Purification, Identification and Functional Analysis of a Novel Immunomodulatory Peptide from Silkworm Pupa Protein

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.

The Contribution of Antimicrobial Peptides to Immune Cell Function: A Review of Recent Advances

The development of novel antimicrobial agents to replace antibiotics has become urgent due to the emergence of multidrug-resistant microorganisms. Antimicrobial peptides (AMPs), widely distributed in all kingdoms of life, present strong antimicrobial activity against a variety of bacteria, fungi, parasites, and viruses. The potential of AMPs as new alternatives to antibiotics has gradually attracted considerable interest. In addition, AMPs exhibit strong anticancer potential as well as anti-inflammatory and immunomodulatory activity. Many studies have provided evidence that AMPs can recruit and activate immune cells, controlling inflammation. This review highlights the scientific literature focusing on evidence for the anti-inflammatory mechanisms of different AMPs in immune cells, including macrophages, monocytes, lymphocytes, mast cells, dendritic cells, neutrophils, and eosinophils. A variety of immunomodulatory characteristics, including the abilities to activate and differentiate immune cells, change the content and expression of inflammatory mediators, and regulate specific cellular functions and inflammation-related signaling pathways, are summarized and discussed in detail. This comprehensive review contributes to a better understanding of the role of AMPs in the regulation of the immune system and provides a reference for the use of AMPs as novel anti-inflammatory drugs for the treatment of various inflammatory diseases.

The moisture adsorption, caking, and flowability of silkworm pupae peptide powders: The impacts of anticaking agents

This study aimed to explore the impacts of different anticaking agents on the moisture adsorption, caking, and flowability of silkworm pupae peptide powders (SPPP). The characteristics of water distributions in SPPP with anticaking agents were investigated by LF NMR. The morphological observation of powders was analyzed by scanning electron microscope. Moisture sorption curves and moisture sorption isotherm curves indicated that calcium stearate, silicon dioxide and calcium silicate of 20 % reduced hygroscopicity and increased critical relative humidity. The angle of repose analysis revealed that anticaking agents could also increase flowability (45°-49°). LF NMR analysis indicated that anticaking agents reduced the moisture adsorption ability of SPPP. Scanning electron microscope observations demonstrated different shapes and surface morphology of SPPP using different anticaking agents. Notably, silicon dioxide served as the most effective anticaking agent by forming a physical barrier. Overall, anticaking agents can effectively delay moisture adsorption and deliquescence of SPPP by different anticaking fashions.

Nutritional aspects and dietary benefits of "Silkworms": Current scenario and future outlook

In the current scenario, it is estimated that by 2050, there will be an additional 2.5 billion people and a 70% increase in food demand. Crop yields are not increasing fast enough to support global needs, and world agriculture is facing several serious challenges. Therefore, insects can be a nutritious alternative to meet the ever-increasing food demand in the present and future. The majority of insect consumption occurs in developing countries, with approximately 1,900 insect species consumed worldwide. Food and feed derived from them are of high quality, have a high feed conversion ratio and emit a low level of greenhouse gases. Among insects silkworms are beneficial to humans, not only because of their high nutritional value, but also because of their several pharmacological properties. Silkworm eggs, larvae, and pupae contains high amount of proteins, oils, minerals, vitamins, and several other beneficial components which are nutritious as well as have positive effect on human health. Studies have shown that silkworm pupae protect the liver, enhance immunity, inhibit apoptosis, inhibit cancer, inhibit tumor growth, inhibit microbial growth, regulate blood glucose and blood lipids, and lower blood pressure. This review paper summerized the nutritional value of different life stages of silkworm, nutritional comparison of silkworm with the major human foods, and the effects of silkworm consumption on human health, thus ittargets to generate interest toward in sericulture and improve human health by using silkworm as a nutritious food and attain sustainability in food and nutritional security.

Nutritional Composition, Health Benefits, and Application Value of Edible Insects: A Review

For thousands of years, edible insects have been used as food to alleviate hunger and improve malnutrition. Some insects have also been used as medicines because of their therapeutic properties. This is not only due to the high nutritional value of edible insects, but more importantly, the active substances from edible insects have a variety of biofunctional activities. In this paper, we described and summarized the nutritional composition of edible insects and discussed the biological functions of edible insects and their potential benefits for human health. A summary analysis of the findings for each active function confirms that edible insects have the potential to develop functional foods and medicines that are beneficial to humans. In addition, we analyzed the issues that need to be considered in the application of edible insects and the current status of edible insects in food and pharmaceutical applications. We concluded with a discussion of regulations related to edible insects and an outlook on future research and applications of edible insects. By analyzing the current state of research on edible insects, we aim to raise awareness of the use of edible insects to improve human health and thus promote their better use and development.

