Recent advances in developing insect natural products as potential modern day medicines

Anti-Herpes Simplex Virus and Anti-Inflammatory Activities of the Melittin Peptides Derived from Apis mellifera and Apis florea Venom

Herpes simplex virus (HSV) is known to cause cold sores and various diseases in humans. Importantly, HSV infection can develop latent and recurrent infections, and it is also known to cause inflammation. These infections are difficult to control, and effective treatment of the disease remains a challenge. Thus, the search for new antiviral and anti-inflammatory agents is a necessity. Melittin is a major peptide that is present in the venom of the honeybee. It possesses a number of pharmacological properties. In this study, the effects of the melittin peptides from A. mellifera (MEL-AM) and A. florea (MEL-AF) against HSV-1 and HSV-2 were evaluated at different stages during the viral multiplication cycle in an attempt to define the mode of antiviral action using plaque reduction and virucidal assays. The results revealed a new finding that melittin at 5 µg/mL demonstrated the highest inhibitory effect on HSV through the direct inactivation of viral particles, and MEL-AF displayed a greater virucidal activity. Moreover, melittin was also observed to interfere with the process of HSV attachment to the host cells. MEL-AM exhibited anti-HSV-1 and anti-HSV-2 effects with EC50 values of 4.90 ± 0.15 and 4.39 ± 0.20 µg/mL, while MEL-AF demonstrated EC50 values of 4.47 ± 0.21 and 3.95 ± 0.61 µg/mL against HSV-1 and HSV-2, respectively. However, non-cytotoxic concentrations of both types of melittin produced only slight degrees of HSV-1 and HSV-2 inhibition after viral attachment, but melittin at 5 µg/mL was able to reduce the plaque size of HSV-2 when compared to the untreated group. In addition, MEL-AM and MEL-AF also exhibited anti-inflammatory activity via the inhibition of nitric oxide production in LPS-stimulated RAW 264.7 macrophage cells, and they were also found to down-regulate the expressions of the iNOS, COX-2 and IL-6 genes. The highest inhibition of IL-6 mRNA expression was found after treatment with 10 µg/mL of MEL-AM and MEL-AF. Therefore, melittin peptides have displayed strong potential to be used as an alternative treatment for HSV infection and inflammatory diseases in the future.

Mitigating Effects of Tenebrio molitor Larvae Powder Administration in Mice with Dextran Sodium Sulfate (DSS)- Induced Colitis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory bowel disease that affects people worldwide. The causes of UC are diverse, and symptoms include diarrhea, weight loss, anemia, rectal bleeding, and bloody stools. Tenebrio molitor larvae have recently gained attention as edible insects with various physiological and medical effects. Research on the anti-inflammatory effects of ingesting Tenebrio molitor larvae powder (TMLP) is being actively conducted. In this study, TMLP was administered to mice with dextran sodium sulfate (DSS)-induced colitis to investigate its effects in reducing colitis symptoms.

METHODS

Mice were initially given 3% DSS in water to induce colitis and then feed containing 0%, 2%, or 4% TMLP. Pathologic changes in colon tissues were assessed by histology, and neutrophil levels were measured by myeloperoxidase (MPO) assay. Levels of IL-1β, IL-6, and TNF-α were measured using real-time PCR and ELISA assays, and IκB and NF-kB protein levels were measured by western blotting.

RESULT

Disease Activity Index (DAI) scores and MPO activity were reduced in TMLP-treated mice, and colon length increased as much as normal mice. Pathologic changes in the colon tissues of DSS-induced mice were attenuated, and the expression of inflammatory cytokine genes IL-1β, IL-6, and TNF-α decreased. Concomitant decreases in the protein expression of IL-1β and IL-6 were confirmed using ELISA. Western blotting revealed that levels of phosphorylated forms of IκB and NF-κB also decreased.

