Fermented Rice Bran Downregulates MITF Expression and Leads to Inhibition of α-MSH-Induced Melanogenesis in B16F1 Melanoma

Rice (Oryza sativa) Stem Cells as a Novel Promising Active Ingredient with Anti-Proliferative Effects for Potential Skin Cancer Prevention and Skin Whitening Activity

Rice is one of the plants proven to possess antioxidant, anti-inflammatory, anti-proliferative, and whitening properties, making it one of the most beneficial plants in this regard. This study aimed to introduce a novel natural cosmetic and pharmaceutical product based on rice callus as a source of active ingredients that can inhibit skin melanoma cell (B16F10) proliferation and brighten the skin. The 2,4-D hormone at concentrations of 1 µg/mL and 1.5 µg/mL was used to induce rice callus formation. Rice callus extracts were then prepared using aqueous and ethanolic solvents, with a concentration of 1 mg/mL used for characterization tests. To determine the optimal hormone concentration, the phenols/flavonoids, antioxidant activity, proteins, and carbohydrates in the extracts were measured. The optimal concentration of the hormone was found to be 1 µg/mL. Finally, the anti-melanocyte and skin-whitening activity of the extracts was assessed through measurements of their cytotoxicity and inhibition of melanin synthesis-related enzymes. Cellular cytotoxicity measurements revealed that the ethanolic extract induced more cytotoxicity than the aqueous extract, with IC50 values of 566.3 µg/mL for the ethanolic extract and 1327 µg/mL for the aqueous extract. Skin-whitening-related tests demonstrated that the extracts were 1.7 times more effective than arbutin in inhibiting factors that cause hyperpigmentation. The aqueous extract achieved 85% inhibition of melanin biosynthesis at a concentration of 3200 µg/mL, compared to 68% for the ethanolic extract and 50% for arbutin. Based on these findings, rice callus extract can be introduced as a new, effective substance for skin-lightening and anti-melanocyte products in cosmeceutical and pharmaceutical formulations.

Study on the Skincare Effects of Red Rice Fermented by Aspergillus oryzae In Vitro

Red rice, a variety of pigmented grain, serves dual purposes as both a food and medicinal resource. In recent years, we have witnessed an increasing interest in the dermatological benefits of fermented rice extracts, particularly their whitening and hydrating effects. However, data on the skincare advantages derived from fermenting red rice with Aspergillus oryzae remain sparse. This study utilized red rice as a substrate for fermentation by Aspergillus oryzae, producing a substance known as red rice Aspergillus oryzae fermentation (RRFA). We conducted a preliminary analysis of RRFA's composition followed by an evaluation of its skincare potential through various in vitro tests. Our objective was to develop a safe and highly effective skincare component for potential cosmetic applications. RRFA's constituents were assessed using high-performance liquid chromatography (HPLC), Kjeldahl nitrogen determination, the phenol-sulfuric acid method, and enzyme-linked immunosorbent assay (ELISA). We employed human dermal fibroblasts (FB) to assess RRFA's anti-aging and antioxidative properties, immortalized keratinocytes (HaCaT cells) and 3D epidermal models to examine its moisturizing and reparative capabilities, and human primary melanocytes (MCs) to study its effects on skin lightening. Our findings revealed that RRFA encompasses several bioactive compounds beneficial for skin health. RRFA can significantly promote the proliferation of FB cells. And it markedly enhances the mRNA expression of ECM-related anti-aging genes and reduces reactive oxygen species production. Furthermore, RRFA significantly boosts the expression of Aquaporin 3 (AQP3), Filaggrin (FLG), and Hyaluronan Synthase 1 (HAS1) mRNA, alongside elevating moisture levels in a 3D epidermal model. Increases were also observed in the mRNA expression of Claudin 1 (CLDN1), Involucrin (IVL), and Zonula Occludens-1 (ZO-1) in keratinocytes. Additionally, RRFA demonstrated an inhibitory effect on melanin synthesis. Collectively, RRFA contains diverse ingredients which are beneficial for skin health and showcases multifaceted skincare effects in terms of anti-aging, antioxidant, moisturizing, repairing, and whitening capabilities in vitro, highlighting its potential for future cosmetic applications.

Inhibitory Effects of Fermented Sprouted Oat Extracts on Oxidative Stress and Melanin Overproduction

Hyperpigmentation occurs due to irregular secretion of melanin pigment in the skin. This can affect quality of life depending on its severity, so prevention and management are essential. Oats (Avena sativa L.), a grain consumed worldwide, are known to offer improved health benefits upon germination and fermentation. This study is aimed to investigate the protective effects of lactobacilli-fermented sprouted oat extracts on oxidative stress and melanin overproduction in vitro. The anti-melanogenic effect was investigated using melanin content and tyrosinase activity assays in B16F10 cells, as well as a mushroom tyrosinase-based enzyme inhibition assay. The results showed that L. casei-fermented oat extracts were the most effective for reducing melanin formation by reducing the mRNA expression of microphthalmia-associated transcription factor, tyrosinase, and tyrosinase-related protein 2. Furthermore, L. casei fermentation was effective in improving the total phenolic, flavonoid, and avenanthramide A contents of sprouted oat extracts. The results also demonstrated the antioxidant effects of L. casei-fermented sprouted oat extracts in promoting DPPH radical-scavenging activity, superoxide dismutase-like activity, and reduction in reactive oxygen species levels. Overall, the findings indicate that fermented sprouted oat extracts are promising candidates for antioxidant and anti-hyperpigmentation treatments.

Targeting Tyrosinase in Hyperpigmentation: Current Status, Limitations and Future Promises

Hyperpigmentation is a common and distressing dermatologic condition. Since tyrosinase (TYR) plays an essential role in melanogenesis, its inhibition is considered a logical approach along with other therapeutic methods to prevent the accumulation of melanin in the skin. Thus, TYR inhibitors are a tempting target as the medicinal and cosmetic active agents of hyperpigmentation disorder. Among TYR inhibitors, hydroquinone is a traditional lightening agent that is commonly used in clinical practice. However, despite good efficacy, prolonged use of hydroquinone is associated with side effects. To overcome these shortcomings, new approaches in targeting TYR and treating hyperpigmentation are desperately requiredessentialneeded. In line with this purpose, several non-hydroquinone lightening agents have been developed and suggested as hydroquinone alternatives. In addition to traditional approaches, nanomedicine and nanotheranostic platforms have been recently proposed in the treatment of hyperpigmentation. In this review, we discuss the available strategies for the management of hyperpigmentation with a focus on TYR inhibition. In addition, alternative treatment options to hydroquinone are discussed. Finally, we present nano-based strategies to improve the therapeutic effect of drugs prescribed to patients with skin disorders.

Dermatological uses of rice products: Trend or true?

BACKGROUND

Rice has been used for cosmetic purposes for centuries and its benefits have been translated into modern-day skin careproducts.

