Protective properties of melanin from lichen Lobaria pulmonaria (L.) HOFFM. In models of oxidative stress in skeletal muscle

Melanin is a dark pigment from the group of phenolic or indole polymers with inherent biocompatibility and antioxidant capacity. In extremophilic lichen Lobaria pulmonaria, melanin is responsible for protective properties against hostile environments. Herein, the ability of melanin extracted from L. pulmonaria to counteract oxidative stress and related damages was studied in the mouse diaphragm, the main respiratory muscle. Initial in vitro experiments demonstrated ultraviolet (UV)-absorbing, antioxidant and metal chelating activities of melanin. This melanin can form nanoparticles and stabile colloidal system at concentration of 5 μg/ml. Pretreatment of the muscle with melanin (5 μg/ml) markedly reduced UV-induced increase in intracellular and extracellular reactive oxygen species (ROS) as well as antimycin A-mediated enhancement in mitochondrial ROS production accompanied by lipid peroxidation and membrane asymmetry loss. In addition, melanin attenuated suppression of neuromuscular transmission and alterations of contractile responses provoked by hydrogen peroxide. Thus, this study shed the light on the perspectives of the application of a lichen melanin as a protective component for treatment of skeletal muscle disorders, which are accompanied with an increased ROS production.

Production, physico-chemical properties and antioxidant activity of melanin from Annulohypoxylon stygium (Lév.) Y.M. Ju, J.D. Rogers and H.M. Hsieh

To obtain higher melanin production in liquid culture, culture conditions of Annulohypoxylon stygium (Lév.) Y.M. Ju, J.D. Rogers and H.M. Hsieh were optimised. The results showed that using single factor experiment and orthogonal test, the optimised production of melanin reached 2.20 g/L, which was 2.06 times higher than that of the control group. In addition, it was speculated that A. stygium melanin (AsM) was 3,4-dihydroxyphenylalanine (DOPA) melanin and showed an amorphous irregular structure. Moreover, it had good solubility in alkaline solution. AsM showed good antioxidant activity at a concentration of 500 mg/L, with DPPH, ABTS and OH radicals scavenging activities of 90.83%, 75.36% and 70.90%, respectively. AsM prevented alcohol-induced oxidative damage and oxidative stress in HepG2 cells by inhibiting the decrease of antioxidant key enzyme activity under alcohol stimulation. It was proved to have a great potential for application as a natural antioxidant and a substitute for synthetic pigments.

Structural elucidation of an active polysaccharide from Radix Puerariae lobatae and its protection against acute alcoholic liver disease

Radix Pueraria lobata can be used as medicine and food, whose polysaccharide is one of the main bioactive ingredients. To explore the effect and mechanism of Pueraria lobata polysaccharide, a homogeneous and novel water-soluble polysaccharide (PLP1) was successfully isolated and purified from P. lobata by column chromatography in the current study. Structure analysis revealed that PLP1 (Mw = 10.43 kDa) was constituted of the residues including (1 → 4)-α-d-glucose and (1 → 4, 6)-α-d-glucose, which were linked together at a ratio of 5:1 and represented the main glycosidic units. In vitro experiments indicated that PLP1 exhibited a better free radical-scavenging ability than amylose and amylopectin, meanwhile in vivo experiments indicated that PLP1 effectively protected against liver injury in mice with acute ALD through significantly inhibiting oxidative stress to regulate lipid metabolism, increasing short-chain fatty acid production, and maintaining intestinal homeostasis by regulating intestinal flora. Taken together, our results illustrate that PLP1 can regulate intestinal microecology as a feasible therapeutic agent for protecting against ALD on the ground of the gut-liver axis, thus laying a theoretical foundation for the rational exploitation and utilization of P. lobata resources in the clinic.

