteria. The lesions were treated by topical hypopigmenting formulations. Products were applied twice daily for 2 or 3 months. Assessments at 1-month intervals were made using narrow-band reflectance spectrophotometry, image analysis of video-recorded ultraviolet light reflection and photodensitometry- and image-analysis-assisted corneomelametry.. A 20% azelaic acid formulation and another one containing 5% ascorbyl glucosamine, 1% kojic acid and alpha-hydroxyacid esters appeared inefficacious on solar lentigines. A stabilized soy extract showed a better although modest lightening effect when assessed by corneomelametry. The subclinical or faint mottled skin revealed by ultraviolet light examination better responded (p < 0.05) to treatments.. Focal epidermal hyperpigmentation is better controlled by topical whitening agents when the increase in melanin content reflects a modest functional hyperactivity of melanocytes.

Topics: Administration, Topical; Adult; Ascorbic Acid; Densitometry; Dermatologic Agents; Dicarboxylic Acids; Double Bind Interaction; Drug Combinations; Female; Forearm; Glucosamine; Glycine max; Hand; Humans; Image Processing, Computer-Assisted; Lentigo; Melanins; Melanocytes; Middle Aged; Pilot Projects; Plant Extracts; Pyrones; Sunlight

In this work, we present a new catechol amperometric biosensor fabricated on the basis of naturally available enzymes in common mushrooms. The biosensor response mechanism comprises the reduction of the quinone exclusively produced in the oxidation of the catechol present in the sample, which is catalyzed by tyrosinase enzyme. The new catechol biosensor has demonstrated excellent analytical performance at increasing catechol concentrations in the sample solution, which includes superior reproducibility for several electrodes and long-term stability. On top of that, the biosensing element used in the fabrication is a sustainable material, of low-cost and presents an excellent lifetime of years. Whether the catechol biosensor is operating in the presence of a compound influencing the reactions underlying the amperometric response (such as ascorbic, benzoic, gallic and kojic acids), this serves as an analytical platform to detect these compounds in real samples. Particularly, we introduce herein for the first time different treatments to process the current signal of the biosensor pursuing the linearity needed for the analytical application in real samples. In this sense, the catechol biosensor has been successfully applied to the detection of benzoic, gallic and kojic acids in juices, teas and cosmetic products, respectively.

Topics: Agaricales; Ascorbic Acid; Benzoic Acid; Biosensing Techniques; Catechols; Electrochemistry; Gallic Acid; Monophenol Monooxygenase; Pyrones

Topics: Agaricus; Animals; Catalytic Domain; Cell Line, Tumor; Cinnamates; Enzyme Inhibitors; Free Radical Scavengers; Mice; Molecular Docking Simulation; Monophenol Monooxygenase; Protein Binding; Pyrones; Skin Lightening Preparations; Stilbenes

Pigmentation disorders are attributed to excessive melanin which can be produced by tyrosinase. Therefore, tyrosinase is supposed to be a vital target for the treatment of disorders associated with overpigmentation. Based on our previous findings that an (E)-β-phenyl-α,β-unsaturated carbonyl scaffold can play a key role in the inhibition of tyrosinase activity, and the fact that cinnamic acid is a safe natural substance with a scaffolded structure, it was speculated that appropriate cinnamic acid derivatives may exhibit potent tyrosinase inhibitory activity. Thus, ten cinnamamides were designed, and synthesized by using a Horner-Emmons olefination as the key step. Cinnamamides 4 (93.72% inhibition), 9 (78.97% inhibition), and 10 (59.09% inhibition) with either a 2,4-dihydroxyphenyl, or 4-hydroxy-3-methoxyphenyl substituent showed much higher mushroom tyrosinase inhibition at 25 µM than kojic acid (18.81% inhibition), used as a positive control. Especially, the two cinnamamides 4 and 9 having a 2,4-dihydroxyphenyl group showed the strongest inhibition. Docking simulation with tyrosinase revealed that these three cinnamamides, 4, 9, and 10, bind to the active site of tyrosinase more strongly than kojic acid. Cell-based experiments carried out using B16F10 murine skin melanoma cells demonstrated that all three cinnamamides effectively inhibited cellular tyrosinase activity and melanin production in the cells without cytotoxicity. There was a close correlation between cellular tyrosinase activity and melanin content, indicating that the inhibitory effect of the three cinnamamides on melanin production is mainly attributed to their capability for cellular tyrosinase inhibition. These results imply that cinnamamides having the (E)-β-phenyl-α,β-unsaturated carbonyl scaffolds are promising candidates for skin-lighting agents.

