The anti-photoaging effect of antioxidant collagen peptides from silver carp (Hypophthalmichthys molitrix) skin is preferable to tea polyphenols and casein peptides

The Protective Effects of Silkworm (Bombyx mori) Pupae Peptides on UV-Induced Skin Photoaging in Mice

Silkworm (Bombyx mori) pupae are popular edible insects with high nutritional and therapeutic value. Currently, there is growing interest in the comprehensive application of silkworm pupae. In this study, peptides that exhibited anti-photoaging activity were obtained from silkworm pupae protein, aiming to investigate the protective effects and potential mechanisms of silkworm pupae peptides (SPPs) on skin photoaging. The results showed that SPPs were composed of 900 short peptides and could effectively alleviate skin photoaging progression. They significantly eliminated excessive production of ROS and MDA; meanwhile, they also renovated the antioxidant enzyme activities. The biomarkers related to collagen synthesis and degradation, including hydroxyproline, interstitial collagenase, and gelatinase, demonstrated that SPPs could suppress collagen degradation. Histopathological results showed that SPPs could reduce the inflammatory infiltrate and the thickness of the dermis and epidermis, as well as increase the collagen bundles and muscle fibers. The histopathological and biochemical results confirmed that SPPs could alleviate photoaging by inhibiting abnormal skin changes, reducing oxidative stress, and immune suppression. Overall, these data prove the protective effects of SPPs against the photoaging process, suggesting their potential as an active ingredient in skin photoaging prevention and therapy.

Effects of collagen hydrolysates on UV-induced photoaging mice: Gly-Pro-Hyp as a potent anti-photoaging peptide

This work aimed to investigate the protective effects of collagen hydrolysates containing different contents of Gly-Pro-Xaa tripeptides on UV-induced photoaging mice and to identify potent anti-photoaging peptides. Results showed that oral ingestion of collagen hydrolysates with a higher content of Gly-Pro-Xaa tripeptides (∼11.4%, HCH) dramatically enhanced the absorption of Pro-Hyp, Hyp-Gly, and Gly-Pro-Hyp into the body, which were 1.77-, 2.18-, and 65.07-fold higher in area under the concentration-time curve (AUC) values than that of collagen hydrolysates with a lower content of Gly-Pro-Xaa tripeptides (∼3.8%, LCH), respectively. Furthermore, the protective effects of HCH on the photo-aged skin of mice were significantly stronger than those of LCH in terms of increases in the contents of hyaluronic acid and collagen, improvement in skin elasticity and epidermal thickness, alleviation in inflammation, and decreases in the contents of matrix metalloproteinase-1 (MMP-1) and MMP-3. More importantly, Gly-Pro-Hyp displayed potent anti-photoaging activities comparable to HCH based on an equivalent amount of Hyp. Network pharmacology analysis for potential mechanisms further indicated that Gly-Pro-Hyp might interact with JUN and FOS and regulate IL-17 and TNF signaling pathways. Collectively, our results suggested that HCH had great potential to be applied in functional foods for skin health and Gly-Pro-Hyp was found to be a potent collagen-derived anti-photoaging peptide, which might contribute to the excellent anti-photoaging effects of HCH.

Lipid-Induced Oxidative Modifications Decrease the Bioactivities of Collagen Hydrolysates from Fish Skin: The Underlying Mechanism Based on the Proteomic Strategy