METHODS

Pubmed and google were searched with the terms "skin care" and "cosmetics" in conjunction with the words "rice", "rice bran", and "fermented rice bran". Resulting articles were analysed for potential benefits of ingredients contained within rice for skin care and summarised.

RESULTS

Individual components of rice have been identified including phenolic compounds, betaine, squalene, tricin, and rice bran. These rice-derived ingredients have been found to be antiaging, anti-inflammatory, whitening, photoprotective, and moisturizing. Moreover, rice-derived ingredients have demonstrated benefits for dermatological conditions. Rice bran ash extract increases melanin synthesis and offers protection from radiation and skin injury. Fermented rice bran extract and rice bran broth baths have shown utility in atopic dermatitis treatments. Literature suggests that rice-derived ingredients are also safe, non-irritating, and hypoallergenic.

CONCLUSION

Ingredients isolated from rice and its components have wide potential for use in skin care and cosmetic products.

The Inhibitory Effect of Polyphenon 60 from Green Tea on Melanin and Tyrosinase in Zebrafish and A375 Human Melanoma Cells

Polyphenon 60 (PP60) from green tea has long been used as an antioxidant, anticancer, antimicrobial, and antimutagenic. Aim of the Study. To investigate tyrosinase inhibition-related kinetic mechanism and antimelanogenesis potential of PP60. Materials and Methods. The effect of PP60 on melanin and tyrosinase was evaluated in A375 melanoma cells and zebrafish embryos. The melanoma cells were treated with 20, 40, and 60 µg/mL of PP60, and tyrosinase expression was induced by using L-DOPA. The western blot method was used for the evaluation of tyrosinase expression. Cell lysates were prepared from treated and untreated cells for cellular tyrosinase and melanin quantification. Furthermore, zebrafish embryos were treated with 20, 40, and 60 µg/mL of PP60 and reference drug kojic acid for determination of depigmentation and melanin quantification. In vitro assays were also performed to examine the impact of PP60 on mushroom tyrosinase activity. To determine cytotoxicity, MTT was used against melanoma cell line A375. Results. PP60 showed good tyrosinase inhibitory activity with an IC50 value of 0.697 ± 0.021 µg/mL as compared to kojic acid a reference drug with an IC50 value of 2.486 ± 0.085 µg/mL. Kinetic analysis revealed its mixed type of inhibition against mushroom tyrosinase. In addition, western blot analysis showed that at 60 µg/mL dose of PP60 significantly reduced L-DOPA-induced tyrosinase expression in melanoma cells. PP60 significantly inhibits the cellular tyrosinase (p < 0.05) and reduces the melanin (p < 0.05) contents of melanoma cells. Furthermore, PP60 was found to be very potent in significantly reducing the zebrafish embryos' pigmentation (p < 0.05) and melanin (p < 0.05) content at the dose of 60 µg/mL. Conclusions. Our results demonstrate that PP60 has a strong potency to reduce pigmentation. It may be useful for the cosmetic industries to develop skin whitening agents with minimal toxic effects.

Enhanced Anti-Melanogenic Effect of Adlay Bran Fermented with Lactobacillus brevis MJM60390

Fermentation is a traditional technique used to increase nutrients, flavonoids, vitamins, minerals, and the flavor of raw materials. In this study, adlay bran was fermented by Lactobacillus brevis MJM60390 (FAB), and the anti-melanogenic effect was investigated. The results demonstrated that FAB significantly suppressed melanin accumulation in mouse melanogenic B16F10 cells, and the activity was higher than non-fermented adlay bran (NFAB). The molecular mechanism study showed that FAB inhibited melanin synthesis by suppressing the gene expression of melanocortin 1 receptor (Mc1r), melanocyte-inducing transcription factor (Mitf), tyrosinase (Tyr), tyrosinase-related protein-1 (Trp-1), and tyrosinase-related protein-2 (Trp-2) genes. Western blotting analysis showed that FAB strongly decreased the expression of Tyr, Trp-1, and Trp-2 compared to NFAB. Furthermore, phenolic compounds such as gallic acid, p-coumaric acid, ferulic acid, and sinapic acid, which are known for their anti-melanogenic effects, were significantly increased in FAB compared with NFAB. These findings suggest that FAB holds great potential as an anti-melanogenic agent and can be used for the development of whitening cosmetics.

Enhanced Antioxidant, Antiviral, and Anticancer Activities of the Extract of Fermented Egyptian Rice Bran Complexed with Hydroxypropyl-β-cyclodextrin

Egyptian rice bran was fermented with baker's yeast, and released phenolics were extracted with aqueous methanol to give fermented rice bran extract (FRBE). The analysis of the FRBE with ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry revealed 21 compounds, mainly phenolic acids and flavonoids. The FRBE was then complexed with (2-hydroxypropyl)-β-cyclodextrin (HPβCD) via noncovalent host-guest inclusion complexation using the thin-film hydration technique to improve the hydrophilicity and bioactivity of the FRBE. The formation of the inclusion complex was confirmed using HPLC, ¹H NMR, FT-IR, and a phase solubility study. In addition, the biological activities of the complex were investigated. The FRBE/HPβCD inclusion complex had more pronounced antioxidant, antiviral, and anticancer activities compared to free FRBE. These findings warrant the future investigation of potential medical applications of FRBE.

Pediococcus Pentosaceus from the Sweet Potato Fermented Ger-Minated Brown Rice Can Inhibit Type I Hypersensitivity in RBL-2H3 Cell and BALB/c Mice Models

In this study, the effect of GBR fermented with the Pediococcus pentosaceus SP024 strain on IgE/Ag mediated passive cutaneous anaphylaxis (PCA) was investigated. Protocatechuic acid and trans-ferulic acid levels in GBR-SP024 increased more than those in unfermented GBR, respec-tively. The inhibitory activity of GBR-SP024 on β-hexosaminidase release and the level of proin-flammatory cytokine mRNA expression (tumor necrosis factor-α (TNF-α) and interleukin 4 (IL-4)) was observed in IgE/Ag-stimulated RBL-2H3 cells. Western blot analysis showed that GBR-SP024 significantly inhibited the phosphorylation of the linker for activation of T cell (LAT) and nuclear factor-κB (NF-κB) in IgE/Ag-stimulated RBL-2H3 cells. Further, we investigated the anti-allergic effect of GBR-SP024 using PCA murine model. The number of infiltrated immune cells and degranulated mast cells in GBR-SP024 treated dermis was lower than that in the GBR-treated mice. In addition, mRNA expression of 5-lipoxygenase (5-LOX) in the dermis of ear tissue declined in the GBR-SP024–treated group, compared to that in the GBR group. GBR-SP024 was also more effective than GBR at reducing the levels of IL-33 protein expression in IgE/Ag-stimulated BALB/c mice. Our study suggests the potential usage of GBR-SP024 as a dietary supplement or an adjuvant for treating IgE-dependent-allergic diseases.

