Antimalarial actions of Lawsonia inermis, Tithonia diversifolia and Chromolaena odorata in combination.

ETHNOPHARMACOLOGICAL RELEVANCE: Chromolaena odorata, Tithonia diversifolia and Lawsonia inermis are medicinal plants used in treating malaria in traditional medicine system. Previous studies however showed that their dichloromethane, methanol (1:1) extracts were more active against Plasmodium parasite than the aqueous extracts. AIM OF THE STUDY: To determine the in vitro and in vivo antiplasmodial activity of dichloromethane, methanol (1:1) extracts of Chromolaena odorata, Tithonia diversifolia and Lawsonia inermis in combination and evaluate their safety using acute limit toxicity test. MATERIALS AND METHODS: Dichloromethane, methanol (1:1) extracts of Chromolaena odorata, Tithonia diversifolia and Lawsonia inermis leaves were combined at ratios 1:1, 1:3, 3:1, 1:5 and 5:1 using in vitro semi-automated microdilution technique against P. falciparum Chloroquine sensitive (D6) and Chloroquine resistant (W2) strains, with chloroquine and artemisinin as controls. The in vivo antiplasmodial activity of the crude extracts was carried out singly, and in combination at the different combination ratios on Plasmodium berghei Anka infected Swiss albino mice using Peters' 4-day suppressive test. Acute toxicity test was done in mice at 5000mg/kg. RESULTS: The in vitro combination of L. inermis and T. diversifolia (1:1) extracts against P. falciparum showed the highest synergy with IC50 of 0.43±0.02µg/mL and 2.55±0.19µg/mL against D6 and W2 respectively; while the combination of C. odorata with T. diversifolia and L. inermis were antagonistic. A synergy with chemosuppression of 83.6% against P. berghei infected mice was observed in L. inermis and T. diversifolia (1:1) treated animals. In contrast to the in vitro result, combination of C. odorata with T. diversifolia and L. inermis showed some degrees of synergy in vivo. Extracts were not toxic at the concentration tested. CONCLUSION: These findings rationalized the use of these plants in combination as antimalarials in traditional medicine. However, the combination of Chromolaena odorata with other medicinal plants should be used with caution because of its possible antagonistic effect.

Synergistic effect of aqueous extract of Telfaria occidentalis on the biological activities of artesunate in Plasmodium berghei infected mice.

BACKGROUND: Resistance to most antimalarial drugs has encouraged the use of herbal preparations along with prescribed orthodox drugs. OBJECTIVE: this study investigated effect of co-administration of aqueous extract of T. occidentalis leaves, commonly used as antimalarial and haematinic agent in Nigeria, and artesunate using P. berghei animal model. METHODS: In vivo curative antiplasmodial effect of T. occidentalis (200mg/kg) alone and in combination with artesunate (2mg/kg) were evaluated using albino mice infected with 10(6) parasitized erythrocytes of P. berghei intraperitoneally. The haematological parameters: haemoglobin level, red blood cells and white blood cells and packed cell volume were monitored using standard methods. RESULTS: Aqueous extract of T. occidentalis, artesunate and the combination gave 72.17±4.07%, 70.43± 4.27% and 85.43±3.65% reduction in parasitaemia after 48hours respectively. A significant enhancement of the PCV was obtained with the co-administration of artesunate and aqueous extract (p < 0.01). Similar trends were also observed with heamatological parameters at 72 hours of administration. CONCLUSION: This study revealed a synergistic effect of the co-administration on parasite clearance rate of P. berghei infection in mice, with a significant enhancement of haematological parameters within 48 hours of administration. This indicates a rapid rate of recovery from plasmodial infections with the co-administration.