arbutin and kojic-acid

Facial hyperpigmented disorders are a common complaint in the adult population of all races. First-line topical treatments are usually hydroquinone or topical retinoids, which can cause irritant reactions. The need for better tolerated, yet effective, skin lightening agents that could be utilized by a wider population has led to the investigation of several potential botanical/natural compounds. There are currently many topical cosmetic formulations claiming skin depigmenting effects. A few of the ingredients (e.g. soy) are supported not only by in vitro results but also by a body of controlled clinical efficacy studies; other ingredients, instead, are backed mostly by in vitro data and a few small uncontrolled clinical studies. In this review, we describe the most common natural ingredients used for skin depigmentation and their major published studies: soy, licorice extracts, kojic acid, arbutin, niacinamide, N-acetylglucosamine, COFFEEBERRY(™) and green tea.

Topics: Administration, Topical; Arbutin; Cosmetics; Glycyrrhiza; Humans; Hyperpigmentation; Plant Extracts; Pyrones; Soybean Proteins

Pigmentary disorders are one of the most common skin disorders among people of color. Dyspigmentation in the form of either hyperpigmentation or hypopigmentation is often psychologically devastating to patients with darker skin. There is marked contrast between normally pigmented hyperpigmented, hypopigmented or depigmented skin in people of color. Despite being common, pigmentary disorders remain difficult to treat.

Topics: Administration, Cutaneous; Arbutin; Black People; Dicarboxylic Acids; Humans; Hydroquinones; Keratolytic Agents; Pigmentation Disorders; Pyrones; Tretinoin

Structured lipids (SLs) are defined as lipids that are modified chemically or enzymatically in order to change their structure. This review deals with structured triacylglycerols (STGs) and structured phospholipids (SPLs). The most typical STGs are MLM-type STGs, having medium chain fatty acids (FAs) at the 1- and 3-positions and a long chain fatty acid at the 2- position. MLM-type STGs are synthesized by: 1) 1,3-position-specific lipase-catalyzed acyl exchange of TG with FA or with FA ethylester (FAEt); 2) 1,3-position-specific lipase-catalyzed acylation of glycerol with FA, giving symmetric 1,3-diacyl-sn-glycerol, followed by chemical acylation at the sn-2 position, and; 3) 1,3-position-specific lipase-catalyzed deacylation of TG, giving 2-monoacylglycerol, followed by reacylation at the 1- and 3-positions with FA or with (FAEt). Enzymatic preparation of SPLs requires: 1) acyl group modification, and 2) head group modification of phospholipids. Acyl group modification is performed using lipases or phospholipase A2-mediated transesterification or ester synthesis to introduce arbitrary fatty acid to phospholipids. Head group modification is carried out by phospholipase D-catalyzed transphosphatidylation. A wide range of compounds can be introduced into the polar head of phospholipids, making it possible to prepare various SPLs.

Topics: Arbutin; Enzymes; Fats; Fatty Acids; Fungi; Lipase; Lipid Metabolism; Lipids; Molecular Structure; N-Acetylneuraminic Acid; Nucleosides; Oils; Phosphatidylserines; Phospholipases; Phospholipids; Pyrones; Triglycerides; Vitamins