Antioxidant and Antimelanogenic Activities of Kimchi-Derived Limosilactobacillus fermentum JNU532 in B16F10 Melanoma Cells

Melanin is a natural skin pigment produced by specialized cells called melanocytes via a multistage biochemical pathway known as melanogenesis, involving the oxidation and polymerization of tyrosine. Melanogenesis is initiated upon exposure to ultraviolet (UV) radiation, causing the skin to darken, which protects skin cells from UVB radiation damage. However, the abnormal accumulation of melanin may lead to the development of certain skin diseases, including skin cancer. In this study, the antioxidant and antimelanogenic activities of the cell-free supernatant (CFS) of twenty strains were evaluated. Based on the results of 60% 2,2-diphenyl-1-picrylhydrazyl scavenging activity, 21% 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) scavenging capacity, and a 50% ascorbic acid equivalent ferric reducing antioxidant power value, Limosilactobacillus fermentum JNU532 was selected as the strain with the highest antioxidant potential. No cytotoxicity was observed in cells treated with the CFS of L. fermentum JNU532. Tyrosinase activity was reduced by 16.7% in CFStreated B16F10 cells (but not in the cell-free system), with >23.2% reduction in melanin content upon treatment with the L. fermentum JNU532-derived CFS. The inhibitory effect of the L. fermentum JNU532-derived CFS on B16F10 cell melanogenesis pathways was investigated using quantitative reverse transcription polymerase chain reaction and western blotting. The inhibitory effects of the L. fermentum JNU532-derived CFS were mediated by inhibiting the transcription of TYR, TRP-1, TRP-2, and MITF and the protein expression of TYR, TRP-1, TRP-2, and MITF. Therefore, L. fermentum JNU532 may be considered a potentially useful, natural depigmentation agent.

Boolean model for melanogenesis

Melanogenesis is a highly regulated process through which the pigment melanin is produced in skin cells. Irregularities in the molecular events that govern the process of skin pigmentation can cause disorders like vitiligo. In order to understand the biology of disease progression, it is important to have an in depth understanding of intracellular events. Mathematical models provide an integrated view of intracellular signalling. There are very few models to date that incorporate intracellular processes relevant to melanogenesis and only one to our knowledge that simulates the dynamics of response to varying levels of input. Here, we report the formulation of the largest Boolean model (265 nodes) for melanogenesis to date. The model was built on the basis of a detailed interaction network graph published by Raghunath et al. Through additional manual curation of the reported interactions, we converted the graph into a set of Boolean rules, following the procedure of the first Boolean model (62 nodes) for melanogenesis published by Lee et al. Simulations show that the predicted response to varying UV levels for most of the nodes is similar to the predictions of the existing model. The greater complexity allows investigation of the sensitivity of melanin to additional nodes. We carried out perturbation analysis of the network through node deletion and constitutive activation to identify sensitivity of outcomes, and compared the nodes identified as sensitive to previous reports.

Spermidine promotes melanin production through an MITF signalling pathway

Melanin plays an important role in determining skin colour. Apoptosis of melanocytes and defect in melanin production cause vitiligo. Various studies have been conducted to treat the disease, but its treatment is still difficult. Therefore, this study aimed to investigate the effect of spermidine, which is known as an inhibitor of ageing-related oxidized proteins, on melanogenesis. Even though spermidine above 50 μM had no effect on antioxidant activity and DOPA oxidation, it displayed tyrosinase activity. However, spermidine at 2000 μM was cytotoxic in B16F1 cells using MTT assay. Spermidine above 125 μM decreased the amount of intracellular hydrogen peroxide in a concentration-dependent manner in DCFH-DA analysis. It was also found that spermidine above 2000 μM increased melanin synthesis in living cells. However, spermidine above 1000 μM increased melanin synthesis in a concentration-dependent manner in H₂ O₂ -treated B16F1 cells. Furthermore, spermidine enhanced the expression of tyrosine hydroxylase via MITF transcription factor involved in melanogenesis in H₂ O₂ -treated B16F1 cells. Therefore, these results suggest that spermidine could be applied as a potential stimulator of melanin synthesis for the prevention of hair greying.

Viability and Antioxidant Effects of Traditional Cooling Rice Powder (bedak sejuk) Made from Oryza sativa ssp. Indica and Oryza sativa ssp. japonica on UVB-Induced B164A5 Melanoma Cells

BACKGROUND

Traditional cooling rice powder (bedak sejuk) is a fermented rice-based cosmetic that is applied topically on one's skin, as an overnight facial mask. According to user testimonies, bedak sejuk beautifies and whitens skin, whereby these benefits could be utilised as a potential melanoma chemopreventive agent.

OBJECTIVE

Hence, this study aimed to determine the effects of bedak sejuk made from Oryza sativa ssp. indica (Indica) and Oryza sativa ssp. japonica (Japonica) on UVB-induced B164A5 melanoma cells, and also identify the antioxidant capacities of both types of bedak sejuk.

METHODS

The optimum dose of Indica and Japonica bedak sejuk to treat the cells was determined via the MTT assay. Then, the antioxidant capacities of both types of bedak sejuk were determined using the FRAP assay.

RESULTS

From the MTT assay, it was found that Indica and Japonica bedak sejuk showed no cytotoxic effects towards the cells. Hence, no IC50 can be obtained and two of the higher doses, 50 and 100 g/L were chosen for treatment. In the FRAP assay, Indica bedak sejuk at 50 and 100 g/L showed FRAP values of 0.003 ± 0.001 μg AA (ascorbic acid)/g of bedak sejuk and 0.004 ± 0.0003 μg AA/g of bedak sejuk. Whereas Japonica bedak sejuk at 50 g/L had the same FRAP value as Indica bedak sejuk at 100 g/L. As for Japonica bedak sejuk at 100 g/L, it showed the highest antioxidant capacity with the FRAP value of 0.01 ± 0.0007 μg AA/g of bedak sejuk which was statistically significant (p < 0.05) when compared to other tested concentrations.

CONCLUSION

In conclusion, Japonica bedak sejuk has a higher antioxidant capacity compared to Indica bedak sejuk despite both being not cytotoxic towards the cells. Regardless, further investigations need to be done before bedak sejuk could be developed as potential melanoma chemoprevention agents.