Anti-ultraviolet, antibacterial, and biofilm eradication activities against Cutibacterium acnes of melanins and melanin derivatives from Daedaleopsis tricolor and Fomes fomentarius

Fomes fomentarius and Daedaleopsis tricolor produced significant amounts of water-insoluble melanins, and our previous study successfully enhanced their water solubility by arginine modification. This research aimed to investigate the anti-ultraviolet, antibacterial, and biofilm eradication activities of both the melanins and arginine-modified melanin (melanin derivatives) from these two fungi against an acne-causing bacterium (Cutibacterium acnes). Apart from these, the cytotoxicity of the melanins and melanin derivatives on human skin cells was also evaluated. Melanin derivatives of both two fungi showed significantly higher antibacterial and biofilm eradication activities compared with their original forms. Specifically, the MIC50 values of the melanin derivatives (1,000 μg/mL) are the same as those of erythromycin. Regarding biofilm eradication capacity, the MBEC50 value of D. tricolor melanin derivative (250 μg/mL) was just half of both erythromycin and F. fomentarius melanin derivative. However, it required a 2-fold higher concentration of melanin derivatives than erythromycin to inhibit 90% of the bacterial population and eradicate 90% of their biofilm. Regarding anti-ultraviolet activity, blending melanins or melanin derivatives with a moisturizer/sunscreen enhanced their UV light absorption and the sun protection factor (SPF) values. In addition, melanins showed better effects than their derivatives, and those of D. tricolor were better than F. fomentarius. Remarkably, adding D. tricolor melanin (10%) to a Nivea pure cream could turn this cream into a broad-spectrum sunscreen, with its SPF value and critical wavelength increasing from 7.74 and 338.67 to 14.02 and 377.0, respectively. In addition, adding melanin or a melanin derivative of D. tricolor to an Olay sunscreen enhanced the SPF and the critical wavelength of the sunscreen from 17.25 and 371.67 to 23.82 and 374 and 23.38 and 372, respectively. Notably, melanins and melanin derivatives showed no toxicity in human fibroblasts. The obtained data suggest that arginine modification significantly enhanced the antibacterial and biofilm eradication activities of melanins from D. tricolor and F. fomentarius. However, this is not the case when it comes to their anti-ultraviolet activities. In addition, melanin and melanin derivatives from D. tricolor are potential candidates for anti-acne sunscreen products and are worth further investigation.

Recent Advances in Characterization of Melanin Pigments in Biological Samples

The melanin pigments eumelanin (EM) and pheomelanin (PM), which are dark brown to black and yellow to reddish-brown, respectively, are widely found among vertebrates. They are produced in melanocytes in the epidermis, hair follicles, the choroid, the iris, the inner ear, and other tissues. The diversity of colors in animals is mainly caused by the quantity and quality of their melanin, such as by the ratios of EM versus PM. We have developed micro-analytical methods to simultaneously measure EM and PM and used these to study the biochemical and genetic fundamentals of pigmentation. The photoreactivity of melanin has become a major focus of research because of the postulated relevance of EM and PM for the risk of UVA-induced melanoma. Our biochemical methods have found application in many clinical studies on genetic conditions associated with alterations in pigmentation. Recently, besides chemical degradative methods, other methods have been developed for the characterization of melanin, and these are also discussed here.

Pathogenic mechanisms and regulatory factors involved in alcoholic liver disease

Alcoholism is a widespread and damaging behaviour of people throughout the world. Long-term alcohol consumption has resulted in alcoholic liver disease (ALD) being the leading cause of chronic liver disease. Many metabolic enzymes, including alcohol dehydrogenases such as ADH, CYP2E1, and CATacetaldehyde dehydrogenases ALDHsand nonoxidative metabolizing enzymes such as SULT, UGT, and FAEES, are involved in the metabolism of ethanol, the main component in alcoholic beverages. Ethanol consumption changes the functional or expression profiles of various regulatory factors, such as kinases, transcription factors, and microRNAs. Therefore, the underlying mechanisms of ALD are complex, involving inflammation, mitochondrial damage, endoplasmic reticulum stress, nitrification, and oxidative stress. Moreover, recent evidence has demonstrated that the gut-liver axis plays a critical role in ALD pathogenesis. For example, ethanol damages the intestinal barrier, resulting in the release of endotoxins and alterations in intestinal flora content and bile acid metabolism. However, ALD therapies show low effectiveness. Therefore, this review summarizes ethanol metabolism pathways and highly influential pathogenic mechanisms and regulatory factors involved in ALD pathology with the aim of new therapeutic insights.

