Beneficial sterols in selected edible insects and their associated antibacterial activities

The importance of choosing the appropriate cholesterol quantification method: enzymatic assay versus gas chromatography

Cholesterol is a major lipid of the animal realm with many biological roles. It is an important component of cellular membranes and a precursor of steroid hormones and bile acids. It is particularly abundant in nervous tissues, and dysregulation of cholesterol metabolism has been associated with neurodegenerative diseases such as Alzheimer's and Huntington's diseases. Deciphering the pathophysiological mechanisms of these disorders often involves animal models such as mice and Drosophila. Accurate quantification of cholesterol levels in the chosen models is a critical point of these studies. In the present work, we compare two common methods, gas chromatography coupled to flame-ionization detection (GC/FID) and a cholesterol oxidase-based fluorometric assay to measure cholesterol in mouse brains and Drosophila heads. Cholesterol levels measured by the two methods were similar for the mouse brain, which presents a huge majority of cholesterol in its sterol profile. On the contrary, depending on the method, measured cholesterol levels were very different for Drosophila heads, which present a complex sterol profile with a minority of cholesterol. We showed that the enzyme-based assay is not specific for cholesterol and detects other sterols as well. This method is therefore not suited for cholesterol measurement in models such as Drosophila. Alternatively, chromatographic methods, such as GC/FID, offer the required specificity for cholesterol quantification. Understanding the limitations of the quantification techniques is essential for reliable interpretation of the results in cholesterol-related research.

Unlocking the Potential of Substrate Quality for the Enhanced Antibacterial Activity of Black Soldier Fly against Pathogens

Globally, antibiotics are facing fierce resistance from multidrug-resistant bacterial strains. There is an urgent need for eco-friendly alternatives. Though insects are important targets for antimicrobial peptides, it has received limited research attention. This study investigated the impact of waste substrates on the production of antibacterial agents in black soldier fly (Hermetia illucens L.) larvae (HIL) and their implications in the suppression of pathogens [Bacillus subtilis (ATCC 6051), Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853), and Escherichia coli (ATCC 25922)]. The 20% acetic acid (AcOH) extract from market waste had the highest antibacterial activity with an inhibition zone of 17.00 mm, followed by potato waste (15.02 mm) against S. aureus. Hexane extract from HIL raised on market waste also showed a significant inhibitory zone (13.06 mm) against B. subtilis. .Minimum inhibitory concentration (MIC) values recorded were 25 mg/mL against all test pathogens. The fastest time-kill of 20% AcOH extract was 4 h againstB. subtilis, E. coli, ,andP. aeruginosa. Lauric acid was also identified as the dominant component of the various hexane extracts with concentrations of 602.76 and 318.17 μg/g in HIL reared on potato and market waste, respectively. Energy from the market waste substrate correlated significantly (r = 0.97) with antibacterial activities. This study highlights the key role of substrate quality and extraction methods for enhancing the production of antibacterial agents in HIL, thus providing new insights into the development of potential drugs to overcome the alarming concerns of antimicrobial resistance.

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).