Evaluation of the Antimalarial Activity of Ethanol Extracts of the Leaves of Three Plant Species Collected from Yayu Coffee Forest Biosphere Reserve, Southwest Ethiopia

Evaluation of the antimalarial and CD4+ T-cell modulatory effects of leaf methanol extract of Phyllanthus muellerianus (Kuntze) Exell (Phyllanthaceae) in Plasmodium berghei-infected mice

ETHNOPHARMACOLOGICAL RELEVANCE

Phyllanthus muellerianus (Kunze) Exell, a member of the Phyllanthaceae family, is a medicinal plant widely distributed in Africa. Decoctions from the leaves are used in Nigeria to treat fevers, convulsions, some neurological disorders and malaria.

AIM OF THE STUDY

This study is to evaluate the anti-malarial properties of methanol extract of Phyllanthus muellerianus (MEPM) leaves and its ethyl acetate fraction using a murine malaria model infected with Plasmodium berghei. Additionally, we seek to investigate the potential modulatory effects of this extract and fraction on CD4+ T-cell populations in the context of malaria infection.

MATERIALS AND METHODS

The anti-malarial effects of the leaf methanol extract of Phyllanthus muellerianus (MEPM) were screened using three established in vivo models of anti-plasmodial screening namely the curative, suppressive and prophylactic models. The methanol extract (MEPM) was afterwards fractionated into hexane (HFPM), ethyl acetate (EAFPM), and methanol (MFPM) fractions. In the pilot anti-malarial screening of the fractions, EAFPM exhibited the best antiparasitic activity. Subsequently, EAFPM was screened for anti-malarial activity using the three models above. The effects of the MEPM and EAFPM on haematological indices (Hb and PCV) of the inoculated animals were further screened and the mean survival time (MST) of the animals was monitored. CD4+ T cells of various groups were counted before and after treatment using a flow cytometer. The EAFPM was further subjected to HPLC analysis for identification of its major compounds.

RESULTS

The EAFPM (100 and 200 mg/kg) elicited 88% and 93% cure respectively in the curative model, while artesunate (5 mg/kg,- the positive control) gave 87% protection. The MEPM and EAFPM also gave significant suppression of parasitemia in the suppressive model. The treated groups survived beyond 28 days as against 11 days by the control group (infected but not treated). The treated groups also prevented anaemia seen in the negative control. The EAFPM group significantly modulated the CD4+ T cell. Compounds identified were Gallocatechin, Quercetin -3-O-gallate, Ellagic acid, and Methylellagic acid rhamnoside).

CONCLUSION

The study established that the leaf of Phyllanthus muellerianus possesses antimalarial activity, thus lending support to its use in the folkloric treatment of malaria.

In vivo antiplasmodial activity of hydromethanolic leaf extract and solvent fractions of Maytenus gracilipes (Celastraceae) against Plasmodium berghei in mice

BACKGROUND

The incidence of resistance among currently available antimalarial drugs, as well as the high economic cost of malaria, has prompted researchers to look for novel antimalarial molecules. As a result, the current study was proposed to evaluate the antiplasmodial activity (in vivo) of Maytenus gracilipes based on the plant's traditional claims.

METHODS

A cold maceration procedure using 80% methanol as a solvent was employed to obtain a crude extract from M. gracilipes leaves. Chloroform, n-butanol, and pure water were used to fractionate the hydromethanolic extract. Standard procedures were followed for an acute oral toxicity test. The antimalarial effects of the plant at 200, 400, and 600 mg/kg doses were investigated using three rodent malaria models (4-day suppressive, rane's, and repository tests). Thirty mice were utilized in each experiment (3 treatment and 2 control groups, each with six mice). Parasitemia, survival time, body weight, temperature, and packed cell volume were all used to assess the extracts' antiplasmodial activity. To compare results between groups, a one-way ANOVA with Post Hoc Tukey's HSD was used.

RESULTS

In a 4-day suppressive investigation, all doses of the crude extract and fractions suppressed parasitemia significantly (P < 0.001) as compared to the negative control. The crude extract had the greatest chemosuppressive effect (74.15%) at 600 mg/kg dose. Chloroform had the greatest parasitemia suppression among the fractions; however it was less than the crude extract. In Rane's test, all doses of the crude extract produced substantial (P < 0.001) curative effects as compared to the negative control.

CONCLUSION

According to this study, the crude extract and solvent fractions of M. gracilipes leaves contain antimalarial activity with a substantial suppressive effect. The antiplasmodial effects were more active in the chloroform and n-butanol fractions, indicating that the plant's non-polar and medium polar constituents are responsible. Nonetheless, further analysis is required to isolate and characterize the active compounds responsible for the study plant's antimalarial activity.