Fermented Unpolished Black Rice (Oryza sativa L.) Inhibits Melanogenesis via ERK, p38, and AKT Phosphorylation in B16F10 Melanoma Cells

Melanin is a major factor that darkens skin color as one of the defense systems to prevent the harmful effects of UV light. However, darkened skin from the localized or systemic accumulation of melanin is viewed in many cultures as an esthetic problem. Consequentially, searching for antimelanogenic agents from natural sources is very popular worldwide. Previous screening of fermented rice products, obtained from various rice cultivars fermented with different sources of loog-pang (Thai traditional fermentation starter), revealed that the highest ability to reduce the melanin content in B16F10 melanoma cells was from unpolished black rice fermented with a defined starter mixture of microbes isolated from loog-pang E11. The aim of this study was to investigate the mechanism of the fermented unpolished black rice (FUBR) on the inhibition of melanogenesis in B16F10 melanoma cells. The strongest reduction of cellular melanin content was found in the FUBR sap (FUBRS). The melanin reduction activity was consistent with the significant decrease in the intracellular tyrosinase activity. The FUBRS showed no cytotoxic effect to B16F10 melanoma or Hs68 human fibroblast cell lines. It also significantly reduced the transcript and protein expression levels of tyrosinase, tyrosinase-related protein 1 (TYRP-1), TYRP-2, and microphthalmia-associated transcription factor. Furthermore, it induced a significantly increased level of phosphorylated ERK, p38 and Akt signaling pathways, which likely contributed to the negative regulation of melanogenesis. From these results, a model for the mechanism of FUBRS on melanogenesis inhibition was proposed. Moreover, these results strongly suggested that FUBRS possesses antimelanogenesis activity with high potential for cosmeceutical application as a skin depigmenting agent.

Neobavaisoflavone Inhibits Melanogenesis through the Regulation of Akt/GSK-3β and MEK/ERK Pathways in B16F10 Cells and a Reconstructed Human 3D Skin Model

Previous studies have confirmed the anti-melanogenic effect of the aerial part of Pueraria lobata, however, due to its inherent color, P. lobata has limited commercial use. In this study, an extract (GALM-DC) of the aerial part of P. lobata having improved color by the use of activated carbon was obtained. Furthermore, the active compound neobavaisoflavone (NBI) was identified from GALM-DC. The effect of NBI on melanogenesis, tyrosinase activity, α-glucosidase activity, and mechanism of action in melanocytes was investigated. Tyrosinase activity, melanin contents and the expression of melanin-related genes and proteins were determined in B16F10 cells. NBI reduced melanin synthesis and tyrosinase activity. Furthermore, NBI treatment reduced the mRNA and protein expression levels of MITF, TRP-1, and tyrosinase. NBI also works by phosphorylating and activating proteins that inhibit melanogenesis, such as GSK3β and ERK. Specific inhibitors of Akt/GSK-3β (LY294002) and MEK/ERK (PD98059) signaling prevented the inhibition of melanogenesis by NBI. NBI inhibited melanin production through the regulation of MEK/ERK and Akt/GSK-3β signaling pathways in α-MSH-stimulated B16F10 cells. NBI suppresses tyrosinase activity and melanogenesis through inhibition of α-glucosidase activity. Besides, NBI significantly reduced melanogenesis in a reconstructed human 3D skin model. In conclusion, these results suggest that NBI has potential as a skin-whitening agent for hyperpigmentation.

Inhibition of melanin production and promotion of collagen production by the extract of Kuji amber

Kuji amber is fossilized tree resin of the Late Cretaceous in Japan. In this study, new biological activities of ethanol extract of Kuji amber (EtOH ext.) and supercritical carbon dioxide fluid extract of Kuji amber (scCO2 ext.) were examined. Both EtOH ext. and scCO2 ext. inhibited melanin production in B16 mouse melanoma cells and promoted collagen production in human skin fibroblast SF-TY cells. The scCO2 ext. had more potent activity than that of EtOH ext. and may depend on the efficiency of the extraction. The main new biologically active compound in Kuji amber, kujigamberol had no activities against melanin production, however, it promoted collagen production at low concentrations. A biologically active compound having a different structure, spirolactone norditerpenoid, showed both the inhibition activity against melanin production and the promotion activity of collagen production in a dose dependent manner. EtOH ext. and scCO2 ext., which include both kujigamberol and spirolactone norditerpenoid, have not only anti-allergy activity, but also inhibit melanin production and promote collagen production.

Pigmentation Effect of Rice Bran Extract in Hair Follicle-Like Tissue and Organ Culture Models

BACKGROUND

Melanogenesis is a biological process resulting in the production of melanin pigment, which plays an important role in the prevention of sun-induced skin injury and determines the hair and skin color. Melanin has the ability to block ultraviolet radiation and scavenge free oxygen radicals, thus protecting the skin from their harmful effects. Agents that increase melanin synthesis in melanocytes may reduce the risk of photodamage and skin cancer. Hence, various approaches have been proposed to increase the synthesis of melanin.

METHODS

The current study aimed to develop a three-dimensional hair follicle-like tissue (HFLT) model with human dermal papilla, melanocytes, and outer root sheaths cells. This model showed enhanced melanogenesis-related protein expression after rice bran ash extract (RBE) treatment. Next, we investigated the melanogenic effect of RBE in the HFLT and compared the results to those of hair follicle (HF) organ culture model.

RESULTS

RBE was found to significantly increase the expression of microphthalmia-associated transcription factor, a key transcription factor involved in melanin production, in both HFLT and organ culture models. Results showed that melanogenesis-related protein expression levels were higher in the RBE group compared to those in the control group. Similar results were obtained by immunohistochemistry.

CONCLUSION

Our data suggested that RBE promotes melanin biosynthesis. Taken together, this simple in vitro HFLT model system has the potential to provide significant insights into the underlying molecular mechanisms of HF melanogenesis, and hence can be used for controlled evaluation of the efficacy of new materials for melanogenesis.

The anti-cancer activity and potential clinical application of rice bran extracts and fermentation products

Rice bran is the main by-product of rice processing and contains approximately 64% of the nutrients in rice. Its various nutrient elements include rice bran proteins, oil, oryzanol, vitamins, polysaccharides, etc. The use of fermented technology can increase the content of bioactive peptides, promote the absorption efficiency, and further improve the functionality and added value of rice bran. In recent years, the nutritional value and function of the extracts and fermented products of rice bran have been emphatically studied. Rice bran extracts and fermentation products serve a critical role in the anti-inflammatory reaction, reducing the plasma lipid effect and increasing anti-cancer activity. Moreover, few review studies have been reported on the anti-cancer activity and potential mechanism of action of rice bran extract and its fermentation products. In this review, we focused on the anti-cancer function, mechanisms, and potential clinical usage of rice bran extracts and fermentation products in the adjuvant therapy of cancer patients.

