Novel hepatoprotective peptides derived from protein hydrolysates of mealworm (Tenebrio molitor)

Fetal bovine serum substitution efficacy of mealworm (Tenebrio molitor) protein hydrolysates and its physicochemical properties

Fetal bovine serum (FBS) is widely used in cell culture media but raises ethical, cost, and environmental concerns. This study hypothesized that mealworm protein hydrolysates (TAH), rich in essential amino acids and known for their protective effects against oxidative stress, could serve as an FBS substitute. Short- and long-term cultivation experiments replacing 70 % of FBS with TAH in various adherent (HaCaT, C2C12, L6, H460, Panc-1) and suspension (HL-60, Jurkat) cell lines revealed no significant differences in cell growth or morphology compared to controls. Transcriptomic analysis in HaCaT cells further confirmed a high level of equivalence between TAH and FBS. Additionally, TAH demonstrated excellent thermal stability and favorable physicochemical properties, including high zeta potential and small particle size within the typical pH range for cell culture media. These results suggest TAH's broad applicability as an FBS substitute, addressing ethical, environmental, safety, and cost concerns.

Anticancer and Antioxidant Effects of Bioactive Peptides from Black Soldier Fly Larvae (Hermetia illucens)

BACKGROUND

Protein hydrolysates from insects are recognized for their biological activities. Black soldier fly larvae (BSFL) have drawn attention due to their antioxidant protein hydrolysates. However, research on bioactive peptides derived from these hydrolysates, particularly their cancer chemopreventive potential, remains limited. This study aims to evaluate the antioxidant, anti-inflammatory, antimutagenic, and anticancer activities of BSFL-derived bioactive peptides and explore the molecular mechanisms.

METHODS

Alkali-soluble BSFL protein (ASBP) was extracted and hydrolyzed using Alcalase and bromelain under optimized conditions. Antioxidant activity was assessed via FRAP, ABTS, and DPPH assays. The hydrolysate with the highest antioxidant activity was fractionated into molecular weight (MW) groups (>30, 10, and <3 kDa). The bioactivity of fractionated peptides was evaluated through antioxidant, anti-inflammatory (nitric oxide production in RAW 264.7 cells), antimutagenic (Ames test), and anticancer (CCK-8 assay on HCT 116, COLO205, Cw-2, and Caco-2 cells) assays. Mechanistic insights were obtained via microarray and Western blot analyses. Peptides were identified by LC-MS/MS.

RESULTS

The ASBP-Alcalase hydrolysate (ASBP-AH) showed optimal antioxidant activity at 3% (w/w) for 4 h. The ASBP-AH 30 (MW > 30 kDa) fraction exhibited the highest antioxidant capacity. In contrast, the ASBP-AH3 (MW < 3 kDa) fraction exhibited significant antimutagenic effects, reduced nitric oxide production, and decreased COLO205 cell viability. Treatment with ASBP-AH3 at its LC50 dose modulated the SKP2/p21/cyclin D1 pathways. Mostly peptides from ASBP-AH3 were composed of hydrophobic and charged amino acids.

CONCLUSIONS

BSFL-derived bioactive peptides exhibit potential as multifunctional agents for cancer chemoprevention. In vivo studies are required to explore their clinical applications.

Exploring Tenebrio molitor as a source of low-molecular-weight antimicrobial peptides using a n in silico approach: correlation of molecular features and molecular docking

BACKGROUND

Yellow mealworm (Tenebrio molitor) larvae are increasingly recognized as a potential source of bioactive peptides due to their high protein content. Antimicrobial peptides from sustainable sources are a research topic of interest. This study aims to characterize the peptidome of T. molitor flour and an Alcalase-derived hydrolysate, and to explore the potential presence of antimicrobial peptides using in silico analyses, including prediction tools, molecular docking and parameter correlations.

RESULTS

T. molitor protein was hydrolysed using Alcalase, resulting in a hydrolysate (TMH10A) with a 10% degree of hydrolysis. The peptidome was analysed using LC-TIMS-MS/MS, yielding over 6000 sequences. These sequences were filtered using the PeptideRanker tool, selecting the top 100 sequences with scores >0.8. Bioactivity predictions indicated that specific peptides, particularly WLNSKGGF and GFIPYEPFLKKMMA, showed significant antimicrobial potential, particularly against bacteria, fungi and viruses. Correlations were found between antifungal activity and physicochemical properties such as net charge, hydrophobicity and isoelectric point.