Isolation and characterization of blackish-brown BY2-melanin accumulated in cultured tobacco BY-2 cells

The tobacco BY-2 cell line is one of the most utilized plant cell lines. After long-term culture, the cells turn brown to black, but the causal pigment is unknown. We successfully isolated a blackish-brown pigment from BY-2 cells cultured for 3 weeks. Morphological and spectroscopic analyses indicated that the pigment had similar features to a melanin-like substance reported previously. Furthermore, physicochemical analyses revealed that this pigment possessed most of the properties of melanin-like pigments. In addition, the high nitrogen content suggested that it differed from common plant melanins classified as allomelanins, suggesting a novel eumelanin-like pigment: "BY2-melanin". This is the first example showing that eumelanin-like pigments are produced in the cultures of plant cells for which the accumulation of melanin has not been reported. This tobacco BY-2 cell culture technique may represent a customizable and sustainable alternative to conventional melanin production platforms, with significant potential for industrial and pharmacological applications.

Extraction, physicochemical properties, and antioxidant activity of natural melanin from Auricularia heimuer fermentation

Introduction

Natural melanin from Auricularia heimuer have numerous beneficial biological properties, which were used as a safe and healthy colorant in several industries.

Methods

In this study, single-factor experiments, Box-Behnken design (BBD), and response surface methodology (RSM) were employed to investigate the effects of alkali-soluble pH, acid precipitation pH, and microwave time on the extraction yield of Auricularia heimuer melanin (AHM) from fermentation. Ultraviolet-visible spectrum (UV-Vis), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), and high-performance liquid chromatography (HPLC) were used to analyze the extracted AHM. The solubility, stability, and antioxidant activities of AHM were also measured.

Results

The results showed that alkali-soluble pH, acid precipitation pH, and microwave time significantly affected the AHM yield, with the following optimized microwave-assisted extraction conditions: alkali-soluble pH of 12.3, acid precipitation pH of 3.1, and microwave time of 53 min, resulting in an AHM extraction yield of 0.4042%. AHM exhibited a strong absorption at 210 nm, similar to melanin from other sources. FT-IR spectroscopy also revealed that AHM exhibited the three characteristic absorption peaks of natural melanin. The HPLC chromatogram profile of AHM showed a single symmetrical elution peak with a 2.435 min retention time. AHM was highly soluble in alkali solution, insoluble in distilled water and organic solvents, and demonstrated strong DPPH, OH, and ABTS free radical scavenging activities.

Discussion

This study provides technical support to optimize AHM extraction for use in the medical and food industries.

Melanin of fungi: from classification to application

Melanin is a secondary metabolite composed of complex heterogeneous polymers. Fungal melanin is considered to be a sustainable and biodegradable natural pigment and has a variety of functional properties and biological activities. On one hand, due to its own specific properties it can play the role of antioxidant, anti-radiation, adsorption, and photoprotection. On the other hand, it has good biological activities such as hepatoprotective effect, hypolipidemic effect and anti-cancer. Therefore, it is widely used in various fields of daily life, including dyeing, food, biomedical and commercial industry. It is conducive to environmental protection and human health. However, the insolubility of fungal melanin in water, acids and organic solvents has been an obstacle to its commercial applications. Thus, the chemical modification methods of fungal melanin are summarized to increase its solubility and expand the application fields. Although fungal melanin has been used in many industries, as the structure and function of fungal melanin and modified melanin are further studied, more functional properties and bioactivities are expected to be discovered for a wide range of applications in the future.