Integrated analysis of RNA-seq and microRNA-seq depicts miRNA-mRNA networks involved in stripe patterns of Botia superciliaris skin

Botia superciliaris, an endemic cobitid fish in China, is widely accepted by Chinese consumers because its edibility. Recently, the black and yellow stripes of B. superciliaris skin have made this species increasingly popular as a novel ornamental fish. However, the genetic basis of the stripe patterns in B. superciliaris skin has not been extensively studied. In this study, Illumina sequencing was employed to identify the mRNAs and miRNAs involved in stripe pattern formation in B. superciliaris skin. A total of 147.25 and 155.15 million (M) high-quality transcriptome reads were generated from three black and yellow skin libraries respectively, which resulted in 159,327 unigenes that were used as reference sequences. A total of 3169 genes exhibited significantly differential expression patterns (fold-change ≥ 2 or ≤ 0.5 and q ≤ 0.05), including 1891 upregulated genes (59.67%) and 1278 downregulated genes (40.33%) in black vs yellow skin. These genes were enriched in 50 GO terms and 10 KEGG pathways (q ≤ 0.05), including melanogenesis, with 21 upregulated genes and 5 downregulated genes in black vs yellow skin. Based on the zebrafish genome, miRNA-seq identified a total of 355 miRNAs, which included 38 novel miRNAs. Furthermore, 87 differentially expressed miRNAs including 50 upregulated and 37 downregulated miRNAs were identified in different color skin (fold-change ≥ 2 or ≤ 0.5 and q ≤ 0.05). Then, target prediction revealed a variety of putative target genes; differentially expressed mRNAs and miRNAs patterns of high-throughput sequencing were validated in 5 mRNAs and miR-217-5p by qRT-PCR. In vivo tests and dual-luciferase reporter assay revealed that overexpression of miR-217-5p can inhibit pheomelanin formation by targeting Zgc. In this study, a comparative analysis was conducted to profile the transcriptome of black and yellow skin for B. superciliaris, and we detected key genes and important miRNAs involved in the B. superciliaris skin pigmentation process. These results will enhance understanding of molecular mechanisms underlying skin pigmentation and facilitate molecular-assisted selection of highly valued skin colors.

Rice Bran Ash Mineral Extract Increases Pigmentation through the p-ERK Pathway in Zebrafish (Danio rerio)

The purpose of the present study is to evaluate the effect of rice bran ash mineral extract (RBM) on pigmentation in zebrafish (Danio rerio). Melanin has the ability to block ultraviolet (UV) radiation and scavenge free oxygen radicals, thus protecting the skin from their harmful effects. Agents that increase melanin synthesis in melanocytes may reduce the risk of photodamage and skin cancer. The present study investigates the effect of RBM on pigmentation in zebrafish and the underlying mechanism. RBM was found to significantly increase the expression of microphthalmia-associated transcription factor (MITF), a key transcription factor involved in melanin production. RBM also suppressed the phosphorylation of extracellular signal-regulated kinase (ERK), which negatively regulates zebrafish pigmentation. Together, these results suggest that RBM promotes melanin biosynthesis in zebrafish.

Fermentation Biotechnology Applied to Cereal Industry By-Products: Nutritional and Functional Insights

Cereals are one of the major food sources in human diet and a large quantity of by-products is generated throughout their processing chain. These by-products mostly consist of the germ and outer layers (bran), deriving from dry and wet milling of grains, brewers' spent grain originating from brewing industry, or others originating during bread-making and starch production. Cereal industry by-products are rich in nutrients, but still they end up as feed, fuel, substrates for biorefinery, or waste. The above uses, however, only provide a partial recycle. Although cereal processing industry side streams can potentially provide essential compounds for the diet, their use in food production is limited by their challenging technological properties. For this reason, the development of innovative biotechnologies is essential to upgrade these by-products, potentially leading to the design of novel and commercially competitive functional foods. Fermentation has been proven as a very feasible option to enhance the technological, sensory, and especially nutritional and functional features of the cereal industry by-products. Through the increase of minerals, phenolics and vitamins bioavailability, proteins digestibility, and the degradation of antinutritional compounds as phytic acid, fermentation can lead to improved nutritional quality of the matrix. In some cases, more compelling benefits have been discovered, such as the synthesis of bioactive compounds acting as antimicrobial, antitumoral, antioxidant agents. When used for baked-goods manufacturing, fermented cereal by-products have enhanced their nutritional profile. The key factor of a successful use of cereal by-products in food applications is the use of a proper bioprocessing technology, including fermentation with selected starters. In the journey toward a more efficient food chain, biotechnological approaches for the valorization of agricultural side streams can be considered a very valuable help.

H2O2 promotes the aging process of melanogenesis through modulation of MITF and Nrf2

The purpose of this study is to investigate the effect of H₂O₂ on the aging of melanogenesis in human melanocytes. The staining of SA-β-galactosidase, an aging marker, was remarkably increased in the cells aged with H₂O₂ at 62.5 µM or more compared with young cells. The intracellular H₂O₂ level and melanin synthesis were also reduced in both H₂O₂-treated cells and senescent cells compared with young cells in DCFH-DA assay. Both the senescent cells and the H₂O₂-treated cells showed higher expression level of Catalase than young cells in western blot and immunofluorescence staining. Furthermore, the expression levels of TRP-1, TRP-2 and p300 were reduced in both senescent cells and the H₂O₂-treated cells, but that of SIRT-1 was inverted compared with young cells. In addition, H₂O₂ reduced the expression level of MITF but increased that of Nrf2 in nucleus. Those results indicate that the expression levels of antioxidant enzymes in senescent cells and H₂O₂-treated cell are upregulated, but the expression levels of proteins involved in melanin synthesis are downregulated. Above findings suggest that H₂O₂ could play a key role in the aging process of melanogenesis through modulation of MITF and Nrf2.

Pulsed Electromagnetic Fields Increase Pigmentation through the p-ERK/p-p38 Pathway in Zebrafish (Danio rerio)

Melanogenesis is a biological process resulting in the production of melanin pigment, which plays an important role in the prevention of sun-induced skin injury, and determines hair and skin color. So, a wide variety of approaches have been proposed to increase the synthesis of melanin. This study evaluated the effects of pulsed electromagnetic fields (PEMFs) on the pigmentation of zebrafish (Danio rerio) in vivo. We stimulated pigmentation in zebrafish by using specific frequencies and intensities of PEMFs. This study focuses on pigmentation using PEMFs, and finds that PEMFs, at an optimal intensity and frequency, upregulate pigmentation by the stimulated expression of tyrosinase-related protein 1 (TRP1), dopachrome tautomerase (DCT) through extracellular signal-regulated kinase(ERK) phosphorylation, and p38 phosphorylation signaling pathways in zebrafish. These results suggest that PEMFs, at an optimal intensity and frequency, are a useful tool in treating gray hair, with reduced melanin synthesis in the hair shaft or hypopigmentation-related skin disorders.

