Toxic Effects of Crude Aqueous Stem Bark and Leaf Extracts of Phyllanthus niruri on Lymnaea acuminata

Many aquatic snails like Lymnaea (Radix) acuminate Lamarck are well known carriers or vectors of larvae of trematodes and are known causing a harmful disease, fascioliasis. Thus, use of plant origin molluscides is being in practice as an alternative approach to prevent the transmission of snail-borne parasitic diseases. The aim of the present study is to evaluate the toxic effect and potency of the molluscicidal activity of aqueous stem bark and leaf extracts of the plant Phyllanthus niruri (a tropical small herb, commonly known as a Bhumi Amla), (family-Phyllanthaceae), on various tissues of the vector snail Lymnaea acuminata. After being exposed for 24 hours to sublethal doses i.e. 107.156μM and 214.312 μM (40% and 80% of 24h LC50 of L.acuminata), of the crude aqueous stem bark extracts and 95.97 μM and 191.93 μM (40% and 80% of 24h LC50 of L.acuminata), of the crude aqueous leaf extracts of P.niruri respectively, biochemical parameters were assessed in various snail tissues. Sub-lethal doses (40% and 80% of LC50of 24h) of aqueous stem bark and leaf extracts of this plant show significant (P<0.05) alteration in the carbohydrates and nitrogenous metabolismsin nervous, hepatopancreas, and ovotestis tissues of the vector snail Lymnaea acuminata in time and dose dependent manner. After the withdrawal of toxic aqueous extracts, the snail tissues recovered in part after 7days completely. This study therefore signifies that, the aqueous extracts of stem bark and leaf of P. niruri may be used as a potent source of molluscicides; being less expensive, easily available, easily soluble in water.