Topics: Agaricales; Amides; Animals; Cell Line, Tumor; Cinnamates; Enzyme Inhibitors; Free Radical Scavengers; Melanins; Mice; Molecular Docking Simulation; Molecular Structure; Monophenol Monooxygenase; Pyrones; Skin Lightening Preparations; Structure-Activity Relationship

Laccases have a great potential for use in industrial and biotechnological applications. It has affinity towards phenolics and finds major applications in the field of bioremediation. Here, Surface Plasmon Resonance (SPR) as a biosensor with immobilized laccase on chip surface has been studied. Laccase was immobilized by thiol coupling method and compounds containing increasing number of hydroxyl groups were analyzed for their binding affinity at various concentrations in millimolar range. The small molecules like phloroglucinol (1.532×10(-8) M), crocin (3.204×10(-3) M), ascorbic acid (8.331×10(-8) M), kojic acid (6.411×10(-7) M) and saffron (3.466×10(-7) M) were studied and respective KD values are obtained. The results were also confirmed by inhibition assay and IC50 values were calculated. All these molecules showed different affinity towards laccase in terms of KD values. This method may be useful for preliminary screening and characterization of small molecules as laccase substrates, inhibitors or modulators of activity. This method will be useful for rapid screening of phenolics in waste water because of high sensitivity.

Topics: Ascorbic Acid; Biodegradation, Environmental; Biosensing Techniques; Carotenoids; Computer Systems; Crocus; Enzymes, Immobilized; Fungal Proteins; Inhibitory Concentration 50; Laccase; Phloroglucinol; Protein Binding; Pyrones; Substrate Specificity; Surface Plasmon Resonance; Trichophyton

Crude extracts of Ataulfo exhibited polyphenol oxidase (PPO) activity with pyrogallol, 3-methylcatechol, catechol, gallic acid, and protocatechuic acid. The substrate dependent pH optima ranged from pH 5.4 to 6.4 with Michaelis-Menten constants between 0.84 ± 0.09 and 4.6 ± 0.7 mM measured in MES or phosphate buffers. The use of acetate buffers resulted in larger Michaelis-Menten constants, up to 14.62 ± 2.03 mM. Sodium ascorbate, glutathione, and kojic acid are promising inhibitors to prevent enzymatic browning in Ataulfo. PPO activity increased with ripeness and was always higher in the skin compared to the pulp. Sodium dodecyl sulphate (SDS) enhanced PPO activity, with pulp showing a stronger increase than skin. SDS-PAGE gels stained for catecholase activity showed multiple bands, with the most prominent bands at apparent molecular weights of 53, 112, and 144 kDa.

