In vitro antioxidant and anticholinesterase activity of Aegle marmelos fruit: implications for Alzheimer’s disease treatment

Abstract Background Increased antioxidant and anticholinesterase activity are key pathological hallmarks of Alzheimer’s disease (AD). In various Ayurvedic formulations Aegle marmelos (AM) belonging to family Rutaceae have traditionally been used as a brain tonic. However, there was no scientific validate proof of it. Hence, the present study was aimed to identify bioactive extract/fraction/constituent of AM fruit having potential to treat AD. Method Four different crude extracts of AM fruits by using different solvents on basis of increasing polarity‐such as petroleum ether, chloroform, methanol and distilled water‐by successive Soxhlet extraction were prepared and evaluated for in‐vitro antioxidant and anticholinesterase inhibition assay by using DPPH and Ellman’s assay respectively. Most bioactive extract was further subjected to fractionation by using solvent‐solvent partioning followed by flash chromatography for further sub fractionation of most bioactive fraction. Total phenolic (TPC) and flavonoid content (TFC) was also calculated Result Comparative evaluation of all four prepared extracts for in‐vitro antioxidant and anticholinesterase inhibition assays showed that the methanol extract (ME) was most bioactive. Furthermore, bioactivity‐guided fractionation of this bioactive ME revealed that Dichloromethane (DCM) fraction evinced highest antioxidant and anticholinesterase activity with IC 50 value 74.56±1.43 µg/ml and 47.65±2.76 µg/ml due to presence of higher phenolic and flavonoid content. However, further sub‐fractionation of DCM fraction showed significantly higher IC 50 values thus decreased activity. Conclusion This preliminary study clearly suggested that the DCM fraction from the ME of A. marmelos may prove to be potential candidate for the treatment of AD may be due to synergistic effect of phenolic and flavonoid content present in it. However, to validate the neuroprotective effect of DCM fraction of AM fruit against AD further exploration at cellular and molecular level is required to underlying its pharmacological mechanism as well as identification of the active phytoconstituents responsible for anti‐Alzheimer’s effect.