Collagen peptides exhibit various bioactivities, including antioxidation and ACE inhibition. However, the bioactivities of collagen peptides decrease gradually due to oxidation deterioration during storage, and this degradation of bioactive peptides is rarely studied. In this study, the oxidative levels and the bioactivities of collagen peptides were investigated during an oxidative-induced storage accelerated by lipids. The results suggested that the oxidation of collagen peptides was divided into three stages. At the early stage, the carbonyl content of collagen peptides increased rapidly (from 2.32 to 3.72 μmol/g peptide), showing a close correlation with their bioactivities (for antioxidation, r = -0.947; for ACE inhibition, r = -0.911). The oxidation level in the middle stage continued but was stable, and the bioactivities decreased. At the later stage, the Schiff base and dityrosine content increased significantly and showed a strong correlation with the bioactivities (antioxidation, r = -0.820, -0.801; ACE inhibition, r = -0.779, -0.865). The amino acid and proteomic analyses showed that Met, Lys, and Arg were susceptible to oxidation and revealed their oxidative modification types. This study provided an insight into the dynamic oxidative modifications of collagen peptides, which were shown to correlate well with the change in bioactivities.

Enrichment of antiplatelet peptides and removal of fishy odor from silver carp skin collagen hydrolysates by macroporous resins: pH value of loading sample affects the peptides separation

Enrichment of antiplatelet peptides from silver carp skin collagen hydrolysates (CH) was studied using macroporous resins. Static adsorption showed that XAD-16 resin was the suitable resin due to its high adsorption capacity. The dynamic desorption of CH was studied on XAD-16 resin by ethanol gradient elution. Interestingly, pH value of loading sample had a great impact on the peptides separation. Results revealed that the yield and the antiplatelet activity of Ethl-20% fraction were highest at loading sample pH 6.0. The antiplatelet peptides were enriched in the 20% ethanol fraction with IC₅₀ 2.03 mg/mL compared to IC₅₀ of CH, 4.7 mg/mL. Besides, the Ethl-20% fraction had a weakest fishy odor. Moreover, a series of peptides containing Hyp-Gly or Pro-Gly were identified from Ethl-20% fraction, which contributed to the antiplatelet activities. This study provided a simple and efficient method for large-scale separation enrichment of antiplatelet peptides as functional foods from CH.

Flavonoids and their therapeutic applications in skin diseases

Flavonoids are a class of plant polyphenols found in a variety of fruits, vegetables, teas, and flowers. These compounds are present in many common dietary sources, such as green tea, wine, pomegranates, and turmeric, and possess a broad spectrum of biological activity due to their unique chemical structure. Flavonoids exhibit antioxidant, anti-inflammatory, antiviral, and anticarcinogenic properties that have been widely studied as potential therapeutics for diseases ranging from Alzheimer's disease to liver disease. There is currently significant research into therapeutic benefits of flavonoids in various skin conditions as these compounds have been shown to absorb ultraviolet radiation and modulate cancer and inflammation signaling pathways. This review discusses the current research in the application of flavonoids in skin diseases (e.g., prevention of premature photoaging, prevention and treatment of skin cancer, and promotion of skin wound healing) and their proposed mechanisms to provide a basis for future basic and translational research of flavonoids as potential drugs in the prevention and treatment of skin disorders.

Flavonoids and their therapeutic applications in skin diseases

Flavonoids are a class of plant polyphenols found in a variety of fruits, vegetables, teas, and flowers. These compounds are present in many common dietary sources, such as green tea, wine, pomegranates, and turmeric, and possess a broad spectrum of biological activity due to their unique chemical structure. Flavonoids exhibit antioxidant, anti-inflammatory, antiviral, and anticarcinogenic properties that have been widely studied as potential therapeutics for diseases ranging from Alzheimer's disease to liver disease. There is currently significant research into therapeutic benefits of flavonoids in various skin conditions as these compounds have been shown to absorb ultraviolet radiation and modulate cancer and inflammation signaling pathways. This review discusses the current research in the application of flavonoids in skin diseases (e.g., prevention of premature photoaging, prevention and treatment of skin cancer, and promotion of skin wound healing) and their proposed mechanisms to provide a basis for future basic and translational research of flavonoids as potential drugs in the prevention and treatment of skin disorders.