Topics: Ascorbic Acid; Catechol Oxidase; Electrophoresis, Polyacrylamide Gel; Enzyme Inhibitors; Glutathione; Kinetics; Mangifera; Molecular Weight; Plant Extracts; Protein Binding; Pyrones; Sodium Dodecyl Sulfate

Ramalin (γ-glutamyl-N'-(2-hydroxyphenyl)hydrazide), a novel compound, was isolated from the methanol-water extract of the Antarctic lichen Ramalina terebrata by several chromatographic methods. The molecular structure of ramalin was determined by spectroscopic analysis. The experimental data showed that ramalin was five times more potent than commercial butylated hydroxyanisole (BHA) in scavenging 1-diphenyl-2-picryl-hydazil (DPPH) free radicals, 27 times more potent in scavenging 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid free radicals (ABTS(+)) than the vitamin E analogue, trolox, and 2.5 times more potent than BHT in reducing Fe(3+) to Fe(2+) ions. Similarly, ramalin was 1.2 times more potent than ascorbic acid in scavenging superoxide radicals and 1.25 times more potent than commercial kojic acid in inhibiting tyrosinase enzyme activity, which ultimately leads to whitening of skin cells. Ramalin showed no or very little cytotoxicity in human keratinocyte and fibroblast cells at its antioxidant concentration. Furthermore, ramalin was assessed to determine its antioxidant activity in vivo. One microgram per milliliter ramalin significantly reduced the released nitric oxide (NO) and 0.125 μg/ml ramalin reduced the produced hydrogen peroxide (H(2)O(2)) in LPS (lipopolysaccharide)-stimulated murine macrophage Raw264.7 cells. Considering all the data together, ramalin can be a strong therapeutic candidate for controlling oxidative stress in cells.

Topics: Animals; Antarctic Regions; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Butylated Hydroxyanisole; Cell Line; Cell Survival; Chromans; Fibroblasts; Free Radicals; Fungal Proteins; Glutamates; Humans; Hydrogen Peroxide; Keratinocytes; Lichens; Mice; Molecular Structure; Monophenol Monooxygenase; Nitric Oxide; Picrates; Pyrones; Sulfonic Acids

We previously found that administration of ascorbic acid (AA) enhances the liver tumor-promoting activity of kojic acid (KA) in mice. To examine the reproducibility of these results in rats and the underlying mechanism of this effect, we employed a two-stage liver carcinogenesis model using male F344 rats. Two weeks after initiation with diethylnitrosamine (DEN), the animals received a diet containing 2% KA and drinking water with or without 5,000 ppm AA for a period of 7 weeks. A DEN-alone group was also established as a control. One week after the commencement of the administration, the animals were subjected to two-thirds partial hepatectomy. At the end of the experiment, the livers were analyzed immunohistochemically, and the mRNA expression level and extent of lipid peroxidation were measured. AA treatment enhanced the KA-induced tumor-promoting activity in terms of the number and area of liver cell foci that were positive for glutathione-S-transferase placental form. AA coadministration increased the number of hepatocytes positive for proliferating cell nuclear antigen and inversely decreased the number of TUNEL-positive cells. However, the increased level of thiobarbituric acid reactive substances resulting from KA treatment was suppressed by coadministration of AA. Gene expression analyses using low-density microarrays and real-time RT-PCR showed that coadministration of AA resulted in upregulation of genes related to cell proliferation and downregulation of those involved in apoptosis and/or cell cycle arrest. These results indicate that the concerted effects of AA on cell proliferation and apoptosis/cell cycle arrest probably through its antioxidant activity are involved in this enhancement.

Topics: Animals; Apoptosis; Ascorbic Acid; Carcinogens; Cell Cycle; Cell Proliferation; Diethylnitrosamine; Drug Synergism; Gene Expression Profiling; Lipid Peroxidation; Liver; Male; Oligonucleotide Array Sequence Analysis; Pyrones; Rats; Rats, Inbred F344; Thiobarbituric Acid Reactive Substances