Hyperpigmentary disorders like melasma, actinic and senile lentigines are a major cosmetic concern. Therefore, many topical products are available, containing various active ingredients aiming to reduce melanin production and distribution. The most prominent target for inhibitors of hyperpigmentation is tyrosinase, the key regulator of melanin production. Many inhibitors of tyrosinase are described in the literature; however, most of them lack clinical efficacy.. We were interested in evaluating the inhibition of skin pigmentation by well-known compounds with skin-whitening activity like hydroquinone, arbutin, kojic acid and 4-n-butylresorcinol. We compared the inhibition of human tyrosinase activity in a biochemical assay as well as inhibition of melanin production in MelanoDerm skin model culture. For some compounds, the in vivo efficacy was tested in clinical studies.. Arbutin and hydroquinone only weakly inhibit human tyrosinase with a half maximal inhibitory concentration (IC(50)) in the millimolar range. Kojic acid is 10 times more potent with an IC(50) of approximately 500 μmol/L. However, by far the most potent inhibitor of human tyrosinase is 4-n-butylresorcinol with an IC(50) of 21 μmol/L. In artificial skin models, arbutin was least active with an IC(50) for inhibition of melanin production > 5000 μmol/L. Kojic acid inhibited with an IC(50) > 400 μmol/L. Interestingly, hydroquinone inhibited melanin production in MelanoDerms with an IC(50) below 40 μmol/L, probably due to a mechanism different from tyrosinase inhibition. Again, 4-n-butylresorcinol was the most potent inhibitor with an IC(50) of 13.5 μmol/L. In vivo efficacy of 4-n-butyl-resorcinol was confirmed in clinical studies. Subjects with age spots on the forearm treated twice daily two age spots with a formula containing 4-n-butylresorcinol and two control age spots with the corresponding vehicle. Within 8 weeks, 4-n-butylresorcinol reduced visibly the appearance of age spots, while the control spots showed no improvement. A second study showed that 4-butylresorcinol was more effective than 4-hexylresorcinol and 4-phenylethylresorcinol.. The present in vitro and in vivo data prove the high inhibitory capacity of 4-n-butylresorcinol on human tyrosinase activity, exceeding by far the potency of hydroquinone, arbutin and kojic acid. The resulting clinical improvement of skin hyperpigmentations reveals 4-n-butylresorcinol as a very valuable active compound for the management of pigmentation disorders.

Topics: Administration, Topical; Aged; Arbutin; Female; Humans; Hydroquinones; Hyperpigmentation; Melanins; Middle Aged; Monophenol Monooxygenase; Pyrones; Resorcinols; Single-Blind Method; Skin; Skin Lightening Preparations; Tissue Culture Techniques; Treatment Outcome

Hyperpigmentation can be either diffused or localized. In treating diffused hyperpigmentation, larger surface area coverage is the requirement. Novel user-friendly spray formulation loaded with depigmenting agents can cater the night time need in treating skin darkening. Kojic acid and arbutin, the selected actives for the study exhibit low permeability and high irritancy generating hurdles in topical delivery.. The aim of this study was to develop novel kojic acid and arbutin-loaded spray formulation as a night care product.. "Thermosensitive gel spray" was fabricated by simple industry feasible cooling technique and evaluated for its ability to improve skin retention, penetration, improved anti-tyrosinase activity, and suppressed dermal irritancy.. Comparative in-vitro and ex-vivo release profile showed the marked effect of poloxamer 407 and Methocel K100M in improving penetration and extending release over longer time period. Retention of actives in the skin layer was found to be eight times more in case of thermosensitive gel spray as compared to conventional gel formulation. The thermosensitive gel spray was free from any dermal irritancy and had higher tyrosinase inhibitory effect as against conventional gel. Furthermore, thermosensitive gel spray exhibited good stability and did not show any change in morphology and drug content during the 3-month storage.. Kojic acid and arbutin-loaded thermosensitive gel spray can prove to be a promising strategy to treat hyperpigmentation.

Topics: Animals; Arbutin; Chick Embryo; Chorioallantoic Membrane; Cosmeceuticals; Drug Compounding; Drug Liberation; Drug Stability; Gels; Hyperpigmentation; Monophenol Monooxygenase; Photoperiod; Pyrones; Skin; Skin Care; Toxicity Tests

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

Hyperpigmentation is considered by many to be a beauty problem and is responsible for photoaging. To treat this skin condition, medicinal cosmetics containing tyrosinase inhibitors are used, resulting in skin whitening. In this study, taraxerol methyl ether (

Topics: Antioxidants; Arbutin; Cell Line, Tumor; Cell Proliferation; Flavonoids; Humans; Hydroxybenzoates; Manilkara; Monophenol Monooxygenase; Neoplasms; Oleanolic Acid; Phytochemicals; Pyrones; Stigmasterol