CONCLUSIONS

The study identified specific T. molitor-derived peptides with strong predicted antimicrobial activity through in silico analysis. These peptides, particularly WLNSKGGF and GFIPYEPFLKKMMA, might offer potential applications in food safety and healthcare. Further experimental validation is required to confirm their efficacy. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Sustainable Protein Sources: Functional Analysis of Tenebrio molitor Hydrolysates and Attitudes of Consumers in Poland and Spain Toward Insect-Based Foods

This study explores the potential of Tenebrio molitor protein hydrolysates as functional food ingredients, evaluating their bioactivity and consumer acceptance of the incorporation of edible insects into food across Poland and Spain. By aligning technical advancements with consumer preferences, this research bridges the gap between laboratory innovation and market feasibility, contributing to the development of sustainable functional foods. The study optimized the process of enzyme hydrolysis using serine protease from Cucurbita ficifolia, thereby enhancing DPPH scavenging capacity increased from 3.15 ± 0.53 to 8.17 ± 0.62 µM Trolox/mL and ABTS decolorization capacity increased from 4.29 ± 0.01 to 10.29 ± 0.01 µM Trolox/mL after 5 h of hydrolysis. Consumer surveys incorporating the Food Neophobia, Insect Phobia, and Entomophagy Scales revealed demographic and cultural influences on entomophagy acceptance. Among respondents, 27.1% in Poland and 25.7% in Spain had previously consumed insect-based products, while Polish participants showed a higher willingness to adopt insect-enriched foods. The study confirmed that hydrolysis enhances the antioxidant activity of T. molitor protein hydrolysates and that demographic and cultural factors significantly influence consumer acceptance of insect-based foods.

Mealworm-Derived Protein Hydrolysates Enhance Adipogenic Differentiation via Mitotic Clonal Expansion in 3T3-L1 Cells

Adipocytes secrete adipokines, bioactive molecules crucial for various physiological processes, such as enhancing insulin sensitivity, promoting wound healing, supporting hair growth, and exhibiting anti-aging effects on the skin. With the growing global demand for sustainable and alternative protein sources, insect-derived proteins, particularly from Tenebrio molitor (mealworms), have gained attention due to their high nutritional value and functional bioactivities. This study aims to explore the potential of mealworm-derived protein hydrolysates as novel bioactive materials for promoting adipogenesis and improving adipokine expression, with applications in metabolic health and skin regeneration. Protein hydrolysates (<1 kDa) were prepared using enzymatic hydrolysis with three proteases (alcalase, flavourzyme, and neutrase) and evaluated for their adipogenic activity in 3T3-L1 preadipocytes. Among them, the flavourzyme-derived hydrolysate (Fh-T) exhibited the most significant effects, enhancing adipogenic differentiation and lipid accumulation. Fh-T facilitated adipogenesis by promoting mitotic clonal expansion (MCE) during the early stage of differentiation, which was associated with the upregulation of C/EBPδ and the downregulation of p27. These findings underscore the potential of mealworm-derived protein hydrolysates, particularly Fh-T, as sustainable and functional ingredients for use in glycemic control, skin health, and tissue regeneration. This study provides valuable insights into the innovative use of alternative protein sources in functional foods and cosmeceuticals.

Tenebrio molitor (Mealworm) protein as a sustainable dietary strategy to improve health span in D-galactose-induced aged mice

Aging is an irreversible and continuous biological process involving intricate and interconnected mechanisms. The present work is focused on unravelling the anti-aging mechanisms of mealworm protein and protein-enriched fruit bar and vegetable soup in D-galactose-induced aged mice. Mealworm protein and enriched products significantly enhanced body weight, organ indices, and gut health. Behavioral assessments reflected enhanced neuroprotective effects. Mealworm protein and its enriched products demonstrated protective effects through anti-inflammatory activity with the highest reduction of TNFα (17.1 %), IL-6 (55.5 %), and IL-1β (75.1 %) levels and upregulated the anti-inflammatory marker (IL-4). Gene expression studies confirmed the induction of anti-aging effects by promoting metabolism, reducing cellular senescence, and enhancing anti-oxidant enzyme activity. The treatments extended telomere lengths by 3-4 times, further affirming the potential anti-aging efficacy of mealworm protein and its enriched products. Mealworm protein demonstrated positive effects on weight gain, anti-inflammatory responses, and telomere length; while fruit and vegetable products enhanced antioxidant activity, and positively influenced gut health. Further, a synergistic effect was observed by combining them, which resulted in improved overall anti-aging effect. The present work provides valuable insights into the multifaceted anti-aging mechanisms associated with mealworm protein and enriched products, highlighting their potential as functional foods with significant health-promoting effects.

Anti-muscle atrophy effect of fermented Tenebrio molitor larvae extract by modulating the PI3K-Akt-mTOR/FoxO3α pathway in mice treated with dexamethasone

