In silico analysis of selected components of grapefruit seed extract against SARS-CoV-2 main protease

At the end of December 2019, first identified cases of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) started emerging. Ever since the emergence of the first case of infection with SARS-CoV-2 or COVID-19, it became the hottest research topic of numerous studies, in which scientists are trying to understand the path of infection, transmission, replication and viral action, all in order of finding a potential cure or vaccine applying various fundamental principles and methodologies. Using in silico method via AutoDock Vina 1.1.2., we analysed the binding affinity of six selected compounds from grapefruit seed extract (GSE) (narirutin, naringin, naringenin, limonin, ascorbic acid and citric acid) to SARS-CoV-2 main protease M^pro (PDB ID: 6Y84), using acetoside, remdesivir and gallic acid as a positive controls of binding affinity. Results showed highest affinity (rmsd l.b. 0.000; rmsd u.b. 0.000) for narirutin (-10.5), then for naringin (-10.1), acetoside (-10.0), limonin (-9.9), remdesivir (-9.6), naringenin (-8.2), ascorbic acid (-6.7), citric acid (-6.4) and gallic acid (-6.4), all expressed in kcal/mol. Our findings suggest that selected compounds from grapefruit seed extract represent potential inhibitors of SARS-CoV-2 M^pro, but further research is needed as well as preclinical and clinical trials for final confirmation of inhibitory functionality of these compounds.