Today, insects from order Orthoptera, Coleoptera and Diptera represent the most prevalent groups of insects which are used as an alternative feedstuff, either as a full fat insect meal, defatted insect meal, or insect derived oil. Their inclusion is in many cases considered as a good quality protein or fat addition in feed mixtures, but edible insects pose as much more when it comes to their physiological and biological activity.
R&D Manager
Green Cell Innovation, Serbia
Product Manager
Green Cell Innovation, Serbia
With the world population projected to reach 9.8 billion people by 2050, both accessibility and affordability of alternative proteins are to be taken into account if they are to play a substantial role in addressing these challenges. Showing great potential for future food systems, edible insects are considered an environmentally friendly choice as alternative sources of proteins. Their primary benefit is reflected in a good nutritional profile — high percentage of protein with high-quality amino acids, fatty acids (e.g. omega-3), fibers, vitamins (e.g. vitamin B12), and minerals such as calcium and iron, as well as highly efficient conversion of ingested matter into biomass. Many insects possess the potential for recycling agricultural waste products, which they can use as feeding substrates and transform them into nutritious food and feedstuff, which is then returned to the production cycle.
Today, insects from order Orthoptera, Coleoptera and Diptera represent the most prevalent groups of insects which are used as an alternative feedstuff, either as a full fat insect meal, defatted insect meal, or insect derived oil. Their inclusion is in many cases considered as a good quality protein or fat addition in feed mixtures, but edible insects pose as much more when it comes to their physiological and biological activity. The bioactivities of various edible insect species have been tested using in vitro assays and in vivo models, either as extracts from the whole insect or as isolated compounds.
ANTIOXIDATIVE ACTIVITY
Oxidative stress is a physiological imbalance between the production of reactive oxygen species (ROS) and the ability of the body to detoxify them or repair the resulting damage. Essentially, it occurs when there’s an overabundance of these harmful molecules compared to the body’s antioxidant defenses. ROS are highly reactive molecules containing oxygen, such as superoxide radicals, hydrogen peroxide, and hydroxyl radicals, which can damage cells, proteins, and DNA if not neutralized. It is considered that the eating habits of insects have a significant influence on antioxidative activity of their meals. Luckily, the commercially available edible insects which have vegetarian dietary habits endowed the highest antioxidant capacity in vivo test which were aiming on activity of radical scavenging and ferric reducing antioxidant power (FRAP). Both approved species from the family Tenebrionidae, yellow mealworm Tenebrio molitor and buffalo mealworm Alphitobius diaperinus can play an important role in the prevention of oxidative stress-related diseases. Inclusion of T. molitor insect meal in the pig diet containing suitable levels of antioxidants, like vitamin E and selenium. In vitro tests showed increased activity of important antioxidant enzymes (CAT, GPX and SOD) in liver and gastrocnemius muscles of growing pigs.
ANTI INFLAMMATORY ACTIVITY
The anti-inflammatory activity of insect meals refers to their ability to reduce inflammation within the body. Inflammation is a natural response by the immune system to injury or infection, but chronic inflammation can contribute to various diseases such as arthritis, cardiovascular diseases, and certain cancers. Insects, particularly from the order Orthoptera (Grylloides genus) have bioactive compounds, which have been studied for their potential to mitigate inflammation. These bioactive compounds belong to the group of peptides and various fatty acids. Research suggests that certain edible insects, when consumed as part of the diet, may exhibit anti-inflammatory effects. Anti-inflammatory mechanisms within the animal body are divided into several groups:
• Modulation of immune cells: Certain compounds in insect meals may modulate the activity of immune cells, such as macrophages and lymphocytes, involved in the inflammatory response. By regulating immune cell function, insect meals can help maintain immune homeostasis and reduce excessive inflammation.
• Inhibition of inflammatory enzymes: Some insect-derived bioactive compounds may inhibit the activity of enzymes involved in the production of inflammatory mediators, such as cyclooxygenase (COX) and lipoxygenase (LOX). By blocking these enzymes, insect meals can suppress the synthesis of pro-inflammatory prostaglandins and leukotrienes.
• Gut microbiota modulation: Insect meals may influence the composition and activity of the gut microbiota, which plays a crucial role in immune regulation and inflammation. By promoting the growth of beneficial bacteria and inhibiting pathogenic microbes, insect meals can help maintain intestinal barrier integrity and reduce inflammation in the gut.
