Anxiolytic and Hypoglycemic Effect of Pectins from Galician Lemon Citrus Fruit on Adult Zebrafish (Danio rerio): An In Vivo and In Sílico Approach

Diabetes mellitus is a medical condition characterized by elevated blood glucose levels, known as hyperglycemia, which can damage other organs of the human body through metabolic alterations. Pectin, a naturally occurring polysaccharide, is present in the cell walls of plants and is composed of a polymer chain of galacturonic acid with additional sugar branches. Pectins, which are more often found in citrus fruits, have been gaining prominence in the pharmacological sector and are widely applied in the food industry. Thus, the main objectives of this study were to obtain amidated pectin from Galician lemon, evaluate its hypoglycemic and anxiolytic potential, and perform a molecular docking study. Pectin from Galician lemon was extracted with ammonium oxalate, and a glucose soak test was performed on zebrafish to determine the potential of pectin from Galician lemon in the treatment of hyperglycemia. A computational study was performed using the AutoDock Vina software and employing the molecular docking technique to prove the efficiency of pectin from Galician lemon as a hypoglycemic agent in comparison with alpha-acarbose (a reference inhibitor) and metformin (a reference drug). The zebrafish assay showed that pectin had a similar effect to metformin (positive control), reducing the animals' baseline blood glucose levels. The results of the molecular docking study proved that pectin had a higher affinity than alpha-acarbose and metformin. In addition, pectin demonstrated anxiolytic effects via GABAergic neurotransmission, like the positive control, diazepam.