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Peptides, functional nutrients with a size between those of large proteins and small amino acids, are easily absorbed by the human body. Therefore, they are seeing increasing use in clinical medicine and have revealed immunomodulatory and anti-inflammatory properties which could make them effective in healing skin wounds. This review sorted and summarized the relevant literature about peptides during the past decade. Recent works on the extraction, modification and synthesis of peptides were reviewed. Importantly, the unique beneficial effects of peptides on the skin were extensively explored, providing ideas for the development and innovation of peptides and laying a knowledge foundation for the clinical application of peptides.

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Objectives Tithonia diversifolia (Asteraceae) is used in Cameroonian traditional medicine for the treatment of several diseases amongst which are hepatic disorders. Anti-inflammatory, analgesic and anti-diabetic properties have been reported but, there is no scientific information on its hepato-protective effects. The aim of this study was to evaluate the curative effects of the Tithonia diversifolia (T. diversifolia) leaves aqueous extract on ethanol induced-hepatotoxicity in rats. Methods Ethanol 40° (4 g/kg) was administered daily by intragastric gavage for 21 days, and then the extract was administered concomitantly with ethanol for two more weeks. Some biochemical serum and tissue parameters were evaluated. Histopathologic analysis of the liver was carried out. Results The ingestion of ethanol induced a significant reduction of body weight and a significant increase in some markers of hepatic function (Alanine Amino-transferase, Aspartate Amino-transferase, alkaline phosphatase, gamma glutamyl-transferase, total bilirubin and albumin). These alterations were accompanied by a significant increase in the levels of serum triglycerides (p<0.001). Intoxicated animals were also characterized by a significant decrease of reduced glutathione and nitrites concentrations, catalase and superoxide dismutase activities as well as an increase of malondialdehyde levels. The histopathological examination showed vascular congestion, disorganized parenchyma, liver inflammation and dilation of sinusoid. The extract at the doses of 60 and 120 mg/kg reversed ethanol-induced adverse effects. Conclusion Our study found that, the aqueous extract of T. diversifolia leaves has hepato-protective activity against ethanol-induced liver damages due partly to its antioxidant effect. This result justifies its empirical use for the treatment of liver problems.

The continuous ovulation of laying hens during the peak period is likely to cause oxidative stress, resulting in a reduction in the laying cycle over time. The aim of this study was to evaluate the antioxidant effects of Aronia melanocarpa (AM) in the diet and its effect on the yolk precursor content caused by ovulation in laying hens during the peak period. A total of 300 25-week-old Roman brown laying hens were randomly divided into five groups with six replicates in each group, 10 in each replicate. The control group was fed a basal diet, the positive control group was fed a Vitamin C (VC) plus basal diet, and the experimental group was fed 1%, 4%, and 7% doses of AM plus diet according to the principle of energy and nitrogen requirements, which lasted eight weeks. At the end of the study, the egg quality, biochemical, and antioxidant markers, as well as mRNA and protein expressions, were evaluated to determine the potential signaling pathways involved. Results showed that the addition of AM to the feed increased the weight of laying hens at the peak of egg production and improved egg quality. The biochemical markers, as well as the antioxidant parameters in the serum, liver, and ovarian tissues, were ameliorated. The gene and protein expression of recombinant kelch-like ECH-associated protein 1 (Keap1) in the liver and ovarian tissues was decreased, while nuclear factor erythroid-2 related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expression was increased. The feed supplemented with AM also increased the estrogen contents and lipid parameters, as well as the gene and protein expressions related to the yolk precursor. Feed supplemented with AM could improve the egg quality and the oxidative stress caused by the ovulation process of laying hens during the peak egg production period by activating the Keap1/Nrf2 signaling pathway. These results suggest that the feed supplemented with 1% AM and 4% AM can improve egg production in peak laying hens.

Flammulina velutipes polysaccharides (FVP) have been proven to induce apoptosis in HepG2 cells. It is well known that endoplasmic reticulum stress (ERS) is involved in apoptosis. However, ERS mediates FVP-induced apoptosis in HepG2 cells remains unclear. In our study, the results indicated that FVP caused ERS in HepG2 cells. They showed that FVP were water-soluble polysaccharides with the weight average molecular weight of 1972 kDa, which were mainly composed of mannose, gluconic acid, glucose, galactose, xylose and fructose in a molar ratio of 6.6 : 1.3 : 79.9 : 7.4 : 3.4 : 1.5. After FVP treatment, the expression levels of genes and proteins related to ERS were upregulated. The inhibition of ERS by 4-phenylbutyric acid (4-PBA) pretreatment could significantly reduce the role of FVP in inducing apoptosis. We further found the results of immunofluorescence and flow cytometry showing that Ca 2+ in the ERS leaked out, and the intracellular Ca 2+ concentration increased after FVP treatment. The pretreatment with the phospholipase C (PLC) inhibitor U73122 proved that FVP caused excessive intracellular Ca 2+ concentration by activating the phospholipase C-inositol-1,4,5-triphosphate (PLC-IP3) pathway, resulting in ERS, and ultimately leading to apoptosis. In summary, our results indicated that FVP induced ERS-mediated apoptosis by activating PLC-IP3 pathway in HepG2 cells.