Bioassay Guided Fractionation and Anti-Trypanosomal Effect of Fractions and Crude Aqueous and Methanolic Extracts of Terminalia Avicennioides (Guill. & Perr.) Parts

Abstract

In vitro and in vivo anti-trypanosomal effects as well as reagent-based chemical screening of the aqueous and methanolic extracts of the roots, leaves and stem bark of Terminalia avicennioides were undertaken. In vitro, cessation or drop in the parasite motility, compared to the control, was taken as a measure of the anti-trypanasomal efficacy of the extracts following incubation of the parasite, Trypanosoma brucei brucei, with different extract concentrations (0, 5, 10 and 20 mg/ml) in 96-well micro titre plate. In vivo, groups of infected white albino rats were treated with 50, 100 and 200 mg/kg and the effect of treatment on parasitemia, packed cell volume (PCV) and lifespan were monitored. The root and stem bark extracts completely immobilized trypanosomes within 30 minutes of incubation at 20 mg/ml concentration, with the aqueous root extract displaying the highest activity, and the methanol extract of the leaf, the least. This effect compared favorably with that of the standard drug, diminazine aceturate. In vivo, significant (P<0.05) suppression of parasitemia, alleviation of anemia and prolongation of lifespan occurred in a dose dependent fashion with both the crude extracts and the bioassay-guided fractions. Reagent-based chemical analyses of the crude extracts showed presence of anthraquinones, tannins, saponins, flavonoids and cardiac glycosides, but the ethylacetate: methanol fraction which was most active revealed strong presence of saponins. These results suggest that the use of Terminalia avicennioides for management of trypanosomiasis in traditional medicine has scientific basis, and thus warrants further detailed evaluation.

Evaluation of Acute Toxicity and In vitro Antitrypanosomal Activity of the Methanolic Leaves Extract of Ficus exasperata

“…Although not comparable to the effect of the standard drug diminazene aceturate and the plant extract at different concentrations used in this study showed considerable dose dependent antitrypanosomal activity. This finding is in line with earlier reports by [17], [18], [19] and [20] which clearly indicated that plants of different families could possess potent trypanocidal activity.…”

Antitrypanosomal Evaluation of Methanol Fractions of Stem Bark Extract of Acacia nilotica (Linn) against Trypanosoma congolense Infection in Albino Mice

“…However, restlessness and loss of appetite were observed immediately after administration of the extracts, which lasted for 2 hours. The results of this study agree with an earlier report, 21 which recorded no deaths or adverse effects after administering daily oral dose (3000 mg/kg) of the crude methanol extract of A. nilotica to rats for 14 days. However, another study, 22 reported 50% mortality after intraperitoneal administration of 2000 mg/kg of the extract to the experimental animals for 14 days.…”

Anti–trypanosomal effect of Peristrophe bicalyculata extract on Trypanosoma brucei brucei–infected rats

“…The significant decrease in PCV of T. brucei brucei infected rats is in consonance with earlier reports [4,25] in trypanosome-infected animals. This has been attributed to the release of hemolytic factors into the animals blood by dead trypanosomes causing destruction of erythrocytes and hence, reduction in PCV [22,26] . It has also been reported that anaemia may be caused by erythrocyte injury caused by lashing action of trypanosome flagella, undulating pyrexia, platelet aggregation, toxins and metabolites from trypanosomes, lipid peroxidation and malnutrition [27] .…”

“…A cessation or drop in motility of the parasites in treated blood compared to that of parasite-loaded control blood without extract was taken as a measure of anti-trypanosomal activity, since motility constitutes a relatively reliable indicator of the viability of most zooflagellate parasites [21] . The shorter the time of cessation of motility of the parasite, the more active the extract was considered to be [22] .…”