Molecular cloning of the hepcidin gene from crescent sweetlips (Plectorhinchus cinctus) and characterization of its encoded antimicrobial peptide.

Hepcidin has been identified as an important antimicrobial peptide exerting important innate immunomodulatory activities in many fish species. In the present study, reverse transcription PCR coupled with the rapid amplification of cDNA ends was used to obtain the full-length cDNA of the crescent sweetlips hepcidin gene, which is 829 bp in length and includes an 273 bp ORF encoding a peptide with 90 amino acid residues. Sequence alignment showed a typical RXKR motif and eight conserved cysteine residues in the deduced amino acid sequences. Four disulfide bonds were predicted to form between these eight cysteines, which may stabilize the hairpin structure in hepcidin molecule. Furthermore, phylogenetic analysis showed that the deduced amino acid sequences of crescent sweetlips hepcidin had high sequence homology to hepcidins from fish species of Eupercaria. In addition, the crescent sweetlips hepcidin peptide demonstrated a strong antimicrobial activity in vitro against several types of pathogenic bacteria in fish. In conclusion, the obtained results suggested that crescent sweetlips hepcidin possessed the typical structure similar to other fish hepcidins and had strong antibacterial activity, which showed great potential in the prevention of fish diseases in aquaculture.

Prokaryotic Expression, Purification, and Antibacterial Activity of the Hepcidin Peptide of Crescent Sweetlips (Plectorhinchus cinctus).

The hepcidin peptide of crescent sweetlips (Plectorhinchus cinctus) is a cysteine-rich, cationic antimicrobial peptide that plays a crucial role in the innate immune system's defense against invading microbes. The aim of this study was to identify the optimal parameters for prokaryotic expression and purification of this hepcidin peptide and characterize its antibacterial activity. The recombinant hepcidin peptides were expressed in Escherichia coli strain Arctic Express (DE3), with culture and induction conditions optimized using response surface methodology (RSM). The obtained hepcidin peptides were then purified before tag cleavage, and their antibacterial activity was determined. The obtained results revealed that induction temperature had the most significant impact on the production of soluble recombinant peptides. The optimum induction conditions were determined to be an isopropylthio-ß-galactoside (IPTG) concentration of 0.21 mmol/L, induction temperature of 18.81 °C, and an induction time of 16.01 h. Subsequently, the recombinant hepcidin peptide was successfully purified using Ni-IDA affinity chromatography followed by SUMO protease cleavage. The obtained hepcidin peptide (without His-SUMO tag) demonstrated strong antimicrobial activity in vitro against V. parahaemolyticus, E. coli, and S. aureus. The results showed prokaryotic (E. coli) expression is a feasible way to produce the hepcidin peptide of crescent sweetlips in a cost-effective way, which has great potential to be used as an antimicrobial agent in aquaculture.

Ferulic acid ameliorates intrahepatic triglyceride accumulation in vitro but not in high fat diet-fed C57BL/6 mice.

Phenolic acids can improve obesity-related and metabolic syndrome-related conditions including non-alcoholic fatty liver disease (NAFLD). In this study, the effects of ferulic acid (FA) on the metabolic changes related to NAFLD were investigated in oleic acid (OA)-treated HepG2 cells and C57BL/6 mice fed a high fat diet (HFD). In vitro, FA (25 and 50 µg/mL) treatment significantly reduced cellular lipid accumulation with no obvious cytotoxicity, in-part mediated by the suppression of ERK1/2, JNK1/2/3, and HGMB1 expression. However, in vivo administration of FA (20 mg/kg bw·day) for 17 weeks led to no obvious effects on body weight and liver weight gain, blood lipid profiles, or histological abnormalities in obese C57BL/6 mice induced by HFD. Taken together, the positive effects of FA on the reduction of hepatic triglyceride accumulation were therefore demonstrated in cellular model, while its hepatic protective effects might need to be further explored in rodent models and clinical trials.

Research on a Specialty Mushroom (Pleurotus tuber-regium) as a Functional Food: Chemical Composition and Biological Activities.

Pleurotus tuber-regium (PTR) is an edible specialty mushroom that has attracted growing interest recently because of its sensory attributes, high nutritional values, and important medicinal properties. PTR is rich in bioactive polysaccharides, proteins with essential amino acids, essential fatty acids, dietary fiber, minerals, and vitamins. Current studies have shown that the nutrients and bioactive ingredients of PTR contribute to their antitumor, antihypercholesterolemic, antihypertensive, antiobesity, hepatic-protective, antimicrobial, antioxidant, and prebiotic activities, indicating that PTR is a promising functional food and nutraceutical. In this review, the chemical constituents and physiological functions of PTR are summarized, which provide the scientific basis to support the further research and development of its application in the food and pharmaceutical industries.