Combining Microbubble Contrast Agent with Pulsed-Laser Irradiation for Transdermal Drug Delivery

The optodynamic process of laser-induced microbubble (MB) cavitation in liquids is utilized in various medical applications. However, how incident laser radiation interacts with MBs as an ultrasound contrast agent is rarely estimated when the liquid already contains stable MBs. The present study investigated the efficacy of the laser-mediated cavitation of albumin-shelled MBs in enhancing transdermal drug delivery. Different types and conditions of laser-mediated inertial cavitation of MBs were first evaluated. A CO₂ fractional pulsed laser was selected for combining with MBs in the in vitro and in vivo experiments. The in vitro skin penetration by β-arbutin after 2 h was 2 times greater in the group combining a laser with MBs than in the control group. In small-animal experiments, the whitening effect on the skin of C57BL/6J mice in the group combining a laser with MBs on the skin plus penetrating β-arbutin increased (significantly) by 48.0% at day 11 and 50.0% at day 14, and then tended to stabilize for the remainder of the 20-day experimental period. The present results indicate that combining a CO₂ laser with albumin-shelled MBs can increase skin permeability so as to enhance the delivery of β-arbutin to inhibit melanogenesis in mice without damaging the skin.

Solid-state fermentation of black rice bran with Aspergillus awamori and Aspergillus oryzae: Effects on phenolic acid composition and antioxidant activity of bran extracts

Black rice bran (BRB) was fermented in solid state using Aspergillus awamori and Aspergillus oryzae for 5 days at 30°C, and then the alcoholic extracts of the fermented BRB were examined in terms of phenolic acid composition and antioxidant activity (DPPH radical scavenging and tyrosinase inhibitory activity). A pre-treatment, moisturizing and autoclaving prior to the fermentation, decreased total phenolic content (TPC) by decomposing the anthocyanin in BRB, but the fermentation increased TPC. Protocatechuic acid and ferulic acid showed the most significant increases, reaching their maximum values by the fermentation for 3 days: 1660.6 µg/g for the extract of BRB fermented by A. awamori. The radical scavenging activity and tyrosinase inhibitory activity of the alcoholic extracts increased by the pre-treatment and fermentation, in accordance with the increase in phenolic acid content. The solid-state fermentation was an effective process to raise the phenolic acid content and antioxidant activity of the extract.

Safety assessment, biological effects, and mechanisms of Myrica rubra fruit extract for anti-melanogenesis, anti-oxidation, and free radical scavenging abilities on melanoma cells

OBJECTIVE

Currently, the cosmetic and medical industries are paying considerable attention to solve or prevent skin damage or diseases, such as hyperpigmentation and oxidation and free radical damage. In this study, the effective compounds in Myrica rubra fruit were extracted and studied the biological effects of these M. rubra fruit extracts.

METHODS

In this study, we extracted M. rubra fruit using solutions with various ratios of water to ethanol (100:0, 50:50, 5:95) and studied the anti-melanogenesis, anti-oxidation and radical scavenging effects of these M. rubra fruit extracts on two melanoma cell lines: mouse melanoma (B16-F0) and human melanoma (A2058). The cytotoxicity, melanin synthesis, mushroom and cellular tyrosinase activities, enzyme kinetics, melanogenesis-related gene expression, melanogenesis-related protein secretion, radical DPPH scavenging activity and ROS inhibition after treatment with M. rubra fruit extracts were determined.

RESULTS

The results showed that the water extract of M. rubra fruit was less cytotoxic to the melanoma cell lines, effectively inhibited melanin synthesis and tyrosinase activity and down-regulated the gene expression and protein secretion of MITF and TRP-1. In addition, the M. rubra fruit extracts also showed the abilities to scavenge DPPH free radicals and suppress ROS production. Finally, the effective compounds in the water extract were Myricetin-O-deoxyhexoside, Quercetin-O-deoxyhexoside, and Kaempferol-O-hexoside determined by LC/MS/MS assay.

CONCLUSION

Overall, the water extract of M. rubra fruit is a safe and effective melanin inhibitor and anti-oxidant and can be applied widely in the fields of cosmetics and medicine.

Rice bran mineral extract increases the expression of anagen-related molecules in human dermal papilla through wnt/catenin pathway

The objective of this study is to evaluate of rice bran mineral extract (RBM) increases the expression of anagen-related molecules in human dermal papilla (DOCs). Four treatment groups were established to evaluate the efficacy of RBM, including a negative control, positive control (ascorbic acid), RBM and ortho-silicic acid (Si(OH)₄) (OSA) group. Three days after the DPCs were administered the various treatments, western blot analysis showed that type I collagen expression was increased 2.5-fold in the OSA group and 4-fold in the RBM group, and ALP expression was increased 1.5-fold in the OSA and RBM group while the expression of fibronectin was increased ~3-fold in the OSA group and 2.5-fold in the RBM group. Also, the expression of Wnt-3α and β-catenin protein was increased in OSA and RBM group compared to control group. Furthermore, the expression of IL-1a was decreased by more than 50% in the OSA and RBM groups compared to the negative control. Analysis of mRNA expression by RT-qPCR showed that type I collagen increased 1.2-fold in the OSA- and RBM-treated DPCs, whereas type IV collagen increased 2.7-fold in the OSA group and 3.5-fold in the RBM group. However, TGF-β2 mRNA decreased about 80% in the OSA and RBM groups, respectively. Immunohistochemical staining of the DPCs for versican protein showed a significant increase in the OSA- and RBM-treated groups compared to the negative control. Thus, RBM have a potential to recover of DPCs activity and decreased inflammatory-related markers. It can be expected that hair loss prevention and hair growth enhancement can be expected when RBM is applied as a cosmetic product.

Acetazolamide Inhibits the Level of Tyrosinase and Melanin: An Enzyme Kinetic, In Vitro, In Vivo, and In Silico Studies

Melanin is the major factor that determines skin color and protects from ultraviolet radiation. In present study we evaluated the anti-melanogenesis effect of acetazolamide (ACZ) using four different approaches: enzyme kinetic, in vitro, in vivo and in silico. ACZ demonstrated significant inhibitory activity (IC50 7.895 ± 0.24 μm) against tyrosinase as compared to the standard drug kojic acid (IC50 16.84 ± 0.64 μm) and kinetic analyses showed that ACZ is a non-competitive inhibitor without cytotoxic effect. In in vitro experiments, A375 human melanoma cells were treated with 20 or 40 μm of ACZ with or without 50 μm of l-DOPA. Western blot results showed that ACZ significantly (P < 0.05) decreased the expression level of tyrosinase at 40 μm. Zebrafish embryos were treated with 10, 20 or 40 μm of ACZ and of positive control kojic acid. At 72 h of treatment with ACZ and kojic acid, ACZ significantly (P < 0.001) decreased the embryos pigmentation to 40.8% of untreated embryos at the dose of 40 μm of ACZ while kojic acid decreased only 25.0% of pigmentation at the same dose of kojic acid. In silico docking were performed against tyrosinase using PyRx tool. Docking studies suggested that His244, Asn260 and His85 are the major interacting residues in the binding site of the protein. In conclusion, our results suggest that ACZ is a good candidate for the inhibition of melanin and it could be used as a lead for developing the drugs for hyperpigmentary disorders and skin whitening.