This study investigated the anti-sarcopenic effect of fermented Tenebrio molitor larvae (mealworms) extract (FME) in both dexamethasone (DEX)-treated C2C12 cells and mice. FME (100 µg/mL) increased the diameter of myotubes and inhibited the gene and protein expression of atrogin-1 compared to DEX- or non-fermented mealworms extract (ME)-treated C2C12 cells. Male C57BL/6N mice were divided into five groups: Normal Control (NC), DEX (10 mg/kg, intraperitoneal), and three groups of DEX+FME (100, 200, or 500 mg FME/kg/day, oral) for two weeks. FME at doses of 200 and 500 mg/kg effectively improved grip strength when compared to the DEX group. Histological analysis of the quadriceps muscle showed a larger muscle fiber size in the DEX+FME groups compared to DEX group. FME (200 and 500 mg/kg) significantly increased cross-sectional area of the muscle fiber compared to DEX group. FME (500 mg/kg) significantly decreased the ubiquitin, atrogin-1 and MuRF-1 protein levels, and increased levels of MHC and MyoG in DEX-treated mice. The puromycin labeling assay revealed that FME increased protein synthesis in DEX-induced muscle atrophy. The FME treatment demonstrated significant upregulation in phosphorylation levels, including mTOR, FoxO3α, Akt, and PI3K compared to DEX group. In conclusion, FME inhibited the increase in proteins associated with muscle atrophy, including, atrogin-1 and MuRF-1, by regulating the PI3K-Akt-FoxO3α pathway. FME improved the PI3K-Akt-mTOR signaling pathway, which was reduced by DEX. This study suggests that FME has the potential for use in sarcopenia therapy, possibly serving as a natural agent that counteracts the negative effects of DEX on muscle tissue.

Production, characterisation, and biological properties of Tenebrio molitor-derived oligopeptides

Three protein hydrolysates from Tenebrio molitor were obtained by enzymatic hydrolysis employing two food-grade proteases (i.e. Alcalase and Flavourzyme), and a complete characterisation of their composition was done. The digestion-derived products were obtained using the INFOGEST protocol. In vitro antioxidant activity and anti-inflammatory activities were evaluated. Tenebrio molitor flour and the protein hydrolysates showed a high ability to scavenge the DPPH radical (EC50 values from 0.30 to 0.87 mg/mL). The hydrolysate obtained with a combination of the two food-grade proteases could decrease the gene expression of pro-inflammatory genes after being digested. Furthermore, the peptidome was fully determined for the first time for T. molitor hydrolysates and digests, and 40 peptides were selected based on their bioactivity to be evaluated by in silico tools, including prediction tools and molecular docking. These results provide new perspectives on the use of edible insects as sustainable and not nutritionally disadvantageous food for human consumption.

Effects of Organic Xenobiotics on Tenebrio molitor Larvae and Their Parasite Gregarina polymorpha

Environmental contamination with xenobiotics affects organisms and the symbiotic relations between them. A convenient object to study relationships between parasites and their hosts is the host-parasite system "Tenebrio molitor Linnaeus, 1758 (Coleoptera, Tenebrionidae)-Gregarina polymorpha (Hammerschmidt, 1838) Stein, 1848 (Eugregarinorida, Gregarinidae)". For this experiment, we took 390 T. molitor larvae and 24 organic compounds. Groups of mealworms, 15 in each, were subjected to those compounds for 10 days. Then, we recorded the vitality of both the larvae of T. molitor and G. polymorpha. To assess how G. polymorpha had affected the hosts' wellbeing, we looked for changes in the larvae's body mass and compared them to the number of gregarines in their intestines. The vitality of the larvae was inhibited by cyclopentanol and 2-naphthol. The intensity of gregarine invasion was reduced by diphenyl ether, benzyl alcohol, catechol, and 3-aminobenzoic acid. No effect on the number of gregarines was produced by 3,4,5-trihydroxybenzoic acid, cyclohexanemethanol, phenol, benzalkonium chloride, maleic anhydride, cyclohexanol, resorcin, benzoic acid, 2-methylfuran, terpinen-4-ol, 1-phenylethylamine, dibutyl phthalate, 3-furancarboxylic acid, 5-methyl furfural, 6-aminohexanoic acid, succinic anhydride, o-xylene, and benzaldehyde. In the infected T. molitor individuals, the mean number of G. polymorpha equaled 45 specimens per host. The groups of smaller mealworms had fewer gregarines. Positive correlation was seen between growth rates of T. molitor larvae and the intensity of invasion by gregarines.

Bioactive peptides as a novel strategy to prevent alcoholic liver injury

Alcohol intake has become one of the leading risks to human health and wellness, among which acute and/or chronic alcohol-induced liver injury is a leading threaten, with few therapeutic options other than abstinence. In recent years, studies suggested that certain bioactive peptides from food sources could represent natural and safe alternatives for the prevention of alcoholic liver injury. Hence, this chapter focus on the advanced research on bioactive peptides exerting hepatoprotective activity against alcoholic liver injury. The main sources of protein, strategies for the preparation of hepatoprotective hydrolysates and peptides, underlying mechanisms of peptides on hepatoprotection, and possible structure-activity relationship between peptides and hepatoprotective activity were summarized and discussed, aiming to give a systematic insight into the research progress of hepatoprotective peptides. However, more efforts would be needed to give a clearer insight into the underlying mechanisms and structure-activity relationship before using hepatoprotective peptides as functional food ingredients or dietary supplements.

