Inhibitory Action of Omega-3 and Omega-6 Fatty Acids Alpha-Linolenic, Arachidonic and Linoleic acid on Human Erythrocyte Acetylcholinesterase

Inhibition potential of n-hexadecanoic and oleic acids from edible insects against α-glucosidase, α-amylase, tyrosinase, and acetylcholinesterase: in vitro and in silico studies

BACKGROUND

Edible insects are used for consumption and traditional medicine due to their rich bioactive compounds. This study examined the bioactive compounds and inhibitory effects of crude extracts from Bombyx mori and Omphisa fuscidentalis on α-glucosidase, α-amylase, acetylcholinesterase (AChE), and tyrosinase. Fatty acids, including n-hexadecanoic acid and oleic acid, were identified in the extracts and evaluated for their inhibitory potential against the enzymes in vitro and in silico.

RESULTS

The total phenolic content of the edible insect extracts correlated with enzyme inhibitory activity. The quercetin and kaempferol content of B. mori ethyl acetate (EtOAc) extract was also closely related to α-amylase inhibitory activity. The EtOAc and hexane extracts of B. mori showed similar inhibition potential to acarbose and tacrine against α-amylase and AChE, respectively. The hexane extract of O. fuscidentalis exhibited comparable tyrosinase inhibitory activity to kojic acid. n-Hexadecanoic acid and oleic acid were the predominant bioactive compounds in all of the extracts. A kinetic study revealed that n-hexadecanoic acid acted as a mixed-type inhibitor against α-amylase, similar to acarbose, whereas oleic acid showed non-competitive inhibition against AChE, unlike tacrine. Docking studies suggested that these fatty acids bind to the active sites of α-amylase and AChE.

CONCLUSION

The findings suggest that n-hexadecanoic acid and oleic acid from edible insects could be potential candidates for treating diabetes mellitus and Alzheimer's disease. An animal model might be used for further examination to confirm these findings. © 2025 Society of Chemical Industry.

The role of unsaturated fatty acids in modulating human butyrylcholinesterase activity: insights from kinetics and molecular docking

Butyrylcholinesterase is an abundant detoxification enzyme in human serum that is mainly synthesized in the liver. It plays a crucial role in the hydrolysis of a variety of choline esters and xenobiotics, and there is emerging evidence that it is also involved in lipid metabolism. In this study, the inhibitory effects of the major unsaturated fatty acids - arachidonic acid (AA), linoleic acid (LA), oleic acid (OA), and alpha-linolenic acid (α-LA) - on human BChE are investigated using enzyme kinetics experiments and molecular modeling analyses. These fatty acids, integral components of membrane phospholipids, differ in chain length and degree of unsaturation, which influence their inhibitory effect on BChE. Our results showed that AA had the highest IC₅₀ value of 611 µM against BChE, followed by OA, α-LA, and LA. All fatty acids showed noncompetitive inhibition, in contrast to AA, which displayed uncompetitive inhibition. Inhibitory constants (Ki) showed that OA had the strongest binding affinity due to its lowest Ki value of 321.4 µM, followed by AA, α-LA, and LA. Molecular modeling supported the in vitro results. The fatty acids were predicted to bind to a newly proposed allosteric site on BChE. Our results demonstrate that the number and position of double bonds in the alkenyl chains of fatty acids significantly influence their interactions with BChE, providing new insights into how dietary lipids regulate the enzyme. This study offers a foundation for further exploration of BChE's role in lipid metabolism and its implications for neurodegenerative and metabolic diseases.

Disposable electrochemical biosensor based on acetylcholinesterase for inhibition assays using a natural substance and plant extracts

In general, insects are considered pests in agricultural areas, and their control is essential for high productivity of the cultivated areas. Control of these insects can be achieved by the inhibition of enzymes present in the insect's body. The enzyme acetylcholinesterase (AChE) is present in the neuromuscular junctions of vertebrates and invertebrates, and it is an important target for pest control. Herein, we present the development of a disposable electrochemical biosensor based on AChE (Bio-AChE) to rapidly evaluate the presence of new potential inhibitors in crude extracts of plants. Bio-AChE was constructed by modifying the disposable screen-printed carbon electrode (SPCE) with glutathione-decorated gold nanoparticles on which AChE was covalently immobilized. Electrochemical studies confirm the effective immobilization of the enzyme, and the Bio-AChE was applied to assess the inhibitory activity of azadirachtin, obtained from Azadirachta indica, which is a well-known AChE inhibitor. The proposed biosensor showed excellent results, demonstrating the inhibition activity of azadirachtin against AChE. The crude extracts of Picramnia riedelli, P. ciliata, and Toona ciliata were evaluated with the Bio-AChE, and all showed inhibition percentage values of around 50%. The extracts were evaluated by 1H NMR spectra, which identified classes of natural compounds that could be responsible for the inhibition activity. The proposed disposable Bio-AChE was shown to be a reliable method for simple and rapid screening of new inhibitors in plant extracts, opening an avenue for the screening of new natural products with potential for pest control.

