Papaver somniferum for COVID-19

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.