Teratogenic and embryotoxic effects of methanolic crude extract of Peperomia pellucida (l.) kunth on Danio rerio (Hamilton,1822) embryos

Abstract

Widespread belief that herbal medicines have no adverse effects warrants a growing need for studies to investigate the embryotoxicity and teratogenicity of these plant medicines. Peperomia pellucida (L.) Kunth is an herb widely documented to have various beneficial properties, but few studies have investigated its embryotoxicity and teratogenicity. This study aims to determine the embryotoxicity and teratogenicity of the methanolic crude extract of P. pellucida using the Zebrafish Embryo Acute Toxicity Test (ZFET). Twenty zebrafish (Danio rerio) embryos per replicate were exposed to varying concentrations of plant extract namely 12.5 mg/L, 30 mg/L, 47.5 mg/L, 65 mg/L and 82.5 mg/L, and to the positive control (5% ethanol), negative control (reconstituted water) and solvent control (1% DMSO). Lethal and sublethal endpoints were observed and noted every 12 hours for four days. Heart rate and body length were taken at 48 hpf and 96 hpf, respectively. Statistical analysis was then done. The extract was found to be embryotoxic at 60.61 mg/L and teratogenic at concentrations of 30 mg/L or greater. There was a dosedependent decrease of hatching rate and body length and a dose-dependent increase in coagulation, lack of heartbeat, yolk sac edema and spinal curvature. There were significant differences found between the heart rates of 12.5 mg/L embryos and the negative control; heart rates of 12.5 mg/L and 30 mg/L plant extract; and body lengths from 12.5 mg/L to 82.5 mg/L plant extract. These could be attributed to the presence of secondary metabolites like saponins and tannins or identified constituents of P. pellucida such as dillapiole and peperomin E. The late acting lethality of the extract could also be attributed to the presence of the chorion.