Therapeutic Activity of Crude Ethanol Extracts of Rosmarinus Officinalis against Trypanosoma evansi in Experimental Models - Abstract
Natural products are still major potential sources of innovative therapeutic agents for various conditions, including infectious diseases as they represent an unmet source of chemical diversity. This study was conducted to determine the antitrypanosomal properties of Rosmarinus officinalis crude ethanol extract (CEERO) following intraperitoneal exposure to rabbits. New Zealand white rabbits were divided into six major groups; namely pre-infection (Group1), concurrent (Group 2), post-infection (Group 3), positive control (Group 4), negative control (Group 5) and reference group (Group 6). Animals in Group 1- were treated intraperitoneally with 100 mg kg-1 of extracts two days before T. evansi infection until 4 days after infection. Group 2- rabbit was infected and concurrently treated with 100 mg kg-1 of extract for 6 days; Group 3- rabbit was treated with 100 mg kg-1 of extract for 6 days after detection of parasitemia; Group 4 (positive control) was treated via intramuscular with 3.5 mg kg-1 Berenil® after establishment of parasitemia following T. evansi infection; Group 5-( negative control) was not treated but infected; Group 6- served as reference group and treated interperitoneally with Alsever’s solution and not infected. The course of T. evansi infection in rabbits was followed for 48 days post-infection (DPI). Rabbits were closely observed for clinical examination. Blood samples were taken to measure haematological and biochemical parameters. Rabbits in group 5 showed prominent clinical signs that were characteristic of T. evansi infection, which included anemia, poorer general condition, oedema of the face, ocular discharges, encrustation of the lips and mortality rates. The isolate also induced alterations with increased levels of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and decreased levels of blood indices; notably packed cell volume (PCV), haemoglobin (Hb) and red blood cells (RBC). Mortality rates were also significantly (p<0.05) recorded among the infected rabbits. These data suggest the crude ethanol extracts of R. officinalis possess relatively antitrypanosomal activity, and reinforce the use of this plant as alternative remedy for T. evansi infection in traditional medicine.