In-vitro and molecular docking studies of plant secondary metabolites isolated from Hypericum oblongifolium as antibacterial agents and lipoxygenase (5-LOX) inhibitors

Abstract

Natural Products are bases for modern pharmaceuticals as they are precursors for many synthetic drugs. People also use natural products directly in the form of herbal medicines due to their less harmful effects. This research project aimed to investigate the new pharmacological potential of natural products found in Hypericum oblongifolium. Five compounds were identified from chloroform and ethyl acetate soluble fractions of H. oblongifolium. These compounds were identified as 21-β-hydroxyursolic acid (1), β-sitosterol (2), 7,4′-dihydroxy-5,3′-dimethoxyisoflavone (3), α-D-glucopyranosyl-6′-O-hexadecanoate (4), Quercetin-3′-O-ß-D-glucopyranoside (5). When these compounds were tested for antibacterial potential compound 5 showed maximum inhibition against gram-positive Bacillus subtilis and was highly active against Escherichia coli gram-negative bacterium. Minimum inhibition was shown by compounds 2 and 3 against Shigella flexneri among gram-negative bacteria. Compound 5 also exhibited the least binding energy in the molecular modeling of these compounds against Escherichia coli proteins GlcN-6-P synthase (PDB ID: 1MOQ). Compound 5 also showed good inhibition of lipoxygenase (5-LOX) enzyme with an IC50 value of 30.1 ± 0.20 as it exhibited maximum hydrogen bondings and minimum energy when docked with LOX-5 (PDB ID 3V99) using a patch dock.