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

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. [ABSTRACT FROM AUTHOR]