Insect natural products and processes: new treatments for human disease

Insect-derived extracts and peptides in neuroprotection

Throughout history, various cultures have recognized the significance of insects and have integrated them into traditional medicinal practices. In addition to medicines, insects are garnering attention as a sustainable and nutritious dietary alternative. Although edible insects have long been recognized as food sources in many Asian cultures, recent scientific studies have highlighted their potential therapeutic benefits, particularly in the field of neuroprotection. This review explores insect-derived extracts and peptides, elucidating their neuroprotective potential. This review highlights the potential use of insects as a source of neuroprotective agents. Advancements in neuroprotection may find a key ally in insects as our understanding of the symbiotic relationship between insects and human health becomes more profound.

Periostracum Cicadae Extract and N-Acetyldopamine Regulate the Sleep-Related Neurotransmitters in PCPA-Induced Insomnia Rats

Insomnia is the second most prevalent mental illness worldwide. Periostracum cicadae (PC), as an animal traditional Chinese medicine with rich pharmacological effects, has been documented as a treatment for children's night cries, and later extended to treat insomnia. This study aimed to investigate the effects of PC extract and N-acetyldopamine compounds in ameliorating insomnia. The UPLC-ESI-QTOF-MS analysis determined that PC extract mainly contained N-acetyldopamine components. Previously, we also isolated some acetyldopamine polymers from PC extract, among which acetyldopamine dimer A (NADA) was present in high content. Molecular docking and molecular dynamic simulations demonstrated that NADA could form stable complexes with 5-HT1A, BDNF, and D2R proteins, respectively. The effects of PC extract and NADA on insomnia were evaluated in the PCPA-induced insomnia model. The results indicated that PC extract and NADA could effectively ameliorate hypothalamic pathology of insomnia rats, increase the levels of 5-HT, GABA, and BDNF, and decrease the levels of DA, DOPAC, and HVA. Meanwhile, the PC extract and NADA also could significantly affect the expression of 5-HT1A, BDNF, and DARPP-32 proteins. This study proved that PC extract and acetyldopamine dimer A could effectively improve PCPA-induced insomnia in rats. It is speculated that the main pharmacological substances of PC were acetyldopamine components.

Safe utilization and remediation potential of the mulberry-silkworm system in heavy metal-contaminated lands: A review

Mulberry cultivation and silkworm rearing hold a prominent position in the agricultural industries of many Asian countries, contributing to economic growth, sustainable development, and cultural heritage preservation. Applying the soil-mulberry-silkworm system (SMSS) to heavy metal (HM)-contaminated areas is significant economically, environmentally, and socially. The ultimate goal of this paper is to review the main research progress of SMSS under HM stress, examining factors affecting its safe utilization and remediation potential for HM-contaminated soils. HM tolerance of mulberry and silkworms relates to their growth stages. Based on the standards for HM contaminants in various mulberry and silkworm products and the bioconcentration factor of HMs at different parts of SMSS, we calculated maximum safe Cd and Pb levels for SMSS application on contaminated lands. Several remediation practices demonstrated mulberry's ability to grow on barren lands, absorb various HMs, while silkworm excreta can adsorb HMs and improve soil fertility. Considering multiple factors influencing HM tolerance and accumulation, we propose a decision model to guide SMSS application in polluted areas. Finally, we discussed the potential of using molecular breeding techniques to screen or develop varieties better suited for HM-contaminated regions. However, actual pollution scenarios are often complex, requiring consideration of multiple factors. More large-scale applications are crucial to enhance the theoretical foundation for applying SMSS in HM pollution risk areas.

Consumers' Perceptions about Edible Insects' Nutritional Value and Health Effects: Study Involving 14 Countries

Insects have been consumed for time immemorial in many regions of the globe. However, in other parts, they are not traditionally eaten. Because they are a more sustainable source of animal protein and provide valuable nutrients as well as bioactive compounds with beneficial effects on the human body, their consumption is encouraged. Knowledge can serve as a tool for better acceptance of insects as food. In this context, the present work investigated the knowledge about the nutritional value and health effects of edible insects in different countries. Data were collected by employing a questionnaire survey translated into the different languages of all participating countries and were treated using statistical tools. A total of 7222 responses were obtained. The results indicated that for many issues, the participants manifested a neutral opinion (neither agree nor disagree), but the participants who manifested agreement/disagreement were generally well informed. They were also able to identify untrue facts and answer accordingly by disagreeing. Factor analysis showed four groups of questions: nutritive value, negative perception and risks, safety and benefits of insects and contamination and harmful components. Finally, significant differences were observed according to the sociodemographic variables studies (sex, age, education, living environment and country), with age and country being the most influential of the sociodemographic factors on knowledge. Therefore, increasing knowledge is envisaged as an essential factor in augmenting the recognition of edible insects as a nutritional food, presenting health benefits apart from being a more sustainable source of animal protein when compared with beef or pork meats.

Blap-6, a Novel Antifungal Peptide from the Chinese Medicinal Beetle Blaps rhynchopetera against Cryptococcus neoformans

Cryptococcus neoformans (C. neoformans) is a pathogenic fungus that can cause life-threatening meningitis, particularly in individuals with compromised immune systems. The current standard treatment involves the combination of amphotericin B and azole drugs, but this regimen often leads to inevitable toxicity in patients. Therefore, there is an urgent need to develop new antifungal drugs with improved safety profiles. We screened antimicrobial peptides from the hemolymph transcriptome of Blaps rhynchopetera (B. rhynchopetera), a folk Chinese medicine. We found an antimicrobial peptide named blap-6 that exhibited potent activity against bacteria and fungi. Blap-6 is composed of 17 amino acids (KRCRFRIYRWGFPRRRF), and it has excellent antifungal activity against C. neoformans, with a minimum inhibitory concentration (MIC) of 0.81 μM. Blap-6 exhibits strong antifungal kinetic characteristics. Mechanistic studies revealed that blap-6 exerts its antifungal activity by penetrating and disrupting the integrity of the fungal cell membrane. In addition to its direct antifungal effect, blap-6 showed strong biofilm inhibition and scavenging activity. Notably, the peptide exhibited low hemolytic and cytotoxicity to human cells and may be a potential candidate antimicrobial drug for fungal infection caused by C. neoformans.

Structurally Diverse Alkaloids with Anti-Renal-Fibrosis Activity from the Centipede Scolopendra subspinipes mutilans

Twelve new alkaloids, scolopenolines A-L (1-7, 9-11, 13, 14), along with six known analogues, were isolated from Scolopendra subspinipes mutilans, identified by analysis of spectroscopic data and quantum chemical and computational methods. Scolopenoline A (1), a unique guanidyl-containing C14 quinoline alkaloid, features a 6/6/5 ring backbone. Scolopenoline B (2) is a novel sulfonyl-containing heterodimer comprising quinoline and tyramine moieties. Scolopenoline G (7) presents a rare C12 quinoline skeleton with a 6/6/5 ring system. Alkaloids 1, 8, 10, and 15-18 display anti-inflammatory activity, while 10 and 16-18 also exhibit anti-renal-fibrosis activity. Drug affinity responsive target stability and RNA-interference assays show that Lamp2 might be a potentially important target protein of 16 for anti-renal-fibrosis activity.