CONCLUSION

These results show that feeding TMLP to DSS-induced mice inhibited the typical inflammatory pathway of colitis. Therefore, TMLP shows potential as a food additive that can help treat colitis.
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Pharmacological properties and therapeutic potential of honey bee venom

Honey bee venom (BV) is a valuable product, and has a wide range of biological effects, and its use is rapidly increasing in apitherapy. Therefore, the current study, we reviewed the existing knowledge about BV composition and its numerous pharmacological properties for future research and use. Honey bee venom or apitoxin is produced in the venom gland in the honey bee abdomen. Adult bees use it as a primary colony defense mechanism. It is composed of many biologically active substances including peptides, enzymes, amines, amino acids, phospholipids, minerals, carbohydrates as well as some volatile components. Melittin and phospholipase A₂ are the most important components of BV, having anti-cancer, antimicrobial, anti-inflammatory, anti-arthritis, anti-nociceptive and other curative potentials. Therefore, in medicine, BV has been used for centuries against different diseases like arthritis, rheumatism, back pain, and various inflammatory infections. Nowadays, BV or its components separately, are used for the treatment of various diseases in different countries as a natural medicine with limited side effects. Consequently, scientists as well as several pharmaceutical companies are trying to get a new understanding about BV, its substances and its activity for more effective use of this natural remedy in modern medicine.

A Review of the Antimicrobial Potential of Musca domestica as a Natural Approach with Promising Prospects to Countermeasure Antibiotic Resistance

Drug-resistant pathogens have become a serious public health concern worldwide considering the rapid emergence and distribution of new strains, which outpace the development of antimicrobial drugs. It is a complex and serious clinical problem that can cause an epidemic of a disease; consequently, numerous research studies are conducted to determine the solution to these problems, including the development of new antibiotics derived from natural sources such as insects. The housefly (Musca domestica L.), an insect known as a cosmopolitan pest, possesses several qualities that can ameliorate diseases; consequently, they can be used as a bioactive component in the development of medicines. These qualities include its potential as a source of antibacterial agents. The external surface components, wings, internal organs, and whole body extract of M. domestica can all contribute antimicrobial potential due to bioactive compounds they produce. This article discusses several antimicrobial properties of M. domestica that could be utilized for healthcare benefits.

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.

Indigenous knowledge system associated with the uses of insects for therapeutic or medicinal purposes in two main provinces of Burkina Faso, West Africa

BACKGROUND

Some insects are harmful to humans, plants and animals, but some of them can also be a source of proteins, fats, vitamins and minerals and be of therapeutic value. The therapeutic potential requires that medicinal insects and their derived products need to be scrutinized. This study highlights the indigenous knowledge related to their use of medicinal insects in peri-urban and urban areas of Burkina Faso.

METHODS

The survey was carried out among 60 traditional healers spread across two phytogeographical zones of Burkina Faso. The questionnaire focused on medicinal insects used by experienced traditional healers. Chi-square tests and principal component analysis were performed to test for significant differences regarding knowledge of how insects in phytogeographically different areas were used therapeutically in connection with different disease categories.

RESULTS

A total of 19 species of medicinal insects belonging to 6 orders were cited in connection with treatments of at least 78 pathologies and symptoms. Most frequently mentioned was gastroenteritis. Our study showed that 48.78% of the insects and their products were associated with 46 plant species for the treatment of pathologies. In addition, honey, beeswax and nests were the most widely insect products used.

CONCLUSION

The current study allows us to identify medicinal insects as well as their products used in the treatment of pathologies and symptoms, suggesting the presence of a considerable diversity of therapeutically important insect species. These insects are used alone and/or with their products but often in association with medicinal plants. The results constitute a useful database for future studies of medicinal insects in central and western parts of Burkina Faso.

Microbiological investigation study for Apis mellifera yemenitica and Apis mellifera carnica bee venoms on selected bacterial strains

Bees are one of the ancient and the most social insects worldwide. They are of great economic and medical importance. Bee venom (BV) has many therapeutic effects and has been used since ancient times for the treatment of many diseases. The present study aimed to evaluate and compare the antibacterial effect of BV from two different bee subspecies Apis mellifera yemenitica (A. m. yemenitica) (indigenous strain) and Apis mellifera carnica (A. m. carnica) (carniolan strain) against selected Gram-positive and Gram-negative bacteria. Experimentally, venoms were extracted using an electrical venom collector from honey bee colonies of the subspecies, A. m. yemenitica and A. m. carnica, in Hail, Saudi Arabia. Each venom was tested against selected medically important Gram-negative strains, Salmonella Typhimurium, Pseudomonas aeruginosa, and Escherichia coli, while Staphylococcus aureus was selected as Gram-positive test organism. The minimum inhibitory concentration (MIC) method was used to compare the effect of BV from the two subspecies on the growth of the selected bacterial strains. Results showed that BV from both subspecies could equally inhibit the growth of Salmonella Typhimurium, Pseudomonas aeruginosa, and Escherichia coli at an MIC of 10 mg/ml. However, S. aureus was inhibited by an MIC of 5 and 10 mg/ml of BV from A. m. carnica and A. m. yemenitica, respectively. This suggested that the BV of the carnica subspecie was more inhibitory to this Gram-positive pathogen than its counterpart produced by the yemenitica subspecies. The present study shows that bee venom has a promising antibacterial effect.