Transepithelial transport and cellular mechanisms of food-derived antioxidant peptides

Considering the involvement of oxidative stress in the etiology of many non-communicable diseases, food-derived antioxidant peptides (FDAPs) are strong candidates for nutraceutical development for disease prevention and management. This paper reviews current evidence on the transepithelial transport and cellular mechanisms of antioxidant activities of FDAPs. Several FDAPs have multiple health benefits such as anti-inflammatory and anti-photoaging activities, in addition to antioxidant properties through which they protect cellular components from oxidative damage. Some FDAPs have been shown to permeate the intestinal epithelium, which could facilitate their bioavailability and physiological bioactivities. Molecular mechanisms of FDAPs include suppression of oxidative stress as evidenced by reduction in intracellular reactive oxygen species production, lipid peroxidation and apoptotic protein activation as well as increase in antioxidant defense mechanisms (enzymatic and non-enzymatic). Since many FDAPs have demonstrated promising antioxidant activity, future investigation should focus on further elucidation of molecular mechanisms and human studies to explore their practical application for the prevention and management of oxidative stress-related diseases.

Mechanism of Ser-Ala-Gly-Pro-Ala-Phe treatment with a pulsed electric field to improve ethanol-induced gastric mucosa injury in mice

This paper focused on the mechanism of Ser-Ala-Gly-Pro-Ala-Phe (SAGPAF) treatment to improve gastric mucosal injury in mice. A gastric mucosa injury model induced by ethanol was established, and the superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, nitric oxide (NO) content and myeloperoxidase (MPO) level were determined. We performed macroscopic and histopathological evaluation of the gastric organs. Moreover, we analyzed the mechanism of SAGPAF treatment by western blotting. Compared with the model group, the SOD activity and NO content in the medium-dose and high-dose SAGPAF groups of treated with 10 kV cm^-1 field intensity were significantly increased. The MDA content and MPO level were decreased significantly. They significantly reduced the gastric mucosal injury induced by ethanol (21.17 ± 3.51% and 13.99 ± 2.00%) and the histopathological scores (3.83 ± 0.40 and 4.33 ± 0.37) (P < 0.05). Western blotting analysis showed that SAGPAF after pulsed electric field (PEF) treatment improved gastric injury by reducing protein phosphorylation. These findings provided strong evidence that PEF-treated SAGPAF enhanced the gastric mucosal barrier function by inhibiting the activation of the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signaling pathways, reducing the ethanol-induced inflammatory response and oxidative stress.

Antioxidative, Anti-Inflammatory, Anti-Obesogenic, and Antidiabetic Properties of Tea Polyphenols-The Positive Impact of Regular Tea Consumption as an Element of Prophylaxis and Pharmacotherapy Support in Endometrial Cancer

Endometrial cancer (EC) is second only to cervical carcinoma among the most commonly diagnosed malignant tumours of the female reproductive system. The available literature provides evidence for the involvement of 32 genes in the hereditary incidence of EC. The physiological markers of EC and coexisting diet-dependent maladies include antioxidative system disorders but also progressing inflammation; hence, the main forms of prophylaxis and pharmacotherapy ought to include a diet rich in substances aiding the organism’s response to this type of disorder, with a particular focus on ones suitable for lifelong consumption. Tea polyphenols satisfy those requirements due to their proven antioxidative, anti-inflammatory, anti-obesogenic, and antidiabetic properties. Practitioners ought to consider promoting tea consumption among individuals genetically predisposed for EC, particularly given its low cost, accessibility, confirmed health benefits, and above all, suitability for long-term consumption regardless of the patient’s age. The aim of this paper is to analyse the potential usability of tea as an element of prophylaxis and pharmacotherapy support in EC patients. The analysis is based on information available from worldwide literature published in the last 15 years.

