Evaluation of developmental toxicity and genotoxicity of aqueous seed extract of Croton tiglium L. using zebrafish

Abstract

Croton tiglium L. has been used in Ayurvedic and Chinese herbal medicinal formulations from ancient times. Although its seeds are widely prescribed as traditional medicine, there is a dearth of information, regarding its toxic effects, and the mechanisms underlying its toxicity. This study aims to investigate the developmental toxicity and genotoxicity of the aqueous seed extract of C. tiglium L. (AECT) in zebrafish. We have examined the effects of AECT on the early embryonic development of zebrafish. Zebrafish embryos, treated with different concentrations of the AECT, suffered embryonic lethality and displayed various developmental defects. The 96 h-LC₅₀ of AECT was found to be 162.78 µg/ml. Interestingly, the developmental abnormalities observed, such as pericardial edema (PE), yolk sac edema (YSE), spinal curvature (SC), and delayed hatching, varied in severity, in a dose-dependent manner. Zebrafish embryos, treated with different concentrations of AECT, exhibited exaggerated cell death in the anatomical regions of brain, heart, and trunk. Our data suggest that the phenomenon of apoptosis is probably responsible for both embryonic lethality and developmental toxicity in zebrafish embryos. Furthermore, the genotoxic potential of the AECT, in vivo, was evaluated using micronucleus assay and comet assay, on the peripheral blood of zebrafish. The results suggest that AECT has the potential to cause genotoxicity in the peripheral blood of zebrafish.

Keywords:

• Genotoxicity
• developmental toxicity
• apoptosis
• Croton tiglium
• zebrafish
• pericardial edema

Acknowledgements

The authors are grateful to Department of Life Sciences, Manipur University and UGC for providing financial assistance during the research period. The authors also acknowledged the Indian Institute of Science (IISc) for financial assistance. Authors are thankful to Ms. Meenakshi Sen and Ms. Deepti Bapat at IISc Confocal Facility for their help in taking confocal images and image processing. Amartya Mukherjee helps in editing the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Author contributions

TY, MDD and UN conceived the idea and planed the experiment, TY did all the experiments, TY and DR did microscopic imaging and image processing. TY and UN analyzed the data and manuscript writing.