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Abstract

Hypertension is well known as one of the major risk factors for cardiovascular disease. The angiotensin converting enzyme (ACE) plays a key role in blood pressure regulation process. Hypertension treatment by synthetic ACE inhibitors (e.g. captopril, lisinopril, enalapril) is effective but their use can cause serious side effects, such as hypotension, cough, reduced renal function and angioedema. Therefore, research was focused on natural ACE inhibitory peptides sources such as foodstuffs and recently, also insects, promoted by the Food and Agricultural Organization of the United Nations (FAO) as a more environmentally sustainable, nutritious and functional alternative food to conventional livestock for human consumption. The purpose of this study is to investigate the ACE inhibitory activity in protein hydrolysates derived from the larval and pupal stages of the edible insect Tenebrio molitor (Coleoptera: Tenebrionidae). Each insect protein extract was hydrolyzed by the gastrointestinal enzymes (pepsin, trypsin and chymotrypsin) to simulate digestive process and compared to the crude extract. ACE inhibitory activity was measured by an indirect assay method based on the quantity of hippuric acid released by ACE from hippuryl-L-histidyl-leucine and determined by reverse-phase high performance liquid chromatography. Captopril was used as positive control and ACE inhibition degree expressed as the concentration of protein extract that inhibits 50% of ACE activity (IC50), assuming that the activity of the blank is equal to 100%. The IC50 value of captopril was 2.6x10-6 mg/mL. A significantly lower IC50 was detected after gastrointestinal hydrolysis of the protein extracts obtained from larvae (0.720 vs. 0.097 mg/mL after gastrointestinal hydrolysis) and pupae (0.484 vs. 0.132 mg/mL after gastrointestinal hydrolysis). Based on experimental data, T. molitor larvae represent the most promising development stage for the purification and identification of bioactive ACE inhibitory peptides, confirming the potential benefits of this coleopteran for human health.

Biography

Annarita Cito has completed her PhD in Biochemistry and Enzymology from the University of Siena (Italy) in 2010. Her dissertation investigated the role of homocysteine and some oxidative stress markers in neurodegenerative disorders (Alzheimer disease) and in autoimmune digestive disorders (such as celiac disease). She has expertise in cardiovascular disease mechanism and prevention. Currently, she is conducting research, as a Post-doctoral Researcher at CREAResearch Centre for Agrobiology and Pedology in Florence (Italy), on the evaluation of the potential use of the edible insect species Tenebrio molitor and Galleria mellonella as human diet supplement of polyunsaturated fatty acids and ACE inhibitory bioactive peptides for cardiovascular disease prevention.

Email: annarita.cito@isza.it