Photoprotective effects of sweet potato leaf polyphenols and caffeic acid against UV-induced skin-damage in BALB/C nude mice

This study aimed at clarifying the mechanism by which sweet potato leaf polyphenols (SPLPs) ameliorate ultraviolet (UV) radiation damage, using the BALB/c hairless female mouse model. The moisture and hydroxyproline (HYP) contents of the model mouse skin and the thickness of the epidermis and dermis were determined by staining and histological examination. Anti-oxidative enzyme activities, malondialdehyde (MDA) content, and protein carbonyl content in skin tissue and serum were investigated. Expression of inflammatory markers and mitogen-activated protein kinase signaling pathways were evaluated. Topical caffeic acid at 30 mg kg^-1 most strongly inhibited the decrease in skin moisture, HYP content, and the thickening of the epidermis. Topical SPLP at 100 mg kg^-1 most significantly inhibited the dermal thickening, increased the activities of the superoxide dismutase, catalase as well as glutathione peroxidase, and decreased the content of serum MDA and protein carbonyls markedly. Furthermore, the topical SPLP suppressed the UV-induced rise in the inflammatory markers MMP-1, TNF-α, and NF-κB, and alleviated phosphorylation levels of the stress-signaling proteins JNK and p38. Thus, topical SPLP provided the best overall protection for mouse skin from UV-induced damage.

Oral Intake of Chicken Bone Collagen Peptides Anti-Skin Aging in Mice by Regulating Collagen Degradation and Synthesis, Inhibiting Inflammation and Activating Lysosomes

The effect of diet on skin aging has become an interesting research topic. Previous studies have mostly focused on the beneficial effects of collagen peptides derived from marine organisms on the aging skin when administered orally, while the beneficial effects of collagen peptides derived from poultry on aging skin have been rarely reported. In this study, collagen peptides were prepared from chicken bone by enzymatic hydrolysis, and the effect and mechanism of action of orally administered collagen peptides on alleviating skin aging induced by UV combined with D-galactose were investigated. The results showed that the chicken bone collagen had typical characteristics of collagen, and the chicken bone collagen peptides (CPs) were mainly small molecular peptides with a molecular weight of <3000 Da. In vivo experiments showed that CPs had a significant relieving effect on aging skin, indicated by the changes in the compostion and structure of the aging skin, improvement of skin antioxidant level, and inhibition of inflammation; the relieving effect was positively correlated with the dose of CPs. Further investigation showed that CPs first reduce the level of skin oxidation, inhibit the expression of the key transcription factor AP-1 (c-Jun and c-Fos), then activate the TGF-β/Smad signaling pathway to promote collagen synthesis, inhibit the expression of MMP-1/3 to inhibit collagen degradation, and inhibit skin inflammation to alleviate skin aging in mice. Moreover, the skin transcriptome found that lysosomes activated after oral administration of CPs may be an important pathway for CPs in anti-skin aging, and is worthy of further research. These results suggested that CPs might be used as a functional anti-aging nutritional component.

Bioactive peptides identified from enzymatic hydrolysates of sturgeon skin

BACKGROUND

Recent studies demonstrate that fish byproducts can be used as sources of bioactive peptides for functional foods. Sturgeon skin contains abundant proteins but it has commonly been discarded during sturgeon processing. The objective of the present work was to identify and characterize the bioactive peptides from protein hydrolysates of sturgeon skin.

RESULTS

Sturgeon skin protein extract (SKPE) hydrolyzed by flavourzyme for 60 min exhibited high antioxidant activity, dipeptidyl peptidase IV (DPP-IV) and angiotensin converting enzyme (ACE) inhibitory activity. The sequences of peptides from flavourzyme hydrolysates were identified using high-performance liquid chromatography-tandem mass spectrometry. Gly-Asp-Arg-Gly-Glu-Ser-Gly-Pro-Ala (P1) showed the highest DPPH radical scavenging activity (DPPH IC₅₀  = 1.93 mmol L^-1 ). Gly-Pro-Ala-Gly-Glu-Arg-Gly-Glu-Gly-Gly-Pro-Arg (P11) (DPP-IV IC₅₀  = 2.14 mmol L^-1 ) and Ser-Pro-Gly-Pro-Asp-Gly-Lys-Thr-Gly-Pro-Arg (P12) (DPP-IV IC₅₀  = 2.61 mmol L^-1 ) exhibited the strongest DPP-IV inhibitory activity. Gly-Pro-Pro-Gly-Ala-Asp-Gly-Gln-Ala-Gly-Ala-Lys (P6) displayed the highest ACE inhibitory activity (ACE IC₅₀  = 3.77 mmol L^-1 ). The molecular docking analysis revealed that DPP-IV inhibition of P11 and P12 are mainly attributed to hydrogen bonds and hydrophobic interactions, whereas ACE inhibition of P6 is mainly attributed to strong hydrogen bonds.

