Beneficial Effects of Algerian Green Alga Ulva lactuca and Its Hydroethanolic Extract on Insulin Resistance and Cholesterol Reverse Transport in High-Fat/Streptozotocin Diabetic Rats

Abstract

The aim of this study was to evaluate the impact of the green algae <i>Ulva lactuca</i> and its hydroethanolic extract on insulin resistance and cholesterol reverse transport in type 2 diabetic (T2D) rats. Rats had T2D induced by a high-fat diet (HFD) for 5 weeks followed by intraperitoneal injection of streptozotocin. Diabetic rats were divided into three groups and were fed a HFD in the presence or absence of 1% alga (HFD-Alg) or 1% of its hydroethanolic extract (HFD-Ext), for 4 weeks. The control group consumed 20% casein combined with 5% lipids. Hyperglycemia, insulin resistance, hypercholesterolemia, and hypertriglyceridemia were noted in HFD rats <i>vs</i> control rats. Whole alga and its extract decreased these parameters <i>vs</i> the HFD. Moreover, fecal total cholesterol and triacylglycerols levels were lowered in HFD group <i>vs</i> C group, but were increased with HFD-Alg <i>vs</i> HFD. Compared with the Control, the HFD group had decreased lecithin:cholesterol acyltransferase (LCAT) activity, apolipoprotein A-I (ApoA-I), high-density lipoprotein (HDL₃)-phospholipids (PL), and HDL₂-cholesteryl ester (CE) levels, but increased HDL₃-unesterified cholesterol (UC) levels. Furthermore, compared with the HFD group, the HFD-Alg and HFD-Ext groups had increased LCAT activity, ApoA-I, HDL₃-PL, and HDL₂-CE levels and decreased HDL₃-UC levels. In addition, in the HFD-Ext group, LCAT activity and ApoA-1 levels were decreased <i>vs</i> the HFD-Alg whereas HDL₃-UC levels were increased. In conclusion, these results indicate that <i>U. lactuca</i> and its hydroethanolic extract have curative effect on T2D. Therefore, this alga could be considered a functional food supplement for the treatment and prevention of diabetes.