Costunolide protects against alcohol-induced liver injury by regulating gut microbiota, oxidative stress and attenuating inflammation in vivo and in vitro

Costunolide (cos) derived from the roots of Dolomiaea souliei (Franch.), which belongs to the Dolomiaea genus in the family Compositae, exert the anti-inebriation effect mainly by inhibiting the absorption of alcohol in the gastrointestinal tract. However, the protective effect of cos against alcohol-induced liver injury (ALI) remains obscure. The present study was aimed to evaluate the hepatoprotective effects of cos (silymarin was used as positive control) against ALI and its potential mechanisms. MTT was used to examine the effect of cos on the cell viability of L-02 cells. Plasma was separated from blood that used to test the levels of TNF-α, IL-6 and IL-12, and LPS while serum separated from blood which used to detect the level of ALT and AST. Liver tissues were obtained for histopathological examination and western blot analysis. Fresh mice feces samples were collected for the detection of bacterial composition. Cos exhibited protective effect against alcoholic-induced liver injury by regulating gut microbiota capacities (higher relative abundance of Firmicutes and Actinobacteria while lower in Bacteroidetes and Proteobacteria), adjusting oxidative stress (reduced the activities of MDA and ROS while promoted SOD, GSH and GSH-PX in L-02 cells) and attenuating inflammation (decreased the levels of ALT, AST, LPS, IL-6, IL-12 and TNF-α) via LPS-TLR4-NF-κB p65 signaling pathway, which might be an active therapeutic agent for treatment of ALI.

Synergistic hepatoprotective effect of combined administration of Lachnum polysaccharide with silymarin

In recent years, combination therapy has gradually become one of the hot spots. As a new therapy strategy, we investigated the combination treatment of polysaccharide from Lachnum sp. (LEP-2b) with silymarin and compared the effects with mono-therapy. In this study, combining high-dose LEP-2b with silymarin (CH) significantly reduced serum biochemistry indexes (ALT, AST, AKP, LDH), hepatic inflammation (TNF-α, IL-6 and IL-1β) and improved the antioxidant status (SOD, CAT, GSH-Px, GSH, MDA and T-AOC), in which its effect on TNF-α was very significant (P < 0.001). Therefore, the expressions of related proteins in the JNK/p38 signaling pathway associated with TNF-α were examined. The result showed that CH treatment markedly increased the expression of p-p38 and inhibited the JNK phosphorylation. TUNEL staining, immunohistochemical staining and western blot assays demonstrated that the hepatoprotective effect of CH treatment was probably related with inhibiting hepatocyte apoptosis. In summary, combination of high dose LEP-2b with silymarin would be a more effective method to protect liver injury than mono-therapy.

Effect of Auricularia auricula fermentation broth on the liver and stomach of mice with acute alcoholism

In this paper, the protective effect of Auricularia auricula (A. auricula) fermentation broth on the liver and stomach of mice with acute alcoholism was studied. The A. auricula fermentation broth was prepared by adding Bacillus subtilis, lactic acid bacteria, and Saccharomyces cerevisiae to A. auricula solution. The changes of physical and chemical indexes during the fermentation of A. auricula were monitored, and the results showed the content of polysaccharides and protein in the two kinds of fermentation broth after the fermentation was completed. Furthermore, the characteristic structures of active substances such as proteins, polysaccharides and phenolics were found in the A. auricula fermentation by structural analysis. Antioxidant activity test results showed that the A. auricula fermentation broth had a strong ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals. Cell experiments showed that the fermentation broth of A. auricula could significantly enhance the activity of NRK cells and protect NRK cells from H₂O₂ damage. Animal experiments showed that the A. auricula fermentation broth had protective effects on the liver and stomach of mice with acute alcoholism, and significantly reduced the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC) and triglycerides (TG) in serum. These results indicated that the A. auricula fermentation broth had protective effects on the liver and stomach of mice with acute alcoholism, and could be used as a potential functional food to prevent liver and stomach damage caused by acute alcoholism.