The Effects of Silkworm-Derived Polysaccharide (Silkrose) on Ectoparasitic Infestations in Yellowtail (Seriola quinqueradiata) and White Trevally (Pseudocaranx dentex)

The effect of silkworm-derived polysaccharide silkrose on fish ectoparasites was investigated. When juvenile yellowtail (Seriola quinqueradiata) fed diets containing silkrose were artificially infected with Benedenia seriolae, a fish ectoparasite, the numbers of parasitized B. seriolae were significantly lower compared to that in fish in the control group without silkrose treatment. Furthermore, when juvenile yellowtails were severely infected with B. seriolae, no mortality was observed in the silkrose-treated group, compared to more than 60% in the control group. In field studies carried out at a fish farm with yellowtail and white trevally (Pseudocaranx dentex), oral treatment with silkrose significantly reduced B. seriolae parasitism in yellowtail and Caligus longipedis and Neobenedenia girellae parasitism in white trevally. Silkrose treatment also reduced blood levels of cortisol, a stress hormone in both species. The changes in gene expression in the epidermis of yellowtail by silkrose treatment were also investigated, showing that the expression of various genes, including factors involved in immunity, stress response, and wound healing, was changed by the treatment. These findings indicate that silkworm-derived silkrose effectively prevents infection by external parasites in yellowtail and white trevally.

Insects as Diet and Therapy: Perspectives on Their Use for Combating Diabetes Mellitus in Tanzania

More than 450 million people worldwide are suffering from diabetes and this number is expected to increase. In developing countries, such as Tanzania, the number of patients suffering from diabetes and associated diseases is increasing as well. Up to 80% of the Tanzanian people rely on traditional medicines for their health care services. The nature of Tanzanian is very rich in different plant and insect species, and this could be exploited through their implementation in preventive and/or curative approaches in the battle against diabetes. The implementation of healthy insects in the diets of people may help in the prevention of obesity, which is a risk factor in the etiology of diabetes, while the identification of small molecules in insects may help in the discovery of potential new drugs that can be used in the treatment of diabetes. In this paper, an overview on the potential implementation of insects against diabetes is presented.

Apamin-Conjugated Alendronate Sodium Nanocomplex for Management of Pancreatic Cancer

Pancreatic cancer has a low survival rate and has limited therapeutic options due to the peculiarity of the tumor tissue. Cancer nanotechnology provides several opportunities to resolve such difficulties as a result of the high surface-to-volume ratio of nanostructures. Peptide-drug nanocomplexes have proved to have immense potential in anticancer activity against pancreatic cancer cells. Thus, in the present study apamin (APA) and alendronate sodium (ALS) were combined to form nanocomplexes (APA-ALS-NC) against pancreatic cancer cells. Optimization of ALS, incubation time, and sonication time in terms of particle size of the nanocomplex was carried out. The optimized formulation was evaluated for anticancer activities in pancreatic cancer cells (PANC-1 cells). A Box-Behnken design using ALS, incubation time, and sonication time as independent factors and particle size as the response was chosen to optimize the APA-ALS-NC formulation. The optimized APA-ALS-NC had a particle size of 161.52 ± 8.4 nm. The evaluation of APA-ALS-NC in PANC-1 cells was carried out using various in vitro tests. The IC₅₀ values were determined by MTT assay and found to be 37.6 ± 1.65, 13.4 ± 0.59, and 1.01 ± 0.04 µg/mL for ALS, APA, and APA-ALS-NC, respectively. The higher cytotoxicity activity of APA-ALS-NC was confirmed from the higher percentage of cells in the necrosis phase (apoptosis study) and the G2-M phase (cell cycle study) compared to that of ALS and APA. While the loss of mitochondrial membrane potential was less for APA-ALS-NC, the levels of IL-1β, TNF-α, caspase-3, ROS, IL-6, and NF-kB showed that APA-ALS-NC can significantly enhance apoptosis and cytotoxicity in PANC-1 cells. Moreover, Bax (10.87 ± 1.36), Bcl-2 (0.27 ± 0.02), and p53 (9.16 ± 1.22) gene expressions confirmed that APA-ALS-NC had a significant apoptotic effect compared to ALS and APA. In summary, the APA-ALS-NC had a more significant cytotoxic effect than ALS and APA. The results of the present study are promising for further evaluation in pre-clinical and clinical trials for arriving at a successful therapeutic strategy against pancreatic cancer.

