In Vivo Anti-Malarial Activities of Clerodendrum Myricoides; Dodonea Angustifolia and Aloe Debrana against Plasmodium Berghei

Background:Malaria caused by the parasite Plasmodium falciparum is an acute disease which kills an estimated 863;000 people per year according to the WHO report of 2009. The fight against malaria is faced with the occurrence of widespread resistance of P. falciparum. The search for plant-derived antimalarial drugs has great importance in this regard. Thus this study evaluates the toxicity and antimalarial activity of extracts of Clerodendrum myricoides; Dodonia angustifolia and Aloe debrana. Method: Acute and sub acute toxicity studies of the extracts were carried out by giving up to 3000mg/kg to noninfected mice. Weight loss; change in general behavior and mortality were used as indicators of toxicity. Doses of 200; 400 et 600mg/kg/day of each extract of C.myricoides; D. dodonia and A.debrana were given orally to Plasmodium berghei infected mice following the four-day suppressive test procedure. Results: None of the extracts caused symptoms of toxicity at the given doses. Each extract showed variable level of parasitaemia suppression in dose related manner. Methanol extract of C. myricoides leaves exerted 82.50suppression at the dose of 600mg/kg. The methanol extract of the root of D. angustifolia showed the highest (84.52) suppression of parasitaemia at the dose of 600mg/kg. Furthermore; methanol extract of A. debrana induced 73.95suppression; whereas its water extract exerted 54.36suppression of parasitaemia. Conclusion: Crude extracts of C. myricoides; D. angustifolia and A.debrana caused strong activities against P. berghei indicating that they contain some chemical constituents that possibly lead to antimalarial drug development

Enhanced Antimalarial Effects of Chloroquine by Aqueous Vernonia Amygdalina Leaf Extract in Mice Infected with Chloroquine Resistant and Sensitive Plasmodium berghei strains

Background: The emergence and spread of Plasmodium falciparum with resistance to chloroquine (CQ); the safest and cheapest antimalarial drug coupled with the increasing cost of alternative drugs especially in developing countries have necessitated the need to optimize antimalarial actions of plant extracts and restore chloroquine efficacy. Objective: The present study determines the ability of Vernonia amygdalina leaf extract to enhance the prophylactic and therapeutic efficacy of chloroquine against Plasmo- dium berghei malaria in mice. Methods: Chloroquine sensitive (P. bergheiS) and resistant (P.bergheiR) ANKA clones of Plasmodium berghei maintained by serial passage in mice were used to develop respective experimental rodent malaria models based on intraperitoneal injection of 106 parasitize erythrocyte suspension in PBS (pH 7.2) and subsequent development of parasitaemia. These models were then used to investigate the prophylactic enhancement of chloroquine (CQ) at 5 mg/kg via combination with selected doses (31.25; 62.5; 125mg/kbw) of Vernonia amygdalina leaf extracts using a 4-day suppression test. Effect of these combinations on the therapeutic efficacy of CQ at 30mg/kg over 3 days were evaluated. Treatment outcomes including parasite clearance (PCT) and rescrudescent time (RT) were compared with CQchlorpheniramine com-bination. The acute toxicity of the extract-CQ combinations was also determined enzymatically. Results: Prophylatically; chloroquine (5mg/kg) in combination with vernonia extracts achieved a dose-dependent (57.2 - 72.7) suppression of parasitaemia due to CQ sensitive and resistant P berghei strains in the experimental animals. Therapeutically; chloroquine (30mg/kg for 3 days) combined with vernonia to dose-dependently shorten the parasite clearance times (2.6 - 4.4 vs. 4.8 days; P 0.05 for CQ-V62.5/125 combination); prolong the recrudescent times (8.9 - 18.9 vs. 7.2 days; P 0.05) and improve day 14 cure rate (66.7 - 100 vs. 58.3) in the treated P. bergheiS infected mice compared to CQ monotherapy. Whereas CQ monotherapy failed; resolution of parasitaemia due to the CQ resistant parasite with day 14 cure rates of 25 - 100were also observed with these combinations. In therapeutic terms; the potencies of CQ-V125 combination were comparable to those of CQ-chlorpheniramine (0.25mg/kg; 12hourly; 7 days) in the infected animals. Toxicity testing indicates that these combinations elicited mild to - moderate increases in the liver enzymes measured when adminis- tered orally to mice for 7 days. Conclusion: This study indicates that Vernonia amygdalina leaf extract dose - dependently restore the efficacy of CQ against CQ resistance P. berghei malaria in mice

In vivo antiplasmodial activity of ZS-2A: a fraction from chloroform extract of Zizyphus spina-christi root bark against Plasmodium berghei berghei in mice

Zizyphus spina-christi is used in ethnomedical practice for the treatment of fever. Bio-assay guided investigation of the plant's root bark was initiated and ZS-2A; a fraction from the chloroform extract of the material; eluted with hexane-ethylacetate (50:50) using flash column chromatography; was evaluated for in vivo antiplasmodial activity against Plasmodium berghei in mice. Four-day suppressive; curative effect against established infection and prophylactic models of antiplasmodial studies were used. The fraction (25; 50 and 100 mg/kg; p.o.) showed a potent activity against the parasite in the suppressive and curative tests. The result suggests that ZS-2A may be a promising agent for malaria treatment

In Vivo Screening of Antimalarial Activity of Acacia Mellifera (Benth) (Leguminosae) on Plasmodium Berghei in Mice

The activities of total extracts and lupane triterpenes; isolated from the stem bark of Acacia mellifera;were evaluated against Plasmodium berghei strain ANKA in a female Swiss mouse model. Five isolated compounds and the crude extracts were evaluated for antimalarial activity and Quinine hydrochloride was used as a positive control. Only betulin and the methanolic extract produced considerable antimalarial activity in mice infected with P. berghei parasites. This study demonstrated the presence of bioactive agents in Acacia mellifera

Comparative efficacy of dihydroartemisinin, chloroquine and combination of dihydroartemisinin and chloroquine or mefloquine in mice infected with Plasmodium berghei

Comparative efficacy of dihydroartemisinin alone, chloroquine alone, combination of dihydroartemisinin plus mefloquine and combination of dihydroartemisinin plus chloroquine was evaluated in mice. Parasite clearance time was very short in mice treated with dihydroartemisinin alone mean ± SD PCT was (1.64- ± 0.50 days). This was followed by combination of dihydroartemisinin with mefloquine (2.73 ± 0.47), Then combination of dihydroartemisinin with chloroquine (2.84 ± 0.50). The mice that were treated with chloroquine alone had PCT of 4.0 ± 2.32. There was significant difference between the dihydroartemisinin group and the chloroquine group (P<0.0002). There was also significant difference between the dihydroartemisinin group and combination of dihydroartemisinin plus mefloquine and also combination of dihydroartemisinin plus chloroquine (P<0.005). The combination therapy was more effective than when chloroquine was administered alone