CONCLUSIONS

These results indicate that SKPE hydrolysates generated by flavourzyme are potential sources of bioactive peptides that could be used in the health food industry. © 2021 Society of Chemical Industry.

Animal by-products collagen and derived peptide, as important components of innovative sustainable food systems-a comprehensive review

In 2020, the world's food crisis and health industry ushered into a real outbreak. On one side, there were natural disasters such as the novel coronavirus (2019-nCoV), desert locusts, floods, and droughts exacerbating the world food crisis, while on the other side, the social development and changes in lifestyles prompted the health industry to gradually shift from a traditional medical model to a new pattern of prevention, treatment, and nourishment. Therefore, this article reviews animal by-products collagen and derived peptide, as important components of innovative sustainable food systems. The review also considered the preparation, identification, and characterization of animal by-product collagen and collagen peptides as well as their impacts on the food system (including food processing, packaging, preservation, and functional foods). Finally, the application and research progress of animal by-product collagen and peptide in the food system along with the future development trend were discussed. This knowledge would be of great significance for a comprehensive understanding of animal by-product collagen and collagen peptides and would encourage the use of collagen in food processing, preservation, and functional foods.

Effect of Fish Bone Bioactive Peptides on Oxidative, Inflammatory and Pigmentation Processes Triggered by UVB Irradiation in Skin Cells

In the present study, we evaluated for the first time the photoprotective effect of fish bone bioactive peptides (FBBP) preparation isolated from silver carp (Hypophthalmichthys molitrix) discarded tissue using in vitro experimental models of skin cells exposed to ultraviolet B (UVB) irradiation and stressing agents. FBBP preparation was obtained by papain treatment of minced bones and centrifugal ultrafiltration, and the molecular weight (MW) distribution was characterized by size exclusion and reversed-phase high performance liquid chromatography (RP-HPLC). In vitro assessment of the effect of FBBP pretreatment in UVB-irradiated L929 fibroblasts and HaCaT keratinocytes revealed their cytoprotective activity. Their capacity to efficiently reduce reactive oxygen species (ROS) production and lipid peroxidation varied in a dose-dependent manner, and it was greater in fibroblasts. A decrease of proinflammatory cytokines secretion, in particular of tumor necrosis factor alpha (TNF-α), was found after FBBP pretreatment of THP-1-derived inflamed macrophages. Melanin production and tyrosinase activity investigated in UVB-irradiated Mel-Juso cells were lowered in direct relation to FBBP concentrations. FBBP fractions with high radical scavenging activity were separated by ion exchange chromatography, and two collagenic sequences were identified. All these results offer new scientific data on aquaculture fish bone-derived peptides confirming their ability to control the antioxidant, anti-inflammatory and pigmentation processes developed during UV irradiation of skin cells and recommend their use as valuable natural ingredients of photoprotective cosmeceutical products.