Improving the nutritional values of yellow mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) larvae as an animal feed ingredient: a review

Yellow mealworm larvae (YML; Tenebrio molitor) are considered as a valuable insect species for animal feed due to their high nutritional values and ability to grow under different substrates and rearing conditions. Advances in the understanding of entomophagy and animal nutrition over the past decades have propelled research areas toward testing multiple aspects of YML to exploit them better as animal feed sources. This review aims to summarize various approaches that could be exploited to maximize the nutritional values of YML as an animal feed ingredient. In addition, YML has the potential to be used as an antimicrobial or bioactive agent to improve animal health and immune function in production animals. The dynamics of the nutritional profile of YML can be influenced by multiple factors and should be taken into account when attempting to optimize the nutrient contents of YML as an animal feed ingredient. Specifically, the use of novel land-based and aquatic feeding resources, probiotics, and the exploitation of larval gut microbiomes as novel strategies can assist to maximize the nutritional potential of YML. Selection of relevant feed supplies, optimization of ambient conditions, the introduction of novel genetic selection procedures, and implementation of effective post-harvest processing may be required in the future to commercialize mealworm production. Furthermore, the use of appropriate agricultural practices and technological improvements within the mealworm production sector should be aimed at achieving both economic and environmental sustainability. The issues highlighted in this review could pave the way for future approaches to improve the nutritional value of YML.

Nrf2-mediated protective effect of protein hydrolysates from Protaetia brevitarsis larvae against oxidative stress-induced hepatotoxicity

In this study, we hypothesized that Protaetia brevitarsis larvae (PBL) protein hydrolysates, which have been previously reported to exhibit strong antioxidant activity, might protect liver cells against oxidative stress-induced injury. Thus, the cytoprotective effects and related mechanisms of PBL hydrolysates were investigated in AML12 liver cells. Among PBL hydrolysates prepared by three different proteases, the PBL flavouryzme hydrolysate showed significantly higher protective effect against H2O2-induced cytotoxicity than other hydrolysates in AML12 cells. Further mechanistic studies showed that pretreatment with PFH reduces cellular level of reactive oxygen species through induction of Nrf2-mediated antioxidant enzymes such as catalase and heme oxygenase-1. In addition, the free amino acid analysis revealed that PFH was rich in branched-chain amino acids, aromatic amino acids, and hydrophobic amino acids as compared to other hydrolysates, which could contribute to its hepatoprotective effect. These findings suggest that PFH represents a potential source of nutraceuticals that supports liver functions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01279-0.

Heme Oxygenase 1-Mediated Anti-Inflammatory Effect of Extract from the Aerial Part of Heracleum moellendorffii Hance

In this study, the anti-inflammatory effects of a methanolic extract from the aerial part of Heracleum moellendorffii Hance (HmAPE) and its underlying mechanisms were investigated. HmAPE demonstrated a significant reduction in nitric oxide production in lipopolysaccharide (LPS)-treated murine macrophage RAW264.7 cells, and HmAPE decreased the protein and mRNA expression of inducible nitric oxide synthase. Further mechanistic studies on inflammatory signaling pathways revealed that HmAPE-mediated downregulation of inflammatory gene expressions was not associated with mitogen-activated protein kinases or nuclear factor-κB signaling pathways. However, HmAPE treatment activated nuclear factor E2-related factor 2 (Nrf2) and upregulated heme oxygenase-1 (HO-1) expression, which is known to suppress pro-inflammatory cytokine production. Additionally, treatment with a selective HO-1 inhibitor, tin protoporphyrin IX, partially reversed the effects of HmAPE in LPS-treated RAW264.7 cells, indicating that HmAPE inhibited LPS-induced NO production, at least in part, through induction of Nrf2-mediated HO-1 expression. These findings suggest that HmAPE could serve as a potential edible source with anti-inflammatory properties, and further studies are required to ascertain its anti-inflammatory efficacy in vivo.

Enzymatic Hydrolysis of Tenebrio molitor (Mealworm) Using Nuruk Extract Concentrate and an Evaluation of Its Nutritional, Functional, and Sensory Properties

Enzymatic protein hydrolysis is a well-established method for improving the quality of dietary proteins, including edible insects. Finding effective enzymes from natural sources is becoming increasingly important. This study used nuruk extract concentrate (NEC), an enzyme-rich fermentation starter, to produce protein hydrolysate from defatted Tenebrio molitor (also called mealworm, MW). The nutritional, functional, and sensorial properties of the hydrolysate were then compared to those obtained using commercial proteases (alcalase and flavourzyme). The protease activities of the crude nuruk extract (CNE), NEC, alcalase, and flavourzyme were 6.78, 12.71, 11.07, and 12.45 units/mL, respectively. The degree of hydrolysis and yield of MW hydrolysis by NEC were 15.10 and 35.92% (w/w), respectively. MW hydrolysate was obtained using NEC and had a significantly higher free amino acid content (90.37 mg/g) than alcalase (53.01 mg/g) and flavourzyme (79.64 mg/g) hydrolysates. Furthermore, the NEC hydrolysis of MW increased the antioxidant and angiotensin-converting enzyme inhibitory activity, with IC₅₀ values of 3.07 and 0.15 mg/mL, respectively. The enzymatic hydrolysis also improved sensory properties, including umaminess, sweetness, and saltiness. Overall, this study found that the NEC hydrolysis of MW outperformed commercial proteases regarding nutritional quality, sensory attributes, and biological activity. Therefore, nuruk could potentially replace commercial proteases, lowering the cost of enzymatic protein hydrolysis.

