Onchocerciasis is a major public health problem caused by Onchocerca volvulus parasite and transmitted to humans via black flies (simulium) bites. The control of onchocerciasis relies much on the use of the chemical drug ivermectin, which is only effective against microfilariae and has led to drug resistance. This study was carried out to assess the in vitro antifilarial activity of methanolic extract of Indigofera tinctoria and its most active fractions on adult male O. ochengi worm, the closest model to O. volvulus, after 48 h and 72 h of treatment. Worms’ viability was determined biochemically by MTT/formazan colorimetry assay. The promising plant extract’s acute and subacute oral toxicity were evaluated on both mice and rats. The result revealed a highest antifilarial activity of the methanolic extract ( L C 50 = 12.28   μ g / mL ) compared to ivermectin ( L C 50 = 26.50   μ g / mL ) after 72 h of treatment. Out of the eight (08), chromatographic fractions screened, only three (03) fractions (C, F, and G) revealed the highest anti-Onchocerca activity after 72 h of treatment. An oral administration of the plant extract at a single dose of 2000 mg/kg did not produce any toxicity in mice. After repeated daily administration of methanolic extract of I. tinctoria (250 mg/kg, 500 mg/kg, and 1000 mg/kg) for 28 days, no significant changes in body weight, biochemical, and haematological parameters was observed. Histopathological examination of organs did not reveal any sign of alteration. The phytochemical analysis of the methanolic extract of I. tinctoria revealed the presence of various phenolic compounds. Therefore, this study demonstrated the potential antifilarial activity of Indigofera tinctoria and offered an alternative to treating onchocerciasis. Moreover, further studies could be developed in promising new antifilarial sources of the isolated compound and in vivo antifilarial activity of Indigofera tinctoria in the animal model needs to be studied.

Onchocerciasis is a disease caused by a parasitic nematode Onchocerca volvulus in human.  Ivermectin who is the main drug recommended for the treatment of this disease is only effective against the microfilarial stage of the parasite. Reports of emergence of parasite resistance to ivermectin have complicated onchocerciasis treatment and require to discover novel drugs. The objective of the present study was to investigate in vitro anthelmintic properties against the cattle filarial parasite Onchocerca ochengi, a model closely related to Onchocerca volvulus; and evaluate the toxicity (in vivo) of local medicinal plant Vernonia perrottetii. This plant is used as alternative medicine in the treatment of human onchocerciasis in central and coastal regions of Cameroon. Fifteen crude extracts were prepared from various parts of V. perrottetii using three organic solvents (70% ethanol, methanol, methylene chloride) and distilled water. The nematocidal activity was evaluated on adult worms of O. ochengi, worm viability was assessed biochemically using the dimethylthiazol (MTT) formazan assay. Oral toxicity of the promising extract was investigated in mice. The ethanolic extracts of the leaves and roots of V. perrottetii recorded the highest activities against adult male worms (LC50 of 29.80 μg/mL for leaves and 39.36 μg/mL for root). By contrast, the methanol and aqueous extracts of leaves and roots, of the plant as well as the mixture methylene chloride/methanol extracts. For acute treatment, a single dose of 2000 mg/kg no induced critical behavioral changes or death. In sub- acute treatment, daily oral administration of hydro-ethanolic extracts of leaves at the dose of 250, 500 and 750 mg/kg revealed disturbances in the normal growth of animals as well as liver and kidney alterations. Phytochemical analysis of the active extracts revealed the presence of Polyphenols, tannins, saponins and flavonoids. This study revealed the anti-Onchocerca activities of V. perrottetii, indicating a possible new source for developing a phytomedicine or drug for the treatment of human onchocerciasis.

Background: The resistance of gastrointestinal worms to synthetic anthelmintics (Levamisole) leads us to highlight the Cameroonian pharmacopoeia. The main objective of the present work is to look for an alternative treatment for haemonchosis, based on active secondary metabolites, from Portulaca oleracea, with less or no side effects and accessible to all. Methods: The Haemonchus contortus cycle test was performed at varying concentrations. Levamisole and PBS were the positive and negative controls respectively. Phytochemical screening was performed by standard staining and precipitation methods. Acute and sub-acute toxicity tests of Portulaca oleracea EA were performed according to OECD 425 and 407 respectively. Results: EM at 48 h of incubation inhibited eggs with an LC50 of 3.44. There was more larvicidal effect of ME with an LC50 value of 3.54 at 48 h incubation. At 24 h of incubation at the final concentration of 1000 µg/mL the anthelmintic effect of EA, ME and levamisole were noted with LC50 values of 0.057, 0.096, and 0.069 respectively. Phytochemical screening revealed the presence of some secondary metabolites in EA and ME of Portulaca oleracea. The result of the assays shows that ME is richer in total polyphenol (50.884 mg EAG/g DM) and flavonoids (5.688 mg RE/g DM) compared to EA which has (12.998 mg EAG/g DM) and (1.847 mg EC/g DM) respectively. However, there are more tannins in EA (5.688 mg RE/g DM) compared to ME (1.847 mg EC/g DM). The acute and subacute toxicity test showed no toxicity in mice and rats respectively. Conclusion: In view of the above, Portulaca oleracea possesses anthelmintic effects on the parasite Haemonchus contortus and is not toxic at the experimental therapeutic dose, which may open a way for the searching of a new anthelmintic drug. Keywords: Haemonchus contortus; Portulaca oleracea; Levamisole; Phytochemical screening; Toxicity.