In vitro anthelminthic efficacy of Dichrocephala integrifolia (Asteraceae) extracts on the gastro-intestinal nematode parasite of mice: Heligmosomoides bakeri (Nematoda, Heligmosomatidae)

<p><b>OBJECTIVE</b>To evaluate the ovicidal and larvicidal activities of aqueous and ethanolic extracts of leaves of Dichrocephala integrifolia (D. integrifolia) against the eggs (fresh and embryonnated), the first and second larval stages of Heligmosomoides bakeri. In order to verify if this medicinal plant possesses active compounds capable of inhibiting the embryonation and hatching of eggs or to induce the mortality of larvae (L1 and L2).</p><p><b>METHODS</b>dried extracts were diluted in distilled FIV water to obtain five different concentrations: 625, 1,250, 2,500, 3,750 and 5,000 µg/mL. Fresh eggs obtained from artificially infected mice feces were exposed to these different concentrations for 48 h. Time of contact for embryonated eggs was 6 h while L1 and L2 larvae were exposed for 24 h. Distilled water (placebo) and 1.5% DMSO were used as negative controls.</p><p><b>RESULTS</b>Distilled water, and 1.5% DMSO had no effect on embryonation, hatching and larval survival. Aqueous extracts of D. integrifolia showed a weak activity against all stages of the parasite at all concentrations tested. On the contrary, the ethanolic extract of D. integrifolia inhibited the embryonation of 87.5% of fresh eggs, the hatching of 81.1% of embryonated eggs and induced the mortality of 98.1% and 98% of L1 and L2 larvae respectively at 5,000 µg/mL.</p><p><b>CONCLUSIONS</b>The results of the present study indicate that the ethanolic extracts of D. integrifolia contained compounds with ovicidal and larvicidal properties. In spite of these results, in vivo tests, studies on toxicity and mechanism of action of active compounds are also needed to validate the utilisation of this medicinal plant by population of Dschang-Cameroon to treat gastro-intestinal parasites.</p>

Study of Host-Parasite Relationship among Loranthaceae Flowering Shrubs Myrmecophytic Fruit Trees-Ants in Logbessou District, Cameroon.

The objective of this study is host-parasite relationship among Loranthaceae flowering shrubs, Myrmecophytic fruit trees and ants. The study was conducted in 2009 in the garden plots and orchards of houses in the Logbessou district of Douala, Cameroon. We inventoried a total of 141 myrmecophytic fruit trees (diameter ≤ 45 cm) of which 95 (67.3%) were parasitized by flowering-shrub epiphytes (Loranthaceae). These trees belong to 14 species, 11 genera and 8 families. Among the eight species of ants inventoried on the trees, two were arboreal-dwelling and six were ground-dwelling, arboreal-foraging species. They belonged to two sub-families: the Formicinae, which were mostly represented by two genera, Camponotus and Paratrechina; and the Myrmicinae, which were more abundant (87.5%). The ants nested in the domatia of myrmecophyte hosts or hollow branches, trunks and dead suckers of Loranthaceae. Crematogaster was the most frequent genus and dominant ant on all of the parasitized host trees.

Acute and sub-acute toxicity of ethanolic extract of Canthium mannii Hiern stem bark on Mus musculus.

Acute and sub-acute toxicity of ethanolic extract (ETE) of C. mannii was assessed on white mice (Mus musculus). After 48 h of extract administration, no death was registered. It was deduced that the LD50 was indisputably higher than 16 g/kg body weight. The sub-acute toxicity test was based on the daily administration of three doses of ETE (300, 600 and 1200 mg/kg body weight) for four weeks; 1% DMSO served as negative control. As for the first experiment, no sign of toxicity was registered. Conversely, the sub acute doses stimulated and increased the weight-rate of mice after 7 days of treatment. Except for the spleen weight, the doses administrated did not modify the weight index. It was observed that, sub-acute doses induced and increased (a) the food (particularly) and water consumption according to time and (b) the number of red and white blood cells. It was thought that, ETE can stimulate the haematopoietic function. Finally, no time variation of the activity of alanine aminotransferase and aspartate aminotransferase enzyme was observed in the serum of euthanized mice. The results showed the innocuity of ETE of C. mannii and thus validated his utilization in cameroonian traditional pharmacopoea.