Photoactivated chlorophyllin and acetylcholinesterase/ cytochrome oxidase activity in Fasciola gigantica cercaria larvae

Objective: The effect of chlorophyllin (CHL), CHL + freeze dried cow urine (FCU) and FCU on acetylcholinesterase (AChE) and cytochrome oxidase activity in the nervous tissue of the host snail Lymnaea acuminata, and parasitic cercaria larvae of Fasciola gigantica were studied. Methods: Whole cercaria larvae and snail nervous tissue was homogenized and supernatant was used as an enzyme source. Enzyme activity was measured in 10-mm path length cuvette using incubation mixtures and change in optical density was recorded. Results: Sublethal 4 h LC₅₀ 40% and 80% of these formulations in sunlight and laboratory conditions caused no significant change in AChE activity in the nervous tissue of host snail. It was noted that sublethal in vivo 8 h exposure to 40% and 80% of 4 h LC₅₀ of single and binary combination of CHL+FCU, CHL and FCU significantly altered the AChE and cytochrome oxidase activity in the cercaria larvae. Binary combinations of CHL+FCU in sunlight were more effective in inhibiting both the enzymes. Conclusion: The present study reported that enzymes AChE and cytochrome oxidase were inhibited by chlorophyllin formulations and thus causing the larval death inside the snail body without affecting the snail itself which is an important bioindicator of aquatic ecosytem.