Edible Insects as a Novel Source of Bioactive Peptides: A Systematic Review

The production of food and feed to meet the needs of the growing world's population will soon become a serious challenge. In search for sustainable solutions, entomophagy is being proposed as an alternative source of proteins, with economic and environmental advantages when compared to meat. Edible insects are not only a valuable source of important nutrients, but their gastrointestinal digestion also originates small peptides with important bioactive properties. The present work intends to provide an exhaustive systematic review on research articles reporting bioactive peptides identified from edible insects, as demonstrated by in silico, in vitro, and/or in vivo assays. A total of 36 studies were identified following the PRISMA methodology, gathering 211 potentially bioactive peptides with antioxidant, antihypertensive, antidiabetic, antiobesity, anti-inflammatory, hypocholesterolemia, antimicrobial, anti-severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), antithrombotic, and immunomodulatory properties, originated from the hydrolysates of 12 different insect species. From these candidates, the bioactive properties of 62 peptides were characterized in vitro and 3 peptides were validated in vivo. Data establishing the scientific basis of the health benefits associated with the consumption of edible insects can be a valuable contribution to overcoming the cultural issues that hinder the introduction of insects in the Western diet.

Alternative Protein Sources and Novel Foods: Benefits, Food Applications and Safety Issues

The increasing size of the human population and the shortage of highly valuable proteinaceous ingredients has prompted the international community to scout for new, sustainable, and natural protein resources from invertebrates (e.g., insects) and underutilized legume crops, unexploited terrestrial and aquatic weeds, and fungi. Insect proteins are known for their nutritional value, being rich in proteins with a good balance of essential amino acids and being a valuable source of essential fatty acids and trace elements. Unconventional legume crops were found rich in nutritional, phytochemical, and therapeutic properties, showing excellent abilities to survive extreme environmental conditions. This review evaluates the recent state of underutilized legume crops, aquatic weeds, fungi, and insects intended as alternative protein sources, from ingredient production to their incorporation in food products, including their food formulations and the functional characteristics of alternative plant-based proteins and edible insect proteins as novel foods. Emphasis is also placed on safety issues due to the presence of anti-nutritional factors and allergenic proteins in insects and/or underutilized legumes. The functional and biological activities of protein hydrolysates from different protein sources are reviewed, along with bioactive peptides displaying antihypertensive, antioxidant, antidiabetic, and/or antimicrobial activity. Due to the healthy properties of these foods for the high abundance of bioactive peptides and phytochemicals, more consumers are expected to turn to vegetarianism or veganism in the future, and the increasing demand for such products will be a challenge for the future.

Hepatoprotective Effect of Albumin Peptide Fractions from Corn Germ Meal against Alcohol-Induced Acute Liver Injury in Mice

Acute alcoholic liver disease can cause serious liver damage. This study reports on the hepatoprotective effect of albumin peptide fractions from corn germ meal (MW < 1 kDa) (APF4) on acute alcohol hepatic damage in mice. In the mice model, the results indicated that APF4 at a dose of 800 mg/kg/bw could markedly boost alcohol metabolism, which was shown in the reduced duration of the loss of the righting reflex; the reduced level of blood alcohol concentration (BAC), cytochrome P450 2E1 (CYP2E1), alanine aminotransferase (ALT), aminotransferase (AST), triglycerides (TG), and malondialdehyde (MDA) (p < 0.01); the enhanced activity of aldehyde dehydrogenase (ALDH); and the superoxide dismutase (SOD) and glutathione (GSH) levels being increased by up to 84.02% and 193.22% (p < 0.01) compared to the control group. The antioxidant capability and lipid peroxidation inhibition activity of APF4 may be responsible for its protective effect against liver damage induced by alcohol. The findings suggested that APF4 had the hepatoprotective property against liver damage induced by alcohol.

Bioactive Peptide Discovery from Edible Insects for Potential Applications in Human Health and Agriculture

In the past decade, there has been fast-growing interest among researchers to discover bioactive peptides from edible insects and to evaluate their potential applications in the management of human, livestock, and plant health. This review summarizes current knowledge of insect-derived peptides and their potential role in tackling human health issues and solving agriculture problems by protecting crops and livestock against their pathogens. Numerous bioactive peptides have been identified from edible insect species, including peptides that were enzymatically liberated from insect proteins and endogenous peptides that occur naturally in insects. The peptides exhibited diverse bioactivities, encompassing antioxidant, anti-angiotensin-converting enzyme, anti-dipeptidyl peptidase-IV, anti-glucosidase, anti-lipase, anti-lipoxygenase, anti-cyclooxygenase, anti-obesity, and hepatoprotective activities. Such findings point to their potential contribution to solving human health problems related to inflammation, free radical damage, diabetes, hypertension, and liver damage, among others. Although most of the experiments were performed in vitro, evidence for the in vivo efficacy of some peptides is emerging. Evidence of the protective effects of insect-derived endogenous antimicrobial peptides in combating farm animal and plant pathogens is available. The ability of insect-derived endogenous neuropeptides to protect plants against herbivorous insects has been demonstrated as well. Nevertheless, the potency of peptides identified from insect protein hydrolysates in modulating livestock and plant health remains a knowledge gap to be filled.