Immunomodulatory potential of Sarcophaga argyostoma larval hemolymph as a natural alternative to berenil in treating Trypanosoma evansi in vivo

This study compared effects of diminazene aceturate (berenil), commonly used to treat domestic animals infected with Trypanosoma evansi, with the hemolymph of Sarcophaga argyostoma larva. The hemolymph may be acting as a possible natural alternative to berenil, based on immunomodulation mediated inflammatory response. Inflammatory mediators and histopathological changes in liver, kidney, and spleen of albino mice experimentally infected with T. evansi were studied. Mice were divided into five groups: G1, uninfected, untreated (negative control); G2, T. evansi infected (positive control); G3, infected and treated with berenil; G4, infected and treated with hemolymph; G5, infected and treated with hemolymph 3 days before infection (prophylactic group). Animals in (G4) and (G5) exhibited a significant overall reduction in serum levels of IFN-γ. However, the reduction in TNF-α and IL-6 levels was more limited compared to (G2) and (G3). Notably, an elevation in IL-10 levels was observed compared to animals in other groups. Furthermore, the groups treated with hemolymph demonstrated an alleviation of T. evansi infection in contrast to the other groups. This study highlights that the administration of Sarcophaga argyostoma larval hemolymph at a dosage of 0.5 ml/kg significantly inhibited T. evansi organisms in vivo, showcasing a pronounced trypanocidal effect.

Revisiting edible insects as sources of therapeutics and drug delivery systems for cancer therapy

Cancer has been medicine's most formidable foe for long, and the rising incidence of the disease globally has made effective cancer therapy a significant challenge. Drug discovery is targeted at identifying efficacious compounds with minimal side effects and developments in nanotechnology and immunotherapy have shown promise in the fight against this complicated illness. Since ancient times, insects and insect-derived products have played a significant role in traditional medicine across several communities worldwide. The aim of this study was to inspect the traditional use of edible insects in various cultures and to explore their modern use in cancer therapy. Edible insects are sources of nutrients and a variety of beneficial substances with anticancer and immunomodulatory potential. Recently, insect derived bioactive-components have also been used as nanoparticles either in combination with chemotherapeutics or as a nano-cargo for the enhanced delivery of chemotherapeutic drugs due to their high biocompatibility, low bio-toxicity, and their antioxidant and anticancer effects. The crude extracts of different edible insects and their active components such as sericin, cecropin, solenopsin, melittin, antimicrobial peptides and fibroin produce anti-cancer and immunomodulatory effects by various mechanisms which have been discussed in this review.

Cloning, expression and molecular analysis of recombinant Netrin-A protein of Lucilia sericata Meigen (Diptera: Calliphoridae) larvae

Objectives

Lucilia sericata (Diptera: Calliphoridae) is used in larval therapy for wound healing. Netrin-A is an enzyme secreted from the salivary glands of these larvae, and has a central role in neural regeneration and angiogenesis. This study aimed to produce the recombinant Netrin-A protein from Lucilia sericata larvae by the baculovirus expression vector system in the Sf9 insect cell line.

Methods

The coding sequence of Netrin-A was cloned, amplified in the pTG19 vector, and then cloned in the pFastBac HTA vector. It was then transformed into DH10Bac, and the recombinant Bacmid was subsequently transfected into Sf9 cells. The recombinant Netrin-A was purified by Ni-NTA agarose. The evaluation was done using SDS-PAGE and western blot, respectively. Finally, its concentration was calculated with the Bradford assay.

Results

The molecular weight of this protein was 52 kDa with 404 amino acids. The signal peptide was located between amino acids 24 and 25. The concentration of Netrin-A was calculated to be 48.8 μg/ml. It reaffirmed the characterized gene codes of Lucilia sericata Netrin-A in a previous study.

Conclusions

The generation of recombinant Netrin-A could be used in larval therapy, and as a biomarker in certain diseases. The netrin-A of Lucilia sericata was unprecedentedly cloned and expressed in a eukaryotic cell line. Given that this larva is FDA-approved, and non-pathogenic, it conduces to research on the development of maggot therapy in future.

Dietary and Therapeutic Benefits of Edible Insects: A Global Perspective

Edible insects are gaining traction worldwide for research and development. This review synthesizes a large and well-established body of research literature on the high nutritional value and variety of pharmacological properties of edible insects. Positive benefits of insect-derived products include immune enhancement; gastrointestinal protection; antitumor, antioxidant, and anti-inflammatory capacities; antibacterial activities; blood lipid and glucose regulation; lowering of blood pressure; and decreased risk of cardiovascular diseases. However, the pharmacological mechanisms of these active components of edible insects in humans have received limited research attention. In addition, we discuss health risks (safety); application prospects; regulations and policies governing their production and consumption with a view to promote innovations, intraglobal trade, and economic development; and suggestions for future directions for further pharmacological functional studies. The aim is to review the current state of knowledge and research trends on edible insects as functional ingredients beneficial to the nutrition and health of humans and animals (livestock, aquatic species, and pets).

Diversity and antimicrobial activity of the tropical ant-derived actinomycetes isolated from Thailand

Antibiotic resistance is one of the most important global healthcare challenges and is responsible for the mortality of millions of people worldwide every year. It is a crisis attributed to misuse of antibiotics and a lack of new drug development. Actinomycetes constitute a group of Gram-positive bacteria known for their distinctive high guanine-cytosine (G+C) content in their genomic DNA. These microorganisms are widely recognized for their capability to generate a wide range of secondary metabolites with diverse biological activities. These versatile microorganisms are ubiquitous in diverse ecosystems, including soil, freshwater, marine sediments, and within the bodies of insects. A recent study has demonstrated that social insects, such as ants, host a diverse array of these bacteria. In this study, we involved the isolation and characterization of a total of 72 actinomycete strains obtained from 18 distinct ant species collected from various regions across Thailand. Utilizing 16S rRNA gene analysis, these isolated actinomycetes were classified into four distinct genera: Amycolatopsis (2 isolates), Micromonospora (1 isolate), Nocardia (8 isolates), and Streptomyces (61 isolates). Among the Streptomyces strains, 23 isolates exhibited antimicrobial activity against a panel of Gram-positive bacteria, including Bacillus subtilis ATCC 6633, Staphylococcus epidermidis ATCC 12228, Staphylococcus aureus ATCC 25923, Kocuria rhizophila ATCC 9341, and Methicillin-resistant Staphylococcus aureus (MRSA) DMST 20646. Additionally, two isolates displayed antifungal activity against Candida albicans TISTR 5554. Based on 16S rRNA gene sequence similarity studies, these two isolates, ODS25 and ODS28, were demonstrated to be closely related to Streptomyces lusitanus NBRC 13464T (98.07%) and Streptomyces haliclonae DSM 41970T (97.28%), respectively. The level of 16S rRNA gene sequence similarity below 98.65% cutoff indicates its potential as a novel actinomycete species. These findings underscore the potential of actinomycetes sourced from ants as a valuable reservoir of novel antimicrobials.

A Review on Chemical Structures and Biological Activities of Dopamine Derivatives from Medicinal Insects

Medicinal insects play an important role in the treatment of refractory diseases due to their unique and rich pharmacological activities. However, compared to plants, microorganisms, and marine organisms, medicinal insects have been largely ignored. Some small molecules isolated from insects are known to have defensive effects, but their majority roles remain unknown. In-depth research on the small molecules of medicinal insects has been conducted in recent years. Then alkaloids, dopamine derivatives, nucleoside derivatives, and other components are obtained. Among them, dopamine derivatives are a unique class of components from medicinal insects. Thus, we present a comprehensive overview of chemical structures and biological activities of dopamine derivatives from some medicinal insects, which will bring more attention to other researchers for further chemical and biological investigations on the unique dopamine derivatives as well as medicinal insects.

