Antiplasmodial activities of hydro-ethanol extracts of Ancylobotrys amoena Hua leaf and twig on Swiss mice

Aim: The study evaluated the antiplasmodial activities potential of the leaf, twig and combination of leaf and twig hydroethanol extracts of Ancylobotrys amoena in Swiss mice.
Methodology: The plant samples were collected, separated, dried, powdered and extracted in 70 % ethanol.  The extracts were concentrated in vacuo and freeze-dried. The LD₅₀ of the extracts was assessed using the Lorke’s method. Each extract was subjected to Peters four-day chemosuppressive and the residual infection test respectively to evaluate the suppressive and the prophylactic activities. In the chemosuppressive test, adult Swiss mice (18-20 g) infected with chloroquine-sensitive Plasmodium berghei NK65 parasite, were divided into five groups (n=5 per group), for three doses (50, 100, and 200 mg/kg) of the extracts, 0.2 ml of normal saline (negative control) and 10 mg/kg chloroquine (positive control) for 4 days and the average percentage parasitaemia taken on the fifth day. In the residual infection test, the same doses above except 1.2 mg/kg pyrimethamine used in place of chloroquine, were administered to another five groups of 5 mice for 3 days prior to inoculation with the parasites. The average percentage parasitaemia was assessed after 72 hours. Statistical analysis was done using Graph Pad Prism 5.0 (Graph Pad Software, San Diego, CA).
Results: The leaf, twig and combination of leaf and twig extracts of Ancylobotrys amoena at 50, 100 and 200 mg/kg showed significant (P < 0.05) antiplasmodial activities which was dose dependent compared with standard drug (Chloroqiune). The results also demonstrated that the percentage chemo-suppression at doses of 50, 100 and 200 mg/kg twig extract (80.55%, 89.67% and 91.03% respectively) were better than the leaf extract (60.33 %, 63.83 % and 79.18 % respectively), and combination of leaf and twig extract (69.6%, 70.36% and 74.62% respectively) when compared to chloroquine (77.05 %) in the suppressive test. For the prophylactic test, the percentage chemo-suppression at doses of 50, 100 and 200 mg/kg; the leaf extract (68.75 %, 77.72 % and 77.72 % respectively), twig extract (64.95 %, 67.66 % and 75.82 % respectively) and combined extract (39.94 %, 61.96 % and 80.16 %), revealed that only at 200 mg/kg were they comparable to pyrimethamine (73.37 %).
Conclusion: The study concluded that Ancylobotrys amoena extracts had potential antimalarial activities and is safe for oral administration.