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.

Dipteran Carboxymethyl Chitosan as an Inexhaustible Derivative with a Potential Antiproliferative Activity in Hepatocellular Carcinoma Cells

Traditional folk therapies indicate that insects have diverse medicinal potentials. However, the therapeutic application of insect chitosan and its derivatives has not been explored. To investigate the application of chitosan and its derivatives, the carboxymethyl derivative of chitosan (CM-Ch) was extracted from two dipteran larvae species, Chrysomya albiceps and Sarcophaga aegyptiaca. The degree of deacetylation (DD) and CM-Ch functional groups were validated using Fourier-transform infrared (FTIR) spectroscopy analysis and proton nuclear magnetic resonance spectroscopy (¹H NMR), respectively. The molecular weight was estimated using MALDI-TOF MS analysis. The effect of CM-Ch on the morphology and proliferation of human liver HepG2 cancer cells was assessed. IC₅₀ of CM-Ch induced significant growth-inhibitory effects in HepG2 cells. CM-Ch treatment altered the morphology of HepG2 in a dose-dependent manner and induced apoptosis in a caspase-dependent manner. CM-Ch treatment showed no signs of toxicity, and no alterations in liver and kidney biochemical markers were observed in albino rats. A CM-Ch derivative from commercial crustacean chitosan was used to assess the efficacy of the insect-derived CM-Ch. The data presented here introduce insect CM-Ch as a promising, inexhaustible, safe derivative of chitosan with antitumor potential in liver cancer. This is the first report highlighting the anticancer activity of insect CM-Ch in hepatocellular carcinoma cells.

Salp15, a Multifunctional Protein From Tick Saliva With Potential Pharmaceutical Effects

Ixodes ticks are the main vectors for a number of zoonotic diseases, including Lyme disease. Ticks secrete saliva directly into a mammalian host while feeding on the host's blood. This action serves to modulate host immunity and coagulation, thus allowing ticks to attach and feed upon their host. One of the most extensively studied components of tick saliva is Salp15. Research has shown that this protein binds specifically to CD4 molecules on the surface of T lymphocytes, interferes with TCR-mediated signaling transduction, inhibits CD4+ T cell activation and proliferation, and impedes the secretion of interleukin 2 (IL-2). Salp15 also binds specifically to dendritic cell dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) to up-regulate the expression of CD73 in regulatory T cells. Collectively, these findings render this salivary protein a potential candidate for a range of therapeutic applications. Here, we discuss our current understanding of Salp15 and the mechanisms that might be used to treat disease.

Deciphering Biological Processes at the Tick-Host Interface Opens New Strategies for Treatment of Human Diseases

Ticks are obligatory blood-feeding ectoparasites, causing blood loss and skin damage in their hosts. In addition, ticks also transmit a number of various pathogenic microorganisms that cause serious diseases in humans and animals. Ticks evolved a wide array of salivary bioactive compounds that, upon injection into the host skin, inhibit or modulate host reactions such as hemostasis, inflammation and wound healing. Modulation of the tick attachment site in the host skin involves mainly molecules which affect physiological processes orchestrated by cytokines, chemokines and growth factors. Suppressing host defense reactions is crucial for tick survival and reproduction. Furthermore, pharmacologically active compounds in tick saliva have a promising therapeutic potential for treatment of some human diseases connected with disorders in hemostasis and immune system. These disorders are often associated to alterations in signaling pathways and dysregulation or overexpression of specific cytokines which, in turn, affect mechanisms of angiogenesis, cell motility and cytoskeletal regulation. Moreover, tick salivary molecules were found to exert cytotoxic and cytolytic effects on various tumor cells and have anti-angiogenic properties. Elucidation of the mode of action of tick bioactive molecules on the regulation of cell processes in their mammalian hosts could provide new tools for understanding the complex changes leading to immune disorders and cancer. Tick bioactive molecules may also be exploited as new pharmacological inhibitors of the signaling pathways of cytokines and thus help alleviate patient discomfort and increase patient survival. We review the current knowledge about tick salivary peptides and proteins that have been identified and functionally characterized in in vitro and/or in vivo models and their therapeutic perspective.

