In vivo ameliorative effects of methanol leaf extract of Lawsonia inermis Linn on experimental Trypanosoma congolense infection in Wistar rats

Abstract

The aim of this study was to investigate the ameliorative effect of Lawsonia inermis Linn used traditionally against trypanosomosis. Twenty-five adult Wistar rats of both sex were individually infected intraperitoneally (IP) with 10⁶Trypanosoma congolense per ml of blood. Following establishment of infection, the rats were randomly divided into five groups of 5 rats each. Rats in groups I, II, and III were treated with 125, 250 and 500 mg/kg of the extract, respectively, while rats in groups IV and V were treated with 3.5 mg/kg and 2 ml/kg of diminazene aceturate (DM) once and physiological buffered saline, respectively. All treatments except DM were given orally for 7 days IP. The antitrypanosomal effect of the plant was assessed by observing the level of parasitaemia daily, packed cell volume (PCV) weekly, erythrocyte osmotic fragility (EOF) and malondialdehyde (MDA) concentration on day 21. Phytochemical screening of the extract revealed the presence of alkaloids, carbohydrates, triterpenes, steroids, cardiac glycosides, saponins, tannins and flavonoids. The extract significantly (P < 0.05) reduced levels of parasitaemia at 250 mg/kg. PCV was higher (P > 0.05) in extract treated groups but significantly higher (P < 0.05) in group II at week 2 when compared to group V. Rats in group II had significantly lower values of EOF and MDA when compared with groups IV and V. Thus, the leaf of L. inermis has in addition to an antitrypanosomal effect against T. congolense in rats, an attenuating effect on the trypanosomosis pathology probably mediated via protection of the erythrocyte membrane against trypanosome-induced oxidative damage to the erythrocytes.

Keywords: ANOVA, analysis of variance; Antioxidant; Antitrypanosomal; EOF, erythrocyte osmotic fragility; Erythrocyte osmotic fragility; IP, intraperitoneal; L, lawsonia; MDA, malondialdehyde; Malondialdehyde; PCV, packed cell volume; PSS, physiological buffered saline; Phytochemistry; SEM, standard error of mean; T, trypanosoma; TBA, thiobarbituric acid; TCA, trichloroacetic acid; US, United States; kDNA, kinetoplast deoxyribonucleic acid.

Fig. 1

Effect of methanol extract of the leaf of L. inermis on the level of parasitaemia in rats infected with T. congolense. MLELI = Methanol leaf extract of L. inermis; DA = Diminazene aceturate; PBS = Physiologic buffered phosphate saline.

Fig. 2

Effect of treatment with extract of the leaf Lawsonia inermis on mean survival periods of experimental rats. ^a,bMeans with different superscript letters are statistically significant (P < 0.05). MLELI = Methanol leaf extract of L. inermis; DA = Diminazene aceturate; PBS = Physiologic buffered phosphate saline.

Fig. 3

Effect of treatment with extract of the leaf Lawsonia inermis on mean weekly PCV of experimental rats. ^a,bMeans with different superscript letters are statistically significant (P < 0.05). MLELI = Methanol leaf extract of L. inermis; DA = Diminazene aceturate; PBS = Physiologic buffered phosphate saline.

Fig. 4

Effect of Lawsonia inermis extract on EOF of treated rats experimentally infected with T. congolense. ^a,bMeans with different superscript letters are statistically significant (P < 0.05). MLELI = Methanol leaf extract of L. inermis; DA = Diminazene aceturate; PBS = Physiologic buffered phosphate saline.

Fig. 5

Effect of Lawsonia inermis extract on serum MDA of treated rats experimentally infected with T. congolense. ^a,bMeans with different superscript letters are statistically significant (P < 0.05). MLELI = Methanol leaf extract of L. inermis; DA = Diminazene aceturate; PBS = Physiologic buffered phosphate saline.