Chemical profile, antioxidant and anti-Alzheimer activity of leaves and flowers of Markhamia lutea cultivated in Egypt: in vitro and in silico studies

Abstract

Background

Nowadays Alzheimer’s disease and its treatment methods are global concerns. Patients with this disease have poor prognosis and need supportive treatment. The antioxidant activity, anti-acetylcholinesterase (anti-AChE), anti-butyryl cholinesterase (anti-BChE) and Aβ-amyloid-42 inhibition activities of the ethanolic extracts of both leaves and flowers (LEE and FEE) of Markhamia lutea were assessed. The antioxidant activity of LEE and FEE was evaluated using 2,2-diphenyl-1-picryl-hydrazyl-hydrate, oxygen radical absorbance capacity and ferrozine iron metal chelation assays. Additionally, their total flavonoids and total phenolics were determined. The phytochemicals of LEE were analysed using LC–MS/Q-TOF in both positive and negative modes. Also, molecular docking was done for phytochemicals identified in LEE.

Result

LEE exhibited higher antioxidant and anti-Alzheimer activities in all techniques due to its high flavonoids content. LEE showed better activity than donepezil in case of anti-butyryl cholinesterase than both donepezil and rivastigmine in case of Aβ-amyloid-42 inhibition. A total of 62 compounds were tentatively identified using Ultra-performance Liquid Chromatography-Electrospray Ionization-Quadrupole Time-of-Flight Mass Spectrometry (UHPLC–ESI–TOF–MS), viz. 35 flavonoids, 11 phenolic acids, 2 terpenoids, 2 phenylpropanoids derivatives, 7 polyphenols, 3 coumarins and 2 organic acids. The molecular docking of some constituents showed that isorhamnetin-O-rutinoside, sissotrin, 3,5,7-trihydroxy-4'-methoxyflavone (diosmetin), rosmarinic acid, kaempferol hexoside, kampferol-7-neohesperoside, acacetin, taxifolin and apigenin-O-hexoside exert a promising activity as anti-Alzheimer drugs.

Conclusion

The LEE of Markhamia lutea contains secondary metabolites that is promising to act as natural antioxidants, acetylcholinesterase, butyryl cholinesterase and Aβ-amyloid-42 inhibition inhibitors, which can aid in the treatment of Alzheimer’s.

Graphical Abstract