Antihyperglycemic Effect of Lavandula pedunculata: In Vivo, In Vitro and Ex Vivo Approaches.

Salima Boutahiri,Ferdinand Kouoh Elombo,Mohamed Bouhrim,Bernard Gressier,Ali S Alqahtani,Hamza Mechchate,Chayma Abidi,Touriya Zair,Sevser Sahpaz,Jehan-François Desjeux,Bruno Eto,Omar M Noman,Mohamed Bnouham

doi:10.3390/pharmaceutics13122019

Abstract

Lavandula pedunculata (Mill.) Cav. (LP) is one of lavender species traditionally used in Morocco to prevent or cure diabetes, alone or in the form of polyherbal preparations (PHP). Therefore, the primary objective of this study was to test the antihyperglycemic effect of the aqueous extract of LP, alone and in combination with Punica granatum L. (PG) and Trigonella foenum-graecum L. (FGK). The secondary objective was to explore some mechanisms of action on the digestive functions. The antihyperglycemic effect of the aqueous extract of LP, alone and in combination with PG and FGK, was studied in vivo using an oral glucose tolerance test (OGTT). In addition, LP extract was tested on the activities of some digestive enzymes (pancreatic α-amylase and intestinal α-glucosidase) in vitro and on the intestinal absorption of glucose ex vivo using a short-circuit current (Isc) technique. Acute and chronic oral administration of LP aqueous extract reduced the peak of the glucose concentration (30 min, p < 0.01) and the area under the curve (AUC, p < 0.01). The effect of LP + PG was at the same amplitude to that of the positive control Metformin (MET). LP aqueous extract inhibited the pancreatic α-amylase with an IC50 almost identical to acarbose (0.44 ± 0.05 mg/mL and 0.36 ± 0.02 mg/mL, respectively), as well as the intestinal α-glucosidase, (IC50 = 131 ± 20 µg/mL) and the intestinal glucose absorption (IC50 = 81.28 ± 4.01 µg/mL) in concentration-dependent manners. LP aqueous extract exhibited potent actions on hyperglycemia, with an inhibition on digestive enzymes and glucose absorption. In addition, the combination with PG and FGK enhanced oral glucose tolerance in rats. These findings back up the traditional use of LP in type 2 diabetes treatment and the effectiveness of the alternative and combinative poly-phytotherapy (ACPP).

Highlights

Diabetes is a group of metabolic diseases of which blood hyperglycaemia is the main characteristic
The previously mentioned information was the basis on which we relied to carry out this study that aims to investigate the antihyperglycemic activity of Lavandula pedunculata (Mill.) Cav. (LP), one of lavender species that has never been studied for its antidiabetic activity
Coumarin, protocatechuic acid, herniarin, caffeic acid, apigenin, luteolin, myricetin, and chlorogenic acid are present in this extract but with a lower abundance, as well as gallic acid and cinnamic acid that are present as traces

Summary

Introduction

Diabetes is a group of metabolic diseases of which blood hyperglycaemia is the main characteristic. This hyperglycaemia results from a lack of insulin secretion and/or a failure in insulin action. Type 1 diabetes is mostly induced by autoimmune diseases causing the destruction of the pancreatic β-cells responsible of the insulin production. In the more common type 2 diabetes, the main mechanism is insulin resistance. The latter is related to abnormalities in the insulin action on the target tissues (decrease in tissue responses and/or in insulin secretion) [1,2]. The long-term exposure to hyperglycaemia causes serious damages in the eyes (retinopathy), kidneys (nephropathy), and nerves (peripheral and autonomic neuropathy), as well as in the heart and blood vessels (cardiovascular and cerebrovascular diseases) [1]

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