Ellman’s assay using chicken and fish brain extracts an alternate to rodent brain extract: acetylcholinesterase inhibitory activity of methanolic extract of Psidium guajava Linn

Abstract Background Guava ( Psidium guajava Linn) leaf, a traditional memory booster, has been investigated for its acetylcholinesterase (AchE) inhibitory activity using isolated chicken and fish brain homogenates as substitutes for rodent brain homogenates. The study employed a household mixer jar for mincing chicken and fish brains, circumventing the need for expensive tissue homogenizers. Method Following minor adjustments, the in vitro AchE inhibition experiment was conducted according to Ellman et al. (1961). Results Utilizing the mixer jar technique for tissue homogenization, the IC50 values (in µg/ml) for the reference medication, neostigmine, were 9.019 ± 3.43 and 0.587 ± 0.04 for chicken brain and fish brain, respectively. The IC50 values (in µg/ml) of the methanolic extract of P. guajava Linn leaf were 1086 ± 86.31 and 185.8 ± 13.68 for chicken brain and fish brain, respectively, using the mixer jar method. Furthermore, the mixer jar homogenization approach indicated a higher yield of AchE in chicken brain extract compared to fish brain extract. Conclusion The utilization of chicken and fish brains as alternatives to rodents’ brains for AchE inhibition in vitro assay offers an ethical means to avoid unnecessary laboratory animal euthanasia. The methanolic extract of P. guajava Linn leaf exhibited significant AchE inhibitory effects using in vitro Ellman’s assay with chicken and fish brains. Graphical abstract