Review of Distribution, Extraction Methods, and Health Benefits of Bound Phenolics in Food Plants.

Phenolic compounds are important functional bioactive substances distributed in various food plants. They have gained wide interest from researchers due to their multiple health benefits. There are two forms of phenolic compounds: free form and bound form. The latter is also called bound phenolics (BPs), which are found mainly in the cell wall and distributed in various tissues/organs of the plant body. They can either chemically bind to macromolecules and food matrixes or be physically entrapped in food matrixes and intact cells. Various isolation methods, including chemical, biological, and physical methods, have been employed to extract BPs from plants. BPs have been shown to have strong biological activities, including antioxidant, probiotic, anticancer, anti-inflammation, antiobesity, and antidiabetic effects as well as beneficial effects on central nervous system diseases. This review summarizes research findings on these topics to help in better understanding of BPs and provide comprehensive information on their health effects.

The effect of dealuminated jellyfish in mitigating toxicity on mice exposed to aluminum.

In the present study, the removal effect of dealuminated jellyfish on Aluminum (Al) in mice was evaluated. The results showed that the consumption of dealuminated jellyfish significantly decreased Al accumulation in the liver of mice, indicating an Al-removing effect of dealuminated jellyfish on Al-enriched mice. In addition, the effect of dealuminated jellyfish consumption on an Al-overload model was further evaluated. The result showed that the Al content in different tissues and organs of mice was significantly reduced, but it had no significant effect on the other metallic element content. These results indicated that the samples from oral administration have a certain Al-removing effect in Al-overloaded mice. Moreover, the cluster analysis of differentially expressed proteins in blood and liver showed that a high dose of dealuminated jellyfish improve the expression of amine oxidase B and enhance the effect of Al discharge.

Anti-obesity effect of trans-cinnamic acid on HepG2 cells and HFD-fed mice.

Trans-cinnamic acid (tCA) is a phenylpropenoic acid, which occurs naturally in a number of plants. In this study, the anti-obese effects of tCA were evaluated in oleic acid (OA)-induced HepG2 cells and high fat diet (HFD)-fed mice. The results showed tCA treatment significantly decreased lipid accumulation in HepG2 cells exposed to OA. Furthermore, administration of tCA (40 mg/kg/day) curbed body weight gains, reduced liver and adipose tissue weight, and ameliorated hepatic steatosis and adipose hypertrophy in mice fed with HFD. In addition, significant decrease in plasma levels of TG, TC and LDL-C were also observed in HFD-fed mice with tCA treatment. Collectively, tCA may play a vital role in preventing and treating diet induced obesity.

Role of intestinal microecology in the regulation of energy metabolism by dietary polyphenols and their metabolites.

BACKGROUND: Polyphenols are a class of plant secondary metabolites with a variety of physiological functions. Polyphenols and their intestinal metabolites could greatly affect host energy metabolism via multiple mechanisms. OBJECTIVE: The objective of this review was to elaborate the role of intestinal microecology in the regulatory effects of dietary polyphenols and their metabolites on energy metabolism. METHODS: In this review, we illustrated the potential mechanisms of energy metabolism regulated by the crosstalk between polyphenols and intestinal microecology including intestinal microbiota, intestinal epithelial cells, and mucosal immune system. RESULTS: Polyphenols can selectively regulate the growth of susceptible microorganisms (eg. reducing the ratio of Firmicutes to Bacteroides, promoting the growth of beneficial bacteria and inhibiting pathogenic bacteria) as well as alter bacterial enzyme activity. Moreover, polyphenols can influence the absorption and secretion of intestinal epithelial cells, and alter the intestinal mucosal immune system. CONCLUSION: The intestinal microecology play a crucial role for the regulation of energy metabolism by dietary polyphenols.

n-Butanol Extract of Lotus Seeds Exerts Antiobesity Effects in 3T3-L1 Preadipocytes and High-Fat Diet-Fed Mice via Activating Adenosine Monophosphate-Activated Protein Kinase.

In this study, the antiobesity effects of n-butanol extract of lotus seeds (LBE) were evaluated in cultured 3T3-L1 preadipocytes and in high-fat diet (HFD)-fed mice. LBE decreased lipid contents in mature 3T3-L1 cells without obvious cytotoxicity. Meanwhile, LBE supplementation also led to weight loss and improved plasma lipid profiles in HFD-fed mice. Furthermore, LBE could activate AMP-activated protein kinase (AMPK) accompanied by down-regulation of lipogenesis related genes (PPARγ, aP2, LPL, C/EBPα, FAS, SREBP-1c) and up-regulation of lipolysis genes (adiponectin and PPARα) in vitro and in vivo. Collectively, our data demonstrated LBE possesses antiadipogenic and antilipogenic activities which are, at least partially, mediated by the activation of AMPK signaling pathways.