Tenebrio molitor Larva Trypsin Hydrolysate Ameliorates Atopic Dermatitis in C57BL/6 Mice by Targeting the TLR-Mediated MyD88-Dependent MAPK Signaling Pathway

Atopic dermatitis (AD) is a widely researched chronic inflammatory skin disease with a complex etiology. The increased prevalence of AD necessitates exploration of natural sources as potential therapeutic agents with limited side effects. In the current study, a 1-chloro-2,4-dinitrobenzene (DNCB)-induced AD mouse model was used to examine the anti-AD effects of Tenebrio molitor trypsin hydrolysate (TMTH) and its underlying molecular mechanism. DNCB-treated mice were treated with TMTH (1 and 10 mg/kg), and prednisolone (3 mg/kg) was used as the positive control. Serum and skin tissue samples were collected for subsequent analyses. The expression levels of proteins linked to the myeloid differentiation primary response 88 (MyD88)-dependent mitogen-activated protein kinase (MAPK) signaling pathway and serum IgE levels were estimated via Western blotting technique and ELISA (enzyme-linked immunosorbent assay), respectively. Inflammatory cell infiltration and thickening of the dorsal skin were measured using toluidine blue and hematoxylin and eosin staining, respectively. Oral administration of TMTH significantly reduced mast cell infiltration and dermal and epidermal thickness. Moreover, TMTH treatment reduced serum IgE levels. Western blotting confirmed that TMTH treatment suppressed the MyD88-dependent MAPK signaling pathway. Therefore, TMTH substantially inhibited AD-like skin lesion formation via immunomodulation, showing considerable potential for AD treatment.

Innovation in Alternative Food Sources: A Review of a Technological State-of-the-Art of Insects in Food Products

Insects present great potential for the food industry due to their easier rearing conditions and high nutritional value, in comparison with traditional livestock. However, there is a lack of evaluation of the technological status of food products developed with edible insects. Therefore, this study aims to analyze the emergent technological and scientific applications of edible insects in the food industry through a prospective study of patent documents and research articles. Espacenet was used as a research tool, applying the terms Insect, Pupa, Larva, or Nymph and the codes A23L33 and A23V2002. A total of 1139 documents were found-341 were related to the study. Orbit® was used to evaluate technological domains and clusters of concepts. Scopus database research was performed to assess the prevalence of insect research, with the term "edible and insect*". The main insects used were silkworms, bees, beetles, mealworms, crickets, and cicadas. Protein isolates were the predominant technology, as they function as an ingredient in food products or supplements. A diverse application possibility for insects was found due to their nutritional composition. The insect market is expected to increase significantly in the next years, representing an opportunity to develop novel high-quality/sustainable products.

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.

Recent Insight on Edible Insect Protein: Extraction, Functional Properties, Allergenicity, Bioactivity, and Applications

Due to the recent increase in the human population and the associated shortage of protein resources, it is necessary to find new, sustainable, and natural protein resources from invertebrates (such as insects) and underutilized plants. In most cases, compared to plants (e.g., grains and legumes) and animals (e.g., fish, beef, chicken, lamb, and pork), insect proteins are high in quality in terms of their nutritional value, total protein content, and essential amino acid composition. This review evaluates the recent state of insects as an alternative protein source from production to application; more specifically, it introduces in detail the latest advances in the protein extraction process. As an alternative source of protein in food formulations, the functional characteristics of edible insect protein are comprehensively presented, and the risk of allergy associated with insect protein is also discussed. The biological activity of protein hydrolyzates from different species of insects (Bombyx mori, Hermetia illucens, Acheta domesticus, Tenebrio molitor) are also reviewed, and the hydrolysates (bioactive peptides) are found to have either antihypertensive, antioxidant, antidiabetic, and antimicrobial activity. Finally, the use of edible insect protein in various food applications is presented.

Antioxidant Peptides From Protein Hydrolysate of Marine Red Algae Eucheuma cottonii: Preparation, Identification, and Cytoprotective Mechanisms on H2O2 Oxidative Damaged HUVECs