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

Recently, paper has gained traction in the biotechnology research field due to its ability to be a substrate for 3D cell culture. In this work, we demonstrate the application of paper-based 3D cell culture for rapid and easy screening of the effect of natural compounds on melanin production. Whatman No. 1 filter paper was used as the substrate for B16F10 melanoma cell culture. The use of paper is beneficial for supporting the 3D structure of cells, which makes the result more reliable due to the similarity to in vivo conditions. Furthermore, paper is beneficial for melanin observation due to melanin's black color, which is easily in situ visualized after it is cultured on white paper. Matrigel was used to encapsulate cells before being pipetted onto the paper to prevent the passing of cells through paper pores. The intensity of melanin can then be observed with the naked eye and analyzed by scanning the paper. The analysis process took only 20 minutes, which is faster than that of the conventional absorbance spectroscopy, owing to the elimination of centrifugation, melanin solubilization, and the absorbance measurement step. The color intensity on the paper showed a direct proportion with increased α-MSH concentrations, confirming that the color on the paper was melanin. The 3D structure of cells was confirmed by using a scanning electron microscope. To demonstrate the application of the paper-based scaffold, paper-based 3D cell culture was used for screening the effects of Kojic acid and Arbutin on melanin production, which showed increased anti-melanogenesis effects with increased concentrations of natural compounds. High cell viability was observed over 120 hours. In conclusion, the developed paper-based scaffold can be used for screening the effect of natural compounds on melanin production, as a rapid and simple method with low cost.

Topics: alpha-MSH; Animals; Arbutin; Cell Culture Techniques; Cell Line, Tumor; Cell Survival; Drug Evaluation, Preclinical; Limit of Detection; Melanins; Mice; Paper; Pyrones

Thalassotalic acids A-C and thalassotalamides A and B are new N-acyl dehydrotyrosine derivatives produced by Thalassotalea sp. PP2-459, a Gram-negative bacterium isolated from a marine bivalve aquaculture facility. The structures were elucidated via a combination of spectroscopic analyses emphasizing two-dimensional NMR and high-resolution mass spectrometric data. Thalassotalic acid A (1) displays in vitro inhibition of the enzyme tyrosinase with an IC50 value (130 μM) that compares favorably to the commercially used control compounds kojic acid (46 μM) and arbutin (100 μM). These are the first natural products reported from a bacterium belonging to the genus Thalassotalea.

Topics: Arbutin; Gram-Negative Bacteria; Marine Biology; Molecular Structure; Monophenol Monooxygenase; Nuclear Magnetic Resonance, Biomolecular; Proteobacteria; Pyrones; Spain; Tyrosine

Twenty aloe-emodin derivatives were designed, synthesized, and their biological activities were evaluated. Some compounds displayed potent tyrosinase inhibitory activities, especially, compounds with thiosemicarbazide moiety showed more potent inhibitory effects than the other compounds. The structure-activity relationships (SARs) were preliminarily discussed. The inhibition mechanism of selected compounds 1 and 13 were investigated. The results showed compound 1 was reversible inhibitor, however, compound 13 was irreversible. Kinetic analysis indicated that compound 1 was competitive tyrosinase inhibitor. Furthermore, the antibacterial activities and anti-inflammatory activities of some selected compounds were also screened. The results showed that compound 3 exhibited more potent antibacterial activity than the aloe-emodin, compounds 5 and 6 possessed more potent anti-inflammatory activities than the diacerein.

Topics: Agaricales; Animals; Anthraquinones; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Emodin; Mice; Monophenol Monooxygenase; Pyrones; Structure-Activity Relationship

Melanin uncontrollable accumulation is a serious social problem to not only women, but also men, and causes pigment over-expression disorders such as freckles, melasma or pigmented acne scars. The synergism is used widely in medication, and the effectiveness makes the drug applications more valuable. Within this experiment, three well-known compounds were chosen: kojic acid, 1-phenyl-2-thiourea (PTU) and arbutin, and they were combined individually with our substance linderanolide B, which is purified from Cinnamomum subavenium. Hence, deciphering the synergistic action of possible whitening agents was the goal of this study. The tyrosinase activity, melanin content, and the combination index (CI) values were observed in B16F10 cells, in addition, the consequences were detected by isobologram analysis. We discovered that certain melanin inhibitors showed synergistic properties when they were combined together to suppress tyrosinase activities. As a result, linderanolide B has a potential synergy on tyrosinase inhibition, and it can be used widely in cosmetic and medication industries.

