Effect of synthesized niclosamide organophosphortus derivatives on some metabolic aspects of Biomphalaria alexandrina snails and its compatibility to Schistosoma mansoni

ABSTRACT

The Molluscicidal potency of four synthesized Mannich bases and ten organophosphorus derivatives of bayluscide [niclosamide] were determined. Using Biomphalaria alexandrina snail, the intermediate host to Schistosoma mansoni in Egypt, of these derivatives,a single Mannich bases derivative [compound No, 13] showed higher molluscicidal effect than niclosamide, LC[50] 0.4 ppm after 24 hours at 25°C compared with 0.5 ppm for niclosamide. Three other derivatives [No. 15, 12 and 8] showed slightly less effect, their LC[50] 1.9, 3.4 and 4.1 ppm, respectively, Meanwhile, the four compounds showed considerable reducting effect on the cercarial production of schistosome-infected snails previously exposed to LC[5] of each compound before miracidial infection. Thus, the mean periodic number of cercariae/snail [two hours weekly] was found to be 55.8 +/- 41.8, 95.9 +/- 78.9, 162.6 +/- 145 and 209.35 +/- 168.4 cercariae/snail, respectively versus 242 +/- 230.4 and 502 +/- 290.4 in the case of niclosamide-treated and non-treated snails. The effect of the four compounds was tested on the glycolytic enzymes of snails, namely, hexolinase [HK], pyruvate kinase [PK] and glucose phosphate isomerase [GPI]. Much more reduction was recognized in [HK] by compounds No. 8 and 13 in comparison, with niclosamide and nontreated snails, being 2.6 +/- 0.82 and 3.7 +/- 1.6 n moles/min/g tissue versus 3.9 +/- 0.58 and 9.8 +/- 2.7 n moles/min/g tissue in niclosamide-treated and non-treated groups, respectively. PK showed also higher reduction with four compounds namely 15, 13, 12 and 8 compared with niclosamide-treated and non-treated snails, being 0.3 +/- 0.1, 0-.39 +/- 0.29, 0.46 +/- 0.08 and 0.98 +/- 0.138 in comparison with 1.51 +/- 0.52 and 1.8 +/- 0.62, respectively. No considerable change was found in the level of GPI in snails treated with 15, 13, 12 and 8 compounds relative to niclosamide-tested snails. The present results show that reduction in the periodic cercarial production is correlated with the lower level of HK enzyme in treated snails