Soyasaponin Ag inhibits α‑MSH‑induced melanogenesis in B16F10 melanoma cells via the downregulation of TRP‑2

Saponins, which are glycosylated, represent a diverse group of biologically functional products in plants. In the present study, we investigated the effects of soyasaponin Ag, a secondary metabolite extracted from soybean, on α‑melanocyte-stimulating hormone (α‑MSH)‑induced melanin synthesis in B16F10 mouse melanoma cells and the underlying molecular mechanisms. To elucidate the mechanisms through which soyasaponin Ag inhibits melanin synthesis, we performed cellular tyrosinase activity assays and analyzed the expression of the melanogenesis‑related genes, tyrosinase, tyrosinase‑related protein (TRP)‑1 and TRP‑2. We demonstrated that soyasaponin Ag inhibited α‑MSH‑induced melanin synthesis in melanoma cells. Of note, soyasaponin Ag had no inhibitory effect on intracellular tyrosinase activity. However, soyasaponin Ag inhibited TRP‑2 expression in a dose‑dependent manner. Therefore, the depigmenting effect of soyasaponin Ag may be due to the inhibition of tyrosinase expression or the enhancement of tyrosinase degradation. Moreover, soyasaponin Ag did not exert any toxic on B16F10 mouse melanoma cells, suggesting that soyasaponin is a safe component for use in skin care cosmetic formulations that are used for skin whitening.

Pigmentation Effect of Rice Bran Extracted Minerals Comprising Soluble Silicic Acids

Our investigation focused on identifying melanogenesis effect of soluble minerals in rice bran ash extract (RBE) which include orthosilicic acid (OSA). Melanocytes were apparently normal in terms of morphology. It was, however, shown that they were stressed a little in the RBE and OSA added media in aspect of LDH activity. Melanin synthesis and intracellular tyrosinase activity were increased by treatment of RBE which is similar to that of OSA. The Western blotting results showed that TRP-1, tyrosinase, and MITF expression levels were 2-3 times higher in the OSA and RBE groups compared to the control group which promoted melanin synthesis through CREB phosphorylation. Moreover, histology and immunohistochemistry were shown to have similar result to that of protein expression. As a result, minerals which comprise orthosilicic acid has the potential to promote melanogenesis and both RBE and OSA have similar cell viability, protein expression, and immunostaining results, suggesting that RBE comprises specific minerals which promote melanin synthesis through increasing of MITF and CREB phosphorylation. Therefore, RBE could be used as a novel therapeutic approach to combat melanin deficiency related diseases by stimulating melanocytes via its soluble Si and mineral components.

The activation of melanogenesis by p-CREB and MITF signaling with extremely low-frequency electromagnetic fields on B16F10 melanoma

Melanin in the skin determines the skin color, and decreased melanin causes many hypopigmentation disorders and increased damage to skin by ultraviolet B (UVB) light irradiation. Here, we stimulate melanogenesis in B16F10 melanoma cells by using specific frequencies of ELF-EMFs. In this study, we focus on the melanogenesis of EMF-ELFs and find that 60-75Hz ELF-EMFs upregulate melanin synthesis by stimulated expression of tyrosinase and TRP-1 through inhibition of phosphorylation ERK, activation of CREB, and MITF up-regulation in B16F10 melanoma cells. The results show that 60-75Hz ELF-EMFs significantly increase secreted melanin, cellular melanin content, and tyrosinase activity, and the cell mitochondria activity, cell viability, and cell membrane condition are unchanged. Furthermore, the protein expression level of MITF and p-CREB signaling pathway are significantly increased. Moreover, 60Hz ELF-EMFs reduce the phosphorylate of ERK in B16F10 melanoma cells. These findings indicate that stimulation of melanogenesis by using ELF-EMFs has therapeutic potential for treating hypopigmentation disorders such as vitiligo.

Fermented rice bran prevents atopic dermatitis in DNCB-treated NC/Nga mice

The fermentation of natural plants has a favorable effect on the functional and biological activities of living systems. These include anti-oxidative, anti-inflammatory, and anti-platelet aggregation activities. This is attributed to the chemical conversion of the parent plants to functional constituents, which show more potent biological activity. In our study, rice bran along with oriental medicinal plants (Angelicae gigantis, Cnidium officinale, Artemisia princeps, and Camellia sinensis) was fermented by Lactobacillus rhamnosus and Pichia deserticola (FRBE). We evaluated the effects of oral administration of FRBE on atopic dermatitis in 1-chloro-2,4-dinitrobenzene (DNCB)-treated NC/Nga mice. FRBE significantly ameliorated the macroscopic and microscopic appearance of skin lesions in DNCB-induced atopic dermatitis and reduced levels of serum immunoglobulin E and the differential white blood cell count. In addition, it reduced skin thickness compared to that of atopic dermatitis-affected skin. FRBE treatment also reduced mast cell incorporation in skin lesions of atopic dermatitis. The total cell number in dorsal skin tissue and the axillary lymph node increased following DNCB application, and this was normalized by FRBE treatment. Moreover, it decreased the levels of CD8⁺ helper T cells and Gr-1⁺/CD11b⁺ B cells in peripheral blood mononuclear cells and skin lesions in DNCB-induced atopic dermatitis. Using real-time polymerase chain reaction analysis, we demonstrated that FRBE significantly inhibited mRNA expression of cytokines (e.g., interleukin-5 and interleukin-13) and cyclooxygenase-2 in AD skin lesions. These results suggest that FRBE could be a valuable herbal remedy for the treatment of atopic dermatitis.

N-Nicotinoyl tyramine, a novel niacinamide derivative, inhibits melanogenesis by suppressing MITF gene expression

We synthesized and investigated the inhibitory effects of a novel niacinamide derivative, N-nicotinoyltyramine (NNT) on melanogenesis. NNT inhibited melanin production in B16F10 murine melanoma cells stimulated with α-melanocyte stimulating hormone (α-MSH), in human melanocyte and in three-dimensional cultured human skin model. NNT did not affect the catalytic activity of tyrosinase, but acted as an inhibitor of microphthalmia-associated transcription factor (MITF) and tyrosinase expressions in B16F10 cells. These findings suggest that the hypopigmentary effect of NNT results from the down-regulation of MITF and subsequently of tyrosinase, although NNT did not directly inhibit tyrosinase activity. In addition, safety of NNT was verified through performing neural stem cell morphology assay and Human repeated insult patch test as whitening agent. Our findings indicate that NNT may be a potential and non-skin irritant whitening agent for use in cosmetics and in the medical treatment of pigmentary disorders.

