Study of the Acute Toxicity and Hemostatic Activity of Aqueous and Hydroethanolic Extracts of Pavetta Crassipes. K. schum. (Rubiaceae) Leaves

As part of efforts to promote traditional medicine, a scientific study was conducted on the aqueous and hydroethanolic extracts of Pavetta crassipes leaves, a plant used in sub-Saharan traditional medicine. The study focused on evaluating the hemostatic potential and acute toxicity of both types of extracts. Prior to this, the phytochemical profiles of the extracts were determined using standard secondary metabolite characterization techniques described by Trevan. The results revealed that the hydroethanolic extract contains polyphenols, flavonoids, sterols, polyterpenes, saponins, and quinones. The aqueous extract contains these same compounds plus tannins. Acute toxicity testing was performed in accordance with OECD Guideline 423, and the results indicated that both extracts are non-toxic. Hemostatic activity was evaluated ex vivo (using rabbit blood) and in vivo (in rats) at concentrations of 10⁻⁴, 10⁻³, 10⁻², and 10⁻¹ mg/mL, using phytomenadione as the reference coagulant. Activated partial thromboplastin time (aPTT), prothrombin time (PT), and bleeding time (BT) were measured for each substance. The findings showed that the aqueous extract and phytomenadione exhibited strong hemostatic activity both ex vivo in rabbits and in vivo in rats that was significantly (p < 0.05) greater than that of the hydroethanolic extract. Similar results were observed for prothrombin time (PT) and bleeding time (BT). Notably, this hemostatic activity was found to be dose-dependent. Keywords: Aqueous extract, hydroethanolic extract, hemostatic, acute toxicity, Pavetta crassipes.