The in vitro bioavailability of anti-platelet peptides in collagen hydrolysate from silver carp (Hypophthalmichthys molitrix) skin

Previous animal experiments indicated collagen hydrolysates (CHs) intake decreased platelet release indicators in plasma and highlight potential applications as healthcare supplements to combat cardiovascular disease. The oligopeptides (GPR, GPRG, and GPRGP) have anti-platelet activities. However, it is still unclear whether they are bioactive compounds in CHs from silver carp skin. We investigated the bioavailability of oligopeptides using simulated gastrointestinal digestion and Caco-2 model. Anti-thrombotic activities, in vitro platelet aggregation and formation of platelet thrombus, were evaluated. They resisted gastrointestinal digestion and could be absorbed by Caco-2. Oligopeptides inhibited platelet aggregation induced by adenosine diphosphate and thrombin with IC₅₀ of 0.160, 0.283, 0.251 mg/ml and 0.714, 1.008, 0.917 mg/ml for GPR, GPRG, and GPRGP, respectively. Oligopeptides prolonged the time of platelet thrombus and inhibited coagulation cascades, but CHs performed no bleeding side effect. These results confirmed that oligopeptides could be used as bioactive compounds of dietary supplements for pre-thrombotic to prevent thrombosis. PRACTICAL APPLICATIONS: Oligopeptides, GPR, GPRG, and GPRGP, derived from silver carp (Hypophthalmichthys molitrix) skin collagen, performed anti-thrombotic activities from their anti-platelet aggregation and anticoagulation activities. But the collagen hydrolysates containing these peptides had no side effect of bleeding in the mice model. Furthermore, this study investigated the bioavailability of these three bioactive peptides by the Caco-2 cells model. Thus, oligopeptides GPR, GPRG, and GPRGP are a potential index of bioactive compounds in the preparation of anti-thrombotic functional foods or healthcare supplements for people at the pre-thrombotic state.

Diet and Skin Aging-From the Perspective of Food Nutrition

We regularly face primary challenges in deciding what to eat to maintain young and healthy skin, defining a healthy diet and the role of diet in aging. The topic that currently attracts maximum attention is ways to maintain healthy skin and delay skin aging. Skin is the primary barrier that protects the body from external aggressions. Skin aging is a complex biological process, categorized as chronological aging and photo-aging, and is affected by internal factors and external factors. With the rapid breakthrough of medicine in prolonging human life and the rapid deterioration of environmental conditions, it has become urgent to find safe and effective methods to treat skin aging. For diet, as the main way for the body to obtain energy and nutrients, people have gradually realized its importance to the skin. Therefore, in this review, we discuss the skin structure, aging manifestations, and possible mechanisms, summarize the research progress, challenges, possible directions of diet management, and effects of foodborne antioxidants on skin aging from the perspective of food and nutrition.

Bioactive peptides derived from crimson snapper and in vivo anti-aging effects on fat diet-induced high fat Drosophila melanogaster

Crimson snapper scale peptides (CSSPs) prepared from crimson snapper scales exhibited significant antioxidant activity in vitro and anti-aging effects in vivo on fat diet-induced high fat Drosophila melanogaster.

Protective effects of collagen polypeptide from tilapia skin against injuries to the liver and kidneys of mice induced by d-galactose

We wished to investigate the role of a tilapia skin collagen polypeptide (TSCP; molecular weight <3 kDa) in alleviating liver and kidney injuries in aging mice induced by d-galactose (d-gal) and its underlying mechanism of action. First, we characterized TSCP. TSCP was passed through a 3-kDa ultrafiltration membrane, desalted in water by a solid-phase extraction column, purified further by reverse phase-high performance liquid chromatography, and analyzed by electrospray ionization mass spectrometry and tandem mass spectrometry. TSCP contained 17 types of amino acids (AAs) and 41 peptide chains of length 7 AAs to 22 AAs. The content of free AAs and total AAs of TSCP was 13.5% and 93.79%, respectively. Next, we undertook animal experiments. Mice were injected once-daily with D-gal (300 mg/kg body weight, s.c.) for 8 weeks, and TSCP was administered simultaneously once-daily by intragastric gavage. TSCP could visibly improve the decreased body weight, depressed appetite, and mental deterioration of mice triggered by d-gal. TSCP could also alleviate d-gal-induced damage to the liver and kidneys according to histopathology (especially high-dose TSCP). Consistent with these macroscopic and pathologic changes, TSCP could also prevent d-gal-induced increases in serum levels of alanine aminotransferase, aspartate transaminase, alkaline phosphatase, lipid peroxidation, creatinine and uric acid, as well as decreases in serum levels of immunoglobulin (Ig)G and IgM. Moreover, TSCP improved the activities of superoxide dismutase, catalase, and glutathione peroxidase, but also inhibited the increases in the levels of malondialdehyde and inducible nitric oxide synthase expression in the liver and kidneys of d-gal-treated mice. These results suggest that TSCP can alleviate the injuries to the liver and kidneys in aging mice induced by d-gal, and that its mechanism of action might be, at least partially, associated with attenuation of oxidative stress and enhancement of immune function.

