Antitrypanosomal Activity of Rosemary (Rosmarinus officinalis) Plant Extract on Trypanosoma evansi Experimental Infection

Abstract

The current study entitled “Antitrypanosomal activity of rosemary (Rosmarinus officinalis) plant extract on Trypanosoma evansi experimental infection” aimed to evaluate the in vitro and in vivo anti-trypanosomal activity of rosemary (R. officinalis) plant extracts on T. evansi infection compared with diminazene aceturate drug. The study design and plan of work were as follows:  Plant samples were collected from the aerial parts (stem, leaves, and flowers) of rosemary, and eight extracts were prepared using different solvents.  Petroleum ether, ethyl acetate, ethyl alcohol, and distilled water are organic and aqueous solvents used in ascending polarity.  The presence of phenols, saponins, tannins, flavonoids, and alkaloids were determined by phytochemical screening of the extracts.  The eight extracts using different solvents were prepared at concentrations of 4, 10, and 20 mg/ml (four from leaves and four from stem bark) of the rosemary plant collected from Matrouh Governorate, Egypt.  T. evansi parasites were isolated from a naturally infected camel, then identified as RoTat 1.2 strain and maintained in the laboratory by the continuous passage in white Swiss mice of mixed sexes (20–25 g) to give parasitaemia of approximately 105 parasites/ ml.  In vitro test for trypanocidal activity was carried out using a microtiter plate to evaluate the viability of T. evansi after treatments for different plant extracts to calculate LC50 –LC90 by using ELISA titer plates.  The toxicity test was assessed to the different solvents. However, groups of Albino rats were administrated extracts at the suitable in vitro concentration to notice toxicity and calculating LD50 – LD90.