Novel Bioactive Peptides from Meretrix meretrix Protect Caenorhabditis elegans against Free Radical-Induced Oxidative Stress through the Stress Response Factor DAF-16/FOXO.

The hard clam Meretrix meretrix, which has been traditionally used as medicine and seafood, was used in this study to isolate antioxidant peptides. First, a peptide-rich extract was tested for its protective effect against paraquat-induced oxidative stress using the nematode model Caenorhabditis elegans. Then, three novel antioxidant peptides; MmP4 (LSDRLEETGGASS), MmP11 (KEGCREPETEKGHR) and MmP19 (IVTNWDDMEK), were identified and were found to increase the resistance of nematodes against paraquat. Circular dichroism spectroscopy revealed that MmP4 was predominantly in beta-sheet conformation, while MmP11 and MmP19 were primarily in random coil conformation. Using transgenic nematode models, the peptides were shown to promote nuclear translocation of the DAF-16/FOXO transcription factor, a pivotal regulator of stress response and lifespan, and induce the expression of superoxide dismutase 3 (SOD-3), an antioxidant enzyme. Analysis of DAF-16 target genes by real-time PCR reveals that sod-3 was up-regulated by MmP4, MmP11 and MmP19 while ctl-1 and ctl-2 were also up-regulated by MmP4. Further examination of daf-16 using RNA interference suggests that the peptide-increased resistance of C. elegans to oxidative stress was DAF-16 dependent. Taken together, these data demonstrate the antioxidant activity of M. meretrix peptides, which are associated with activation of the stress response factor DAF-16 and regulation of the antioxidant enzyme genes.

Spectrum-Effect Relationships between High-Performance Liquid Chromatography (HPLC) Fingerprints and the Antioxidant and Anti-Inflammatory Activities of Collagen Peptides.

A total of 13 batches of collagen peptide samples were extracted, isolated, and purified from chicken sternal cartilage under various process parameters. The fingerprint profiles of 13 batches of collagen peptides were established by high-performance liquid chromatography (HPLC). In addition, the amino acid profiles and molecular weight distributions of collagen peptides were investigated. The in vitro antioxidant activities of the peptide samples were measured using the 2,2'-Azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) assay, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the ferric-reducing antioxidant power (FRAP) assay and an assay of the oxidative damage induced by hydrogen peroxide (H2O2) in the degenerative cartilage cells from the knee joint of rat C518 (C518 cell line). The anti-inflammatory activities of the peptide samples were assessed by measuring the inflammatory responses induced by lipopolysaccharides (LPSes) in C518 cells. Subsequently, the spectrum-effect relationships between HPLC fingerprints and the antioxidant and anti-inflammatory activities of collagen peptides were investigated using grey relational analysis (GRA). Fifteen common peaks were obtained from the HPLC fingerprints of collagen peptides. Each collagen peptide sample had a characteristic set of amino acid types and contents. All of the hydrolysates of the collagen peptides were primarily composed of fractions II (500⁻1000 Da) and III (1000⁻3000 Da). Collagen peptides exhibited good scavenging activity on ABTS radical, DPPH radical, and ferric-reducing antioxidant power. Collagen peptides were also effective against H2O2-induced cellular oxidative damage in C518 cells. The antioxidant activity of collagen peptides was due to the low molecular weight and the presence of antioxidant and hydrophobic amino acid residues within its sequence. Collagen peptides significantly inhibited the secretion of inflammatory cytokines IL-1ß, TNF-α, and PGE2 in C518 cells. The anti-inflammatory activity of collagen peptides may include increased synthesis of the key components of extracellular matrix (ECM) and inhibited apoptosis of chondrocytes. The GRA results showed that peaks 2, 3, and 8 were the main components contributing to the antioxidant activity of the collagen peptides, whereas peaks 11 and 14 were the main components contributing to the anti-inflammatory activity of the collagen peptides. The components of peaks 8 and 14 were identified as GPRGPPGPVGP and VAIQAVLSLYASGR by UPLC-MS/MS. Those identified collagen peptides offer a potential therapeutic strategy for the treatment of osteoarthritis (OA) due to their antioxidative stress and due to them disturbing the catabolism and anabolism processes in arthrodial cartilage.

