Toxicity and teratogenicity investigation of methanolic bark extract of Terminalia arjuna (Roxb.) wight and arn in zebrafish (Danio rerio) embryo model

Abstract

The present research work aims to establish the teratogenic effect of the Terminalia arjuna (T.arjuna) bark extract using fish embryos through zebrafish embryo model. In the present study, selected zebrafish embryos were exposed to a range of methanolic extract of T.arjuna bark and the changes the embryos undergo were identified by comparing them with a control group. The embryo toxicity was assessed by observing morphological abnormalities after 24, 48, 72 and 96 h exposure and end teratogenicity points were assessed after 48 h exposure. All the embryos were imaged and analyzed for various developmental anomalies such as coagulated embryos, lack of somite formation, non-detachment of the tail, and lack of heartbeat, using imageJ software. From the results obtained, it was found that the embryos exposed with 10 mg/L of T.arjuna showed regular developmental patterns similar to control up to 72 h 5 % mortality was observed post 72 h period. 50 and 100 mg/L showed 100 % mortality after 96 h and 72 h respectively. At 48 h, Embryos treated with 50 mg/L of T.arjuna showed 5.58 % decreased heart beat rate, 7.89 % of decrease in eye diameter decreased head trunk angle of 3.56 % and increased yolk sac width of 0.79 %. After 48 h exposure to 50 and 100 mg/L of T.arjuna extract, 45 % and 85 % of the embryos showed the teratogenic endpoint of coagulation respectively with bent tail. Increased yolk sac width was observed in 100 mg/L treated embryos with 1.01 % after 24 h, also at 48 h decreased heart beat rate of 4.02 %,16.8 % of increased eye diameter, with decreased head trunk angle of 2.35 %, decreased yolk sac width of 5.13 % were observed. After 48 h exposure of T.arjuna bark extract, the morphological, physiological changes and teratogenic end points were eminent in 50 and 100 mg/L treated embryos, thus the results signify that methanolic bark extract of T. arjuna possess teratogenic effects at this concentration in zebrafish embryos.