Inhibitory effects of chestnut inner skin extracts on melanogenesis

The Modulation of Melanogenesis in B16 Cells Upon Treatment with Plant Extracts and Isolated Plant Compounds

Plants are a rich source of secondary metabolites that exhibit numerous desired properties. The compounds may influence the biology of melanocytes, pigment cells that produce melanin, by modulating numerous signaling pathways, including cAMP/PKA, MAPKs and PI3K/AKT. Its downstream target is microphthalmia-associated transcription factor, responsible for the expression of the tyrosinase enzyme, which plays a major role in melanogenesis. Therefore, this literature review aims to provide insights related to melanogenesis modulation mechanisms of plant extracts and isolated plant compounds in B16 cells. Database searches were conducted using online-based library search instruments from 2012 to 2022, such as NCBI-PubMed and Google Scholar. Upregulation or downregulation of signaling pathways by phytochemicals can influence skin hypo- and hyperpigmentation by changing the level of melanin production, which may pose a significant cosmetic issue. Therefore, plant extracts or isolated plant compounds may be used in the therapy of pigmentation disorders.

Effect of in vitro digestion on chestnut outer-skin and inner-skin bioaccessibility: The relationship between biotransformation and antioxidant activity of polyphenols by metabolomics

Chestnut skin is rich in polyphenols that have been linked to health for their antioxidant activity. However, chestnut outer-skin extract (COE), chestnut inner-skin extract (CIE), and their digested products have different compositions of polyphenols, and therefore their antioxidant activities might differ as well. Here, we study the effect of in vitro digestion on their total phenol content, antioxidant capacity, and individual phenolic profile to clarify the relationship between biotransformation and antioxidant activity. Compared to undigested samples, total phenol content and antioxidant activity of digested chestnut outer-skin extract (DCOE) and digested chestnut inner-skin extract (DCIE) had significantly higher values. The changes of phenolic composition and antioxidant activity after digestion were mainly due to the anthocyanin biosynthesis involving glycosylation, acylation, methoxylation and their reverse processes. All these data suggest that as chestnut processing by-products, COE and CIE are raw material sources of antioxidant-rich active substances and need more sufficient utilization.

Bioactive phenolic components and potential health effects of chestnut shell: A review

Chestnut kernels are often used for direct consumption; or processed to produce marron glacé, chestnut purée, and gluten-free products, while chestnut by-products (inner shell and outer shell) are treated as waste residues. Many in vivo and in vitro studies have proved how chestnut shell extract functions as an antioxidant and exhibits anticancer, anti-inflammatory, antidiabetic, and anti-obesity activities. This review introduces the main components of phenolic compounds in chestnut shells, traditional and modern extraction methods, and reported potential health effects. The aim is to have a better understanding of the functional active ingredients in chestnut shells and their value-added uses, to increase understanding of future applications of this agricultural and sideline product in the food, pharmaceutical, and cosmetic industries. PRACTICAL APPLICATIONS: In recent years, chestnut shells have become a hot research topic because of their rich bioactive ingredients. Due to the large amount of phenolic compounds in chestnut shells and their potential health functions (antioxidant, anticancer, antibacterial, anti-inflammatory, hypoglycemic, and treatment of obesity), extracts of chestnut shells have high biological value in the treatment of diseases. Therefore, this review introduces the main components of phenolic compounds in chestnut shells, traditional and modern extraction methods, and the potential health effects of these compounds. The aim of this review is to better understand the functional, active ingredients in chestnut shells and their value-added uses, and to increase understanding of future applications of this agricultural and sideline product in the food, pharmaceutical, and cosmetic industries.

Identification and Characterization of the Tyrosinase Inhibitory Activity of Caffeine from Camellia Pollen

Tyrosinase inhibitors are important in cosmetic, medical, and food industries due to their regulation of melanin production. A tyrosinase inhibitor was purified from Camellia pollen using high-speed countercurrent chromatography and preparative high-performance liquid chromatography and was identified as caffeine by NMR and mass spectrometry. It showed strong mushroom tyrosinase inhibitory activity with an IC₅₀ of 18.5 ± 2.31 μg/mL in a noncompetitive model. The caffeine did not interact with copper ions in the active center of the enzyme but could quench fluorescence intensity and change the secondary conformation of this tyrosinase. A molecular dynamics simulation showed that caffeine bound this tyrosinase via Lys379, Lys 376, Asp357, Glu356, Thr308, Gln307, Asp312, and Trp358, thus changing the binding sites of l-tyrosine and the loop conformation adjacent to the active center. In vitro cell model analysis revealed that caffeine exhibited significant inhibitory effects on both intracellular tyrosinase activity and melanin production of B16-F10 melanoma cells in a concentration-dependent manner. These comprehensive results suggest that caffeine is a strong tyrosinase inhibitor that has the potential to be developed as skin-whitening agents in the cosmetics and pharmaceutical industries or as antibrowning agents in the food industry.

Effect of Chrysanthemum indicum Linné extract on melanogenesis through regulation of TGF-β/JNK signaling pathway

Although several physiological effects of Chrysanthemum indicum Linné (CL) have been researched, the specific effect and molecular mechanism of CL as a functional food material for skin health remain still unknown. Here, it was observed that the α-MSH and IBMX-initiated B16F10 melanogenesis was suppressed by the CL water extract (CLE) treatment. The CLE treatment also increased the mRNA expression levels of pro-collagen1α2, collagen1α2, and fibronectin via exerting the TGF-β/JNK signaling pathway. Together, the beneficial role of CLE in skin health was demonstrated through the downregulation of melanogenesis and enhancement of skin fibril-related genes. It was also revealed that the function of CLE is mediated with the activation of the TGF-β/JNK signaling pathway. These results may provide evidences for the development of functional foods using CLE for maintaining healthy skin.