We have used on-line microdialysis sampling coupled with high-performance liquid chromatography and UV-vis detection to simultaneously determine the contents of ascorbyl glucoside (AA-2G), kojic acid (KA), and niacinamide (VitB(3)) in commercial bleaching cosmetics. Our results indicate that AA-2G, KA, and VitB(3) separated well within 4.5 min on a reverse-phase Hypersil Fluophase PFP column when eluting with 0.020 M phosphate buffer solution in 40% (v/v) methanol at pH 5.5. The calibration curves were linear over the ranges 0.068-304, 0.071-284, and 0.024-488 microg mL(-1) for AA-2G, KA, and VitB(3), respectively, with correlation coefficients for the linear regression analyses falling within the range 0.9982-0.9999. The detection limits for AA-2G, KA, and VitB(3) were 0.01, 0.01, and 0.007 microg mL(-1), respectively. The detection wavelength was robust when the levels of the analytes in the samples were high (0.1-2%). The analytes were all detected using ultraviolet light (254 nm). The compounds diffuse through the membrane more readily when KA and VitB(3) are in their molecular forms and AA-2G is ionized. The recoveries were in the range 92-106% with good reproducibility (R.S.D.=3.9-8.7%). We used this procedure to assay six commercially available bleaching cosmetics; our results confirmed not only the precision of the method but also the claims made on the labels of the cosmetics. This approach provides a very simple means to determine the contents of AA-2G, KA, and VitB(3) in various dosages in bleaching cosmetics.

Topics: Ascorbic Acid; Chromatography, High Pressure Liquid; Cosmetics; Microdialysis; Niacinamide; Online Systems; Pyrones

To examine the tumor modification activity of kojic acid (KA) by sodium ascorbic acid (AA), 5-week-old male ICR mice were administered intraperitoneally with N-diethylnitrosamine (DEN) as an initiation treatment. Two weeks after the initiation treatment, animals were fed basal diet containing 0 (Group 1: DEN alone) or 3% KA (Group 3: DEN+KA), drinking water containing 5,000 ppm AA (Group 2: DEN+AA) or 3% KA and 5,000 ppm AA (Group 4: DEN+KA+AA) for 6 weeks. One week after the administration of KA and/or AA, all mice were subjected to two-thirds partial hepatectomy. At the end of the experimental period, all surviving mice were sacrificed and removed the liver. The liver weights of the Groups 3 and 4 were significantly increased, and the number of proliferating cell nuclear antigen positive hepatocytes and the gene expressions of Ccnc, Ccnd1, Ercc and Cyp7a1 were significantly increased in the Group 4, as compared to the Group 1. These results of the present study suggest that AA enhances the hepatocellular proliferative activity of KA in mice.

Topics: Animals; Antioxidants; Ascorbic Acid; Body Weight; Diethylnitrosamine; Drug Interactions; Immunohistochemistry; Liver; Liver Neoplasms, Experimental; Male; Mice; Mice, Inbred ICR; Oligonucleotide Array Sequence Analysis; Organ Size; Pyrones; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Up-Regulation

Topics: Arbutin; Ascorbic Acid; Chromatography, High Pressure Liquid; Cosmetics; Pyrones

Kinobeon A is produced from cell cultures of the medicinal plant, safflower. Mushroom tyrosinase activity was inhibited in a concentration-dependent manner when treated with kinobeon A using L-tyrosine or L-3,4-dihydroxyphenylalannine (L-DOPA) as substrates. IC50 values were 22 microM (substrate: L-tyrosine) and 27 microM (L-DOPA). Inhibition of human tyrosinase activity also increased with increasing concentrations of kinobeon A using L-DOPA as the substrate, with an IC50 value of 2.5 microM. Kinobeon A was a more potent competitive inhibitor than kojic acid, arbutin or L-ascorbic acid for both mushroom and human tyrosinase as determined from Lineweaver-Burk plots. These results suggested that kinobeon A could be a potent natural tyrosinase inhibitor.