Tenebrio molitor Proteins-Derived DPP-4 Inhibitory Peptides: Preparation, Identification, and Molecular Binding Mechanism

Inhibition of dipeptidyl peptidase-4 (DPP-4) is an effective way to control blood glucose in diabetic patients. Tenebrio (T.) molitor is an edible insect containing abundant protein. T. molitor protein-derived peptides can suppress the DPP-4 activity. However, the amino acid sequence and binding mechanism of these DPP-4 inhibitory peptides remain unclear. This study used the flavourzyme for T. molitor protein hydrolysis, identified the released peptides with DPP-4 inhibitory effect, and investigated the binding interactions of these peptides with DPP-4. The results showed that flavourzyme efficiently hydrolyzed the T. molitor protein, as demonstrated by the high degree of hydrolysis, disappearance of protein bands in SDS-PAGE, and changes to protein structure. The 4-h flavourzyme hydrolysates showed a good inhibitory effect on DPP-4 (IC₅₀ value of 1.64 mg/mL). The fragment of 1000-3000 Da accounted for 10.39% of the total peptides, but showed the strongest inhibitory effect on DPP-4. The peptides LPDQWDWR and APPDGGFWEWGD were identified from this fraction, and their IC₅₀ values against DPP-4 were 0.15 and 1.03 mg/mL, respectively. Molecular docking showed that these two peptides interacted with the DPP-4 active site via hydrogen bonding, hydrophobic interactions, salt bridge formation, π-cation interactions, and π-π stacking. Our findings indicated that T. molitor protein-derived peptides could be used as natural DPP-4 inhibitors.

Drying methods affect physicochemical and functional characteristics of Clanis Bilineata Tingtauica Mell protein

Clanis Bilineata Tingtauica Mell Protein (CBTMP) was a kind of natural full-price protein which has a bright application prospect in the food industry. Since the functional properties of protein can be significantly affected by drying method, this study aims to explore the effect of different drying methods, namely freeze drying (FD), vacuum drying (VD),and hot-air drying (HD) on the structure and functional properties of CBTMP. The results showed that the degree of oxidation of CBTMP was found to be in the following order: HD > VD > FD. Functional characteristics revealed that the CBTMP prepared by VD had relatively high foaming ability (150.24 ± 5.34°C) among three drying methods. However, the stability of emulsion and rheological properties prepared by FD was superior to other samples. Differential scanning calorimeter (DSC) showed CBTMP made by HD had the relatively good thermal stability (Tp = 91.49 ± 0.19 °C), followed by VD and FD. Digestive properties reflected that heating treatment could significantly increase its degree of hydrolysis in vitro. To sum up, the research could provide experimental guidance and theoretical support for the preparation method and utilization of CBTMP.

Pentapeptide AYP from Isochrysis Zhanjiangensis Exhibits Antiangiogenic Activity in HT1080 Cells and HUVECs by Suppressing Migration and Invasion In Vitro

Microalgae are important biological sources of marine active peptides and renewable biological resources. Isochrysis zhanjiangensis has been widely used in biological ultrafiltration membranes and aquaculture. However, there are relatively few studies on its component structure and diverse activities. In this study, the mechanism of action of previously isolated pentapeptides (AYP, Ala-Tyr-Ala-Pro-Glu) on inflammation and tumor angiogenesis was evaluated. The results showed that AYP could effectively inhibit the invasion and migration of human umbilical vein endothelial cells (HUVECs) and HT1080 cells by downregulating the expression of MMP-2/-9, independent of cytotoxicity. Especially after 100 μM AYP treatment, the ability to inhibit migration was about 67.7% ± 1.9 for HT1080 cells and 63.6% ± 1.3 for HUVECs, respectively. In addition, the activity of iNOS and COX-2 was decreased by inhibiting the oversecretion of VEGF in HT1080 cells induced by CoCl₂ and the activation of VEGFR-2 in HUVECs and by regulating PI3K/AKT and Ras/MAPK signaling pathways. It can prevent inflammation and block tumor angiogenesis. Therefore, AYP is expected to become a drug or functional food to prevent and treat tumor angiogenesis.