Dimeric N-Acetyldopamine Derivatives Featuring a Seco-Benzene System from the Insects Aspongopus chinensis and Periostracum cicadae

Aspongamide F (1), a novel N-acetyldopamine (NADA) dimer possessing a 6/6/6 ring system, and (±)-aspongamides G (2) and H (3), rare NADA derivatives with fragmented benzene rings, were isolated from Aspongopus chinensis. (±)-Cicadamides C (4) and D (5), the first 1,4-Benzodioxane NADA dimers featuring a seco-benzene system, and (±)-cicadamides E (6) and F (7), the NADA dimers derivatives, were isolated from Periostracum cicadae. The structures of all compounds were elucidated by spectroscopic analyses and computational methods. A plausible biosynthetic pathway for compounds 1-5 was proposed. The biological assay revealed that (+)-4 and (-)-4 exhibit renal protection in a dose-dependent manner.

Biology for biomimetics I: function as an interdisciplinary bridge in bio-inspired design

In bio-inspired design, the concept of 'function' allows engineers and designers to move between biological models and human applications. Abstracting a problem to general functions allows designers to look to traits that perform analogous functions in biological organisms. However, the idea of function can mean different things across fields, presenting challenges for interdisciplinary research. Here we review core ideas in biology that relate to the concept of 'function,' including adaptation, tradeoffs, and fitness, as a companion to bio-inspired design approaches. We align these ideas with a top-down approach in biomimetics, where engineers or designers start with a problem of interest and look to biology for ideas. We review how one can explore a range of biological analogies for a given function by considering function across different parts of an organism's life, such as acquiring nutrients or avoiding disease. Engineers may also draw inspiration from biological traits or systems that exhibit a particular function, but did not necessarily evolve to do so. Such an evolutionary perspective is important to how biodesigners search biological space for ideas. A consideration of the evolution of trait function can also clarify potential trade-offs and biological models that may be more promising for an application. This core set of concepts from evolutionary and organismal biology can aid engineers and designers in their search for biological inspiration.

The royal food of termites shows king and queen specificity

Society in eusocial insects is based on the reproductive division of labor, with a small number of reproductive individuals supported by a large number of nonreproductive individuals. Because inclusive fitness of all colony members depends on the survival and fertility of reproductive members, sterile members provide royals with special treatment. Here, we show that termite kings and queens each receive special food of a different composition from workers. Sequential analysis of feeding processes demonstrated that workers exhibit discriminative trophallaxis, indicating their decision-making capacity in allocating food to the kings and queens. Liquid chromatography tandem-mass spectrometry analyses of the stomodeal food and midgut contents revealed king- and queen-specific compounds, including diacylglycerols and short-chain peptides. Desorption electrospray ionization mass spectrometry imaging analyses of ¹³C-labeled termites identified phosphatidylinositol and acetyl-l-carnitine in the royal food. Comparison of the digestive tract structure showed remarkable differences in the volume ratio of the midgut-to-hindgut among castes, indicating that digestive division of labor underlies reproductive division of labor. Our demonstration of king- and queen-specific foods in termites provides insight into the nutritional system that underpins the extraordinary reproduction and longevity of royals in eusocial insects.

Biological behavior of Chrysomya putoria (Wiedemann, 1819) (Diptera: Calliphoridae) after refrigeration: Logistics for use in Biotherapy

The influence of refrigeration on the post-embryonic development of Chrysomya putoria larvae was evaluated, regarding its resistance in the logistics of storage and distribution in biotherapy. Previously sterilized larvae were submitted to four periods of storage under refrigeration (T1=12 h, T2=24 h, T3=48 h and T4=72 h) and control (without sterilization and refrigeration). Newly hatched larvae (0.200 g) were stored between 3 and 9ºC. After refrigeration, 40 neo-larvae (in triplicate) were transferred to 50 g of protein diet and incubated in an acclimatized chamber. There was a significant difference in the larval body mass (T1 and T2) and in the duration of larval, pupal and total development (T3 and T4). The sex ratios found in the four treatments did not differ from what was expected. Normality rates were 100% for all treatments. There was no significant difference between the Control, T1 and T2 treatments for larval, pupal and total viability. There was a significant difference between control (C) and T4 (larval viability), between C, T3 and T4 (pupa) and between C and T4 (total). C. putoria has resistance under refrigeration and storage of up to 56 h, presenting viability above 70% for use in biotherapy.

HSP90AB1 as the Druggable Target of Maggot Extract Reverses Cisplatin Resistance in Ovarian Cancer

Cisplatin resistance is a crucial factor affecting ovarian cancer patient's survival rate, but the primary mechanism underlying cisplatin resistance in ovarian cancer remains unclear, and this prevents the optimal use of cisplatin therapy. Maggot extract (ME) is used in traditional Chinese medicine for patients with comas and patients with gastric cancer when combined with other drug treatments. In this study, we investigated whether ME enhances the sensitivity of ovarian cancer cells to cisplatin. Two ovarian cancer cells-A2780/CDDP and SKOV3/CDDP-were treated with cisplatin and ME in vitro. SKOV3/CDDP cells that stably expressed luciferase were subcutaneously or intraperitoneally injected into BALB/c nude mice to establish a xenograft model, and this was followed by ME/cisplatin treatment. In the presence of cisplatin, ME treatment effectively suppressed the growth and metastasis of cisplatin-resistant ovarian cancer in vivo and in vitro. RNA-sequencing data showed that HSP90AB1 and IGF1R were markedly increased in A2780/CDDP cells. ME treatment markedly decreased the expression of HSP90AB1 and IGF1R, thereby increasing the expression of the proapoptotic proteins p-p53, BAX, and p-H2AX, while the opposite effects were observed for the antiapoptotic protein BCL2. Inhibition of HSP90 ATPase was more beneficial against ovarian cancer in the presence of ME treatment. In turn, HSP90AB1 overexpression effectively inhibited the effect of ME in promoting the increased expression of apoptotic proteins and DNA damage response proteins in SKOV3/CDDP cells. Inhibition of cisplatin-induced apoptosis and DNA damage by HSP90AB1 overexpression confers chemoresistance in ovarian cancer. ME can enhance the sensitivity of ovarian cancer cells to cisplatin toxicity by inhibiting HSP90AB1/IGF1R interactions, and this might represent a novel target for overcoming cisplatin resistance in ovarian cancer chemotherapy.

A minireview of the medicinal and edible insects from the traditional Chinese medicine (TCM)

Entomoceuticals define a subset of pharmaceuticals derived from insects. The therapeutic effect of insect-derived drugs has been empirically validated by the direct use of various folk medicines originating from three sources in particular: the glandular secretions of insects (e.g., silk, honey, venom), the body parts of the insect or the whole used live or by various processing (e.g., cooked, toasted, ground), and active ingredients extracted from insects or insect-microbe symbiosis. Insects have been widely exploited in traditional Chinese medicine (TCM) relative to other ethnomedicines, especially in the prospect of insect species for medicinal uses. It is noticeable that most of these entomoceuticals are also exploited as health food for improving immune function. In addition, some edible insects are rich in animal protein and have high nutritional value, which are used in the food field, such as insect wine, health supplements and so on. In this review, we focused on 12 insect species that have been widely used in traditional Chinese herbal formulae but have remained less investigated for their biological properties in previous studies. We also combined the entomoceutical knowledge with recent advances in insect omics. This review specifies the underexplored medicinal insects from ethnomedicine and shows their specific medicinal and nutritional roles in traditional medicine.