Topics: Agaricales; Alkenes; Arbutin; Ascorbic Acid; Carthamus tinctorius; Dose-Response Relationship, Drug; Humans; Inhibitory Concentration 50; Levodopa; Monophenol Monooxygenase; Peptides; Phytotherapy; Pyrones

To synthesize glycyrrhetinic acid (GA) derivatives (3, 4, 5, 10, 13, 14, 15, and 16), we first removed the ketonic group in the C-11 position, and the carboxylic function at the C-30 position was kept intact, reduced to an alcohol, or transformed to an aldehyde corresponding derivatives 10 and 13. Glycyrrhetinic acid (GA) derivatives (3, 4, 5, 15, and 16) were coupled with 4-amino piperpyridine derivatives (12 and 14) and 4-fluorobenzyl bromide at C-30 carboxylic acid position of glycyrrhetinic acid. In subsequent tyrosinase assays, we found that GA derivatives 4, 5, and 16 were not active at early time points, but strongly inhibited tyrosinase activity at late time points. Of the GA derivatives examined, derivative 5 was most active, with an IC(50) value of 50 microM after 2 h reaction. IC(50) values of derivatives 4 and 16 were 120 and 170 microM, respectively. Further kinetic data indicated that these derivatives are slow-binding inhibitors of tyrosinase. The time-dependent inhibition was reversed when vitamin C or kojic acid was used, that is, both compounds showed active inhibition at early time points. These results suggest that GA derivatives are much more stable than vitamin C or kojic acid, although their intrinsic inhibitory potentials are relatively low. Higher stability and activity suggest that GA derivative 5 might be a useful candidate for skin whitening.

Topics: Agaricales; Ascorbic Acid; Enzyme Activation; Enzyme Inhibitors; Glycyrrhetinic Acid; Kinetics; Molecular Structure; Monophenol Monooxygenase; Pyrones

We have previously reported the oxidation of kojic acid catalyzed by manganese peroxidase (MnP) from Ceriporiopsis subvermispora. This reaction is strictly dependent on Mn(II), although it does not require the addition of hydrogen peroxide. We have extended these studies because this reaction can be considered as a model system for the in situ generation of hydrogen peroxide in natural environments. We show here that oxidation of kojic acid with horseradish peroxidase (HRP) plus hydrogen peroxide or with manganic acetate rendered a product with identical chromatographic and spectral properties as the one obtained in the reaction catalyzed by MnP. The initial lag observed in the latter reaction decreased significantly upon UV irradiation of the substrate. On the other hand, ascorbic acid increased the lag and did not affect the yield of the reaction. The superoxide anion trapping agents glutathione, nitroblue tetrazolium, and superoxide dismutase markedly affected the reaction. In contrast, addition of the hydroxyl radical scavengers mannitol and salicylic acid had no effect. Based on these results, a mechanism for the MnP-catalyzed reaction is proposed.

Topics: Ascorbic Acid; Basidiomycota; Chromatography, High Pressure Liquid; Free Radicals; Horseradish Peroxidase; Hydrogen Peroxide; Manganese; Oxidation-Reduction; Peroxidases; Pyrones; Spectrophotometry, Ultraviolet; Superoxides; Ultraviolet Rays

Kojic acid, a fungal metabolic product, has been used as a skin-depigmenting agent in skin care products marketed in Japan. Iron in the skin is known to be involved in wrinkling as a result of chronic photodamage. Kojic acid was expected to have anti-wrinkling activity, since it possesses iron-chelating activity. We now evaluated the anti-wrinkling activity of kojic acid by using hairless mice exposed to chronic solar-simulating ultraviolet (UV) irradiation as model animal. At the end of a 20-week irradiation period, topical application of kojic acid before UV irradiation was observed to dramatically prevent: (1) the wrinkling, (2) hyperplasia of the epidermis, (3) fibrosis of the lower dermis, and (4) the increase of extracellular matrix components in the upper dermis. These findings indicate that kojic acid is a typical agent preventing wrinkling of the skin due to chronic photodamage.