Silkworm Pupae: A Functional Food with Health Benefits for Humans

Silkworm pupae are insects that are beneficial to human health, not only for their high nutritional value but, more importantly, for the variety of pharmacological functions they can perform when consumed. Currently, there is a lot of interest in the pharmaceutical applications of silkworm pupae. In recent years, the biological functions of domestic silkworm pupae have gradually been identified and confirmed, especially for their beneficial effects on human health. Studies have found that silkworm pupae have positive effects on liver protection, immune enhancement, antiapoptosis, antitumour, antibacterial, regulation of blood glucose and blood lipids, and lowering of blood pressure. However, the pharmacological mechanisms and systemic safety of silkworm pupae have not been systematically evaluated. In this paper, the nutritional composition of the pupae of the domestic silkworm is first summarised. The pharmacological functions of silkworm pupae and their components are then classified, and their mechanisms of occurrence are described. In addition, we provide a preliminary evaluation of the safety of silkworm pupae, analyse their application prospects, and suggest future directions for further pharmacological function studies. The aim is to generate interest in the promotion of human health through the use of silkworm pupae.

Effect of ultrasonic pretreatment on the emulsification properties of Clanis Bilineata Tingtauica Mell protein

Clanis Bilineata Tingtauica Mell Protein (CBTMP) is a naturally high-quality insect protein resource, while its poor emulsification has limited its application in food industry. In order to change the present situation, in this research, the ultrasonic pretreatment (0 W, 200 W, 400 W, 600 W, and 800 W) method was used to improve the emulsification properties of CBTMP. Results indicated that ultrasound treatment especially at 400 W could significantly change the particle sizes, further increase the content of sulfhydryl group and surface hydrophobicity. The emulsification properties of emulsions were enhanced (from 4.16 ± 1.07 m²/g to 27.62 ± 2.20 m²/g) by sonicated CBTMP solution. Moreover, the physical stability of the emulsions to salt stress and centrifugation treatment was also promoted. Additionally, rheology revealed that a stronger network was formed at 400 W and all samples exhibited frequency-dependent and amplitude-dependent properties. The experiment demonstrated that ultrasound pretreatment was an effective means to improve the emulsification properties of CBTMP and it could provide a promising perspective for the application of CBTMP in food industry.

Purification and Identification of Novel Antioxidant Peptides from Enzymatically Hydrolysed Samia ricini Pupae

The emergence of excessive free radicals leads to the destruction of various systems within the body. These free radicals also affect nutritional values, color, taste, and emit an odor akin to rancid food. Most food industries use synthetic antioxidants, such as BHT (butylated hydroxytoluene) or BHA (butylated hydroxy anisole). However, high doses of these can be harmful to our health. Therefore, an antioxidant compounds, such as bioactive peptides from edible animals or plants, have emerged to be a very promising alternative as they reduce potential side effects. This study focused on the purification and identification of antioxidant peptides from protein hydrolysates of wild silkworm pupae (Samia ricini). Antioxidant peptides were purified from the hydrolysate by ultrafiltration and RP-HPLC. The results showed that protein hydrolysate from S. ricini pupae by trypsin with a molecular weight lower than 3 kDa and highly hydrophobic property, exhibited strong DPPH radical scavenging activity and chelating activity. Further identification of peptides from the fraction with the highest antioxidant activity was carried out using LC-MS/MS. Three novel peptides, i.e., Met-Ley-Ile-Ile-Ile-Met-Arg, Leu-Asn-Lys-Asp-Leu-Met-Arg, and Glu-Asn-Ile-Ile-Leu-Phe-Arg, were identified. The results of this study indicated that the protein hydrolysate from S. ricini pupae possessed potent biological activity, and the novel antioxidant peptides could be utilized to develop health-related antioxidants in food industry.

Use of Alcalase in the production of bioactive peptides: A review

This review aims to cover the uses of the commercially available protease Alcalase in the production of biologically active peptides since 2010. Immobilization of Alcalase has also been reviewed, as immobilization of the enzyme may improve the final reaction design enabling the use of more drastic conditions and the reuse of the biocatalyst. That way, this review presents the production, via Alcalase hydrolysis of different proteins, of peptides with antioxidant, angiotensin I-converting enzyme inhibitory, metal binding, antidiabetic, anti-inflammatory and antimicrobial activities (among other bioactivities) and peptides that improve the functional, sensory and nutritional properties of foods. Alcalase has proved to be among the most efficient proteases for this goal, using different protein sources, being especially interesting the use of the protein residues from food industry as feedstock, as this also solves nature pollution problems. Very interestingly, the bioactivities of the protein hydrolysates further improved when Alcalase is used in a combined way with other proteases both in a sequential way or in a simultaneous hydrolysis (something that could be related to the concept of combi-enzymes), as the combination of proteases with different selectivities and specificities enable the production of a larger amount of peptides and of a smaller size.