Exploring beetroot (<i>Beta vulgaris</i> L.) for diabetes mellitus and Alzheimer's disease dual therapy: <i>in vitro</i> and computational studies

Abstract

This study explored the flavonoid-rich extract of beetroot (<i>Beta vulgaris</i> L.) for type 2 diabetes mellitus (T2D) and Alzheimer's disease (AD) dual therapy by using <i>in vitro</i> and molecular simulation studies. Flavonoid-rich extracts of <i>B. vulgaris</i> fruit were evaluated for their antidiabetic and anti-alzheimic activities. Molecular docking and dynamic simulation were performed to identify potential bioactive flavonoids with dual therapeutic effects on T2D and AD. Flavonoid-rich extracts of <i>B. vulgaris</i> fruit (IC₅₀ = 73.062 ± 0.480 μg mL^-1) had moderate activity against α-amylase compared to the standard acarbose (IC₅₀ = 27.104 ± 0.270 μg mL^-1). Compared with acarbose, flavonoid-rich extracts of <i>B. vulgaris</i> fruit had appreciable activity against α-glucosidase (IC₅₀ = 17.389 ± 0.436 μg mL^-1) (IC₅₀ = 37.564 ± 0.620 μg mL^-1). For AChE inhibition, flavonoid-rich extracts of <i>B. vulgaris</i> fruit exhibited (<i>p</i> < 0.0001) inhibitory activity (IC₅₀ = 723.260 ± 5.466 μg mL^-1), albeit weaker than that of the standard control, galantamine (IC₅₀ = 27.950 ± 0.122 μg mL^-1). Similarly, flavonoid-rich extracts of <i>B. vulgaris</i> fruit showed considerable (<i>p</i> < 0.0001) inhibitory effects on BChE (IC₅₀ = 649.112 ± 0.683 μg mL^-1). In contrast, galantamine (IC₅₀ = 23.126 ± 0.683 μg mL^-1) is more potent than the extracts of <i>B. vulgaris</i> fruit. Monoamine oxidase (MAO) activity increased in FeSO₄-induced brain damage. In contrast, flavonoid-rich extracts of <i>B. vulgaris</i> fruit protected against Fe²⁺-mediated brain damage by suppressing MAO activity in a concentration-dependent manner. HPLC-DAD profiling of the extracts identified quercetrin, apigenin, rutin, myricetin, iso-quercetrin, <i>p</i>-coumaric acid, ferulic acid, caffeic acid, and gallic acid. Molecular docking studies revealed quercetrin, apigenin, rutin, iso-queretrin, and myricetin were the top docked bioactive flavonoids against the five top target proteins (α-amylase, α-glucosidase AchE, BchE, and MAO). Molecular dynamic simulations revealed that the complexes formed remained stable over the course of the simulation. Collectively, the findings support the prospect of flavonoid-rich extracts of <i>B. vulgaris</i> root functioning as a dual therapy for T2D and AD.