Topics: 4-Butyrolactone; Animals; Arbutin; Cell Line, Tumor; Drug Synergism; Enzyme Inhibitors; Melanins; Mice; Monophenol Monooxygenase; Phenylthiourea; Pyrones

In recent years, laser toning has gained popularity for the treatment of melasma, and tyrosinase inhibitors are conventionally used to prevent its recurrence after this treatment. The effectiveness of this treatment modality, however, is still questionable, and additional in vivo studies are needed to validate the method. In this study, we used adult zebrafish skin as an adult melanocyte regenerative system and examined the simulated human skin response to laser toning. Melanosomes regenerated after selective photothermolysis, and these organelles showed a bi-directional translocation pattern in accordance with the changes of intact melanosome patterns. Furthermore, a tyrosinase inhibitor, 1-phenyl-2-thiourea (PTU), completely blocked melanosome regeneration after laser irradiation, but this inhibitor failed to prevent melanosome regeneration after the medication was discontinued. Finally, arbutin and kojic acid, the commercially available tyrosinase inhibitors, slowed down but did not completely block melanosome regeneration. Based on these findings, we describe the limitations of laser toning treatment of melasma and the combined use of tyrosinase inhibitors. We suggest that melanosomes in adult zebrafish skin can be utilized for studying melanosome regeneration response to laser irradiation and for developing a system to assess the comparative efficacy of melanogenic regulatory compounds.

Topics: Animals; Arbutin; Humans; Lasers, Solid-State; Melanocytes; Melanosis; Melanosomes; Models, Animal; Monophenol Monooxygenase; Phenylthiourea; Pyrones; Regeneration; Skin; Skin Pigmentation; Statistics, Nonparametric; Zebrafish

Tyrosinase (TYR) catalyzes rate-limiting steps of melanogenesis and thus its inhibitors are potentially useful as hypopigmenting agents. Recently, p-coumaric acid (p-CA) has been suggested to interfere with the pro-melanogenic actions of tyrosine due to its structural similarity with tyrosine (An SM et al., Br J Dermatol 2008. 159: 292). In this study, we compared the inhibitory effects of p-CA and two other well known TYR inhibitors used in cosmetics--arbutin and kojic acid--on the catalytic activities of mushroom, murine and human TYRs in vitro, using tyrosine and 3,4-dihydroxyphenylalanine (DOPA) as substrates. The results showed that p-CA is a weaker inhibitor of mushroom TYR but much stronger inhibitor of human or murine TYR in comparison with kojic acid and arbutin. In addition, p-CA inhibited human TYR at much lower concentrations than those required for the inhibition of murine or mushroom TYRs. Enzyme kinetics analysis indicated that p-CA is a mixed type (for tyrosine) or competitive inhibitor (for DOPA) of human TYR. Potent antimelanogenic effects of p-CA were observed in human epidermal melanocytes exposed to UVB. The present study demonstrated that p-CA is a potent and selective inhibitor of human TYR and is potentially useful as a hypopigmenting agent.

Topics: Agaricales; Animals; Arbutin; Cells, Cultured; Coumaric Acids; Dihydroxyphenylalanine; Epidermal Cells; Humans; Melanocytes; Melanoma, Experimental; Mice; Molecular Structure; Monophenol Monooxygenase; Pigmentation; Propionates; Pyrones; Tyrosine; Ultraviolet Rays

Arbutus andrachne L. is widely distributed in Jordan. Tyrosinase is the key enzyme in the biosynthesis of melanin. This preliminary study was carried out to assess the possible anti-tyrosinase activity of A. andrachne extracts. Arbutin, hydroquinone and kojic acid were selected as inhibitor standards. Five different extracts (chloroform, butanol, ethanol, methanol and water) were prepared from A. andrachne stems and their activities were compared with the selected tyrosinase inhibitors. IC(50) was measured for both, standard and plant extracts. Among the different extracts, the methanolic extract exhibited the highest anttyrosinase activity with an IC(50) value (1 mg mL(-1)). Furthermore, 9 mg A. andrachne methanolic extract showed 97.49% inhibition of tyrosinase activity. Arbutin, hydroquinone, beta-sitosterol and ursolic acid were identified in the different extracts of A. andrachne by thin layer chromatography (TLC) and isolated by preparative TLC from the methanolic and chloroform stem extracts, respectively.