Mixed polysaccharides derived from Shiitake mushroom, Poriacocos, Ginger, and Tangerine peel enhanced protective immune responses in mice induced by inactivated influenza vaccine.

Influenza viruses are responsible for severe respiratory tract infections of individuals and may cause pandemics with a high risk of mortality and morbidity. Although vaccination is a primary means for prevention of influenza virus infections, poor vaccine performance or inadequate immune responses limits the efficacy of current vaccines and raises question regarding whether a better correlates of protection procedures should be performed. Here, we want to evaluate whether mixed polysaccharides (MPs) derived from shiitake mushroom, poriacocos, ginger, and dried tangerine peel could promote the immune response of inactivated influenza vaccine. Firstly, MPs were given to mice each day and for a total of 30 days, during which two immunizations were performed on mice on days 14 and 21. The results showed that serum total IgG and IgG2a levels were increased in MPs-treated mice on day 30. Following A/WSN/33 (H1N1) virus challenge, we found that MPs pretreatment in mice could increase mice weight gain and attenuate their clinical symptoms. Additional protective factors were also observed including prevention of excessive lung inflammation, promotion of CD19+ and CD278+ cell proportions in lung, elimination of virus in lung, and elevation of IFN-γ levels in serum. The current study demonstrate that MPs from shiitake mushroom, poriacocos, ginger, and dried tangerine peel could promote the immune efficacy and alleviate lung inflammation in mice with vaccines against H1N1 virus infection by activating both humoral and cellular immunity.

Coadministration with Tea Polyphenols Enhances the Neuroprotective Effect of Defatted Walnut Meal Hydrolysate against Scopolamine-Induced Learning and Memory Deficits in Mice.

The present study aimed to investigate the combined effects of defatted walnut meal hydrolysate (DWMH) and tea polyphenols (TP) on learning improvement and to explain mechanistically why the combined treatments were more effective than either subject alone. In the step-down avoidance test and the Morris water maze test, codelivery of DWMH and TP was more effective than either individual supplement in reversing memory impairment in scopolamine-treated mice. Mixing with TP significantly facilitated the protective effects of DWMH or DWMH-derived peptides (cationic peptide P1 and anionic peptide P2) on H2O2-injured SH-SY5Y cells. Although combination treatment with TP and DWMH did not significantly alter systemic exposure to P1 or P2 in rats, it significantly increased the accumulation of the two peptides in the mouse brain. In addition, TP significantly improved cellular uptake of P1 and P2 by brain capillary endothelial cells, indicating that TP enhanced the blood-brain barrier permeation of DWMH-derived peptides. The proposed explanation for the advantage of combined treatment with TP and DWMH in reversing memory impairment was that TP enhanced both the protective effects of DWMH on nerve cells and the accumulation of DWMH in the brain. Our study can aid efforts to develop products and investigate the effects of nutrient combinations on brain disorders.

Antioxidant and anti-aging effects of a sea cucumber protein hydrolyzate and bioinformatic characterization of its composing peptides.

Sea cucumbers have been used as food delicacies and traditional medicine for centuries, and their health benefits are partly attributed to their repertoire of proteins. Peptides prepared from the sea cucumber Apostichopus japonicus are reported to have in vitro antioxidant activities. Here, we investigated the in vivo antioxidant capacity of AjPH, a peptide-rich A. japonicus protein hydrolyzate, and found that AjPH is capable of increasing the survival rate and reducing the reactive oxygen species (ROS) level in the animal model Caenorhabditis elegans under increased oxidative stress induced by paraquat. AjPH is also shown to enhance the antioxidant defense system in paraquat-exposed nematodes, including upregulation of superoxide dismutase and catalase activities and reduction of malondialdehyde contents. To explore underpinning antioxidant mechanisms, cellular and chemical assays were used to demonstrate that AjPH not only reduces ROS accumulation in cells but also directly scavenges DPPH free radicals. Further studies indicate that AjPH can decrease age pigments and extend lifespan but does not reduce food intake, body length and brood size of the nematodes, demonstrating its capacity to delay physiological aging. Using activity-guided fractionation by ultrafiltration and gel filtration, we then isolated antioxidant fractions from AjPH and identified the sequences of their composing peptides, which were subjected to in silico analysis for prospective motifs, physicochemical properties and antioxidant potential. Taken together, our results provide an insight into the nutraceutical potential of the sea cucumber protein hydrolyzate for aging and related conditions and also a basis for future mechanistic studies of individual antioxidant peptides.