Diversity of the Antimicrobial Peptide Genes in Collembola

Multidrug-resistant bacteria are a current health crisis threatening the world's population, and scientists are looking for new drugs to combat them. Antimicrobial peptides (AMPs), which are part of the organism's innate immune system, are a promising new drug class as they can disrupt bacterial cell membranes. This study explored antimicrobial peptide genes in collembola, a non-insect hexapod lineage that has survived in microbe-rich habitats for millions of years, and their antimicrobial peptides have not been thoroughly investigated. We used in silico analysis (homology-based gene identification, physicochemical and antimicrobial property prediction) to identify AMP genes from the genomes and transcriptomes of five collembola representing three main suborders: Entomobryomorpha (Orchesella cincta, Sinella curviseta), Poduromorpha (Holacanthella duospinosa, Anurida maritima), and Symphypleona (Sminthurus viridis). We identified 45 genes belonging to five AMP families, including (a) cysteine-rich peptides: diapausin, defensin, and Alo; (b) linear α-helical peptide without cysteine: cecropin; (c) glycine-rich peptide: diptericin. Frequent gene gains and losses were observed in their evolution. Based on the functions of their orthologs in insects, these AMPs potentially have broad activity against bacteria, fungi, and viruses. This study provides candidate collembolan AMPs for further functional analysis that could lead to medicinal use.

The therapeutic effect of larval saliva and hemolymph of Lucilia sericata on the treatment of Leishmania major lesion in BALB/c mice946

BACKGROUND

Treatment of cutaneous leishmaniasis (CL) remains a major challenge for the public health and medical community. It has been claimed that natural compounds derived from fly larvae have anti-leishmania properties against some species of Leishmania. The present study aimed at assessing the in vitro effects of larval products of Lucilia sericata against the promastigote and intracellular amastigote forms of Leishmania major. Also, the therapeutic effect of larval products on lesions induced by L. major infection was evaluated in BALB/c mice models.

METHODS

Parasite specimens and macrophage cells were exposed to varying concentrations of larval products for 24-120 h. Lesion progression and parasite load were investigated in the models to assess the therapeutic effects of the products.

RESULTS

The larval products displayed more potent cytotoxicity against L. major promastigotes. The IC₅₀ values for larval saliva and hemolymph were 100.6 and 37.96 ug/ml, respectively. The IC₅₀ of glucantime was 9.480 ug/ml. Also, the saliva and hemolymph of L. sericata exhibited higher cytotoxicity against the promastigotes of L. major but were less toxic to the macrophage cells. Treatment with leishmanicidal agents derived from larvae of L. sericata decreased the infection rate and the number of amastigotes per infected host cell at all concentrations. Lesion size was significantly (F _{(7, 38)} = 8.54, P < 0.0001) smaller in the treated mice compared with the untreated control group. The average parasite burden in the treated mice groups (1.81 ± 0.74, 1.03 ± 0.45 and 3.37 ± 0.41) was similar to the group treated with a daily injection of glucantime (1.77 ± 0.99) and significantly lower (F _{(7, 16)} = 66.39, P < 0.0001) than in the untreated control group (6.72 ± 2.37).

CONCLUSIONS

The results suggest that the larval products of L. sericata were effective against L. major parasites both in vivo and in vitro. However, more clinical trial studies are recommended to evaluate the effects of these larval products on human subjects.

Periplaneta americana L. a potential source of traditional medicine: chemometric analysis, in vitro and in silico study

'Mayurbhanj is the ethnic dominant tribal population district in Odisha, India. The triabl's of Mayurbhanj depends on traditional medicines since time immemorial for health-related issues. Due to the imperative ethnic claim of traditional healers, the financial stringency of the patient community and the necessity to produce a better therapeutic effect has led to investigate ethno zoological sources and to find out the biochemical moiety responsible for the healing process. Considering the ethnic communities' acceptability of the zoological source as traditional medicine, the current evidence-based research study is conducted to investigate the biochemical moiety present in Periplaneta americana, responsible for therapeutic activity. The whole powdered Periplaneta americana was extracted using maceration techniques with n-hexane and methanol as solvent. The obtained extracts were subjected to GC-MS analysis to identify the biochemical moiety. To check the potential biological activity, an in-vitro antimicrobial test was carried out in both turbidimetry and a viable count method against E. coli. Moreover, the obtained biochemical molecules were exposed to in silico studies for their binding modes and their affinity using Discovery studio software. The major compounds were found to be hexadecanoic acid, methyl ester, n-hexadecanoic acid, oleic acid, octadecanoic acid along with other minor constituents. The maximum inhibitory activity of n-hexane and methanol extract against S. aureus at a concentration of 400 µg/mL was found to be 89 and 87%, respectively. The binding models of almost all identified compounds confer very good binding affinities with some key and strong non-covalent interactions with various amino acid residues of receptor active site pocket, which predict the compounds to be potent inhibitors of various infectious bacteria. These findings suggested that the hexane extract of P. americana could be exploited as a potential natural source. Communicated by Ramaswamy H. Sarma.

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.

A Brief Review of Natural Products with Urate Transporter 1 Inhibition for the Treatment of Hyperuricemia

Hyperuricemia is a common disease caused by a high level of uric acid. Urate transporter 1 (URAT1) is an important protein and mediates approximately 90% of uric acid reabsorption. Therefore, the URAT1 inhibitor is a class of uricosuric medicines widely used in the clinic for the treatment of hyperuricemia. To find the new medicine with stronger URAT1 inhibition and lower toxicity, researchers have been exploring natural products. This study systematically summarizes the natural products with URAT1 inhibition. The results show that many natural products are potential URAT1 inhibitors, such as flavonoids, terpenoids, alkaloids, coumarins, stilbenes, and steroids, among which flavonoids are the most promising source of URAT1 inhibitors. It is worth noting that most studies have focused on finding natural products with inhibition of URAT1 and have not explored their activities and mechanisms toward URAT1. By reviewing the few existing studies of the structure-activity relationship and analyzing common features of natural products with URAT1 inhibition, we speculate that the rigid ring structure and negative charge may be the keys for natural products to produce URAT1 inhibition. In conclusion, natural products are potential URAT1 inhibitors, and exploring the mechanism of action and structure-activity relationship will be an important research direction in the future.

The in vitro and in vivo antibacterial activities of uniflorous honey from a medicinal plant, Scrophularia ningpoensis Hemsl., and characterization of its chemical profile with UPLC-MS/MS

ETHNOPHARMACOLOGICAL RELEVANCE

According to the Compendium of Materia Medica, honey has been used as a traditional medicine in treatment against mucositis, tinea, hemorrhoids and psoriasis. In complementary medicine, due to its significant antimicrobial activity, honey has been widely used as a remedy for skin wounds and gastrohelcosis for thousands of years.

AIM OF THE STUDY

This study is aimed at exploring the antimicrobial activity and mechanisms of honey sourced from medicinal plants, and revealing the composition-activity relationship, to facilitate their complementary and alternative application in the therapy of bacterial infectious diseases.

MATERIALS AND METHODS

Eight kinds of medicinal plant-derived uniflorous honey, native to China, were gathered. Their antimicrobial activities were evaluated in vitro, and then in vivo with the systemically infected mouse model and the acute skin infection model. SYTOX uptake assay, scanning electron microscopy, DNA binding assay, and quantitative real-time PCR, were carried out to elucidate the antibacterial mechanisms. This was followed by an investigation of the componential profile with the UPLC-MS/MS technique.