Inhibitor Action of Unsaturated Fatty Acids on Equine Serum Butyrylcholinesterase

Butyrylcholinesterase (BChE; EC 3.1.1.8), a serine hydrolase found in various tissues, hydrolyses choline esters such as acetylcholine and succinylcholine, as well as other esters such as heroin and acetylsalicylic acid. It is considered to play a role in lipid metabolism as it belongs to the same enzyme group as lipases and its catalytic subunits are similar. In this study, the effects of unsaturated fatty acids, namely arachidonic (AA), linoleic (LA), alpha-linolenic (ALA) and oleic acid (OA), on equine serum BChE (EqBChE) were investigated. Enzyme activity was measured by the modified Ellman method. When the activity results were evaluated, the IC50 values were found 45.49, 8.465, 1556, and 56.57 μM; while the Ki values were 63.92, 11.46, 1800, and 15.24 μM for AA, ALA, LA, and OA, respectively. Analysis of the kinetic results showed that ALA was compatible with mixed inhibition and other fatty acids were compatible with non-competitive inhibition, a special type of mixed inhibition. Molecular docking predicted binding of the fatty acids to the active site, as well as to predicted allosteric sites. The results of this study provide another support to the hypothesis that cholinesterases are associated with lipid metabolism.

Identifying Organic Chemicals with Acetylcholinesterase Inhibition in Nationwide Estuarine Waters by Machine Learning-Assisted Mass Spectrometric Screening

Neurotoxicity is frequently observed in the global aquatic environment, threatening aquatic ecosystems and human health. However, a very limited proportion of neurotoxic effects (∼1%) has been explained by known chemicals of concern. Here, we integrated machine learning, nontargeted analysis, and in vitro biotesting to identify neurotoxic drivers of acetylcholinesterase (AChE) inhibition in estuarine waters along the coast of China. Machine learning was used to predict AChE inhibitors in a large chemical space. The prediction output was profiled into a suspect screening list to guide high-resolution mass spectrometry (HRMS) screening of AChE inhibitors in estuarine water samples. Ultimately, 60 chemicals with diverse known and presently unknown structures were identified, explaining 82.1% of the observed AChE inhibition. Polyunsaturated fatty acids were unexpectedly found to be neurotoxic drivers, accounting for 80.5% of the overall effect. This proof-of-concept study demonstrates that machine learning-based toxicological prediction can achieve a virtual fractionation role to pinpoint HRMS features with the bioactivity potential. Our approach is expected to enable rapid and comprehensive screening of organic pollutants associated with various in vitro end points for large-scale monitoring of water quality.

Fatty Acid Profiles and Biological Activities of the Vegetable Oils of Argania spinosa, Pinus halepensis and Pistacia atlantica Grown in Tunisia: A Preliminary Study

Several foods are used in both the nutraceutical and health sectors; vegetable oils, for example, can prevent the onset of numerous diseases. The properties of these oils are related to their chemical composition and primarily to the presence of fatty acids. The present work aimed to determine the chemical profiles of Argania spinosa, Pinus halepensis, and Pistacia altantica oils, used in traditional Tunisian foods, and to evaluate some biological properties. We evaluated their antioxidant, anti-enzymatic, antimicrobial, and anti-inflammatory properties. Linoleic acid was the main component of the three oils. P. atlantica oil showed more significant inhibitory activity against the enzymes studied than A. spinosa and P. halepensis. All three oils showed similar antioxidant and anti-inflammatory activity. Furthermore, A. spinosa and P. halepensis oils showed antibiofilm activity against P. aeruginosa, with 30-40% inhibition. These results focus on the possible use of these oils in the nutraceutical and healthcare sectors.