Topics: Animals; Ascorbic Acid; Dose-Response Relationship, Drug; Edetic Acid; Female; Iron Chelating Agents; Lipid Peroxidation; Malondialdehyde; Mice; Oxidation-Reduction; Oximes; Phenanthrolines; Pyrones; Skin; Skin Aging; Sunscreening Agents; Ultraviolet Rays

The activation of NF-kappaB induced by kojic acid, an inhibitor of tyrosinase for biosynthesis of melanin in melanocytes, was investigated in human transfectant HaCaT and SCC-13 cells. These two keratinocyte cell lines transfected with pNF-kappaB-SEAP-NPT plasmid were used to determine the activation of NF-kappaB. Transfectant cells release the secretory alkaline phosphatase (SEAP) as a transcription reporter in response to the NF-kappaB activity and contain the neomycin phosphotransferase (NPT) gene for the dominant selective marker of geneticin resistance. NF-kappaB activation was measured in the SEAP reporter gene assay using a fluorescence detection method. Kojic acid showed the inhibition of cellular NF-kappaB activity in both human keratinocyte transfectants. It could also downregulate the ultraviolet ray (UVR)-induced activation of NF-kappaB expression in transfectant HaCaT cells. Moreover, the inhibitory activity of kojic acid in transfectant HaCaT cells was found to be more potent than known antioxidants, e.g., vitamin C and N-acetyl-L-cysteine. These results indicate that kojic acid is a potential inhibitor of NF-kappaB activation in human keratinocytes, and suggest the hypothesis that NF-kappaB activation may be involved in kojic acid induced anti-melanogenic effect.

Topics: Acetylcysteine; Ascorbic Acid; Cell Line; Down-Regulation; Free Radical Scavengers; Humans; Indicators and Reagents; Keratinocytes; Melanins; Mycotoxins; NF-kappa B; Pyrones; Transfection; Ultraviolet Rays

Novel hybrid L-ascorbic acid (vitamin C) derivatives with other biologically active substances, 5-hydroxy-2-hydroxymethyl-beta-pyrone (kojic acid) and alpha-tocopherol (vitamin E), linked at the C-2 or C-3 hydroxyl group were synthesized, and their thermal stability and inhibitory effects on tyrosinase activity, active oxygen species (AOS), and free radicals were estimated in vitro. It was found that a hydrophilic derivative, 2-O-(5-hydroxy-4H-pyran-4-one-2-methyl)-L-ascorbic acid (1), exhibited good thermal stability and inhibitory activities against tyrosinase catalyzed melanin formation, AOS, and free radicals compared to vitamin C and its conventional derivatives (such as the 2-phosphate 6-stearate and 2.6-dipalmitate, and 2-O-octadecylascorbic acid), as well as vitamin E, kojic acid, and arbutin. It is apparent that 1 has the biological properties of vitamin C and kojic acid, and acts synergistically. The hydroxyl groups at the C-3 position of the vitamin C moiety and the C-5 position of the kojic acid moiety are critical for the biological activities. We consider that the kojic acid moiety of 1 counterbalances the diminution of the biological activity due to shielding of the biologically important C-2 hydroxyl group of the vitamin C moiety. In addition, the thermal stability was significantly improved relative to not only vitamin C but also kojic acid. Further, a lipophilic derivative, 3-O-[(alpha-tocopheryloxy)-2-hydroxypropyl]-L-ascorbic acid, 2, was far more stable than vitamin C and its typical lipophilic derivatives. Compound 2 exhibited almost the same inhibitory activities against tyrosinase-catalyzed melanin formation, AOS, and free radicals as typical lipophilic derivatives, although these biological activities of 2 were lower than those of vitamin C.

Topics: Ascorbic Acid; Bepridil; Biphenyl Compounds; Free Radicals; Melanins; Monophenol Monooxygenase; Oxidation-Reduction; Photochemistry; Picrates; Pyrones; Reactive Oxygen Species; Superoxides; Temperature; Tyrosine; Vitamin E

Topics: Animals; Ascorbic Acid; Characidae; Hexoses; Ketoses; Pyrones; Tetracycline