Topics: Arbutin; Ericaceae; Hydroquinones; Inhibitory Concentration 50; Peptides; Plant Extracts; Plant Stems; Pyrones; Tyrosine

A tyrosinase inhibitor was isolated from the sprout of Polygonum hydropiper L. (Benitade) by activity-guided fractionation and identified as (2R,3R)-+-taxifolin (1) by spectroscopic means. Compound 1 inhibited 70% of tyrosinase activity at a concentration of 0.50 mM. ID50 (50% inhibition dose) value of compound 1 was 0.24 mM. As compared with tyrosinase inhibitor known cosmetic agent such as arbutin and kojic acid, compound 1 was more inhibited than the former and showed inhibitory effect equal to that of the latter. To study the inhibitory effect of (2R,3R)-+-taxifolin derivatives against tyrosinase activity, 3,7,3',4'-taxifolin tetraacetate (2) and 5,7,3',4'-taxifolin teramethyl ether (3) were also assayed together with compound 1.

Topics: Arbutin; Chemical Fractionation; Enzyme Inhibitors; Flavonols; Magnetic Resonance Spectroscopy; Molecular Structure; Monophenol Monooxygenase; Plant Shoots; Polygonum; Pyrones; Quercetin; Spectrometry, Mass, Electrospray Ionization

A statistical experimental design was used to optimize one micellar electrokinetic capillary electrophoresis (MEKC) for simultaneous analysis of arbutin (AR), kojic acid (KA) and hydroquinone (HQ). Untreated fused-silica capillaries were operated using a phosphate buffer (20mM, pH 6.5) under 20 kV and detection at 200 nm. Quantitative linear ranges were 20-200 microg/ml for AR, 20-100 microg/ml for KA and 8-80 microg/ml for HQ with correlation coefficients >or=0.9994. R.S.D. and R.E. were less than 3.0% for the intra-day and inter-day analysis, and all recoveries were greater than 99%. Our method was applied to assay commercial cosmetics. The results were within the labeled amount of 99.6-102.5%.

Topics: Arbutin; Buffers; Cosmetics; Electrophoresis, Capillary; Hydrogen-Ion Concentration; Hydroquinones; Phosphates; Pyrones; Reference Standards; Regression Analysis; Reproducibility of Results; Research Design; Urea; Water

Although many hypo-pigmenting agents are currently available, the demand for novel whitening agents is increasing, in part due to the weak effectiveness and unwanted side effects of currently available compounds. To screen for novel hypo-pigmenting agents, many methodologies such as cell culture and enzymatic assays are routinely used. However, these models have disadvantages in terms of physiological and economic relevance. In this study, we validated zebrafish as a whole-animal model for phenotype-based screening of melanogenic inhibitors or stimulators. We used both the well-known melanogenic inhibitors (1-phenyl-2-thiourea, arbutin, kojic acid, 2-mercaptobenzothiazole) and newly developed small molecule compounds (haginin, YT16i). All the tested compounds produced inhibitory effects on the pigmentation of zebrafish, most likely due to their inhibitory potential on tyrosinase activity. In simultaneous in vivo toxicity tests, a newly developed melanogenic inhibitor YT16i showed massive abnormalities in terms of deformed morphologies and cardiac function. Together, these results provide a rationale in screening and evaluating the putative melanogenic regulatory compounds. We suggest that the zebrafish system is a novel alternative to mammalian models, with several advantages including the rapidity, cost-effectiveness, and physiological relevance.

Topics: Animals; Antioxidants; Arbutin; Benzimidazoles; Drug Evaluation, Preclinical; Embryo, Nonmammalian; Melanins; Models, Animal; Models, Biological; Monophenol Monooxygenase; Phenotype; Pigmentation; Pyrones; Zebrafish

