Osmotic Effect of Terminalia Catappa Linn. Leaf Extract on Adult Onchocerca Volvulus by Modified in-Vitro Bioassy, Using the Parameter of Weight

Abstract

Background: Onchocerca volvulus is a causative agent of Onchocerciasis, a leading cause of blindness. This study was to determine the osmotic effect of Terminalia catappa (Tropical Almond) leaf extract on the adult Onchocerca volvulus by modified in-vitro bioassay, using the parameter of weight.

Method: A total of 252 adult worms (Onchocerca volvulus) sourced via nodulectomy were used for the study. The crushed leaves of Terminalia catappa was extracted using 95% ethanol, filtered, and evaporated (Tabassam method). The dried extracts were dissolved in sterile dilutions to prepare dose concentrations of 10mg/ml, 20mg/ml and 40mg/ml. Seventeen labeled laboratory beakers were used for the study. At room temperature (25-30°C), six life worms per beaker were individually weighed, using electronic weighing instrument (OHAUS) and weights recorded before they were introduced into the different doses of Terminalia catappa leaf extract. The worms were observed for paralysis and death. Upon death, the worms were again weighed and results recorded.  A positive control beaker contained anthelmintic drug Albendazole and a negative control beaker, contained saline water. The procedure was repeated three times.

Result: The methanolic Terminalia catappa leaf extracts effect on onchocerca volvulus recorded the following mean average results upon the death of worms. The concentraton dose of 40mg/ml leaf extract showed 0.005±0.001 weight loss. The dose of 20mg/ml and 10mg/ml leaf extract recorded 0.003±0.001 and 0.002±0.000 weight loss respectively. The reference drug (Albendazole) showed a reduction in the mean average weight of worms upon death 0.005 ± 0.006 compared to the live weight. And worms in Saline water recorded a weight increase of .001± 0.006 upon dead.   

Conclusion: This weight reduction was observed as a consistent pattern with the methanolic Terminalia catappa leaf extract and therefore possesses concentration dependent osmotic mechanism on Onchocerca volvulus. With saline water, the worms rather increased in weight upon death.