Effects of rambutan (Nephelium lappaceum) peel phenolics and Leu-Ser-Gly-Tyr-Gly-Pro on hairless mice skin photoaging induced by ultraviolet irradiation

Rambutan peel phenolics (RPP) have high antioxidant and anti-inflammatory activities. Leu-Ser-Gly-Tyr-Gly-Pro (LSGYGP) possesses good radical scavenging activity and matrix metalloproteinase (MMPs) inhibitory ability. These underlying mechanisms indicated that RPP and LSGYGP may be used for antiphotoaging. Few data on the effects of RPP and LSGYGP on in vivo photoaging are available. We evaluated the effects of RPP and/or LSGYGP on ultraviolet (UV)-induced hairless mice skin photoaging. In particular, we analyzed the additive effect of RPP and LSGYGP. The biochemical indices of mice skin, including composition (collagen and hyaluronic acid [HA] contents), oxidant stress (antioxidant enzyme activities and glutathione and malondialdehyde contents), MMPs (MMP-1, MMP-3, and MMP-9 levels), inflammatory cytokines (interleukin (IL)-1α, tumor nuclear factor-α, and IL-6 levels) and the phosphorylation of the mitogen-activated protein kinase pathway, were determined. Results showed a protective effect of RPP and/or LSGYGP on photoaging skin. LSGYGP showed considerable effects on skin collagen and HA contents. RPP showed improved effects on the regulation of the oxidant stress and inflammatory cytokine levels. RPP and LSGYGP exerted an additive effect on the amelioration of the biochemical indices of UV-induced photoaging skin. The histological changes showed that RPP and LSGYGP recovered the changes in skin tissue and endogenous collagen.

A Review of the Role of Green Tea (Camellia sinensis) in Antiphotoaging, Stress Resistance, Neuroprotection, and Autophagy