The Impact of Acute or Chronic Alcohol Intake on the NF-κB Signaling Pathway in Alcohol-Related Liver Disease

Ethanol misuse is frequently associated with a multitude of profound medical conditions, contributing to health-, individual- and social-related damage. A particularly dangerous threat from this classification is coined as alcoholic liver disease (ALD), a liver condition caused by prolonged alcohol overconsumption, involving several pathological stages induced by alcohol metabolic byproducts and sustained cellular intoxication. Molecular, pathological mechanisms of ALD principally root in the innate immunity system and are especially associated with enhanced functionality of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. NF-κB is an interesting and convoluted DNA transcription regulator, promoting both anti-inflammatory and pro-inflammatory gene expression. Thus, the abundancy of studies in recent years underlines the importance of NF-κB in inflammatory responses and the mechanistic stimulation of inner molecular motifs within the factor components. Hereby, in the following review, we would like to put emphasis on the correlation between the NF-κB inflammation signaling pathway and ALD progression. We will provide the reader with the current knowledge regarding the chronic and acute alcohol consumption patterns, the molecular mechanisms of ALD development, the involvement of the NF-κB pathway and its enzymatic regulators. Therefore, we review various experimental in vitro and in vivo studies regarding the research on ALD, including the recent active compound treatments and the genetic modification approach. Furthermore, our investigation covers a few human studies.

Comparison of physicochemical and biochemical properties of natural and arginine-modified melanin from medicinal mushroom Ganoderma lucidum

Melanin is a hydrophobic biomolecule produced widely in fungi. Compared with other fungi, health benefits have been associated with medicinal mushrooms, which may provide an excellent source of natural melanin. Nevertheless, the hydrophobicity of melanin may limit its applications. Consequently, the present study was carried out on isolation of melanin from the medicinal mushroom Ganoderma lucidum (GLM) and modification with arginine to improve its solubility. The physicochemical and biochemical properties of melanin were evaluated including structural characterization, solubility, stability, antioxidant activities, and inhibitory effect on pancreatic lipase activity. Arginine-modified melanin showed better solubility, higher color value, stronger antioxidant activity, and stronger inhibitory effect on pancreatic lipase activity in vitro than GLM. In addition, both have good stability in the dark and natural light. These results opened possibilities for providing an excellent source of natural melanin in health food or food additives fields.

Differences in melanin type and content among color variations in American mink (Neovison vison)

Coat colour is one of the most important qualitative traits of fur animals. Determining melanin pigments forming the basics of visible coat colour may contribute to a better understanding of the process of creating different coat colour variations in fur-bearing animals. This study aimed to (i) isolate pigment cells from the hair of American mink of 11 colour variations (standard brown, silverblue, palomino, black, wild type, sapphire, black cross, pearl, palomino cross, glow, and amber) using acid and alkali; and (ii) characterise the melanin pigments obtained. The purified pigment cells were observed under a light microscope and verified by spectrophotometry scanning and nuclear magnetic resonance spectroscopy. The method allowed for obtaining pure melanin specimens. Using acid and alkali to extract eumelanosomes did not affect their shape and structure; it also allowed for obtaining pheomelanin from the hair. The results have proven that the hair colour of the American mink is based on all types of melanin, and that its variations differ in terms of how much eumelanin and pheomelanin the hair contains.

The structural characteristics, antioxidant and hepatoprotection activities of polysaccharides from Chimonanthus nitens Oliv. leaves

This work aimed to investigate the structural characteristics, antioxidant activities and hepatoprotection effect of Chimonanthus nitens Oliv. leaves polysaccharides (COP) on alcohol-induced oxidative damage in mice. Physical and chemical analysis showed that COP contained four monosaccharides including arabinose (Ara), mannose (Man), glucose (Glu) and galactose (Gal), with mass percentages of 26.6%, 5.1%, 32.2% and 36.0%, respectively, which was a heteropolysaccharide with both α- and β- configurations. In vivo experiments indicated that oral administration COP significantly reduced the levels of ALT, AST and MDA in serum, and significantly increased the activity of SOD and GSH-Px. Mice pretreated with COP had a higher superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity in liver and lower content of TNF-α, IL-6 and IL-1β in the liver and serum when compared with alcohol exposure. In addition, the liver histopathological changes induced by alcohol returned to normal in the COP pretreatment group. These results suggest that COP has a protective effect on acute liver injury induced by alcohol.