The Use of Tick Salivary Proteins as Novel Therapeutics

The last three decades of research into tick salivary components have revealed several proteins with important pharmacological and immunological activities. Two primary interests have driven research into tick salivary secretions: the search for suitable pathogen transmission blocking or “anti-tick” vaccine candidates and the search for novel therapeutics derived from tick salivary components. Intensive basic research in the field of tick salivary gland transcriptomics and proteomics has identified several major protein families that play important roles in tick feeding and overcoming vertebrate anti-tick responses. Moreover, these families contain members with unrealized therapeutic potential. Here we review the major tick salivary protein families exploitable in medical applications such as immunomodulation, inhibition of hemostasis and inflammation. Moreover, we discuss the potential, opportunities, and challenges in searching for novel tick-derived drugs.

The silk of Plodia interpunctella as a potential biomaterial and its cytotoxic effect on cancer cells

Insect silk has been widely studied for its application in regenerative medicine. However, the data about Plodia interpunctella silk as a biomaterial and its anticancer properties are insufficient. Thus, the aim of this study was to investigate native silk as a substrate for growing normal human fibroblasts MRC-5, and test potential cytotoxic effects of the two silk extracts (with DMSO and Trypsin for sericin isolation) on HCT-116 colorectal carcinoma cells and MRC-5 fibroblasts as a control. Fifth-instar larval silk, collected for 15 and 30 days, was used for testing of proliferation and adhesion of MRC-5, 24 h and 72 h after seeding. Light- and fluorescence-microscope showed cell adhesion and spread on silk, as well as enhanced number of cells after 72 compared to 24 h and nonsignificant percentage of apoptotic cells on the silk. Although insoluble, P. interpunctella silk showed remarkable cytotoxic activity on HCT-116 cells, without significant cytotoxity on normal fibroblasts after 24 h and weak effects after 72 h. This study provides significant information about P. interpunctella silk as a potential biomaterial and shows the presence of some active constituents with anticancer properties, thus pointing to the possibility for exploitation of this worldwide pest insect in biomedical application.

Nutrient ileal digestibility evaluation of dried mealworm (Tenebrio molitor) larvae compared to three animal protein by-products in growing pigs

Objective

This study was to investigate the nutrient ileal digestibility of dried mealworm (Tenebrio molitor) larvae and compare with those of three animal protein by-products in growing pigs.

Methods

A total of 12 crossbred ([Landrace×Yorkshire]×Duroc) growing pigs with average body weights of 24.12±0.68 kg were surgically equipped with simple T-cannulas after being deprived of feed for 24 h according to published surgical procedures. These pigs had a recovery period of two weeks. A total of 12 pigs were assigned to individual metabolic crates and allotted to one of four treatments with 3 replicates in a fully randomized design. Dietary treatments included the following: i) Fish meal, corn-vegetable by-product basal diet+9.95% fish meal; ii) Meat meal, corn-vegetable by-product basal diet+9.95% meat meal; iii) Poultry meal, corn-vegetable by-product basal diet+9.95% poultry meal; iv) Tenebrio molitor, corn-vegetable by-product basal diet+9.95% dried Tenebrio molitor larvae.

Results

Results showed that the apparent ileal digestibility (AID) of Lys was higher (p<0.05) in pigs fed Tenebrio molitor diet than that in pigs fed fish meal diet. Pigs fed Tenebrio molitor diet showed increased (p<0.05) AID of His and Arg compared to pigs fed Fish meal or Meat meal diet. The AID of Cys was increased (p<0.05) in pigs fed poultry meal and Tenebrio molitor diets compared to that in pigs fish meal diet. Pigs fed meat meal, poultry meal, and Tenebrio molitor diets showed higher (p<0.05) standardized ileal digestibility (SID) of total energy compared to pigs fed fish meal diet. The SID of Arg was higher (p<0.05) in pigs fed Tenebrio molitor diet than that in pigs fed fish meal or meat meal diet. Furthermore, pigs fed poultry meal or Tenebrio molitor diets showed increased (p<0.05) SID of Cys compared to pigs fed fish meal diet.