Tea is one of the most widely consumed beverages worldwide, and is available in various forms. Green tea is richer in antioxidants compared to other forms of tea. Tea is composed of polyphenols, caffeine, minerals, and trace amounts of vitamins, amino acids, and carbohydrates. The composition of the tea varies depending on the fermentation process employed to produce it. The phytochemicals present in green tea are known to stimulate the central nervous system and maintain overall health in humans. Skin aging is a complex process mediated by intrinsic factors such as senescence, along with extrinsic damage induced by external factors such as chronic exposure to ultraviolet (UV) irradiation—A process known as photoaging—Which can lead to erythema, edema, sunburn, hyperplasia, premature aging, and the development of non-melanoma and melanoma skin cancers. UV can cause skin damage either directly, through absorption of energy by biomolecules, or indirectly, by increased production of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Green tea phytochemicals are a potent source of exogenous antioxidant candidates that could nullify excess endogenous ROS and RNS inside the body, and thereby diminish the impact of photoaging. Several in vivo and in vitro studies suggest that green tea supplementation increases the collagen and elastin fiber content, and suppresses collagen degrading enzyme MMP-3 production in the skin, conferring an anti-wrinkle effect. The precise mechanism behind the anti-photoaging effect of green tea has not been explored yet. Studies using the worm model have suggested that green tea mediated lifespan extension depends on the DAF-16 pathway. Apart from this, green tea has been reported to have stress resistance and neuroprotective properties. Its ROS scavenging activity makes it a potent stress mediator, as it can also regulate the stress induced by metal ions. It is known that tea polyphenols can induce the expression of different antioxidant enzymes and hinder the DNA oxidative damage. Growing evidence suggests that green tea can also be used as a potential agent to mediate neurodegenerative diseases, including Alzheimer’s disease. EGCG, an abundant catechin in tea, was found to suppress the neurotoxicity induced by Aβ as it activates glycogen synthase kinase-3β (GSK-3β), along with inhibiting c-Abl/FE65—the cytoplasmic nonreceptor tyrosine kinase which is involved in the development of the nervous system and in nuclear translocation. Additionally, green tea polyphenols induce autophagy, thereby revitalizing the overall health of the organism consuming it. Green tea was able to activate autophagy in HL-60 xenographs by increasing the activity of PI3 kinase and BECLIN-1. This manuscript describes the reported anti-photoaging, stress resistance, and neuroprotective and autophagy properties of one of the most widely known functional foods—green tea.

Protective Effect of Bovine Elastin Peptides against Photoaging in Mice and Identification of Novel Antiphotoaging Peptides

This study aimed to investigate the protective effects of bovine elastin hydrolysates on UV-induced skin photoaging in mice and to identify the potent antiphotoaging peptides. Results showed that the ingestion of elastin peptides could obviously ameliorate epidermis hyperplasia and fibroblast apoptosis, and increase the content of hydroxyproline and water in photoaging skin in vivo ( p < 0.05). Furthermore, four peptides with elastase inhibitory activity were purified and identified, including GLPY, PY, GLGPGVG, and GPGGVGAL. Interestingly, GLPY and GPGGVGAL exhibited the highest inhibition activity with 58.77% and 42.91% at 10 mΜ, respectively. This might be attributed to the N-terminal Gly, C-terminal Leu, and Pro at the third position of the N-terminus, which showed stronger affinity and interaction with elastase. Moreover, GLPY and GPGGVGAL could also inhibit the apoptosis of fibroblasts effectively at 50 μΜ ( p < 0.01). It suggested that elastin peptides had great potential to prevent and regulate skin photoaging.

Effect of Collagen Hydrolysates from Silver Carp Skin (Hypophthalmichthys molitrix) on Osteoporosis in Chronologically Aged Mice: Increasing Bone Remodeling

Osteoporosis is a common skeletal disorder in humans and gelatin hydrolysates from mammals have been reported to improve osteoporosis. In this study, 13-month-old mice were used to evaluate the effects of collagen hydrolysates (CHs) from silver carp skin on osteoporosis. No significant differences were observed in mice body weight, spleen or thymus indices after daily intake of antioxidant collagen hydrolysates (ACH; 200 mg/kg body weight (bw) (LACH), 400 mg/kg bw (MACH), 800 mg/kg bw (HACH)), collagenase hydrolyzed collagen hydrolysates (CCH) or proline (400 mg/kg body weight) for eight weeks, respectively. ACH tended to improve bone mineral density, increase bone hydroxyproline content, enhance alkaline phosphatase (ALP) level and reduce tartrate-resistant acid phosphatase 5b (TRAP-5b) activity in serum, with significant differences observed between the MACH and model groups (p < 0.05). ACH exerted a better effect on osteoporosis than CCH at the identical dose, whereas proline had no significant effect on repairing osteoporosis compared to the model group. Western blotting results demonstrated that CHs mainly increased bone remodeling by stimulating the transforming growth factor β1 (TGF-β1)/Smad signaling pathway and improving the interaction between collagen and α2β1 integrin. The results indicated that CHs from fish could be applied to alleviate osteoporosis or treat bone loss.