Main content area

Antiparasitic effect of aqueous and organic solvent extracts of Azadirachta indica leaf against Argulus japonicus in Carassius auratus

Kumari, Puspha, Kumar, Saurav, Ramesh, M., Shameena, S., Deo, Ashutosh D., Rajendran, K.V., Raman, R.P.
Aquaculture 2019
Argulus japonicus, Azadirachta indica, Carassius auratus, acetone, adults, antiparasitic agents, bioassays, chloroform, ethanol, fish culture, goldfish, leaf extracts, leaves, lethal concentration 50, median effective concentration, methanol, ornamental fish, parasitoses, pathogens, phytotherapy, solvents
Argulosis is a serious parasitic disease in aquaculture as well as in the ornamental fish rearing. However, phytotherapy, especially employing neem and its derivative products, is being widely used to combat the pathogens in aquaculture. The present study was conducted to screen various extracts of neem, Azadirachta indica leaf prepared using organic and aqueous solvents of concentration ranging from 1.0 to 3.5 g L−1 for its antiparasitic effect against adult Argulus japonicus in goldfish, Carassius auratus under in vitro and in vivo conditions for 6 and 72 h, respectively. Under in vitro condition for 6 h, antiparasitic efficacy of neem leaf extracts prepared in different solvents such as ethanol, methanol, chloroform and acetone at a concentration of 2.0 g L−1 was found to be 100, 75, 66.66 and 50%, respectively. However, aqueous extracts at a concentration of 3.5 g L−1 showed 100% efficacy. Further, the estimated 6 h median effective concentration (EC50) of ethanol, methanol, chloroform, acetone and aqueous extracts of neem leaf for A. japonicus was 1.056, 1.554, 1.877, 2.075 and 2.113 g L−1, respectively. Compared to other extracts, ethanolic extract of A. indica showed significantly high antiparasitic efficacy. However, as the estimated value of 6 h median lethal concentration (LC50) of ethanolic extract for C. auratus was 1.11 g L−1 and found to be proximate to EC50 value, application of the extract under in vivo condition will not be safe. In the bioassay, the 72 h LC50 of aqueous extract for C. auratus was found to be 3.28 g L−1. Notably, under in vivo condition, the estimated 72 h EC50 value of aqueous extract against A. japonicus was 1.831 g L−1 and calculated therapeutic index was 1.79. The result suggests that under in vitro condition, the ethanolic and aqueous extract of neem leaf solutions can be used as a potential agent for controlling adult A. japonicus. However, aqueous extract only can be applied under in vivo condition.