Density Functional Theory-Based Quantum Rationalization of Flavones From Oroxylum indicum , their Correlation with Redox Effect, Molecular Interaction Studies and Osmotic Hemolysis

Four flavones (chrysin, baicalein, oroxylin A and hispidulin) characterized from ethanolic ischolar_main extract of Oroxylum indicum (a traditional dietary nutraceutical supplement), were compared with both experimental (radical scavenging action and osmotic fragility test on human erythrocytes) and theoretical (Density functional theory (DFT) (B3LYP/6-31G*) calculations and in silico docking with haemoglobin and albumin) for their redox properties. Raman spectra were examined specifically between 2900 and 3700 cm^–1 and the corresponding peaks were identified for hydroxyl group stretching vibrations. Baicalein and hispidulin had the highest and lowest binding energy respectively for oxyhaemoglobin (oxyHb) and vice versa for deoxyhaemoglobin (deoxyHb), which was one of the major findings revealed in their superposed docked structures where the position of baicalein was not changed unlike hispidulin. On the whole, baicalein is the preeminent flavone as it revealed maximum activity in various antioxidant assays, protection against osmotic fragility and binding energy with oxyHb which can be reasoned out by its least HOMO–LUMO energy gap.