Conclusion

In conclusion, providing pigs with diets that contained Tenebrio molitor larvae meal improved AID and SID of nutrients as well as essential and non-essential amino acids. The digestibility of dried mealworm larvae protein and its utilization in vivo are also good. Therefore, dried mealworm larvae protein can be used as protein source at 10% level in growing pigs.

Sarconesin: Sarconesiopsis magellanica Blowfly Larval Excretions and Secretions With Antibacterial Properties

Larval therapy (LT) is an alternative treatment for healing chronic wounds; its action is based on debridement, the removal of bacteria, and stimulating granulation tissue. The most important mechanism when using LT for combating infection depends on larval excretions and secretions (ES). Larvae are protected against infection by a spectrum of antimicrobial peptides (AMPs); special interest in AMPs has also risen regarding understanding their role in wound healing since they degrade necrotic tissue and kill different bacteria during LT. Sarconesiopsis magellanica (Diptera: Calliphoridae) is a promising medically-important necrophagous fly. This article reports a small AMP being isolated from S. magellanica ES products for the first time; these products were obtained from third-instar larvae taken from a previously-established colony. ES were fractionated by RP-HPLC using C18 columns for the first analysis; the products were then lyophilised and their antimicrobial activity was characterized by incubation with different bacterial strains. These fractions' primary sequences were determined by mass spectrometry and de novo sequencing; five AMPs were obtained, the Sarconesin fraction was characterized and antibacterial activity was tested in different concentrations with minimum inhibitory concentrations starting at 1.2 μM. Potent inhibitory activity was shown against Gram-negative (Escherichia coli D31, E. coli DH5α, Salmonella enterica ATCC 13314, Pseudomonas aeruginosa 27853) and Gram-positive (Staphylococcus aureus ATCC 29213, S. epidermidis ATCC 12228, Micrococcus luteus A270) bacteria. Sarconesin has a significant similarity with Rho-family GTPases which are important in organelle development, cytoskeletal dynamics, cell movement, and wound repair. The data reported here indicated that Sarconesin could be an alternative candidate for use in therapeutics against Gram-negative and Gram-positive bacterial infections. Our study describes one peptide responsible for antibacterial activity when LT is being used. The results shown here support carrying out further experiments aimed at validating S. magellanica AMPs as novel resources for combating antibacterial resistance.

Productive performance and blood profiles of laying hens fed Hermetia illucens larvae meal as total replacement of soybean meal from 24 to 45 weeks of age

The aim of the research was to study the effects of an insect meal from Hermetia illucens larvae (HILM) as complete replacement of soybean meal (SBM) on productive performance and blood profiles of laying hens, from 24 to 45 wk of age. A total of 108 24-week-old Lohmann Brown Classic laying hens was equally divided into 2 groups (54 hens/group, 9 replicates of 6 hens/group). From 24 to 45 wk of age, the groups were fed 2 different isoproteic and isoenergetic diets: the control group (SBM) was fed a corn-soybean meal based diet, while in the HILM group the soybean meal was completely replaced by Hermetia illucens larvae meal. Feed intake, number of eggs produced, and egg weight were recorded weekly along the trial. At 45 wk of age, blood samples were collected from 2 hens per replicate. The use of HIML led to a more favorable (P < 0.01) feed conversion ratio in hens but lay percentage, feed intake, average egg weight, and egg mass were higher (P < 0.01) in hens fed the SBM diet. Hens fed insect meal produced a higher percentage of eggs from small (S), medium (M), and extra-large (XL) classes (P < 0.01) than SBM, while the SBM group had a higher percentage of eggs from the large (L) class (P < 0.01). The levels of globulin and albumin to globulin ratio were, respectively, higher and lower (P < 0.05) in HILM than the SBM group. Cholesterol and triglycerides were higher (P < 0.05 and P < 0.01, respectively) in hens from SBM than in the HILM group. Blood levels of Ca were higher (P < 0.01) in hens fed insect meal, while creatinine was higher (P < 0.01) in blood of hens fed SBM. Hermetia illucens larvae meal can be a suitable alternative protein source for laying hens even if the complete replacement of soybean meal needs further investigation to avoid the negative effects on feed intake.