Enhancement of the Production of Bioactive Microalgal Metabolites by Ultraviolet Radiation (UVA 365 nm).

Two marine microalgae, Nitzschia closterium and Isochrysis zhangjiangensis, treated for 9 days with photosynthetically active radiation (PAR), were subjected to 3 days of ultraviolet light band A at 365 nm (UVA365) followed by a 3 day post-UVA PAR treatment. Compared with the control that only had PAR treatment, UVA365 treatment significantly ( p < 0.05) increased the amounts of total xanthophylls in N. closterium and I. zhangjiangensis by up to 3.53- and 1.23-fold, respectively, after 3 days of UVA365 irradiation. In particular, UVA365 treatment markedly ( p < 0.05) increased two major bioactive xanthophyll pigments, fucoxanthin in N. closterium and diadinoxanthin in I. zhangjiangensis, by up to 1.97- and 1.52-fold, respectively. UVA365 treatment significantly ( p < 0.05) increased the accumulation of another bioactive microalgal metabolite, total mycosporine-like amino acids, in N. closterium and I. zhangjiangensis by up to 1.40- and 1.30-fold, respectively. UVA365 irradiation has potential as an efficient approach for enhancing the production of valuable microalgal metabolites.

Mechanistic Study of the In Vitro and In Vivo Inhibitory Effects of Protocatechuic Acid and Syringic Acid on VEGF-Induced Angiogenesis.

The antiangiogenic activities of two structurally similar phenolics, protocatechuic acid (PA) and syringic acid (SA), were investigated. In vitro study using HUVECs demonstrated that both PA and SA (at 25 µM) significantly ( p < 0.05) inhibited VEGF-induced cell proliferation by 22.68 ± 5.6% and 21.93 ± 2.0%, respectively; cell migration by 50.04 ± 3.3% and 39.72 ± 4.7%, respectively; cell invasion by 44.16 ± 4.23% and 51.90 ± 2.73%, respectively; and cellular ROS generation by 11.48 ± 6.32% and 21.17 ± 9.10%, respectively. Our mechanistic study revealed that PA and SA blocked the VEGFR2-dependent Akt/ MMP2 and ERK pathways in HUVECs. These inhibitory effects were further confirmed by a decrease of endogenous alkaline phosphatase activity for PA and SA (21.47 ± 1.77% and 10.37 ± 1.27%, respectively) and the suppression of subintestinal vessel plexus formation in Tg (fli1a:EGFP) y1-type transgenic zebrafish embryos. PA and SA down-regulated the angiogenesis-related signal transduction pathway of VEGFα-VEGFR2 or Ang2- Tie2 in zebrafish. Moreover, it was also found that PA demonstrated a better inhibition on VEGF-induced migration of HUVEC and zebrafish vasculature. This might be due to the different number of hydroxyl and methoxy substituents possessed by PA and SA. Taken together, these findings indicate that phenolics PA and SA have potent antiangiogenic activities and are potential targets for the design and development of anticancer agents.

Occurrence and biosynthesis of carotenoids in phytoplankton.

Naturally occurring carotenoids are important sources of antioxidants, anti-cancer compounds and anti-inflammatory agents and there is thus considerable market demand for their pharmaceutical applications. Carotenoids are widely distributed in marine and freshwater organisms including microalgae, phytoplankton, crustaceans and fish, as well as in terrestrial plants and birds. Recently, phytoplankton-derived carotenoids have received much attention due to their abundance, rapid rate of biosynthesis and unique composition. The carotenoids that accumulate in particular phytoplankton phyla are synthesized by specific enzymes and play unique physiological roles. This review focuses on studies related to the occurrence of carotenoids in different phytoplankton phyla and the molecular aspects of their biosynthesis. Recent biotechnological advances in the isolation and characterization of some representative carotenoid synthases in phytoplankton are also discussed.

Comparison of the Composition and Antioxidant Activities of Phenolics from the Fruiting Bodies of Cultivated Asian Culinary-Medicinal Mushrooms.

