Assessment of the molluscicidal impact of extracted chlorophyllin on some biochemical parameters in the nervous tissue and histological changes in Biomphalaria alexandrina and Lymnaea natalensis snails.

Biomphalaria alexandrina and Lymnaea natalensis snails are the intermediate hosts of schistosomiasis and fasciolosis. The aim of the present study is to evaluate the molluscicidal activity of chlorophyll extract as a photodynamic substance against these snails and how it affected its tissues and the biological system. Chlorophyllin was extracted from deep-frozen Moringa oleifera leaves, and then it was transformed into water-soluble chlorophyllin. The present results showed that it had a molluscicidal activity on B. alexandrina snails (LC50 17.6 mg/l; LC90 20.9 mg/l) and L. natalensis snails (LC50 4.3 mg/l; LC90 6.8 mg/l). Exposing B. alexandrina snails to the sublethal concentrations (LC0, LC10, and LC25) resulted in a significant reduction in their survival rates. Regarding its effect on biochemical parameters, chlorophyllin significantly reduced the acetylcholinesterase activity, protein content, and alkaline and acid phosphatase activity in B. alexandrina nervous tissue compared to the control group. Histopathological changes occurred in the digestive gland of treated B. alexandrina snails where cells lost their nuclei, vacuolated, degenerated, and ruptured, and the lumen increased. Photosynthesizing materials like chlorophyllin are new approaches to control schistosomiasis and fasciolosis in developing countries by affecting their intermediate host. These materials were cheap and environmentally safe to replace the synthetic molluscicides for snail control.

Comparative toxicity of Paraquat herbicide and some plant extracts in Lymnaea natalensis snails.

Paraquat has been shown to be a highly toxic compound for humans and animals, and many cases of acute poisoning and death have been reported over the past few decades. The present study was undertaken to evaluate comprehensively herbicides (Paraquat) and some plant extracts to biochemical aspects of Lymnaea natalensis snails. It was found that the exposure of L. natalensis to Paraquat and plant extracts led to a significant reduction in the infectivity of Fasciola gigantica miracidia to the snail. The glucose level in hemolymph of exposed snails was elevated, while the glycogen showed a decrease in soft tissues when compared with the control group. In addition, the activity level of some enzymes representing glycolytic enzymes as hexokinase (HK), pyruvate kinase (PK), phosphofructokinase (PFK), lactate dehydrogenase (LDH), and glucose phosphate isomerase (GPI) in snail's tissues were reduced in response to the treatment. It was concluded that the pollution of the aquatic environment by herbicide would adversely affect the metabolism of the L. natalensis snails. Snails treated with Agave attenuate, Ammi visnaga, and Canna iridiflora plant had less toxic effect compared to snails treated with Paraquat.

Molluscicidal effect of fungicide, herbicide and plant extract on some biological and physiological parameters of Biomphalaria alexandrina.

In was found that the exposure of B. alexandrina to LC25 of fungicide (Isoprothiolane), herbicide (Anilofos) and plant extract (Euphorbia lactea) led to highly significantly elevated in the number of abnormal egg masses laid by treated snails in comparison with the control ones. The LC25 caused reduction in infection rate of B. alexandrina. It caused reduction in number of cercariae per snail during the patent period and reduction in the period of cercarial shedding. The results obtained showed that adenosine triphosphatase (ATPase) activity of tissue of snails was significantly increased in response to tested substances. The activity level of lactate dehydrogenase (LDH). pyruvate kinase (PK) and phosphoenolpyruvate carboxy kinase (PEPCK) was significantly reduced in response to treatment. This reduction does not reflect on both D. lactate and pyruvate concentrations.