RESULTS

It was found that Scrophularia ningpoensis Hemsl. (figwort) honey (S. ningpoensis honey) exhibited broad-spectrum and the strongest antibacterial potency (MICs of 7.81-125.00%, w/v), comparable to manuka honey. In the in vivo assays, S. ningpoensis honey significantly decreased the bacterial load of the muscles under the acute MRSA-infected skin wounds; the sera level of TNF-α in the S. aureus and P. aeruginosa-infected mice decreased by 45.38% and 51.75%, respectively, after the treatment of S. ningpoensis honey (125 mg/10 g). It was capable of killing bacteria through disrupting the cell membranes and the genomic DNA, as well as down-regulating the expression of genes associated with virulence, biofilm formation and invasion, including icaA, icaD, eno, sarA, agrA, sigB, fib and ebps in S. aureus, and lasI, lasR, rhlI, rhlR and algC in P. aeruginosa. Apart from H₂O₂, some other nonperoxide compounds such as adenosine, chavicol, 4-methylcatechol, trehalose, palmitoleic acid and salidroside, might play a vital role in the antibacterial properties of S. ningpoensis honey.

CONCLUSIONS

This is the first study to thoroughly investigate the antibacterial activity, mode of action, and componential profile of S. ningpoensis honey. It suggested that S. ningpoensis honey might be a potential supplement or substitute for manuka honey, for the prevention or treatment of bacterial infections. It will facilitate the precise application of medicinal plant-sourced honey, provide a new thread for the development of antibacterial drugs, and assist in the distinction of different kinds of honey.

Hemolymph of triatomines presents fungistatic activity against Cryptococcus neoformans and improves macrophage function through MCP-I/TNF-α increase

Background:

Triatomines are blood-feeding arthropods belonging to the subfamily Triatominae (Hemiptera; Reduviidae), capable of producing immunomodulatory and water-soluble molecules in their hemolymph, such as antimicrobial peptides (AMPs). In this work, we evaluated the antifungal and immunomodulatory activity of the hemolymph of Meccus pallidipennis (MPH) and Rhodnius prolixus (RPH) against Cryptococcus neoformans.

Methods:

We assessed the activity of the hemolymph of both insects on fungal growth by a minimum inhibitory concentration (MIC) assay. Further, RAW 264.7 macrophages were cultivated with hemolymph and challenged with C. neoformans. Then, their phagocytic and killing activities were assessed. The cytokines MCP-1, IFN-γ, TNF-α, IL-10, IL-12, and IL-6 were measured in culture supernatants 4- and 48-hours post-infection.

Results:

Both hemolymph samples directly affected the growth rate of the fungus in a dose-dependent manner. Either MPH or RPH was capable of inhibiting fungal growth by at least 70%, using the lowest dilution (1:20). Treatment of RAW 264.7 macrophages with hemolymph of both insects was capable of increasing the production of MCP-I and TNF-α. In addition, when these cells were stimulated with hemolymph in the presence of C. neoformans, a 2- and a 4-fold increase in phagocytic rate was observed with MPH and RPH, respectively, when compared to untreated cells. For the macrophage killing activity, MPH decreased in approximately 30% the number of viable yeasts inside the cells compared to untreated control; however, treatment with RPH could not reduce the total number of viable yeasts. MPH was also capable of increasing MHC-II expression on macrophages. Regarding the cytokine production, MCP-I and TNF-α, were increased in the supernatant of macrophages treated with both hemolymphs, 4 and 48 hours after stimulation.

Conclusion:

These results suggested that hemolymph of triatomines may represent a source of molecules capable of presenting antifungal and immunomodulatory activity in macrophages during fungal infection.

Toxicity effect of the edible pigment carmoisine on Polyrhachis vicina Roger (Hymenoptera: Formicidae)

Carmoisine belongs to a water-soluble synthetic dye and is often used as a food additive. Previous research has shown that carmoisine is toxic to rats and zebrafish, but there have been few reports on the effect of carmoisine on soil-dwelling social insects. The present study evaluated carmoisine toxicity in Polyrhachis vicina Roger. We found that the effects of different concentrations of carmoisine on the mortality of workers were dose-dependent. The 10% lethal dose (LD₁₀), 50% lethal dose (LD₅₀) and 90% lethal dose (LD₉₀) of carmoisine to workers at 96 h was calculated to be 0.504, 5.491 and 10.478 g/L, respectivily. LD₁₀ of workers were selected to treat the fourth instar larvae, pupae and adults for 10 days. The results showed that the survival rate of all ants, except for females, was significantly reduced, especially larvae and workers. The body weight of larvae, pupae and males decreased significantly, while weight gain was observed in the females and workers. The appearance of larvae, pupae and workers changed after carmoisine treatment, such as body darkening and epidermis shrinking of larvae and pupae, as well as body segment expansion of workers. Furthermore, carmoisine altered the expression of the estrogen-related receptor, tailless and homothorax of P. vicina (Pv-ERR, Pv-tll and Pv-hth) to varying degrees in larvae and adults. We believe that variations in body weight can lead to a decrease in survival rate and appearance changes in the ants, which may be related to abnormal gene expressions caused by carmoisine treatment. Therefore, we confirm that carmoisine has negative effects on the growth and development of P. vicina.

Nutritional Composition of Bombyx mori Pupae: A Systematic Review

Simple Summary

The mulberry silkworm (Bombyx mori) is a domesticated insect traditionally reared to produce silk. Its pupae are historically eaten in Asian countries and are obtained as waste products from the silk reeling industry. Pupae are a promising novel food in Western countries as well as a source of proteins, lipids, and minerals. Several varied results are reported in the literature regarding the nutrient composition of silkworm pupa, and several factors must be considered when comparing the research. Some of the variables that could affect the pupal nutritional content include rearing techniques, diets, silkworm strains, killing, and drying techniques. This literature systematic review identifies the most important research areas and aids authorities and producers in the evaluation and development of silkworm pupae for novel uses.

Abstract

As insects have started to enter the eating habits of Western countries, an increasing amount of literature regarding the mulberry silkworm (Bombyx mori) prospective application as food has been published. Despite this growing interest, there is currently no systematic review of silkworm nutritional composition available. In this paper, we performed a systematic review of the recent available literature on the nutrient composition of mulberry silkworm pupae. After screening the titles and abstracts of 14,008 studies retrieved from three scientific databases, data about nutrients was extracted from 29 selected papers, together with their related variables. This systematic review provides an overview of the variety of data reported in the literature and highlights that many elements contribute to hindering a sound comparison of the different nutritional values reported for silkworm pupae. The observed variability of the composition data reported could be due to differences in diet, strains, pretreatments, and origin of the silkworm analyzed. However, all these variables were not always available and should be reported in future studies to simplify the data comparison.

GC-MS analysis of Vespa velutina auraria Smith and its anti-inflammatory and antioxidant activities in vitro

Vespa velutina auraria Smith is an edible and medicinal insect in China. This study demonstrated the in vitro antioxidant and anti-inflammatory bioactivities and the volatile composition identification determined by Gas chromatography mass spectrometry (GC-MS). The antioxidant activity screening results showed that the ethanol extracts of both the fresh and dried samples exhibited an efficient antioxidant activity for three models, 2,2′-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid diammonium salt) free radicals scavenging capacity, 1,1-diphenyl-2-picrylhydrazyl scavenging capacity, and ferric reducing antioxidant power. The anti-inflammatory activity screening in vitro indicated that ethanol extracts had considerable inhibitory effect on Tumor Necrosis Factor-α and Interleukin-1β (IL-1β) in macrophages, but had no influence on IL-6 expression. GC-MS analyses of volatile composition of V. auraria identified 46 components, representing 75.76% of the total peak areas from fresh sample, and 34 components, 84.70% of the total peak areas from dried ones. The volatile constituents were very different in the petroleum ether part of fresh and dried ones. The three major components are hentriacontane (7.76%), n-hexadecanoic acid (6.54%), and palmitoleic acid (4.50%) in the fresh sample, while they are benzeneacetaldehyde (13.11%), dodecanoic acid (7.08%), and oleic Acid (6.72%) in the dried sample.