Comparative study on hepatoprotection of pine nut (Pinus koraiensis Sieb. et Zucc.) polysaccharide against different types of chemical-induced liver injury models in vivo

A novel polysaccharide (PNP80b-2) was obtained from Pinus koraiensis pine nut, which has been proved to possess good hepatoprotective effects in vitro. This study comprehensively investigated its hepatoprotective activities against different types of chemical-induced liver injury in vivo. Carbon tetrachloride, alcohol and acetaminophen were used as hepatic toxicants to establish chemical pollutant-induced liver injury (CILI) model, alcohol induced-liver injury (AILI) model and drug-induced liver injury (DILI) model, respectively. The results showed that PNP80b-2 prevented elevation of biomarkers for liver injury in each model, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and total bilirubin (TBIL). The expression of cytochrome P450 in damaged hepatocytes was also downregulated. Additionally, PNP80b-2 enhanced hepatic antioxidant capacity through upregulating the expression of NRF2 and HO-1, thereby increasing superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities and decreasing malondialdehyde (MDA) levels. The uncontrolled production of inflammatory factors including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2) in CILI, AILI and DILI models was also suppressed by PNP80b-2. By contrast, PNP80b-2 exerted the strongest hepatoprotection against AILI model, through improving hepatic antioxidant capacity via NRF2/ARE pathway and regulating inflammation response. Thus, PNP80b-2 is a promising functional food to prevent AILI.

From Extraction to Advanced Analytical Methods: The Challenges of Melanin Analysis

The generic term "melanin" describes a black pigment of biological origin, although some melanins can be brown or even yellow. The pigment is characterized as a heterogenic polymer of phenolic or indolic nature, and the classification of eu-, pheo- and allo- melanin is broadly accepted. This classification is based on the chemical composition of the monomer subunit structure of the pigment. Due to the high heterogeneity of melanins, their analytical characterization can be a challenging task. In the present work, we synthesized the current information about the analytical methods which can be applied in melanin analysis workflow, from extraction and purification to high-throughput methods, such as matrix-assisted laser desorption/ionization mass-spectrometry or pyrolysis gas chromatography. Our thorough comparative evaluation of analytical data published so far on melanin analysis has proven to be a difficult task in terms of finding equivalent results, even when the same matrix was used. Moreover, we emphasize the importance of prior knowledge of melanin types and properties in order to select a valid experimental design using analytical methods that are able to deliver reliable results and draw consistent conclusions.

A novel polysaccharide obtained from Craterellus cornucopioides enhances immunomodulatory activity in immunosuppressive mice models via regulation of the TLR4-NF-κB pathway

The immunoregulatory effect of a novel Craterellus cornucopioides polysaccharide (CCP) with a triple-helix structure on immunosuppressive BALB/c mice models was investigated; moreover, the immune response of BALB/c mice models in the preventive and therapeutic treatment groups treated with CCP was explored, and its molecular mechanism was elucidated. It was found that the BALB/c mice models in the preventive groups treated with CCP (120 and 240 mg kg^-1 d^-1) had better immunoregulatory activity. The spleen and thymus weight indices of the BALB/c mice models were significantly increased, and the histopathological analysis indicated a protective function of CCP against the immunosuppression induced by cyclophosphamide (CTX). Moreover, CCP displayed definite and clear synergistic effects on the T- or B-lymphocyte proliferation induced by ConA or LPS, respectively, promoted the natural killer (NK) cell activity and significantly increased phagocytic activity to activate peritoneal macrophages in immunosuppressive mice. The western blot and quantitative real-time polymerase chain reaction (qRT-PCR) results provided comprehensive evidence that CCP could upregulate the protein expression of the G-protein-coupled cell membrane receptor TLR4 and the production of its downstream protein kinases (TRAF6, TK1, p-IKKα/β and NF-κB p50); this, in turn, enhanced the production of cytokines (IL-2, IL-6, TNF-α and IFN-α) through both preventive and therapeutic treatments via regulation of the TLR4-NFκB pathway in the peritoneal macrophage of immunosuppressive mice.