The composition profile and the antioxidant properties of phenolics in water extracts obtained from the fresh fruiting bodies of 4 common cultivated Asian edible mushrooms-Agrocybe aegerita, Pleurotus ostreatus, P. eryngii, and Pholiota nameko were compared. The water extract from A. aegerita (AaE) had the highest total phenolic content (TPC) at 54.18 ± 0.27 gallic acid equivalents (µmol/L)/mg extract (P < 0.05), as measured by the Folin-Ciocalteu method, and consisted of the largest number (including gallic acid, protocatechuic acid, chlorogenic acid, ferulic acid, and sinapic acid) and total amounts of phenolic acids identified by Fourier transform-ion cyclotron resonance mass spectrometry. The water extract of Ph. nameko was found to have the second-highest TPC (43.55 ± 0.10 gallic acid equivalents [µmol/L]/mg extract), followed by the water extract of P. eryngii and the water extract of P. ostreatus (39.55 ± 0.25 and 39.02 ± 0.30 gallic acid equivalents/mg extract, respectively). The scavenging activities of the water extracts from these mushrooms were evaluated against 2,2-diphenyl-l-(2,4,6-trinitrophenyl) hydrazyl diphenylpicrylhydrazyl (DPPH), superoxide anion radicals, hydroxyl radicals, and hydrogen peroxide. Based on halfmaximal effective concentrations, AaE was more effective in scavenging hydrogen peroxide (<0.05), followed by DPPH (0.51 mg/mL), superoxide anion radicals (0.85 mg/mL) and hydroxyl radicals (5.94 mg/mL), then the other mushroom water extracts. The differences in the half-maximal effective concentrations of individual mushroom water extracts were probably the result of the different numbers and amounts of individual phenolic acids in the extracts. The antioxidant activities of the mushroom water extracts were correlated with their TPC. The strongest antioxidant properties of AaE were consistent with its highest TPC and with the largest number and amount of phenolics identified in the extract. These results indicated that cultivated edible mushrooms could be a potential source of natural antioxidants with free radical scavenging properties for application as a functional food ingredient.

Phytochemical profiles of marine phytoplanktons: an evaluation of their in vitro antioxidant and anti-proliferative activities.

Marine microorganisms such as phytoplanktons are a rich resource of bioactive components with antioxidant and anti-proliferative activities that can act as novel functional food ingredients. In this study, the pigment profiles, total mycosporine-like amino acids (MAAs) and total phenolic contents (TPCs) in solvent extracts including 90% acetone and methanol from five marine phytoplanktons including Nitzschia closterium (Bacillariophyta), Isochrysis zhangjiangensis (Haptophyta), Platymonas subcordiformis (Chlorophyta), Porphyridium cruentum (Rhodophyta) and Synechocystis pevalekii (Cyanobacteria) were analyzed. Each phytoplankton from different phyla had its unique compositions of carotenoids and chlorophylls. The 90% acetone extract from I. zhangjiangensis had the highest MAA content (508.30 µg per g DW) while the methanol extract from N. closterium had the highest level of TPCs (6.15 mg GAE per g DW) among all the phytoplanktons investigated. The amounts of total carotenoids in all the 90% acetone extracts from the five phytoplanktons as well as total MAAs in those from within the four microalgae except S. pevalekii were found to be strongly correlated with their antioxidant activities evaluated by the DPPH, TEAC and FRAP assays. Only the level of total carotenoids in the phytoplanktons was correlated with their anti-proliferative activities assessed by the MTT assays using MCF-7 cells. Therefore, individual carotenoid pigments seemed to be mainly responsible for the antioxidant and anti-proliferative (or anticancer) activities found in the solvent extracts of the five phytoplanktons. Hence these phytoplanktons have the potential as novel sources of natural food antioxidants and anticancer agents to be used as active ingredients in functional food products.

Antioxidant and antiangiogenic properties of phenolic extract from Pleurotus tuber-regium.

Pleurotus tuber-regium (Fries) Singer (PTR), both an edible and a medicinal mushroom also known as tiger milk mushroom, has experienced growing popularity and economic importance due to its flavor, nutritive value, and medicinal effects. In this study, the antioxidant and antiangiogenic activities of a 60% ethanol extract (EE) obtained from the sclerotium of PTR were investigated. Typical phenolic compounds including protocatechuic, chlorogenic, syringic, ferulic, and folic acid were identified and quantified in EE by the HPLC-UV-ESI/MS analyses. EE possessed strong antioxidant activity and could dose-dependently inhibit vascular endothelial growth factor (VEGF)-induced human umbilical vein endothelial cells (HUVEC) migration and tube formation. qPCR results showed that VEGF-induced FGF, ANG-Tie, and MMP gene expression as well as VEGFR were down-regulated at the mRNA level after treated with EE, suggesting that multiple molecular targets related to angiogenesis was involved. Furthermore, EE also inhibited the formation of subintestinal vessel plexus (SIVs) in zebrafish embryos in vivo. All of these suggested that EE of PTR could be the source of potential inhibitors to target angiogenesis.