The natural yeast extract isolated by ethanol precipitation inhibits melanin synthesis by modulating tyrosinase activity and downregulating melanosome transfer

This study was conducted to examine the effects of EP-2, a natural yeast extract isolated by ethanol precipitation from Saccharomyces cerevisiae, on melanogenesis and to determine its underlying mechanism of action. Our results show that although EP-2 is not a direct tyrosinase inhibitor, when EP-2 was added to the culture media of B16F10 melanoma cells, intracellular tyrosinase activity was decreased. However, EP-2 had no effect on the expression of microphthalmia-associated transcription factor or tyrosinase. EP-2 was found to inhibit melanogenesis and melanosome transfer when it was added to melanocytes and keratinocytes in coculture. In addition, protease-activated receptor 2, a key protein associated with melanosome transfer from melanocytes to keratinocytes, was downregulated in the presence of EP-2. In conclusion, EP-2 is a potent inhibitor of melanogenesis and its hypomelanogenic effect is related to the inhibition of tyrosinase activity and transfer of melanosomes.

Lipoteichoic acid isolated from Lactobacillus plantarum inhibits melanogenesis in B16F10 mouse melanoma cells

Lipoteichoic acid (LTA) is a major component of the cell wall of Gram-positive bacteria. Its effects on living organisms are different from those of lipopolysaccharide (LPS) found in Gram-negative bacteria. LTA contributes to immune regulatory effects including anti-aging. In this study, we showed that LTA isolated from Lactobacillus plantarum (pLTA) inhibited melanogenesis in B16F10 mouse melanoma cells. pLTA reduced the cellular activity of tyrosinase and the expression of tyrosinase family members in a dose-dependent manner. The expression of microphthalmia-associated transcription factor (MITF), a key factor in the synthesis of melanin, was also decreased by pLTA. Further, we showed that pLTA activated melanogenesis signaling, such as extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3-kinse (PI3K)/AKT. In addition, the expression of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) and HuR, which are important RNA-binding proteins (RBPs), was reduced. pLTA likely degrades MITF via regulation of melanogenic signaling and RNA stability of melanogenic proteins, resulting in the reduction of melanin. Thus, our data suggest that pLTA has therapeutic potential for treating hyperpigmentation disorders and can also be used as a cosmetic whitening agent.

Fermented broth in tyrosinase- and melanogenesis inhibition

Fermented broth has a long history of applications in the food, pharmaceutical and cosmetic industries. Recently, the use of fermented broth in skin care products is in ascendance. This review investigates the efficacy of fermented broth in inhibiting tyrosinase and melanogenesis. Possible active ingredients and hypopigmentation mechanisms of fermented broth are discussed, and potential applications of fermented broth in the cosmetic industry are also addressed.

Rice brans, rice bran oils, and rice hulls: composition, food and industrial uses, and bioactivities in humans, animals, and cells

Rice plants produce bioactive rice brans and hulls that have been reported to have numerous health-promoting effects in cells, animals, and humans. The main objective of this review is to consolidate and integrate the widely scattered information on the composition and the antioxidative, anti-inflammatory, and immunostimulating effects of rice brans from different rice cultivars, rice bran oils derived from rice brans, rice hulls, liquid rice hull smoke derived from rice hulls, and some of their bioactive compounds. As part of this effort, this paper also presents brief summaries on the preparation of health-promoting foods including bread, corn flakes, frankfurters, ice cream, noodles, pasta, tortillas, and zero-trans-fat shortening as well as industrial products such bioethanol and biodiesel fuels. Also covered are antibiotic, antiallergic, anticarcinogenic, antidiabetic, cardiovascular, allelochemical, and other beneficial effects and the mechanisms of the bioactivities. The results show that food-compatible and safe formulations with desirable nutritional and biological properties can be used to develop new multifunctional foods as well as bioethanol and biodiesel fuel. The overlapping aspects are expected to contribute to a better understanding of the potential impact of the described health-promoting potential of the rice-derived brans, oils, and hulls in food and medicine. Such an understanding will enhance nutrition and health and benefit the agricultural and industrial economies.

Dual inhibition of γ-oryzanol on cellular melanogenesis: inhibition of tyrosinase activity and reduction of melanogenic gene expression by a protein kinase A-dependent mechanism

The in vitro effects on melanogenesis of γ-oryzanol (1), a rice bran-derived phytosterol, were investigated. The melanin content in B16F1 cells was significantly and dose-dependently reduced (-13% and -28% at 3 and 30 μM, respectively). Tyrosinase enzyme activity was inhibited by 1 both in a cell-free assay and when analyzed based on the measurement of cellular tyrosinase activity. Transcriptome analysis was performed to investigate the biological pathways altered by 1, and it was found that gene expression involving protein kinase A (PKA) signaling was markedly altered. Subsequent analyses revealed that 1 stimulation in B16 cells reduced cytosolic cAMP concentrations, PKA activity (-13% for cAMP levels and -40% for PKA activity), and phosphorylation of the cAMP-response element binding protein (-57%), which, in turn, downregulated the expression of microphthalmia-associated transcription factor (MITF; -59% for mRNA and -64% for protein), a key melanogenic gene transcription factor. Accordingly, tyrosinase-related protein 1 (TRP-1; -69% for mRNA and -82% for protein) and dopachrome tautomerase (-51% for mRNA and -92% for protein) in 1-stimulated B16F1 cells were also downregulated. These results suggest that 1 has dual inhibitory activities for cellular melanogenesis by inhibiting tyrosinase enzyme activity and reducing MITF and target genes in the PKA-dependent pathway.

Involvement of the p38 MAPK and ERK signaling pathway in the anti-melanogenic effect of methyl 3,5-dicaffeoyl quinate in B16F10 mouse melanoma cells

Methyl 3,5-dicaffeoyl quinate (MDQ), an active compound present in Kalopanax pictus, Salicornia herbacea L., Aster oharai and Solidago virga-aurea var. gigantean, is a dicaffeoylquinic acid derivative esterified by methanol. Recent studies have revealed that MDQ possesses multiple pharmacological activities, such as antitumor, antioxidative and cytoprotective activities. To date, there has been no attempt to test the action of MDQ in melanocytes. In this study, we investigated the effect of MDQ on melanogenesis in B16F10 mouse melanoma cells. MDQ inhibited melanin production and tyrosinase activity in B16F10 mouse melanoma cells without a direct inhibitory effect on mushroom tyrosinase activity. Furthermore, we also found that MDQ decreased protein expression levels of microphthalmia-associated transcription factor (MITF) and tyrosinase in B16F10 melanin cells. Meanwhile, phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) was significantly reduced after 6h MDQ treatment, and this expression recovered at 48 h. The phosphorylation of extracellular signal-regulated kinase (ERK) was significantly enhanced at 12-48 h, whereas no effect was observed in the phosphorylation of Akt. In addition, MDQ treatment did not significantly alter the expression levels of total p38 MAPK, ERK, and Akt. Thus, it seems that inhibition of phospho-p38 MAPK and activation of phospho-ERK may lead to the suppression of melanogenesis in MDQ-treated B16F10 mouse melanoma cells.