Characterization of natural melanin from Auricularia auricula and its hepatoprotective effect on acute alcohol liver injury in mice

This study characterized the natural melanin from Auricularia auricula and investigated its hepatoprotective effect on mice with acute alcoholic liver injury. The characterization of the melanin was analyzed based on elemental analysis, gel permeation chromatography (GPC), UV-visible spectroscopy (UV-visible), infrared spectrum (IR) and nuclear magnetic resonance spectra (NMR). To determine the liver protective effect of Auricularia auricula melanin, mice were administered with the melanin once daily for 3 weeks before ethanol induced liver injury. Biochemical parameters of liver function, histopathological sections, mRNA and protein expression of antioxidant enzyme were compared between mice with or without the melanin administered. Results showed that A. auricula melanin was a eumelanin and the average molecular weight was 48.99 kDa. The melanin can protect the mice from ethanol-induced liver injury by extending the duration of the righting reflex, and shortening the duration of the recovery. The liver index, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transpeptidase (γ-GT) and liver malondialdehyde (MDA) levels in mice treated with the melanin were significantly decreased. At the same time, the levels of liver alcohol dehydrogenase (ADH), and antioxidase such as catalase (CAT), and superoxide dismutase (SOD) were increased. Its protective effect may be related to the activation of nuclear factor E2-related factor 2 (Nrf2) and its downstream antioxidant enzymes such as glutamate cysteine ligase catalytic (GCLC), glutamate cysteine ligase modifier (GCLM), and NADP(H) quinine oxidoreductase 1 (NQO-1). These results suggested that A. auricula melanin may be an effective strategy to alleviate alcohol-induced liver damage.

Antioxidant and hepatoprotective activities of modified polysaccharides from Coprinus comatus in mice with alcohol-induced liver injury

A modified polysaccharide named MPCC from Coprinus comatus (MPCC) was obtained by the snailase hydrolysis. And the hepatoprotective effects on alcohol-induced liver injury and preliminary structure features were investigated. For in vivo hepatoprotective abilities, MPCC significantly attenuated the hepatic and serum lipid levels, obviously enhanced antioxidant enzyme activities, markedly improved alcohol metabolism system and inflammatory response, and mitigated alcohol-induced liver injury histopathologically, providing references for the exploitation of MPCC as functional foods or natural drugs against the alcohol-induced liver injury. Additionally, MPCC containing fucose (Fuc), ribose (Rib), arabinose (Ara), xylose (Xyl), mannose (Man), galactose (Gal) and glucose (Glu) with the a α- and β-configuration in a percentage composition of 0.91%, 0.71%, 0.45%, 1.60%, 2.04%, 4.41% and 89.88% via gas chromatography (GC), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) analysis.

Structure, Molecular Modification, and Anti-radiation Activity of Melanin from Lachnum YM156 on Ultraviolet B-Induced Injury in Mice

The purpose of this study was to examine the protective effects of intracellular homogeneous melanin produced by Lachnum YM156 (LIM) against ultraviolet B (UVB) induced damage in mice. The possible structural formula of the LIM was concluded based on elemental analysis, ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and mass spectrometry (MS). The LIM was modified by arginine to improve its water solubility and biological activities. LIM and ALIM show significant anti-radiation activity in which LIM and ALIM protect the skin under UV radiation. Results indicate that activities of anti-oxidant enzymes in skin were improved after treatment of LIM or ALIM. In addition, LIM and ALIM inhibited over expression of the pro-inflammatory cytokines, including interleukin (IL)-1α, IL-1β, and IL-6 and tumor necrosis factor-α (TNF-α). The protection ability of ALIM was higher than that of LIM at the same dose. Thus, applied LIM and ALIM may be a promising radiation-protective agent.

Bioproduction and characterization of extracellular melanin-like pigment from industrially polluted metagenomic library equipped Escherichia coli