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

Exposure of skin cells, particularly keratinocytes to various nuclear factor-kappaB (NF-kappaB) activators (e.g. tumor necrosis factor-alpha, interleukin-1, lipopolysaccharides, and ultraviolet light) leads to phosphorylation and degradation of the inhibitory protein, IkappaB. Liberated NF-kappaB is translocated into the nucleus where it can change or alter expression of target genes, resulting in the secretion of extracellular signaling molecules including melanotrophic factors affecting melanocyte.. In order to demonstrate the possible role of NF-kappaB activation on the synthesis of melanotrophic factors from the keratinocytes, the activities of NF-kappaB induced by melanogenic inhibitors (MIs) were determined in human HaCaT keratinocytes transfected with pNF-kappaB-SEAP-NPT plasmid. Transfectant cells released 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 selection marker for geneticin resistance.. MIs such as niacinamide, kojic acid, hydroquinone, resorcinol, arbutin, and glycolic acid were preincubated with transfectant HaCaT cells for 3 h and then ultraviolet B (UVB) was irradiated. NF-kappaB activation was measured with the SEAP reporter gene assay using a fluorescence detection method.. Of the MIs tested, kojic acid (IC(50)=60 microM) was found to be the most potent inhibitor of UVB-upregulating NF-kappaB activation in transfectant HaCaT cells, which is followed by niacinamide (IC(50)=540 microM). Pretreatment of the transfectant HaCaT cells with the MIs, especially kojic acid and niacinamide, effectively lowered NF-kappaB binding measured by electrophoretic mobility shift assay. Furthermore, these two inhibitors remarkably reduced the secretion level of IL-6, one of melanotrophic factors, triggered by UV-radiation of the HaCaT cells.. These observations suggest that MIs working at the in vivo level might act partially through the modulation of the synthesis of melanotrophic factors in keratinocyte.

Topics: Arbutin; Cell Line; Glycolates; Humans; Hydroquinones; Keratinocytes; NF-kappa B; Niacinamide; Pyrones; Recombinant Proteins; Resorcinols; Transfection; Ultraviolet Rays

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

This study was conducted to evaluate the effects of the prenylated flavonol artocarpin from the heartwood of Artocarpus incisus on ultraviolet (UV)-induced hyperpigmentation of guinea pig skin. An efficient lightening effect was observed following topical application of artocarpin to UV-stimulated hyperpigmented dorsal skins of brownish guinea pigs.

Topics: Animals; Arbutin; Carrier Proteins; Guinea Pigs; Lectins; Male; Mannose-Binding Lectins; Melanins; Molecular Structure; Monophenol Monooxygenase; Moraceae; Plant Lectins; Pyrones; Skin Pigmentation; Ultraviolet Rays

Many melanocyte or skin equivalent models have been used to evaluate the potential efficacy of melanogenic compounds to regulate pigmentation, but there has been great variation in results, partially stemming from the use of different cell lines and diverse conditions for the melanogenic assays. In an earlier report, we optimized a microtiter format assay system to screen potential bioactive compounds using immortalized melan-a melanocytes. That assay system, termed the STOPR protocol, allowed effects on melanocyte proliferation and differentiation to be assessed in a highly sensitive, reproducible, and cost-effective manner. However, in the skin and hair, melanocytes interact with keratinocytes, fibroblasts, and other cell types, and testing of putative bioactive compounds on melanocytes alone in culture does not allow one to observe the interactions with those other cell types, such as would occur in vivo. Therefore, we developed a melanocyte-keratinocyte coculture protocol that allows testing of compounds for potential effects on pigmentation in a more physiologically relevant context. It is a sensitive, reproducible, and reliable model for testing melanogenic regulators, and we have standardized it with known melanogenic inhibitors (hydroquinone, arbutin, kojic acid, and niacinamide) and stimulators (alpha-melanocyte-stimulating hormone, 8-methoxypsoralen, and 3,4-dihydroxyphenylalanine). This coculture system allows for large-scale screening of candidate compounds in conjunction with the STOPR protocol and provides a more physiologically relevant system to study melanocyte-keratinocyte interactions and to elucidate the regulatory mechanisms of melanogenic compounds.

Topics: Animals; Arbutin; Coculture Techniques; Dihydroxyphenylalanine; Hydroquinones; Keratinocytes; Melanocyte-Stimulating Hormones; Melanocytes; Mice; Models, Biological; Monophenol Monooxygenase; Niacinamide; Pigmentation; Pyrones

Varied effects of chemical or biological compounds on mammalian pigmentation have been reported by many groups, but to date, no standardized method has established necessary and/or optimal parameters for testing such agents. A standardized method has been developed to screen compounds with potential effects on pigmentation. The protocol comprises basic parameters to analyze melanogenic effects and allows for further characterization of candidate compounds, providing important insights into their mechanism of action. In this protocol (termed STOPR, for standardized testing of pigmentation regulators), compounds are initially screened using purified tyrosinase and are then tested on melanocytes in culture. After treatment of melanocytes with potentially bioactive compounds, cell proliferation and viability, total melanin accumulated, and melanogenic potential are measured. This protocol is an important first step in characterizing chemical regulation of effects on melanogenesis. When bioactive candidate compounds are identified, testing may proceed for pharmacological or otherwise commercial applications in coculture and/or organ culture models followed by in vivo testing. As an application of this method, results for compounds known to stimulate and/or inhibit melanogenesis (including arbutin, hydroquinone, kojic acid, melanocyte-stimulating hormone, and thymidine dimers) as well as some commercial skin whiteners are reported.