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.

Insect protease inhibitors; promising inhibitory compounds against SARS-CoV-2 main protease

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), has adversely affected global health since its emergence in 2019. The lack of effective treatments prompted worldwide efforts to immediately develop therapeutic strategies against COVID-19. The main protease (Mpro) of SARS-CoV-2 plays a crucial role in viral replication, and therefore it serves as an attractive target for COVID-19-specific drug development. Due to the richness and diversity of insect protease inhibitors, we docked SARS-CoV-2 Mpro onto 25 publicly accessible insect-derived protease inhibitors using the ClusPro server, and the regions with high inhibitory potentials against Mpro were used to design peptides. Interactions of these inhibitory peptides with Mpro were further assessed by two directed docking programs, AutoDock and Haddock. AutoDock analysis predicted the highest binding energy (-9.39 kcal/mol) and the lowest inhibition constant (130 nM) for the peptide 1KJ0-7 derived from SGCI (Schistocerca gregaria chymotrypsin inhibitor). On the other hand, Haddock analysis resulted in the discovery of a different peptide designated 2ERW-9 from infestin, a serine protease inhibitor of Triatoma infestans, with the best docking score (-131), binding energy (-11.7 kcal/mol), and dissociation constant (2.6E-09 M) for Mpro. Furthermore, using molecular dynamic simulations, 1KJ0-7 and 2ERW-9 were demonstrated to form stable complexes with Mpro. The peptides also showed suitable drug-likeness properties compared to commercially available drugs based on Lipinski's rule. Our findings present two peptides with possible protease inhibitor activities against Mpro and further demonstrate the potential of insect-derived peptides and computer-aided methods for drug discovery.

Nature׳s gifts to medicine: The metabolic effects of extracts from cocoons of Larinus hedenborgi (Coleoptera: Curculionidae) and their host plant Echinops cephalotes (Asteraceae) in diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Trehala manna (TM), the edible cocoons of several weevil species, e.g. Larinus hedenborgi Boheman, 1845 (Coleoptera: Curculionidae) and their host plant, i.e. Echinops cephalotes DC. (EC) (Asteraceae), are traditionally used to treat pain, inflammation, infectious diseases, as well as respiratory, renal, reproductive and metabolic disorders.

AIM OF THE STUDY

This study investigated the metabolic effects of aqueous extracts from TM and EC on diabetic male Wistar albino rats.

MATERIALS AND METHODS

Animals were orally gavaged with the extracts (75, 150, and 300 mg/kg), normal saline, and glibenclamide (Glbn), for 28 days. The serum levels of glucose, insulin, lipid profile, and hepatic enzymes, plus the body weight of rats were measured at the beginning and the end of study. The proximate composition of the extracts was determined, additionally. The antioxidant and cytotoxic potency of the extracts were evaluated by radical scavenging/ferric reducing and viability assays, respectively.

RESULTS

Treatment of diabetic rats with the extracts significantly altered metabolic biomarkers compared with diabetic, control and Glbn-treated groups, but not in a dose-dependent manner. However, the antihyperglycemic effects of TM₇₅/EC₃₀₀, the antiobesity effects of EC₁₅₀, and the hepatoprotective effects of TM₁₅₀/EC₁₅₀ were even stronger than those of Glbn. TM/EC-treated groups represented normal cell architecture in the pancreatic and renal tissues. Nutrient analysis displayed that TM is rich in sugar and magnesium, whereas EC is abundant in protein, sodium, potassium, and calcium. The extracts showed no antioxidant and cytotoxic effects, as compared to the control groups.

CONCLUSIONS

The findings suggest that active ingredients in the extracts evaluated are responsible for the metabolic effects by lowering blood sugar and restoring the damaged islets of Langerhans. The close trophic relationship of the TM-producing beetle with the host thistle justifies the overlaps of the bioactivity of the TM and EC extracts.

Purification and structural characterization of lectin with antibacterial and anticancer properties from grubs of hide beetle, Dermestes frischii

Lectins or haemagglutinins are diverse classes of non-immune proteins; they bind to carbohydrates and are abundant in nature. In the present study, a coleopteran lectin from grubs of hide beetle, Dermestes frischii called DFL, was purified by glutaraldehyde (fixative-agent) fixed hen erythrocytes and characterized further for its functional properties. The purified DFL was stable between pH range 5 to 9 and heat-stable up to 50C. It was insensitive to EDTA and did not require any divalent cations. DFL native molecular mass was approximately 69 kDa with three different polypeptide subunits of 33 (pI ~4.4), 22 (pI ~6) and 14 (pI ~4.4) kDa. Haemagglutinating activity of DFL was highly inhibited by N-acetyl-D-glucosamine. DFL partial peptide sequences obtained from peptide mass fingerprinting experiments matched with amino acid sequences of lectins from different organisms confirmed its nature. Biological properties of purified DFL namely antibacterial and bacterial agglutination experiments revealed that DFL have both the effects against laboratory cultures of Aeromonas hydrophila, Enterococcus faecalis, Escherichia coli and habitat bacterial isolates of Staphylococcus cohnii and Bacillus cereus. In addition, the DFL exhibited substantial anticancer properties against HeLa cells. These results concluded that purified DFL could serve as a potent therapeutic agent for various biomedical applications.

Aqueous extracts from Tenebrio molitor larval and pupal stages inhibit early hepatocarcinogenesis in vivo

Hepatocellular carcinoma (HCC), which is the most frequent primary liver malignancy, is ranked as the sixth most common cancer and the third leading cause of cancer-related deaths worldwide, with its incidence expected to continue rising. One of the reasons is that most patients are diagnosed at an advanced stage when therapeutic options are ineffective. The development of HCC is attributed to a chronic exposition to either one or a combination of low amounts of different hepatotoxins, such as in hepatitis virus infection, alcohol consumption, aflatoxin from contaminated foods, metabolic factors, and exposure to chemical carcinogens from tobacco smoke (Forner et al., 2018). Integrative studies combining exome sequencing, transcriptome analysis, and the genomic characterization of HCC have shown that these etiological factors may raise the frequency of particular genetic alterations, resulting in intra-tumor heterogeneity that presents a huge challenge for treatment. For example, mutations in the catenin β-1 (CTNNB1) gene (a proto-oncogene in the WNT signaling pathway that encodes the β‍-catenin transcription factor) are strongly associated with alcohol-related HCC, whereas mutations in the telomerase reverse transcriptase (TERT) promoter and tumor protein p53 (TP53) genes are the most commonly observed in hepatitis B virus (HBV)‍-associated HCC (Calderaro et al., 2017; Cancer Genome Atlas Research Network, 2017). The above findings emphasize the molecular diversity of HCC and the associations of different etiologies with distinct mechanisms in HCC progression. Consequently, prevention strategies are still attractive for HCC management.