To screen, prepare, identify, and evaluate the activities of natural antioxidants for treating chronic diseases caused by oxidative stress. Two algal proteins, namely ZD10 and ZD60, precipitated with 10 and 60% (NH₄)₂SO₄ were extracted from red algae Eucheuma cottonii (E. cottonii) and hydrolyzed using five proteolytic enzymes. The results showed that ZD60 played the most significant role in the enhancement of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH⋅) scavenging activity (25.91 ± 0.24%) among all protein hydrolysates. Subsequently, six antioxidant peptides (EP1-EP6) were isolated from the papain hydrolysate of ZD60 by ultrafiltration and chromatography methods. Their amino acid sequences were identified as Thr-Ala (EP1), Met-Asn (EP2), Tyr-Ser-Lys-Thr (EP3), Tyr-Ala-Val-Thr (EP4), Tyr-Leu-Leu (EP5), and Phe-Tyr-Lys-Ala (EP6) with molecular weights of 190.21, 263.33, 497.55, 452.51, 407.51, and 527.62 Da, respectively. Of which, EP3, EP4, EP5, and EP6 showed strong scavenging activities on DPPH⋅, hydroxyl radical (HO⋅), and superoxide anion radical (O- 2⋅). Moreover, EP4 and EP5 could significantly protect human umbilical vein endothelial cells (HUVECs) from H₂O₂-induced oxidative damage by increasing the levels of antioxidant enzyme systems including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) to reduce the levels of reactive oxygen species (ROS) (60.51 and 51.74% of model group) and malondialdehyde (MDA) (75.36 and 64.45% of model group). In addition, EP4 and EP5 could effectively inhibit H₂O₂-induced apoptosis by preventing HUVECs from early apoptosis to late apoptosis. These results indicated that the antioxidant peptides derived from E. cottonii, especially EP4 and EP5, could serve as the natural antioxidants applied in pharmaceutical products to treat chronic cardiovascular diseases caused by oxidative damage, such as coronary heart disease, atherosclerosis, etc.

Tenebrio molitor as a source of interesting natural compounds, their recovery processes, biological effects, and safety aspects

Nowadays, it is urgent to produce in larger quantities and more sustainably to reduce the gap between food supply and demand. In a circular bioeconomy vision, insects receive great attention as a sustainable alternative to satisfy food and nutritional needs. Among all insects, Tenebrio molitor (TM) is the first insect approved by the European Food Safety Authority as a novel food in specific conditions and uses, testifying its growing relevance and potential. This review holistically presents the possible role of TM in the sustainable and circular solution to the growing needs for food and nutrients. We analyze all high value-added products obtained from TM (powders and extracts, oils and fatty acids, proteins and peptides, and chitin and chitosan), their recovery processes (evaluating the best ones in technical and environmental terms), their nutritional and economical values, and their biological effects. Safety aspects are also mentioned. TM potential is undoubted, but some aspects still need to be discussed, including the health effects of substances and microorganisms in its body, the optimal production conditions (that affect product quality and safety), and TM capacity to convert by-products into new products. Environmental, economic, social, and market feasibility studies are also required to analyze the new value chains. Finally, to unlock the enormous potential of edible insects as a source of nutritious and sustainable food, it will be necessary to overcome the cultural, psychological, and regulatory barriers still present in Western countries.

A dipeptidyl peptidase IV inhibitory peptide relieves palmitic acid-induced endoplasmic reticulum stress in HepG2 cells independent of inhibiting dipeptidyl peptidase IV activity

The peptide VLATSGPG (VLA) is known to inhibit dipeptidyl peptidase IV (DPP-IV), although its mechanism in relieving endoplasmic reticulum (ER) stress is unclear. In this study, we found that treating HepG2 cells with 1.0 mM VLA reduced DPP-IV activity by 73.7 ± 4.8% without changing the DPP-IV mRNA expression level. In addition, 1.0 and 0.5 mM VLA alleviated palmitic acid (PA)-induced cell death and intracellular calcium imbalances. The levels of apoptosis-related proteins (caspase-3, caspase-9, and CHOP) were reduced by VLA treatment, which was presumed to be related to ER stress. Further studies confirmed that VLA alleviated PA-induced morphological damage to the ER and reduced the levels of the ER stress marker proteins (BIP, p-PERK, and p-IRE1α). VLA alleviated PA-induced ER stress in HepG2 cells independent of DPP-IV enzymatic activity inhibition. These findings have implications for developing novel treatment approaches for liver diseases caused by ER stress.

Mealworm (Tenebrio molitor): Potential and Challenges to Promote Circular Economy

Simple Summary

The main objective of this review is to analyse the potential of insects from the perspective of circular economy, focusing our attention on mealworm larvae. After pointing out the key concepts of circular economy and describing the use of insects in bioconversion processes, we discuss the most relevant uses of the mealworm in different industries, which show the great contribution this insect can make within circular productive systems. This topic has attracted a lot of attention due to its implications from an economic and environmental point of view. Recently, mealworm larvae were positively assessed by European Food Safety Authority (EFSA) as a safe novel food. As a matter of fact, the mealworm is the first edible insect to achieve this important milestone in the EU. Due to this new scientific opinion, considerable expectations arise on mealworms and their potential in different fields, which will surely lead to market developments in the following years.