The silkrose of Bombyx mori effectively prevents vibriosis in penaeid prawns via the activation of innate immunity

We previously identified novel bioactive polysaccharides from Bactrocera cucurbitae and Antheraea yamamai that activate innate immunity in RAW264 murine macrophages. However, in terms of potential applications in the cultivation of prawns, there were problems with the availability of these insects. However, we have now identified a polysaccharide from Bombyx mori that activates innate immunity in RAW264 cells and penaeid prawns. This purified polysaccharide, termed silkrose of B. mori (silkrose-BM), has a molecular weight of 1,150,000 and produces a single symmetrical peak on HPLC. Eight of nine constitutive monosaccharides of silkrose-BM are concomitant with dipterose of B. cucurbitae (dipterose-BC) and silkrose of A. yamamai (silkrose-AY). The major differences are found in the molar ratios of the monosaccharides. Silkrose-BM is approximately 500-fold less potent than silkrose-AY (EC₅₀: 2.5 and 0.0043 μg/mL, respectively) in a nitrite oxide (NO) production assay using RAW264 cells. However, the maximum NO production for silkrose-BM and AY were comparable and higher than that of the lipopolysaccharide of Escherichia coli. The survival of penaeid prawns (Litopenaeus vannamei and Marsupenaeus japonicus) after infection with Vibrio penaecida was significantly improved by both dietary silkrose-BM and B. mori pupae. This suggests that silkrose-BM effectively prevents vibriosis in penaeid prawns via the activation of innate immunity.

Insects: an underrepresented resource for the discovery of biologically active natural products

Nature has been the source of life-changing and -saving medications for centuries. Aspirin, penicillin and morphine are prime examples of Nature׳s gifts to medicine. These discoveries catalyzed the field of natural product drug discovery which has mostly focused on plants. However, insects have more than twice the number of species and entomotherapy has been in practice for as long as and often in conjunction with medicinal plants and is an important alternative to modern medicine in many parts of the world. Herein, an overview of current traditional medicinal applications of insects and characterization of isolated biologically active molecules starting from approximately 2010 is presented. Insect natural products reviewed were isolated from ants, bees, wasps, beetles, cockroaches, termites, flies, true bugs, moths and more. Biological activities of these natural products from insects include antimicrobial, antifungal, antiviral, anticancer, antioxidant, anti-inflammatory and immunomodulatory effects.

Natural antimicrobial peptide complexes in the fighting of antibiotic resistant biofilms: Calliphora vicina medicinal maggots

Biofilms, sedimented microbial communities embedded in a biopolymer matrix cause vast majority of human bacterial infections and many severe complications such as chronic inflammatory diseases and cancer. Biofilms’ resistance to the host immunity and antibiotics makes this kind of infection particularly intractable. Antimicrobial peptides (AMPs) are a ubiquitous facet of innate immunity in animals. However, AMPs activity was studied mainly on planktonic bacteria and little is known about their effects on biofilms. We studied structure and anti-biofilm activity of AMP complex produced by the maggots of blowfly Calliphora vicina living in environments extremely contaminated by biofilm-forming germs. The complex exhibits strong cell killing and matrix destroying activity against human pathogenic antibiotic resistant Escherichia coli, Staphylococcus aureus and Acinetobacter baumannii biofilms as well as non-toxicity to human immune cells. The complex was found to contain AMPs from defensin, cecropin, diptericin and proline-rich peptide families simultaneously expressed in response to bacterial infection and encoded by hundreds mRNA isoforms. All the families combine cell killing and matrix destruction mechanisms, but the ratio of these effects and antibacterial activity spectrum are specific to each family. These molecules dramatically extend the list of known anti-biofilm AMPs. However, pharmacological development of the complex as a whole can provide significant advantages compared with a conventional one-component approach. In particular, a similar level of activity against biofilm and planktonic bacteria (MBEC/MIC ratio) provides the complex advantage over conventional antibiotics. Available methods of the complex in situ and in vitro biosynthesis make this idea practicable.

