Exogenous Calcium Fibrin Sealant Loaded with Ageratum conyzoides Linn. Bactericidal Plant Extract: Equilibrium between a Biochemical Activator and Phytochemicals Inhibitors of Thrombin

Objective: It is of primary importance to develop wound healing sealant that prevent bacteria contamination and growth. We propose to formulate poor platelets plasma material supplemented with a bactericidal plant extract, Ageratum conyzoides Linn. (Asteraceae). Aqueous extract of this plant is used as a bactericide.Methodology: Platelet-poor plasma (PPP) containing less than 10,000 platelets per μL were used for all experimentations. Physiological serum (NaCl 0.9%) had served to prepare calcium chloride (CaCl ) solutions at 2 2M, 4M, 6M, 8M and 10M. Clauss fibrinogen assays were done to determine fibrinogen concentrations in each plasma pocket. Clotting times were measured following the addition of the appropriate calcium chloride concentration to the plasma. Plant extract at a concentration of 250 mg/mL in physiological serum was also added to the plasma and followed by the clotting times measured.Results: Clauss fibrinogen assays reflected a global satisfactory fibrinogen concentration. Overall profile of the evolution of clotting time vs calcium concentrations adopts a curve form and the shortest clotting times are those obtained with 4M calcium concentration. However, the presence of extract deeply disturbed clotting process, as clotting times were extremely elongated.Conclusion: Our objective was difficult to achieve because of the thrombin inhibitory side effects of the extract which were added to antithrombin III inhibitory effects in presence of excess calcium. Keywords: Wound healing, fibrin sealant, Ageratum conyzoides Linn., biomaterial, inhibitors. French title: Formation d'un Biomateriau de Fibrine par Apport Exogene de Calcium et Supplementation par un Extrait Bactericide de la planteAgeratum conyzoides Linn. : Equilibre entre un Activateur Biochimique et des Inhibiteurs Phytochimiques de la Thrombine Objectif: Il est d'une importance capitale de developper des pansements cicatrisants qui empechent la contamination et la proliferation bacterienne. Nous nous proposons de formuler un biomateriau cicatrisant de fibrine a base de plasma pauvres en plaquettes et supplemente d'un extrait aqueux de Ageratum conyzoides Linn.Methodes: Du plasma pauvre en plaquettes contenant moins de 10 000 plaquettes par μL a ete utilise pour toutes les experimentations. Le serum physiologique (NaCl 0,9%) a servi a la preparation des differentes solutions de calcium aux concentrations de 2M, 4M, 6M, 8M et 10M. Le dosage du fibrinogene par les tests de Clauss a ete effectue pour chaque poche de plasma. Les temps de gel ont ete determines suite a l'addition du calcium a la concentration adequate. L'extrait de plante a la concentration de 250 mg/mL dans du serum physiologique a egalement ete additionne au plasma suivi de la determination des temps de gel.Resultats: Les tests de Clauss menent a des taux de fibrinogene moyens satisfaisants. Le profil global de l'evolution des temp de gel en fonction de la concentration en calcium adopte une forme hyperbolique et le temps le plus court est obtenu a 4M de calcium. La presence de l'extrait perturbe profondement la formation du gel puisque les temps de gel de ces derniers sont extremement rallonges.Conclusion: Notre objectif a ete difficile a atteindre a cause des effets secondaires inhibiteurs de l'extrait qui se sont ajoutes a ceux de  l'antithrombin III en presence d'un exces de calcium. Mots cle: Cicatrisation ; Pansement fibrine ; Ageratum conyzoides Linn. ; Activateur; Inhibiteurs.