Propriétés hypolipidémiante, antidiabétique et antioxydante d’une diète enrichie en farine de graines de Beilschmiedia obscura chez le rat

Abstract

The prevalence of metabolic syndrome (MetS) is increasing worldwide. This constellation of at least three risk factors (hyperglycemia, dyslipidemia, hypertension, inflammation, obesity) in the same individual leads to multifactorial management (polytherapy). A major research challenge is to find among our local foods a food endowed with biological properties likely to manage the individual components of MetS in order to avoid or reduce polytherapy, given Cameroon's advantage of having a highly diversified flora. The aim of this study was to evaluate the nutritional composition and antihyperlipidemic, hypoglycemic and antioxidant properties of Beilschmiedia obscura seeds in animal models of metabolic syndrome. To achieve this, the nutritional and phytochemical compositions of B. obscura seed flours were first determined. Next, the effects of an HF/HS diet enriched with B. obscura seed meal on hypertriglyceridemia and hypercholesterolemia, as well as organ histology, were determined in albino wistar rats. Finally, the effects of a normocaloric diet enriched with B. obscura seed flour on postprandial hyperglycemia, fasting hyperglycemia and oxidative stress in a rat model made diabetic by streptozotocin injection were determined. The results show that B. obscura seeds are rich in dietary fiber (9 to 22%) and minerals (calcium, potassium, iron and magnesium). They have a mucilage content of 49.33%, of the arabinoxylane type. The seeds contain phenolic compounds such as tannins and flavonoids. The HF/HS diet induced weight gain (6.3%) and disturbed lipid metabolism, with a proven atherogenic risk. It led to tissue damage in the liver, kidney and heart, with leukocyte infiltration and lipid vacuoles. When this diet was enriched with 5% or 10% B. obscura seed flour or 10% fenugreek, body weight was reduced in the treated groups (-1.77 and 1.31%), and an anti-hyperlipidemic effect was achieved by improving lipid profile parameters. The HF/HS-enriched diet protects liver, heart and kidney cell integrity. These activities are more pronounced when the food is enriched with 10% B. obscura, hence the choice of this dose for the latest study. B. obscura seed flour enriched to 10% in a normocaloric diet reduces postprandial hyperglycemia, stimulates insulin production and inhibits glycogenolysis. It also reduces diabetic induced oxidative stress by im MetS proving antioxidant status. These results re-emphasize the beneficial metabolic properties of dietary fiber, as well as phenolic compounds and micronutrients, offering new perspectives in the management of MetS.