To explore the potential genes from the industrially polluted Amlakhadi canal, located in Ankleshwar, Gujarat, India, its community genome was extracted and cloned into E. coli EPI300™-T1^R using a fosmid vector (pCC2 FOS™) generating a library of 3,92,000 clones with average size of 40kb of DNA-insert. From this library, the clone DM1 producing brown colored melanin-like pigment was isolated and characterized. For over expression of the pigment, further sub-cloning of the clone DM1 was done. Sub-clone containing 10kb of the insert was sequenced for gene identification. The amino acids sequence of a protein 4-Hydroxyphenylpyruvate dioxygenase (HPPD), which is know to be involved in melanin biosynthesis was obtained from the gene sequence. The sequence-homology based 3D structure model of HPPD was constructed and analyzed. The physico-chemical nature of pigment was further analysed using ¹H and ¹³C NMR, LC-MS, FTIR and UV-visible spectroscopy. The pigment was readily soluble in DMSO with an absorption maximum around 290nm. Based on the genetic and chemical characterization, the compound was confirmed as melanin-like pigment. The present results indicate that the metagenomic library from industrially polluted environment generated a microbial tool for the production of melanin-like pigment.

The antioxidant activities of alkalic-extractable polysaccharides from Coprinus comatus on alcohol-induced liver injury in mice

The aim of this work was to provide a preliminary characterization of alkalic-extractable polysaccharides (ALPS) from Coprinus comatus, to explore its in vivo antioxidant activities and protective effects on alcohol-induced liver injury. ALPS showed strong antioxidant and anti-inflammatory abilities and markedly low serum enzyme activities, hepatic and serum lipid levels, as well as low hepatic lipid peroxidation levels; moreover, ALPS improved the alcohol metabolism system. These results were also confirmed by an analysis of histopathological section observations. ALPS, in both α- and β-configurations, as analysed by fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR), was mainly composed of rhamnose (Rha), fucose (Fuc), ribose (Rib), xylose (Xyl), mannose (Man), galactose (Gal) and glucose (Glu) with mass percentages of 0.52%, 1.02%, 0.80%, 0.92%, 3.05%, 2.96% and 90.73%, respectively. These results may offer support for the use of ALPS as a functional food or natural drug source that can prevent and treat alcohol-induced liver injury.

Antitumor effects of melanin from Lachnum YM226 and its derivative in H22 tumor-bearing mice

In the present study, we investigated the anti-tumor activities of the intracellular homogeneous melanin (LM) of Lachnum YM226 and its derivative (ALM) on liver cancer using murine H22 hepatocarcinoma model. The results showed that LM and ALM (50 and 200 mg kg-1) could effectively inhibit tumor growth of H22 tumour-bearing mice. The body weight, liver, spleen and thymus indices also improved in the LM and ALM treated groups. Moreover, the levels of alanine aminotransferase (ALT), aspartate aminotransaminase (AST), alkaline phosphatase (ALP), creatinine (CRE), blood urea nitrogen (BUN) and uric acid (UA) were lowered. Serum cytokines of interleukin-2 (IL-2), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) were increased on LM and ALM administration, while LM and ALM significantly decreased the vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) levels. The H&E staining indicated that LM and ALM exhibited antitumor activity in vivo by promoting apoptosis and inhibiting angiogenesis. The anti-tumor effect of ALM was more significant than that of LM for the same dose. In summary, the findings demonstrated that LM and ALM might be promising candidates for the prevention and treatment of HCC.

Antioxidant and Hepatoprotective Activities of Polysaccharides from Spent Mushroom Substrates (Laetiporus sulphureus) in Acute Alcohol-Induced Mice

In order to contribute to the exploitation and utilization of spent mushroom substrates (SMS) of Laetiporus sulphureus, hot-water-extractable polysaccharides (H-SMPS) and enzymatic-extractable polysaccharides (E-SMPS) were successfully isolated from SMS of L. sulphureus. Both H-SMPS and E-SMPS were found to have high reducing power and potential scavenging activities against hydroxyl, DPPH, and superoxide anion radicals. In vivo assays showed that the administration of H-SMPS and E-SMPS has potential hepatoprotective effects against alcohol-induced alcoholic liver disease (ALD), possibly brought about by improving liver function, increasing antioxidant status, and reducing lipid peroxidation. Furthermore, monosaccharide composition analysis showed that fucose may play a vital role in guaranteeing stronger hepatoprotection. These results may provide references for the exploitation of the SMS of L. sulphureus as a source of H-SMPS and E-SMPS, which in turn can be used as functional foods or natural drugs for the prevention of ALD and other liver diseases.