Chitin is mostly produced from crustaceans, but it is difficult to supply raw materials due to marine pollution, and the commonly used chemical chitin extraction method is not environmentally friendly. Therefore, this study aims to establish a chitin extraction process using enzymes and to develop edible insect-derived chitin as an eco-friendly new material. The response surface methodology (RSM) was used to determine the optimal conditions for enzymatic hydrolysis. The optimal conditions for enzymatic hydrolysis by RSM were determined to be the substrate concentration (7.5%), enzyme concentration (80 μL/g), and reaction time (24 h). The solubility and DDA of the mealworm chitosan were 45% and 37%, respectively, and those of the commercial chitosan were 61% and 57%, respectively. In regard to the thermodynamic properties, the exothermic peak of mealworm chitin was similar to that of commercial chitin. In the FT-IR spectrum, a band was observed in mealworm chitin corresponding to the C=O of the NHCOCH₃ group at 1645 cm⁻¹, but this band showed low-intensity C=O in the mealworm chitosan due to deacetylation. Collectively, mealworm chitosan shows almost similar physical and chemical properties to commercial chitosan. Therefore, it is shown that an eco-friendly process can be introduced into chitosan production by using enzyme-extracted mealworms for chitin/chitosan production.

Antimicrobial peptides (AMPs) are the frontline innate defense system evolutionarily preserved in insects to combat invading pathogens. These AMPs could serve as an alternative to classical antibiotics to overcome the burden of treating multidrug resistant bacteria. Psacotheasin, a knottin type AMP was isolated from Psacothea hilaris and shown to exhibit antimicrobial activity, especially against fungi through apoptosis mediated cell death. In this study, we aimed to identify novel probable AMPs from Psacothea hilaris, the yellow spotted longicorn beetle. The beetle was immunized with the two bacterial strains (E. coli and S. aureus), and the yeast strain C. albicans. After immunization, total RNA was isolated and sequenced in Illumina platform. Then, beetle transcriptome was de novo assembled and searched for putative AMPs with the known physiochemical features of the AMPs. A selection of AMP candidates were synthesized and tested for antimicrobial activity. Four peptides showed stronger activity against E. coli than the control AMP, melittin while one peptide showed similar activity against S. aureus. Moreover, four peptides and two peptides showed antifungal activity stronger than and similar to melittin, respectively. Collectively one peptide showed both antibacterial and antifungal activity superior to melittin; thus, it provides a potent antimicrobial peptide. All the peptides showed no hemolysis in all the tested concentrations. These results suggest that in silico mining of insects’ transcriptome could be a promising tool to obtain and optimize novel AMPs for human needs.

Aging, and other disease-related muscle disorders are serious health problems. Dexamethasone (DEX), a synthetic glucocorticoid, can trigger skeletal muscle atrophy. This study examined the effects of mealworm (Tenebrio molitor larva) ethanol extract (TME) on C2C12 myoblast differentiation and DEX-induced myotube atrophy. TME induced myotube formation compared to the differentiation medium (DM) group. TME also significantly increased the mRNA expression of muscle creatine kinase (CKm) and myogenic regulatory factors (MRFs), such as myogenin (MyoG), myogenic factor (Myf)5, and MRF4 (Myf6). TME dramatically increased the muscle-specific protein, MyoG, compared to the control, whereas the expression of myogenic differentiation 1 (MyoD) remained unchanged. It also activated the mammalian target of rapamycin (mTOR) signaling pathway. In the DEX-induced muscle atrophy C2C12 model, TME reduced the gene expression of atrogin-1, muscle RING finger protein-1 (MuRF-1), and myostatin, which are involved in protein degradation in skeletal muscles. Furthermore, TME elevated the phosphorylation of forkhead box O3 (FoxO3α) and protein kinase B (Akt). These findings suggest that TME can enhance myotube hypertrophy by regulating the mTOR signaling pathway, and can rescue DEX-induced muscle atrophy by alleviating atrophic muscle markers mediated by Akt activation. Thus, TME can be a potential therapeutic agent for treating muscle weakness and atrophy.

The increasing global population and the environmental consequences of meat consumption have led to the exploration of alternative sources of protein. Edible insects have gained attention as a sustainable and nutritionally rich meat alternative. We investigated the effects of two commonly consumed insects, Protaetia brevitarsis seulensis larva and Bombyx mori pupa, on beneficial gut microbiota growth, using whole 16s metagenome sequencing to assess diet-associated changes. Seven-week-old female C57BL/6J mice were administered the edible insects, along with fracto-oligosaccharide (FOS) as a positive control and sham (phosphate buffer saline (PBS)) as a negative control, to assess the relative abundance of insect-diet-associated gut microbes. In total, 567 genera and 470 species were observed, and among these, 15 bacterial genera were differentially abundant in all three groups. These results show that among the two insects, Bombyx mori pupa polysaccharides have a greater ability to regulate beneficial probiotics and next-generation probiotics. In particular, Lactococcus garvieae, which has promising effects on the gastrointestinal tracts of humans and animals, was significantly enriched in both Protaetia brevitarsis seulensis larva and Bombyx mori pupa polysaccharides, similar to fracto-oligosaccharide. The results suggest that the consumption of these insects, particularly polysaccharides, can enhance the growth of beneficial gut microbes, potentially leading to improved overall health in healthy populations.

Background/Objectives: The larvae of Protaetia brevitarsis seulensis (PB), an edible insect, exhibit diverse bioactivities, but their effects on inflammatory bone loss remain unclear. We investigated whether a 70% ethanol extract of PB larvae (PBE) suppresses osteoclast differentiation and bone loss under inflammatory conditions. Methods: Osteoclast differentiation was assessed in co-cultures of mouse bone marrow cells and osteocytic cells stimulated with interleukin-1 (IL-1). Direct effects on osteoclast precursors were tested in bone marrow–derived macrophages exposed to receptor activator of nuclear factor-κB ligand (RANKL) or tumor necrosis factor-α (TNF-α). Skeletal effects were evaluated in a mouse model of lipopolysaccharide (LPS)-induced bone loss. Results: PBE inhibited IL-1–induced osteoclast differentiation in co-culture, reduced osteocytic RANKL expression and prostaglandin E2 (PGE2) production, and dampened early IL-1 signaling. In osteoclast precursors, PBE directly suppressed osteoclastogenesis driven by RANKL or TNF-α. In vivo, PBE attenuated LPS-induced bone loss and blunted the associated increases in bone RANKL and PGE2. Conclusions: PBE limits inflammatory osteoclastogenesis by downregulating PGE2 and RANKL production in osteoclast-supporting cells and directly inhibiting osteoclast precursor differentiation, thereby attenuating LPS-induced bone loss. These findings identify PBE as a food-derived candidate for managing inflammation-associated bone loss and support further preclinical and nutritional intervention studies.