Schistosomiasis prevention option: toxicological evaluation of Vernonia amygdalina on the tissues of Bulinus truncatus at different pH conditions

Research into, and the use of plant products in the control of vectors of pathogens is being revived and seriously considered as an alternative or complete replacement for the classical synthetic agents. The study was designed to investigate toxicological assessment of the aqueous leaf extract of Vernonia amygdalina on mortality and tissue level damages of the freshwater snail Bulinus truncatus at different pH levels. The effects of the extract on total protein concentration and activities of acetylcholinesterase, acid phosphatase and alkaline phosphatase in the tissues of the snail were assayed using standard methods. Compared to the control (snail group not treated with the extract of V. amygdalina), there were significant (p < 0.05) reductions in the total protein concentrations and acetylcholinesterase activity in the snails' tissues of the treated groups (0.20 mg/L, 0.40 mg/L and 1.00 mg/L) at all the pH conditions (3.5, 7.0 and 10.5). The reverse of this trend followed in the case of acid and alkaline phosphatases' activities. The study provides a substantial possibility of exploiting local indigenous plant resources such as V. amygdalina for control of freshwater snails and monitor water pollution. The study also raised a possibility of the locals living around freshwater bodies prone to trematode borne diseases to reflexively control freshwater snail population by just squeeze-washing their V. amygdalina around the river banks.

Keywords: Acetylcholinesterase; Acid phosphatase; Alkaline phosphatase; B. trucatus; Biochemistry; Biological sciences; Environmental science; Tissues; Vernonia amygdalina.