Anti-trypanosomal effect of Malva sylvestris (Malvaceae) extract on a Trypanosoma brucei brucei-infected mouse model of sleeping sickness

Purpose: To evaluate the antitrypanosomal activity of Malva sylvestris (MS) extract in a Trypanosoma brucei brucei-infected mouse model of sleeping sickness. Methods: Sleeping sickness was induced by the intraperitoneal injection of Trypanosoma brucei brucei-infected blood in mice. Confirmation of parasitaemia was performed by estimating the parasite count in the plasma on the 12th day after inoculation. All the mice were divided into five groups: control group that received neither infection nor treatment; negative control that was infected with the parasite but did not receive treatment; MS-treated group that receive MS extract (250 and 500 mg/kg, ip) and standard (STD) group that received levamisole (7.5 mg/kg, ip) for 7 days after the development of parasitaemia. A further parasite count was performed in the blood and cerebrospinal fluid (CSF) after the treatment period. Humoral antibody response, delayed hypersensitivity reaction, and mobilization of leucocytes were determined after the treatment period in SRBC-sensitized mice. Results: The results indicate that treatment with MS significantly decreased body weight and parasite count in the blood and CSF of mice with Trypanosoma brucei brucei-induced sleeping sickness compared with that in the negative control group. There was a significant increase in paw swelling and decrease in secondary antibody in the MS-treated group compared with that in the negative control group. However, treatment with MS extract also enhanced the mobilization of the total leucocyte count compared with that in the negative control group. Conclusion: The results demonstrate the anti-trypanosomal activity of Malva sylvestris extract via immunomodutation in a Trypanosoma brucei brucei-infected mouse model of sleeping.