Synthesis, crystallographic study, in silico and in vitro investigation of novel flavonol-amino acid conjugate as an anti-proliferative agent

Abstract

In this article, a flavonol-Aib conjugate; {(4-oxo-2-phenyl-4-H-chromen-3-yl-2-((start-butoxy-carbonyl) amino)-2-methyl-propanoate) (3A)} has been synthesized, purified and characterized through 1H and 13C NMR, mass spectrometry and X-ray crystallography. X-ray crystallography of these molecules revealed that this is a flavonol-Aib conjugate; there is no intramolecular hydrogen bond, while two intermolecular H-bonds occur between two molecules of flavonol-Aib conjugate, between O2 of C=O (flavonol ring) and H1 (Aib NH) is 2.183Å. This intermolecular interaction generates a stacked two-dimensional (2-D) structure. There are weak interactions between H3 of the flavonol-benzene ring and H18B of the tertiary Butyl-CH<inf>3</inf> is 2.804Å., and the same H3 interaction with other molecules' H14 of phenyl of substituted flavonol is 2.332Å. The distance between O2 of C=O (flavonol ring) and H11 (other phenyl-substituted flavonol rings) is 2.610Å, giving a specific molecular conformation. A complete molecular structure investigation of the molecule shows that several inter- and intramolecular weak to strong interactions lead to a peculiar array of molecules in two and three dimensions. In silico studies, molecular docking via Auto doc vina reveals that flavonol with 2-aminoisobutyric acid conjugate, among conjugates of different amino acids (glycine, alanine, valine, leucine, Isoleucine), Aib conjugate shows highest binding affinity with CDC42 (-7.7), BCL2L1 (-8.9), GSK3B (-6.8), MAPK1 (-8.8), PPARG (-7.4), ICAM1 (-7.8), MMP9 (8.0), BCL2 (-8.9), ERBB2 (-9,0), HSP90A1 (9.5) gene. The result of in vitro studies exhibits remarkable inhibitory ability with IC<inf>50</inf> values of 400 µg/ml. The overall outcome indicates that flavonol conjugated with 2-aminoisobutyric acid (Aib) can inhibit the growth of the MCF-7 cancer cell line by targeting multiple biological pathways. © 2025