• Modulation of cytokines: Insect meals may contain bioactive compounds that regulate the production and activity of pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β). By inhibiting the expression of these cytokines, insect meals can attenuate the inflammatory response.
T. molitor and Z. morio full-fat meals, as functional feed additives, increased the growth performance of broiler chickens and changed traits of their immune system (Benzertiha et al. 2020), while defatted Z. morio larvae meals can lead to immunomodulation in the gilthead seabream Sparus aurata (Henry et al. 2022).
ANTI CANCEROGENIC ACTIVITY
Wide range of research aims to prove that different types of edible insects, their exoskeleton, hemolymph, have a negative impact on cancer cell growth. Although the research dealt with human lines of cancer cells it is worth mentioning that insects will have a significant role in the future as a potential novel pharmaceutical. Last 40 years of research mostly shined light on the Hymenoptera species as a source of anti-cancer pharmaceutical, thus testing Apis mellifera, Chalicodoma siculum, and Xylocopa pubescens hemolymph on human liver cancer (HepG2) and human cervical cancer (HeLa) cells, where all hemolymph extracts resulted in inhibition of cell viability against the tested cancer cell lines in a dose-dependent manner. Experiments related to the approved edible insect species like house cricket showed that its Chitin and its degraded products such as chitosan have been shown to exert anticancer and antimicrobial properties.
ANTI MICROBIAL ACTIVITY
Research in this area is ongoing, specifically focusing on the antimicrobial activity of edible insects, some studies have shown promising results.
Several factors may contribute to the antimicrobial potential of edible insects:
• Chitin: Insects are rich in chitin, a polysaccharide that forms their exoskeleton. Chitin and its derivatives have been studied for their antimicrobial properties, particularly against bacteria and fungi.
• Peptides and proteins: Insects produce various peptides and proteins as part of their immune response to pathogens. Some of these peptides have demonstrated antimicrobial activity against a wide range of microorganisms.
• Secondary metabolites: Edible insects, like other organisms, produce secondary metabolites that may possess antimicrobial properties. These compounds could be present in various tissues, such as the gut, fat body, or hemolymph.
• Microbial composition: The gut microbiota of insects might produce antimicrobial substances that could influence the overall antimicrobial activity of the insect.
Research has shown that extracts from certain edible insects exhibit antimicrobial effects against common foodborne pathogens such as Escherichia coli, Salmonella spp., and Staphylococcus aureus. For example, extracts from mealworms (Tenebrio molitor) and crickets (Acheta domesticus) have shown inhibitory effects against these bacteria in laboratory studies.
However, it’s important to note that the antimicrobial activity of edible insects can vary depending on factors such as species, life stage, diet, and processing methods. Additionally, while laboratory studies provide valuable insights, more research is needed to understand how these findings translate to real-world applications, such as food preservation or medical uses.
Overall, while there is evidence to suggest that edible insects may possess antimicrobial properties, further research is necessary to fully understand the mechanisms involved and to explore their potential applications in various fields, including food science, medicine, and agriculture.
Hermetia llucens is a species which is often highlighted as a species whose body and feces are rich in antimicrobial peptides, new molecules with great potential in pharmaceutical and biomedical fields. This species is especially standing out in this field as the progressive misuse of antibiotics has unfortunately favored the selection and spread of resistant populations of bacterial agents. The development of antibiotic-resistant bacterial strains and the reduced availability of effective antibiotics, a need to identify new molecules in which insect species have their spotlight, to be used for the development of alternative therapies. Recent studies have also highlighted the potential antimicrobial activity of some H. illucens AMPs against Staphylococcus aureus, methicillin-resistant S. aureus and Pseudomonas aeruginosa.
CONCLUSION
The exploration of the medicinal properties of edible insects reveals a promising avenue for both food science and healthcare. Delving deep into their potential as sources of anti-cancer, anti-inflammatory, antioxidant, and antimicrobial compounds unveils a wealth of bioactive molecules within these often looked as an exclusive, alternative protein food source. However, while the initial findings are promising, further research is necessary to fully elucidate the mechanisms of action, optimize extraction methods, and assess the safety and efficacy of these compounds for animal and human use. Additionally, considerations such as species variability, life stage, diet, and processing methods must be taken into account to harness the full therapeutic potential of edible insects.
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