Understanding nutrition and immunity in disease management

As we search for answers to modern medicine's most prevalent and challenging problems, the relationship between nutrition, immunity, and biological function of various natural compounds are preimminent. Nutritional research involving genomics provides rational capabilities for preventing disease. Scientific advances in genomic sequencing reveal opportunities for exploring diet-health relationships and potential for individual, genotype based dietary recommendations. Utilizing molecular and genetic technology to analyze impact of nutrition on genomics and metabolism reveals that nutrients may influence certain innate and/or acquired immune functions. By analyzing immune mechanisms including their cells and complex molecules, animal models have offered relevant insight that clarifies interrelations between immunity and nutrition. Plant products also provide numerous resources through bioengineering for designing novel pharmaceuticals. Having long been employed successfully in traditional and folk medicines, plant compounds exhibit anti-inflammatory, antimicrobial, and angiogenic activity. As a result, we now have a promising arsenal for successful application of bioactive compounds.

Antiviral activity of animal venom peptides and related compounds

Viruses exhibit rapid mutational capacity to trick and infect host cells, sometimes assisted through virus-coded peptides that counteract host cellular immune defense. Although a large number of compounds have been identified as inhibiting various viral infections and disease progression, it is urgent to achieve the discovery of more effective agents. Furthermore, proportionally to the great variety of diseases caused by viruses, very few viral vaccines are available, and not all are efficient. Thus, new antiviral substances obtained from natural products have been prospected, including those derived from venomous animals. Venoms are complex mixtures of hundreds of molecules, mostly peptides, that present a large array of biological activities and evolved to putatively target the biochemical machinery of different pathogens or host cellular structures. In addition, non-venomous compounds, such as some body fluids of invertebrate organisms, exhibit antiviral activity. This review provides a panorama of peptides described from animal venoms that present antiviral activity, thereby reinforcing them as important tools for the development of new therapeutic drugs.

Detection and preliminary physico-chemical properties of antimicrobial components in the native excretions/secretions of three species of Chrysomya (Diptera, Calliphoridae) in Brazil

Antibiotic-resistant bacteria in hospitals and communities increasingly threaten public health in Brazil and the rest of the World. There is an urgent need for additional antimicrobial drugs. Calliphorid blowfly larvae are a rich source of antimicrobial factors but the potential of Neotropical species has been neglected. This preliminary study evaluates the antimicrobial activity of the native excretions/secretions of larvae of three species of Brazilian calliphorids, Chrysomya megacephala, Chrysomya albiceps and Chrysomya putoria. Native excretions/secretions were collected from third instar larvae, sterile filtered and tested for antibacterial activity against Staphylococcus aureus 9518, Escherichia coli K12 4401 and Serratia marcescens 365. Turbidometric assays were made in micro-plates, using an ELISA reader, with readings taken up to 22 h. Bacterial suspensions at the start and end of each experiment were also serially diluted, spread on nutrient agar plates and then colony forming units counted. The physico-chemical characteristics of the native excretions/secretions were also tested by freezing/thawing, boiling, and protease digestion. The native excretions/secretions of larvae from these three Chrysomya species significantly inhibited bacterial growth. Therefore, Brazilian calliphorid flies could potentially provide new classes of antibiotics.

Reactive oxygen species, apoptosis, antimicrobial peptides and human inflammatory diseases

Excessive free radical generation, especially reactive oxygen species (ROS) leading to oxidative stress in the biological system, has been implicated in the pathogenesis and pathological conditions associated with diverse human inflammatory diseases (HIDs). Although inflammation which is considered advantageous is a defensive mechanism in response to xenobiotics and foreign pathogen; as a result of cellular damage arising from oxidative stress, if uncontrolled, it may degenerate to chronic inflammation when the ROS levels exceed the antioxidant capacity. Therefore, in the normal resolution of inflammatory reactions, apoptosis is acknowledged to play a crucial role, while on the other hand, dysregulation in the induction of apoptosis by enhanced ROS production could also result in excessive apoptosis identified in the pathogenesis of HIDs. Apparently, a careful balance must be maintained in this complex environment. Antimicrobial peptides (AMPs) have been proposed in this review as an excellent candidate capable of playing prominent roles in maintaining this balance. Consequently, in novel drug design for the treatment and management of HIDs, AMPs are promising candidates owing to their size and multidimensional properties as well as their wide spectrum of activities and indications of reduced rate of resistance.