Studies to determine the effect of some Nigerian Medicinal plants on some haematological parameters of rats infected with T. b. brucei was carried out. The plants investigated and the dose levels per kilogram body weights used are fresh Momordica balsamina pulp (150mg); fresh Aloe vera pulp (1ml); aqueous extracts of Securidaca longipenduculata root and root bark (100mg) and Annona senegalensis leaves (200mg). All the animals were treated orally for seven consecutive days after establishment of parasitaemia. Parasitaemia and some haematological parameters were determined before and after treatment as well as pathochemical composition of each plant. The result showed a significant (P < 0.05) improvement in Packed Cell Volume (PCV) values of rats treated with M. balsamina; A. vera and S. longipenduculata (root bark) when compared with the positive control. Total leukocyte and lymphocyte counts did not change significantly (P > 0.05) in groups treated with M. balsamina and S. longipenduculata (root bark) but increased in other treated and positive control groups. Similarly, no significant changes (P > 0.05) in neutrophils was observed in M. balsamina and S. longipenduculata (root) treated animals but an increase was seen in S. longipenduculata (root bark), A. vera and infected on treated groups. Treatment with M. balsamina, A. vera and S. longipenduculata (root and root bark) prolonged the lives of animals by 4, 1, 3 and 4 days respectively when compared with the positive control. Differences in the composition of various phytochemical of these plants could be responsible for the varied antitrypanosomal activities. Consequently, these plants have great potential which need to be exploited fully in the management of African trypanosomiasis.

The search for new trypanocides has not been keenly pursued due to high cost of design and development with no promise of financial returns. Momordica balsamina fruit pulp extract was screened for antitrypanosomal activity in experimental T. brucei brucei infection in rabbits. The extract was administered prior to parasite inoculation, 24 hours post parasite inoculation and on establishment of infection. The treatment was by oral administration of the extract at 500mg/kg body weight for 14 consecutive days. Parasitaemia was monitored daily while body weight and packed cell volume (PCV) were determined before commencement of studies and subsequently at weekly intervals for 28 days. The result showed a significant (P<0.05) delay in the establishment of T. b. brucei infection in rabbits treated at 24 hours post parasite inoculation. Packed cell volume also increased significantly (P<0.05) in all treated groups when compared to the untreated group (control). This was less in the group treated on establishment of infection. Administration of the extract to the curative group resulted in body weight gain. The other groups suffered weight loss. The infected but not treated group died at day 39 post infection while those treated before parasite inoculation, 24hours post parasite inoculation, and on the establishment of infection survived for 45 days, 53 days, and 61 days respectively. We conclude that M. balsamina pulp extract reduces anaemia in experimentally infected rabbits.

The efficacy of two standard veterinary trypanocides, diminazene aceturate (Berenil-therapeutic) and isometamidium chloride (Samorin-prophylactic) was compared in albino rats experimentally infected with current field isolate of Trypanosoma brucei brucei (Federe strain). The study consisted of forty albino rats, divided into 8 groups of five animals each. The negative control was uninfected and untreated (Group 1), whereas the positive control was infected and untreated (Group 2). Other groups were treated intramuscularly with either 0.5 mg/kg or 3.5 mg/kg body weight of Samorin or Berenil respectively adopting different protocols. Groups 3 and 4 were treated the same day of infection with Berenil and Samorin respectively (treatment was before infection). Groups 5 and 6 were treated at patency (4 days post infection) with Berenil and Samorin respectively. Groups 7 and 8 were infected before treatment on the same day with Berenil and Samorin respectively, and re-challenged with the T.brucei brucei after four days. The results obtained 60 days post treatment showed that the difference between the efficacies of the two drugs was significant (P< 0.05). Berenil cleared the parasites more from the blood of the albino rats than Samorin. From the recorded values of the parameters (body weight, temperature, packed cell volume and parasitaemic profile), it was concluded that Berenil is a more efficacious trypanocide than Samorin, and is recommended as the drug of choice in the treatment of animal trypanosomiasis.

No abstract

Trypanosomiasis has been recognized as a scourge in sub-Saharan Africa for centuries and chemotherapy of the disease still remains unsatisfactory. This study is to explore an alternative source of antitrypanosomal agents from the stem bark of four Acacia species; Acacia nilotica, Acacia sieberiana, Acacia geradii and Acacia hockii. Dried stem bark of each plant was pulverized and extracted with 98% methanol by maceration. Phytochemical screening was carried out followed by in vitro testing of extracts on the motility of Trypanosoma congolense maintained in Ringer solution. Motility assessment of trypanosome was carried out after exposure with varied concentrations of the extracts for 2 hours. Thereafter, infectivity test was carried out using albino mice. Seventy-two mice, divided into twenty-four (24) groups of three animals were each inoculated with 100µl of the mixture containing the varying extract concentrations intraperitoneally. Berenil was used as standard drug control. Establishment of infection and subsequent Parasitaemiawere monitored in the animals for 60 days. The Phytochemical assay revealed the presence of anthraquinones, tannins, glycosides, cardiac glycosides and terpenes in all the extracts. Saponin was only present in Acacia nilotica and Acacia geradii. Incubation of parasites with each of the four acacia species recorded cessation in parasite motility which was concentration dependent. The highest concentration 20 mg/ml showed the highest effect within fifteen (15) minutes of incubation which was similar to the Berenil incubated control. However, lower doses (0.005 and 0.00005) mg/ml did not show difference from the non extract incubated negative control. Incubation of T. congolense with Acacia nilotica, Acacia sieberiana, Acacia geradii and Acacia hockii at 20, 10 and 1 mg/ml inhibited the ability of the parasites to establish infection in the albino mice as compared the standard control drug. The results indicate that the methanolic stem extracts of the four acacia species possess antitrypanosomal activity with potentials for the treatment of trypanosomiasis.