Antioxidative Effects and Mechanism Study of Bioactive Peptides from Defatted Walnut ( Juglans regia L.) Meal Hydrolysate.

The peptide components of defatted walnut ( Juglans regia L.) meal hydrolysate (DWMH) remain unclear, hindering the investigation of biological mechanisms and exploitation of bioactive peptides. The present study aims to identify the peptide composition of DWMH, followed by to evaluate in vitro antioxidant effects of selected peptides and investigate mechanisms of antioxidative effect. First, more than 1 000 peptides were identified by de novo sequencing in DWMH. Subsequently, a scoring method was established to select promising bioactive peptides by structure based screening. Eight brand new peptides were selected due to their highest scores in two different batches of DWMH. All of them showed potent in vitro antioxidant effects on H2O2-injured nerve cells. Four of them even possessed significantly stronger effects than DWMH, making the selected bioactive peptides useful for further research as new bioactive entities. Two mechanisms of hydroxyl radical scavenging and ROS reduction were involved in their antioxidative effects at different degrees. The results showed peptides possessing similar capacity of hydroxyl radical scavenging or ROS reduction may have significantly different in vitro antioxidative effects. Therefore, comprehensive consideration of different antioxidative mechanisms were suggested in selecting antioxidative peptides from DWMH.

Inhibitory activities of some traditional Chinese herbs against testosterone 5α-reductase and effects of Cacumen platycladi on hair re-growth in testosterone-treated mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Many traditional Chinese medicines (TCM) have been used for hundreds of years for hair blackening and hair nourishing, and now many of them are commonly used in Chinese herbal shampoo to nourish the hair and promote hair growth. AIMS OF THE STUDY: The present study was performed to screen 5α-reductase (5αR) inhibitors from traditional Chinese medicines, evaluate its hair growth promoting activity in vivo, and further investigate its effects on androgen metabolism and the expression of 5αR II in hair follicles. MATERIALS AND METHODS: Nine TCM which were dried, ground and extracted by maceration with 75% ethanol or distilled water were used for screening 5αR inhibitors, and enzymes were extracted from the rat epididymis. The leaves of Platycladus orientalis (L.) Franco was used to evaluate the in vivo anti-androgenic activity. Skin color was observed daily and the hair re-growth was assessed by assigning the hair growth score. The longitudinal sections of hair follicles were used for observing follicle morphology, classifying of distinct stages of hair follicle morphogenesis and calculate the average score. The transverse sections were used for determination of hair follicle counts. Testosterone (T), Dihydrotestosterone (DHT) and Estradiol (E2) levels in serum and skin tissue were detected by ELISA kits. The immunofluorescence assay was used to detect the influence of CP-ext on 5αR expression in dorsal skin. RESULTS: We found the extract of Ganoderma lucidum (GL-ext), Polygonum multiflori (PM-ext), Cacumen platycladi (CP-ext) and Cynomorium songaricum (CS-ext) showed stronger 5αR inhibitory activity. CP-ext (5mg and 2mg/mouse/day) could significantly shorten the time of the dorsal skin darkening and got longhaired (P<0.01), and showed high hair re-growth promoting activity. Furthermore the histological data of hair follicles in each group showed that CP-ext could promote the growth of hair follicle and slowed down hair follicles enter the telogen. What's more CP-ext significantly reduced DHT levels and down-regulated the expression of 5αRⅡin skin (P<0.01). CONCLUSIONS: GL-ext, PM-ext, CP-ext and CS-ext showed strong 5αR inhibitory activity. CP-ext possesses high hair growth promoting activity in the in vivo androgen-sensitive mouse model via inhibiting the 5αR activity, decreasing the DHT levels and in turn suppressing the expression of 5αR. Our study may contribute to the development of a new generation of herbal supplements with clearer material basis of pharmacodynamic for treating androgenic alopecia (AGA).