Molecular docking studies on analogues of quercetin with alanine:alanine ligase of Helicobacter pylori

Helicobacter pylori (Hp) is a human pathogen associated with myriad of diseases such as gastritis, peptic ulceration, piles and gastric cancer. The resistance of Hp against antimicrobial agents has increased just as that of other pathogens worldwide, thus emphasizing an urgent need for developing new antibacterial agents. The d-alanine:d-alanine ligase (Ddl, EC 6.3.2.4) has been considered as a putative antimicrobial drug target and a lot of inhibitor screening efforts have been made. Quercetin, a member of the flavonoids, characterized by a flavone nucleus composed of two benzene rings linked through a heterocyclic pyrone ring is reported to possess antibacterial activity against H. pylori Ddl (HpDdl) enzyme. In this milieu, we have performed molecular docking analysis of quercetin and its analogues at the active site of HpDdl. Some of the screened compounds showed better affinity and interaction with HpDdl enzyme. The docking analysis and absorption, distribution, metabolism and toxicity study forward few of them as plausible lead molecule or a novel class of drugs with enhanced pharmacological properties.