Topics: Animals; Arbutin; Cell Division; Cell Line; Cell Survival; Drug Evaluation, Preclinical; Enzyme Activation; Enzyme Inhibitors; Hydroquinones; Melanins; Melanocyte-Stimulating Hormones; Melanocytes; Mice; Monophenol Monooxygenase; Niacinamide; Pyrimidine Dimers; Pyrones; Skin Pigmentation

Normal human melanocytes were amplified and cultured in a new defined culture medium without phorbol esters or cholera toxin. The medium decreased considerably the doubling time and increased the possible passage number. Melanocytes were co-seeded with normal human keratinocytes into 24 well culture dishes to screen potentially active modulators of melanogenesis. For the assay, the co-cultures were exposed to the compounds under investigation in the presence of 14C-thiouracil and 3H-leucine. Control cultures contain L-tyrosine or kojic acid, modulators which served as internal calibration standards. Changes in the rate of melanin synthesis were measured on the basis of 14C-thiouracil incorporation into newly synthesized melanin. A reduction or increase in 3H-leucine incorporation was taken as an indication of cytotoxicity or induction of proliferation, respectively. The NHK-NHM co-culture screening assay provides a useful tool to compare the activity of known modulators of melanogenesis and to perform structure-activity studies with newly identified modulators to improve their activity. The efficacy of particularly interesting new compounds was further evaluated on reconstructed pigmented epidermis after repeated topical application. The same model was used to assess the anti-pigmenting effect of sunscreens on UV-induced pigmentation. Integration of melanocytes from different ethnic origin resulted in pigmented epidermis reflecting different skin phenotypes, Caucasian, Asian and African.

Topics: 1-Methyl-3-isobutylxanthine; 3T3 Cells; Animals; Arbutin; Asian People; Benzofurans; Black People; Cells, Cultured; Coculture Techniques; Culture Media; Epidermal Cells; Ethnicity; Humans; Hydroquinones; Hydroxybenzoates; Indoles; Keratinocytes; Melanins; Melanocytes; Mice; Phenotype; Pyrones; Skin Pigmentation; Skin, Artificial; Theophylline; Thiophenes; Ultraviolet Rays; White People

We assessed the effects of arbutin on the pigmentation of cultured normal human melanocytes. As indicated by a cell-blotting assay, arbutin at concentrations in the range of 0.5-8 mM increased the pigmentation of the cultured melanocytes, while kojic acid at concentrations in the range of 0.5-4 mM decreased the pigmentation. The pigmentation-augmenting effect of arbutin was further confirmed by the results of a cell-pelleting assay, the traditional method of assessment. Treatment of the cells with arbutin increased the melanin content of the cells and the protein content as well. On the other hand, the tyrosinase activity in the cells was reduced by arbutin treatment. The levels of transcription of tyrosinase and tyrosinase related protein-1 genes were not affected by arbutin treatment as indicated by a semi-quantitative reverse transcription-polymerase chain reaction assay. These results demonstrate that arbutin promotes an increase in pigmentation of cultured human melanocytes that is not mediated by augmented tyrosinase activity.

Topics: Arbutin; Cell Division; Cells, Cultured; Dose-Response Relationship, Drug; Humans; Infant, Newborn; Melanins; Melanocytes; Membrane Glycoproteins; Monophenol Monooxygenase; Oxidoreductases; Pigmentation; Proteins; Pyrones

Neoagarobiose, a disaccharide, showed a higher hygroscopic ability than glycerol or hyaluronic acid, typical moisturizing reagents. Beside, neoagarobiose whitened B16 murine melanoma cells, and showed low cytotoxicity. Therefore neoagarobiose was a rare reagent showing both moisturizing and whitening effects.

Topics: Animals; Arbutin; Disaccharides; Melanoma; Mice; Pyrones; Skin Care; Tumor Cells, Cultured; Wettability