In vitro comparative effect of extracts of the seeds of Embelia rowlandii (Myrsinaceae) on the eggs and L1 and L2 larval stages of the parasitic nematode Heligmosomoides bakeri (Nematoda; Heligmosomatidae)

Abstract

In vitro ovicidal and larvicidal activities of extracts of the seeds of Embelia rowlandii were investigated on unembryonated and embryonated eggs, first and second stage larvae of Heligmosomoides bakeri. Three different extracts were prepared with distilled water (DW) and 95% ethanol. The organic extract was first diluted with 3% Tween and then distilled water added to obtain five different concentrations (625, 1250, 2500, 3750 and 5000 µg/ml). These concentrations were put in contact with eggs and larvae of H. bakeri. One milliliter of each extract at different concentrations and controls were added to 1 ml solution containing 30 to 40 eggs or 10 to 15 larvae (L 1 and L 2 larvae) and distributed in different Petri dishes. Both eggs and larvae were incubated at 24°C and exposure time was 48 h for fresh (unembryonated) eggs, 6 h for embryonated eggs, 24 h for L 1 and L 2 larvae, respectively. Distilled water and 3% Tween were used as negative controls in the bioassay. These placebos neither affected egg development, hatching nor larval survival. A significant effect was obtained with cold water extract (CWE), hot water extract (HWE) and ethanolic extract (EtE) and differences were observed depending on the parasitic stage. CWE, HWE and EtE inhibited embryonic development (60.5, 82.5 and 46.9%) and hatching (85.8, 74.1 and 41.0%), respectively at 5000 µg/ml. All the three extracts killed both L 1 larvae (84.5, 86.0 and 61.2%) and L 2 larvae (65.2, 83.7 and 33.3%) respectively at 5000 µg/ml. These in vitro results suggest that extracts of E. rowlandii possess ovicidal and larvicidal properties.

Nematocidal Activity of Ethanol and Aqueous Extracts of Persea americana Seeds against Heligmosomoides polygyrus using the Worm Microtracker Method

“…Similar observations were made by Payne et al [ 32 ]. According to Payne et al [ 32 ], the active compounds found in the extracts may paralyze the larvae by blocking the post-synaptic receptors.…”

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

“…Te larvicidal properties of these extracts may be due to the penetration of active compounds across the cuticle of the larvae on one hand or the absorption of the substance by the larvae. Tis fnding is similar to that obtained by Payne [23]. Payne [23] mentioned that active compounds penetrate the cuticle of nematodes and prevent the absorption of glucose or block postsynaptic receptors, thus paralyzing the larvae.…”

“…Tis fnding is similar to that obtained by Payne [23]. Payne [23] mentioned that active compounds penetrate the cuticle of nematodes and prevent the absorption of glucose or block postsynaptic receptors, thus paralyzing the larvae. Te active compound may inhibit the transmission of nervous impulses by gamma-aminobutyric acid (GABA) whose secretion is stimulated by the active compound [23].…”

“…Payne [23] mentioned that active compounds penetrate the cuticle of nematodes and prevent the absorption of glucose or block postsynaptic receptors, thus paralyzing the larvae. 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.…”

<i>In vitro</i> Anthelmintic Activity of <i>Tephrosia pedicellata</i> on Two Nematodes (<i>Haemonchus contortus, Caenorhaditis elegans</i>) and Its <i>In vivo</i> Toxicity on Rats

“…The larvicidal activity and adult mortality observed in our results may be due to the penetration of active phytochemicals through the cuticle of larvae and adult worms [43]. According to [44], the effect of tannins is similar to that of certain synthetic phenolic anthelmintics such as niclosamide and nitroxynil, which interfere with energy production by decoupling oxidative phosphorylation in parasitic helminths.…”