Noscapine for COVID-19

Abstract Background The recent outbreak of the Coronavirus pandemic resulted in a successful vaccination program launched by the World Health Organization. However, a large population is still unvaccinated, leading to the emergence of mutated strains like alpha, beta, delta, and B.1.1.529 (Omicron). Recent reports from the World Health Organization raised concerns about the Omicron variant, which emerged in South Africa during a surge in COVID-19 cases in November 2021. Vaccines are not proven completely effective or safe against Omicron, leading to clinical trials for combating infection by the mutated virus. The absence of suitable pharmaceuticals has led scientists and clinicians to search for alternative and supplementary therapies, including dietary patterns, to reduce the effect of mutated strains. Main body This review analyzed Coronavirus aetiology, epidemiology, and natural products for combating Omicron. Although the literature search did not include keywords related to in silico or computational research, in silico investigations were emphasized in this study. Molecular docking was implemented to compare the interaction between natural products and Chloroquine with the ACE2 receptor protein amino acid residues of Omicron. The global Omicron infection proceeding SARS-CoV-2 vaccination was also elucidated. The docking results suggest that DGCG may bind to the ACE2 receptor three times more effectively than standard chloroquine. Conclusion The emergence of the Omicron variant has highlighted the need for alternative therapies to reduce the impact of mutated strains. The current review suggests that natural products such as DGCG may be effective in binding to the ACE2 receptor and combating the Omicron variant, however, further research is required to validate the results of this study and explore the potential of natural products to mitigate COVID-19. Graphical abstract

Noscapine is a naturally occurring alkaloid isolated from Papaver somniferum, commonly known as opium poppy or bread seed poppy. It edges over other opioids as it lacks addictive, sedative or euphoric effects. This review chronicles the saga of endeavours with noscapine, from modest efforts in the mid-1950s to its present anticancer potential and futuristic hope in combating COVID-19. We comprehensively searched for publications including noscapine- and noscapinoid-relevant keywords in different electronic databases such as PubMed, Google Scholars, Elsevier, Springer Link and Science Direct up to June 2023. We excluded those in a language other than English. Noscapine has long been used as an antitussive and suppresses coughing by reducing the activity of the cough centre in the brain. A great number of water-soluble noscapine analogues have been found to be impressive microtubule-interfering agents with a superior antiproliferative activity, inhibiting the proliferation of cancer cell lines with more potency than noscapine and bromo-noscapine. With enhanced drug delivery systems, noscapine has exerted significant therapeutic efficacy in animal models of Parkinson’s disease, polycystic ovary syndrome, multiple sclerosis and other disorders. Furthermore, the merit of noscapine in crossing the blood–brain barrier makes it a putative candidate agent against neurodegenerative and psychiatric diseases. Its long safety record, widespread availability and ease of administration make it an ideal candidate for fighting several life-threatening conditions. Recent promising docking studies onnoscapine with main protease (Mpro) of SARS-CoV-2 paves the way for combinatorial drug therapy with anti-viral drugs and is hopeful in fighting and triumphing over any future COVID-19 pandemic.