J Appl Biomed 5:105-113, 2007 | DOI: 10.32725/jab.2007.015

Urtica dioica extract reduces platelet hyperaggregability in type 2 diabetes mellitus by inhibition of oxidant production, Ca²⁺ mobilization and protein tyrosine phosphorylation

Mohammed El Haouari¹, Isaac Jardin², Hasane Mekhfi¹, Juan A. Rosado^2,*, Ginés M. Salido²

¹ Laboratoire de Physiologie et Ethnopharmacologie, Département de Biologie, Université Mohamed 1er, Faculté des Sciences, Bd. Mohamed VI, BP 717, Oujda 60000, Morocco

² Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10071 Cáceres, Spain

Platelet hyperaggregability is involved in the pathogenesis of type 2 diabetes mellitus. Thrombin-evoked platelet aggregation includes the activation of several intracellular pathways, including endogenous generation of reactive oxygen species (ROS), Ca²⁺ mobilization and protein tyrosine phosphorylation. Here we show that crude aqueous extract from Urtica dioica reduces thrombin-evoked aggregation in platelets from healthy donors and diabetics, in a concentration-dependent manner. U. dioica extract showed a potent antioxidant activity and prevented thrombin-evoked ROS generation in platelets from healthy and diabetic donors. Treatment with U. dioica extract reduced Ca²⁺ entry induced by thrombin or selective depletion of the two Ca²⁺ stores in platelets (without altering Ca²⁺ release), reduced protein tyrosine phosphorylation and reversed the abnormal Ca²⁺ mobilization and tyrosine phosphorylation in platelets from diabetics. We conclude that extract from U. dioica shows antiaggregant actions and might be used for the treatment and/or prevention of cardiovascular complications associated with type 2 diabetes mellitus.

Keywords: platelets; type 2 diabetes mellitus; Urtica dioica; calcium mobilization; antioxidant; tyrosine phosphorylation

Received: March 21, 2007; Revised: April 23, 2007; Published: July 31, 2007  Show citation