Discovery of new depigmenting compounds and their efficacy to treat hyperpigmentation: Evidence from in vitro study

Human skin pigmentation is a result of constitutive and facultative pigmentation. Facultative pigmentation is frequently stimulated by UV radiation, pharmacologic drugs, and hormones whereby leads to the development of abnormal skin hyperpigmentation. To date, many state-of-art depigmenting compounds have been studied using in vitro model to treat hyperpigmentation problems for cosmetic dermatological applications; little attention has been made to compare the effectiveness of these depigmenting compounds and their mode of actions. In this present article, new and recent depigmenting compounds, their melanogenic pathway targets, and modes of action are reviewed. This article compares the effectiveness of these new depigmenting compounds to modulate several melanogenesis-regulatory enzymes and proteins such as tyrosinase (TYR), TYR-related protein-1 (TRP1), TYR-related protein-2 (TRP2), microphthalmia-associated transcription factor (MITF), extracellular signal-regulated kinase (ERK) and N-terminal kinases (JNK) and mitogen-activated protein kinase p38 (p38 MAPK). Other evidences from in vitro assays such as inhibition on melanosomal transfer, proteasomes, nitric oxide, and inflammation-induced melanogenesis are also highlighted. This article also reviews analytical techniques in different assays performed using in vitro model as well as their advantages and limitations. This article also provides an insight on recent finding and re-examination of some protocols as well as their effectiveness and reliability in the evaluation of depigmenting compounds. Evidence and support from related patents are also incorporated in this present article to give an overview on current patented technology, latest trends, and intellectual values of some depigmenting compounds and protocols, which are rarely highlighted in the literatures.

Anti-Melanogenic Effect of Chestnut Spike Extract through Downregulation of Tyrosinase-Related Proteins and Activation of ERK 1/2

Melanin has been reported to be the key factor for skin homeostasis. Besides defining an important human phenotypic trait, melanin overproduction may cause various disorders such as vitiligo, Addison's disease, Cushing's syndrome, and melasma. In this study, we aimed to investigate the anti-melanogenic potential of dried spike extract of chestnut. The extract inhibited tyrosinase (TYR) activity in a dose-dependent manner. Cellular melanin content decreased markedly after treatment with the extract. The spike extract inhibited microphthalmia-associated transcription factor (MITF) expression and downregulated TYR, TYRP-1, and TYRP-2 protein expression by increasing the phosphorylation of extracellular signal-regulated kinase (ERK)1/2 signalling pathway in melan-a cells. In addition, treatment with U0126, a specific inhibitor of ERK, restored melanin content. Collectively, these results suggest that the chestnut spike extract attenuated melanogenesis by inhibiting MITF expression and downregulating TYR, TYRP-1, and TYRP-2 protein expressions via activation of ERK1/2 pathway.

Antioxidant and anti-adipogenic activities of chestnut (Castanea crenata) byproducts

The antioxidant and anti-adipogenic activities of chestnut byproducts were evaluated. At 100 μg/mL, the methanol extract (ME) scavenged 34.2% of DPPH and 78.8% of ABTS radicals. The DPPH and ABTS radical scavenging activity of the water extract (WE) was found to be low (13.7 and 33.1%, respectively) compared with controls. WE and ME dose-dependently inhibited lipid accumulation of 3T3-L1 adipocytes. WE and ME at 100 μg/mL suppressed 3T3-L1 adipogenesis by 71.0 and 96.5%, respectively, when compared with mature adipocytes. The results indicated that WE and ME inhibited adipocyte differentiation by down-regulating the mRNA expression levels of CCAAT/enhancer binding protein (C/EBP)-β, C/EBPα, and peroxisome proliferator-activated receptor (PPAR)-γ in 3T3-L1 cells. Our study also revealed that WE and ME inhibited pre- and early stage adipogenesis in 3T3-L1 cells. The results suggest that chestnut byproducts are a promising source of antioxidant and antiobesity molecules.

Comparative analysis of the antioxidant and anticancer activities of chestnut inner shell extracts prepared with various solvents

BACKGROUND

The chestnut inner shell (CIS) has long been used as a medicinal herb for strengthening the antioxidant in the cosmetic industry. However, little is known about the antioxidant and anticancer effects of the CIS.

RESULTS

The antioxidant and anticancer effects of CIS extracts (CISEs) were investigated by the use of various methods and cancer cell lines, respectively. The total polyphenol content of CISEs using ethanol, methanol, butanol, ethyl acetate and water were 53.30, 43.98, 32.16, 26.79 and 11.53 mg gallic acid equivalents g(-1), respectively. The CISEs using ethanol and methanol exhibited high antioxidant activities in the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, β-carotene bleaching and ferric reducing ability of plasma assays; the effects were equivalent to those of butylated hydroxytoluene. All CISEs at 2.5 mg mL(-1) were shown to have a cytotoxic effect over 50%, and the CISE using ethyl acetate at 0.6 mg mL(-1) was proved to have 90% cytotoxic effect against the tested cancer cells.

CONCLUSION

The ethanol and methanol CISEs had potent antioxidant effects, and the ethyl acetate CISE had the highest cytotoxicity. These results suggest that CISEs could be used as functional ingredients for antioxidant and anticancer effects in foods as extraction solvents.