<i>In Vitro</i> Ovicidal and Larvicidal Activities of Stem Bark of <i>Terminalia glaucescens</i> (Combretaceae) against <i>Haemonchus contortus</i>

Abstract

Objectives: To evaluate the in vitro activity of aqueous and methanolic extracts of stem bark of Terminalia glaucescens on the eggs and larval stages of Haemonchus contortus of sheep. Methods: The eggs were exposed for 24 hours in five different concentrations (625, 1250, 2500, 3750 and 5000 µg/ml) of methanol, hot water (decoction) and cold water extracts at room temperature (25˚C). Distilled water, 1.25% DMSO and Albendazole were used as negatives and positive control respectively in the bioassay. Results: A significant effect was obtained with all of the three extracts and differences were observed depending on the parasitic stage. Hot water extract (HWE), Methanol (MET) and Cold water extract (CWE) inhibited embryonic development by 98.1%, 96% and 86.5% respectively at 5000 µg/ml, meanwhile Albendazole had a 77.9% inhibition. For the mean inhibition rate of egg hatching, there was a general increase in the inhibition rate with increase in concentration of the extract from 625 to 5000 µg/ml. Methanol extract had the highest inhibition rate in all concentration from 625 to 5000 µg/ml. Concerning larval mortality, HWE had the highest effect in L1 larval mortality in all concentration above 1250 μg/ml. Distilled water had very little larval mortality on L1 and L2 larvae by 3.3 and 3.3% respectively. Conclusion: This in vitro study brought out the ovicidal and larvicidal properties of stem bark of Terminalia glaucescens.

Anthelmintic efficacity of balanites Aegyptiaca (l.) Delile (Zygophyllaceae) almonds on three developmental stages of haemonchus contortus

“…Indeed, Perry (2002) showed that condensed tannins would be able to bind to the lipoproteins of the eggshell membrane to inhibit osmotic pressure in egg, thus compromising hatching. According to Lem et al (2014), the condensed tannins would be able to penetrate the nematode cuticle and prevent the absorption of glucose, or block the post-synaptic receptors, thus paralyzing the larvae. On adult worms, condensed tannins would act on the digestive epithelium of the parasite to inhibit the functions of nutrition and lead to the death of the latter (Min et al, 2003).…”

Antihelminthic Activity of Lophira Lanceolata on Heligmosomoides polygyrus Using an Automated High-Throughput Method

“…Te active compound may inhibit the transmission of nervous impulses by gamma-aminobutyric acid (GABA) whose secretion is stimulated by the active compound [23]. Lem et al [24] mentioned that active compounds found in food can cross the intestinal lining of larvae and gain access to the circulatory system of the organism. Moreover, active compounds like tannin may bind to the cuticle of the nematode, destabilize the membrane, and increase cell permeability by combining with membrane-associated sterols which lead to death [25].…”