Bioinspiration as a method of problem-based STEM education: A case study with a class structured around the COVID-19 crisis

Bioinspiration is a promising lens for biology instruction as it allows the instructor to focus on current issues, such as the COVID-19 pandemic. From social distancing to oxygen stress, organisms have been tackling pandemic-related problems for millions of years. What can we learn from such diverse adaptations in our own applications? This review uses a seminar course on the COVID-19 crisis to illustrate bioinspiration as an approach to teaching biology content. At the start of the class, students mind-mapped the entire problem; this range of subproblems was used to structure the biology content throughout the entire class. Students came to individual classes with a brainstormed list of biological systems that could serve as inspiration for a particular problem (e.g., absorptive leaves in response to the problem of toilet paper shortages). After exploration of relevant biology content, discussion returned to the focal problem. Students dug deeper into the literature in a group project on mask design and biological systems relevant to filtration and transparency. This class structure was an engaging way for students to learn principles from ecology, evolution, behavior, and physiology. Challenges with this course design revolved around the interdisciplinary and creative nature of the structure; for instance, the knowledge of the participants was often stretched by engineering details. While the present class was focused on the COVID-19 crisis, a course structured through a bioinspired approach can be applied to other focal problems, or subject areas, giving instructors a powerful method to deliver interdisciplinary content in an integrated and inquiry-driven way.

Nutritional, functional, and allergenic properties of silkworm pupae

Edible insects are a food source that has high nutritional value. Domestic silkworm pupae are an important by-product of sericulture and have a long history as food and feed ingredients in East Asia. Silkworm pupae are a good source of protein, lipids, minerals, and vitamins and are considered a good source of nutrients for humans. Silkworm pupae are a valuable insect source of substances used in healthcare products, medicines, food additives, and animal feed. Because silkworm pupae are being increasingly used in the human diet, potential allergic reactions to the substances they contain must be elucidated. Here, we present an overview of the benefits of silkworm pupae. First, we describe their nutritional value. Second, we report their functional properties and applications, focusing on their potential use in the food and pharmaceutical industries. Finally, we consider the current state of research regarding silkworm pupae-induced allergies.

Antimicrobial Peptides from Black Soldier Fly (Hermetia illucens) as Potential Antimicrobial Factors Representing an Alternative to Antibiotics in Livestock Farming

Functional antimicrobial peptides (AMPs) are an important class of effector molecules of innate host immune defense against pathogen invasion. Inability of microorganisms to develop resistance against the majority of AMPs has made them alternatives to antibiotics, contributing to the development of a new generation of antimicrobials. Due to extensive biodiversity, insects are one of the most abundant sources of novel AMPs. Notably, black soldier fly insect (BSF; Hermetia illucens (Diptera: Stratiomyidae)) feeds on decaying substrates and displays a supernormal capacity to survive under adverse conditions in the presence of abundant microorganisms, therefore, BSF is one of the most promising sources for identification of AMPs. However, discovery, functional investigation, and drug development to replace antibiotics with AMPs from Hermetia illucens remain in a preliminary stage. In this review, we provide general information on currently verified AMPs of Hermetia illucens, describe their potential medical value, discuss the mechanism of their synthesis and interactions, and consider the development of bacterial resistance to AMPs in comparison with antibiotics, aiming to provide a candidate for substitution of antibiotics in livestock farming or, to some extent, for blocking the horizontal transfer of resistance genes in the environment, which is beneficial to human and animal welfare.

Antibacterial and antifungal activity of excretions and secretions of Calliphora vicina

Antibiotic-resistant bacteria pose a major threat to global health in the 21st century, requiring a quick, cheap and effective response from public health officials. This study evaluated the antimicrobial activity of native excretions/secretions (NES) produced by third instar (3 days old) larvae of Calliphora vicina using a protocol adapted from the Institute of Clinical and Laboratory Standards (CLSI). The microorganisms tested were: Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and the fungus Candida albicans. After the incubation period, the suspensions were diluted and spread on nutrient agar plates to count the colony-forming units. A turbidimetric test also was carried out to test the action of the NES of C. vicina against S. aureus, a very common bacterial species, with an enormous capacity for adaption and resistance, being one of the bacteria of medical importance that causes the most hospital and community infections in the world. According to our results, the NES of C. vicina exhibits antimicrobial activity at different dilutions, being most effective against the gram-negative bacteria E. coli and K. pneumoniae.

Antiproliferative effects of mealworm larvae (Tenebrio molitor) aqueous extract on human colorectal adenocarcinoma (Caco-2) and hepatocellular carcinoma (HepG2) cancer cell lines

Recently, insects have aroused the interest of researchers as potential therapeutic resources against malignant diseases such as cancer. In this study, the effects of aqueous extracts from mysore thorn borer (MTB) (Anoplophora chinensis) and mealworm larvae (MWL) (Tenebrio molitor) against cancer cells were investigated. MWL aqueous extract showed higher antiproliferative effects against Caco-2 and HepG2 cells compared to MTB. The IC₅₀ (48 hr) of MWL aqueous extract were 11.44 and 20 mg/ml for Caco-2 and HepG2 respectively. Flow cytometry analysis showed that MWL aqueous extract induced apoptosis in Caco-2 and HepG2 increasing from 2.06% to 74.34% and from 0.04% to 42.14% after 24 hr respectively. Caspase activity assay showed that apoptosis was mediated via death receptor pathway mediated by caspase-8 and -9 followed by the activation of caspase-3; caspase-3 may have induced DNA damage and cell death. These effects may be correlated to its free amino acids. The results of this study demonstrate the potentials of MWL in the development of natural anticancer therapeutics in the future. PRACTICAL APPLICATIONS: Natural nutraceuticals from insects might be useful for the treatment and prevention of cancers such as colorectal and liver cancer. In recent years, edible insects have caught the attention of researchers, because of their potential as an alternative source of food and nutraceuticals. The results of our study showed that MWL extract might provide important anticancer compounds against colon and liver cancer.

Gut Extracts of Rhynchophorus ferrugineus Larvae Olivier Affecting Bacterial Dental Caries

In vitro study was conducted to explore antibacterial properties of the larval gut extracts of Rhynchophorus ferrugineus (Red Palm Weevil) Oliver. Larval gut extracts were tested against salivary bacteria causing dental carries using the agar well diffusion method. The gut extracts significantly affected the growth of both Klebsiella spp. and Streptococcus viridans. The two bacterial species revealed significant differences in their sensitivity to the extract. The extract efficacy depended upon the concentration and time of exposure. When using 100%concentration of the extract, the mean of inhibition zones for S. viridans and Klebsiella spp. at 24 h after treatment were 1.61 mm and 2.50 mm, respectively. At 48 h post-treatment, the mean of inhibition zones for S. viridans and Klebsiella spp. were 1.96 mm and 2.66 mm. After 72 hours, the means zones were 2.28 mm and 2.91 mm, respectively. Electron microscopic examinations showed morphological changes of the outer membrane of bacteria with a noticeable damage as a result of exposure to the gut extract. The results suggest potential use of these extracts against dental caries bacteria.

