In vitro study of short-term antiparasitic effect of alcoholic extract of Terminalia catappa L. leaves on Ichthyophthirius multifiliis theronts

Ichthyophthirius multifiliis is one of the parasitic diseases of fish infecting both farmed and wild freshwater fishes at all ages. This parasite penetrates into the fish skin epidermis and creates white spots on the skin accordingly, the disease caused by this parasite is also called white spot disease. Formalin, chloramine-T, malachite green, and other chemical compounds may be used against this disease; however, each of these compounds leads to harm to humans and the environment in some way; hence, it seems necessary to find natural alternative compounds to treat this disease. This study aimed at determining the effectiveness of alcoholic extract of Terminalia catappa L. at different concentrations (0-850 mg/L) and exposure times (1-3 h) in vitro. The findings were statistically compared with those of the control and positive control groups (formalin at a dose of 15 ppm). The results of the present study revealed that the effectiveness of T. catappa L. alcoholic extract on the theront stage of the I. multifiliis parasite is a function of time and concentration and with increasing concentration and time, its effect will enhance. The results of this study indicated that after two hours, a dose of 850 mg/L killed 100% of the theronts and it is the most appropriate dose, even though the possibility of applying this dose to treat live fish should be investigated.