Rapid neurobehavioural analysis based on the effects of an acetylcholinesterase inhibitor from Tephrosia purpurea in Zebrafish

BACKGROUND Zebrafish is an important model organism for human neurobehavioural studies and compound screening for neurodegenerative disorders like Alzheimer's disease and dementia. PURPOSE We wanted to analyse the rapid neurobehavioural effects based on acetylcholinesterase inhibitors from Tephrosia purpurea in zebrafish. METHODS Tephrosia purpurea (a herbal neuroactive molecule) extract was analyzed for its rapid neurobehavioural effects and the corresponding psychotic twitches were quantified. The inhibitory activity of acetylcholinesterase was analysed in Zebrafish. The activity of the molecule was confirmed after column chromatography and RP-HPLC purifications. The toxicity of the molecule was also studied in developing zebrafish embryos. RESULTS The psychotic body twitches were calculated as crude 484.67 ± 18.01 at 10 μg/mL, column purified 616 ± 9.64 at 8 μg/mL, Sep-Pak C18 712.67 ± 19.5 at 6 μg/mL, and HPLC elution showed 815 ± 14.93. The minimum inhibitory concentration of acetylcholinesterase in crude and column purified was 100 ng/mL and 5 ng/mL. The IC50 value of acetylcholinesterase inhibitor was calculated as 626ng/mL for crude (P<0.0001), 28.92 ng/mL for Sep-Pak column elution and 64 ng/mL for Donepezil. The HPLC fifth elution showed inhibition percentage as 96.97 ± 0.12. The organogenesis effects were seen in the drug concentration of 10 μg/mL. Pericardial bulging, trunk and tail flexure with heart edema and head edema were observed in the embryos at higher dose of 30- 40 μg. The LC50 value was 34.87 μg/mL. The studies showed that the inhibitory concentration of acetylcholinesterase is comparatively higher than Donepezil. CONCLUSION Rapid behaviour based screening is an inexpesive assay to identify neuroactive small molecules. This herbal can be further used for the development of drugs for Alzheimer's disease.