Abstract

Over the last few years, the concept of Circular Economy (CE) has received a lot of attention due to its potential contribution to the Sustainable Development Goals (SDGs), especially by reconciling economic growth with the protection of the environment through its grow-make-use-restore approach. The use of insects in circular production systems has been a good example of this concept as insects can transform a wide range of organic waste and by-products into nutritious feedstuffs, which then go back into the production cycle. This paper explores the potential of mealworms (Tenebrio molitor) in circular production systems by reviewing their use and applicability in several industries such as pharmaceuticals, agriculture, food, etc. Despite the high versatility of this insect and its potential as a substitute source of nutrients and other valuable components, there are still many legislative and behavioural challenges that hinder its adoption and acceptance.

Broussochalcone A Is a Novel Inhibitor of the Orphan Nuclear Receptor NR4A1 and Induces Apoptosis in Pancreatic Cancer Cells

The orphan nuclear receptor 4A1 (NR4A1) is overexpressed in pancreatic cancer and exhibits pro-oncogenic activity, and NR4A1 silencing and treatment with its inactivators has been shown to inhibit pancreatic cancer cells and tumor growth. In this study, we identified broussochalcone A (BCA) as a new NR4A1 inhibitor and demonstrated that BCA inhibits cell growth partly by inducing NR4A1-mediated apoptotic pathways in human pancreatic cancer cells. BCA downregulated specificity protein 1 (Sp1)-mediated expression of an anti-apoptotic protein, survivin, and activated the endoplasmic reticulum (ER) stress-mediated apoptotic pathway. These results suggest that NR4A1 inactivation contributes to the anticancer effects of BCA, and that BCA represents a potential anticancer agent targeting NR4A1 that is overexpressed in many types of human cancers.

The three-spot seahorse-derived peptide PAGPRGPA attenuates ethanol-induced oxidative stress in LO2 cells through MAPKs, the Keap1/Nrf2 signalling pathway and amino acid metabolism

Alcoholic liver diseases (ALDs) impose a substantial health burden on many countries. Bioactive peptides isolated from people, marine organisms, animals and plants have shown hepatoprotective effects on animal and hepatocyte models. In this study, an LO2 cell model of ethanol-induced liver injury in vitro was constructed. We investigated the hepatoprotective effects of the three-spot seahorse bioactive peptide (SBP) PAGPRGPA (Pro-Ala-Gly-Pro-Arg-Gly-Pro-Ala; 721.39 Da) and characterised the underlying metabolic pathways and biomarkers through a nontargeted metabolomics approach. We found that ethanol-induced oxidative stress impaired the cellular antioxidant system, leading to an imbalance in cellular homeostasis. However, SBP with a certain antioxidant activity inhibited reactive oxygen species (ROS) production, excessive intracellular Ca2+ level and abnormal apoptosis. It also restored the superoxide dismutase (SOD) and glutathione (GSH) levels and attenuated ethanol-induced oxidative damage and inflammation. SBP suppressed the activation of mitogen-activated protein kinase (MAPK) in ethanol-stimulated LO2 cells. It also regulated the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) signalling pathway to protect LO2 cells from oxidative damage by promoting the expression of antioxidant enzymes, such as heme oxygenase-1 (HO-1). Furthermore, the metabolomics approach demonstrated nine different biomarkers and six metabolic pathways. In summary, the hepatoprotective mechanisms of SBP in vitro, which can be attributed to the upregulation of antioxidant substances and amino acid metabolism, attenuate ethanol-induced oxidative stress.

Metabolomics Study of Serum from a Chronic Alcohol-Fed Rat Model Following Administration of Defatted Tenebrio molitor Larva Fermentation Extract

We have previously showed that defatted mealworm fermentation extract (MWF) attenuates alcoholic liver injury by regulating lipid, inflammatory, and antioxidant metabolism in chronic alcohol-fed rats. The current metabolomics study was performed to monitor biochemical events following the administration of MWF (daily for eight weeks) to a rat model of alcoholic liver injury by gas chromatography-tandem mass spectrometry (GC-MS/MS). The levels of 15 amino acids (AAs), 17 organic acids (OAs), and 19 free fatty acids (FFAs) were measured in serum. Analysis of variance (ANOVA), principal component analysis (PCA), and partial least squares discriminant analysis (PLS-DA) were used to compare the levels of 51 metabolites in serum. In particular, 3-hydroxybutyric acid (3-HB), pyroglutamic acid (PG), octadecanoic acid, and docosahexaenoic acid (DHA) were evaluated as high variable importance point (VIP) scores and PCA loading scores as determined by PLS-DA and PCA, and these were significantly higher in the MWF and silymarin groups than in the EtOH group. MWF showed a protective effect from alcohol-induced liver damage by elevating hepatic β-oxidation activity, and serum 3-HB levels were significantly higher in the MWF group than in the EtOH control group. Glycine levels were higher in the MWF group than in the EtOH group, and PG levels (related to glutathione production) were also elevated, indicating a reduction in alcohol-related oxidative stress. In addition, MWF is protected from alcohol-induced inflammation and steatosis by increasing serum DHA, palmitic, and octadecanoic acid levels as compared with the EtOH group. These results suggest that MWF might attenuate alcoholic liver disease, due to its anti-inflammatory and antioxidant effects by up-regulating hepatic β-oxidation activity and down-regulating liver FFA uptake.