Microbial symbionts of insects as a source of new antimicrobials: a review

To stop the antimicrobial resistance crisis, there is an urgent need for increased investment in antimicrobial research and development. Currently, many researchers are focussing on insects and their microbiota in the search for new antimicrobials. This review summarizes recent literature dedicated to the antimicrobial screening of insect symbionts and/or their metabolites to uncover their value in early drug discovery. We summarize the main steps in the methodology used to isolate and identify active insect symbionts and have noted substantial variation among these studies. There is a clear trend in isolating insect Streptomyces bacteria, but a broad range of other symbionts has been found to be active as well. The microbiota of many insect genera and orders remains untargeted so far, which leaves much room for future research. The antimicrobial screening of insect symbionts has led to the discovery of a diverse array of new active biomolecules, mainly peptides, and polyketides. Here, we discuss 15 of these symbiont-produced compounds and their antimicrobial profile. Cyphomycin, isolated from a Streptomyces symbiont of a Cyphomyrmex fungus-growing ant, seems to be the most promising insect symbiont-derived antimicrobial so far. Overall, insect microbiota appears to be a promising search area to discover new antimicrobial drug candidates.

Insect antimicrobial peptides: potential weapons to counteract the antibiotic resistance

Misuse and overuse of antibiotics have contributed in the last decades to a phenomenon known as antibiotic resistance which is currently considered one of the principal threats to global public health by the World Health Organization. The aim to find alternative drugs has been demonstrated as a real challenge. Thanks to their biodiversity, insects represent the largest class of organisms in the animal kingdom. The humoral immune response includes the production of antimicrobial peptides (AMPs) that are released into the insect hemolymph after microbial infection. In this review, we have focused on insect immune responses, particularly on AMP characteristics, their mechanism of action and applications, especially in the biomedical field. Furthermore, we discuss the Toll, Imd, and JAK-STAT pathways that activate genes encoding for the expression of AMPs. Moreover, we focused on strategies to improve insect peptides stability against proteolytic susceptibility such as D-amino acid substitutions, N-terminus modification, cyclization and dimerization.

Fighting against the second wave of COVID-19: Can honeybee products help protect against the pandemic?

Coronavirus Disease (COVID-19) has infected people in 210 nations and has been declared a pandemic on March 12, 2020 by the World Health Organization (WHO). In the absence of effective treatment and/or vaccines for COVID-19, natural products of known therapeutic and antiviral activity could offer an inexpensive, effective option for managing the disease. Benefits of products of honey bees such as honey, propolis, and bee venom, against various types of diseases have been observed. Honey bees products are well known for their nutritional and medicinal values, they have been employed for ages for various therapeutic purposes. In this review, promising effects of various bee products against the emerging pandemic COVID-19 are discussed. Products of honey bees that contain mixtures of potentially active chemicals, possess unique properties that might help to protect, fight, and alleviate symptoms of COVID-19 infection.

Antimicrobial Peptides and Copper(II) Ions: Novel Therapeutic Opportunities

The emergence of new pathogens and multidrug resistant bacteria is an important public health issue that requires the development of novel classes of antibiotics. Antimicrobial peptides (AMPs) are a promising platform with great potential for the identification of new lead compounds that can combat the aforementioned pathogens due to their broad-spectrum antimicrobial activity and relatively low rate of resistance emergence. AMPs of multicellular organisms made their debut four decades ago thanks to ingenious researchers who asked simple questions about the resistance to bacterial infections of insects. Questions such as "Do fruit flies ever get sick?", combined with pioneering studies, have led to an understanding of AMPs as universal weapons of the immune system. This review focuses on a subclass of AMPs that feature a metal binding motif known as the amino terminal copper and nickel (ATCUN) motif. One of the metal-based strategies of hosts facing a pathogen, it includes wielding the inherent toxicity of copper and deliberately trafficking this metal ion into sites of infection. The sudden increase in the concentration of copper ions in the presence of ATCUN-containing AMPs (ATCUN-AMPs) likely results in a synergistic interaction. Herein, we examine common structural features in ATCUN-AMPs that exist across species, and we highlight unique features that deserve additional attention. We also present the current state of knowledge about the molecular mechanisms behind their antimicrobial activity and the methods available to study this promising class of AMPs.

Neolignans and Norlignans from Insect Medicine Polyphaga plancyi and Their Biological Activities

Ten neolignans or norlignans (1-10) including eight new compounds were isolated from the whole bodies of Polyphaga plancyi Bolivar. Their structures were identified by spectroscopic data. Compounds 3, 4, 8, and 9 are racemates indicated by chiral HPLC analysis. Chiral separation followed by ECD calculations allowed to clarify the absolute configurations of all the antipodes. All the new compounds were evaluated for their biological properties toward extracellular matrix in rat renal proximal tubular cells, human cancer cells (K562, A549, and Huh7), EV71, ROCK2, JAK3, DDR1, and coagulation.

Dual Antimicrobial and Antiproliferative Activity of TcPaSK Peptide Derived from a Tribolium castaneum Insect Defensin

Antimicrobial peptides (AMPs) found in the innate immune system of a wide range of organisms might prove useful to fight infections, due to the reported slower development of resistance to AMPs. Increasing the cationicity and keeping moderate hydrophobicity of the AMPs have been described to improve antimicrobial activity. We previously found a peptide derived from the Tribolium castaneum insect defensin 3, exhibiting antrimicrobial activity against several human pathogens. Here, we analyzed the effect against Staphyloccocus aureus of an extended peptide (TcPaSK) containing two additional amino acids, lysine and asparagine, flanking the former peptide fragment in the original insect defensin 3 protein. TcPaSK peptide displayed higher antimicrobial activity against S. aureus, and additionally showed antiproliferative activity against the MDA-MB-231 triple negative breast cancer cell line. A SWATH proteomic analysis revealed the downregulation of proteins involved in cell growth and tumor progression upon TcPaSK cell treatment. The dual role of TcPaSK peptide as antimicrobial and antiproliferative agent makes it a versatile molecule that warrants exploration for its use in novel therapeutic developments as an alternative approach to overcome bacterial antibiotic resistance and to increase the efficacy of conventional cancer treatments.

The leishmanicidal effect of Lucilia sericata larval saliva and hemolymph on in vitro Leishmania tropica

Background

Leishmaniasis is a major parasitic disease worldwide, except in Australia and Antarctica, and it poses a significant public health problem. Due to the absence of safe and effective vaccines and drugs, researchers have begun an extensive search for new drugs. The aim of the current study was to investigate the in vitro leishmanicidal activity of larval saliva and hemolymph of Lucilia sericata on Leishmania tropica.

Methods

The effects of different concentrations of larval products on promastigotes and intracellular amastigotes of L. tropica were investigated using the mouse cell line J774A.1 and peritoneal macrophages as host cells. The 3-(4.5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and direct observation and counting method were used to assess the inhibitory effects and cell cytotoxicity of the larval products. The effects of larval products on the amastigote form of L. tropica were quantitatively estimated by calculating the rate of macrophage infection, number of amastigotes per infected macrophage cell, parasite load and survival index.

Results

The 50% cytotoxicity concentration (CC₅₀) value of both larval saliva and hemolymph was 750 µg/ml, and the 50% inhibitory concentration (IC₅₀) values were 134 µg/ml and 60 µg/ml for larval saliva and larval hemolymph, respectively. The IC₅₀ for Glucantime, used a positive control, was (11.65 µg/ml). Statistically significant differences in viability percentages of promastigotes were observed for different doses of both larval saliva and hemolymph when compared with the negative control (p ≤ 0.0001). Microscopic evaluation of the amastigote forms revealed that treatment with 150 µg/ml larval hemolymph and 450 µg/ml larval saliva significantly decreased the rate of macrophage infection and the number of amastigotes per infected macrophage cell.

Conclusion

Larval saliva and hemolymph of L. sericata have acceptable leishmanicidal properties against L. tropica.

Graphical Abstract