A review on possible modes of actions of Chloroquine/ Hydroxychloroquine: Repurposing against SAR-COV-2 (COVID 19) pandemic.

Abstract The chloroquine (CQ) and its analogue hydroxychloroquine (HCQ) have been used as frontline drugs for treatment and prophylaxis against all types of human malaria worldwide. Since late December 2019, humans have been under threat due to an outbreak of a novel coronavirus (SARS-CoV-2) disease (COVID-19; previously known as 2019-nCoV), since its first reported cases in Wuhan, China [1] . Consequently, the virus infection has been declared a pandemic. While the World is finding expedited approvals for the development of vaccine, which is time dependent, being preventative and not possibly a cure, physicians and countries’ leaders are considering several concerted clinical trials suggesting that this age-old antimalarial drug, CQ/HCQ could be a potent therapeutic agent against COVID-19 infection. Based on accumulating scientific reports, we have highlighted in this review, the different possible modes of action of chloroquine/hydroxychloroquine that could particularly justify its use against viral infections. Considering the global health crisis of the COVID-19 pandemic, the option of using the drugs and repurposing of old drugs in this instance, chloroquine and hydroxychloroquine, specifically, hydroxychloroquine in the treatment of SARS-CoV-2 could be the best choice. CQ/HCQ has diverse modes of action, like alteration of acidic environment inside lysosome, late endosomes, restriction further with endocytosis, exsosome release, phagolysosomal fusion in systematically and subsequently inhibition of cytokine storm in host cell. One or sum of diverse mechanisms might work against the viral infections and help prevent more deaths. Given that there is no cure for COVID-19, the clinical testing of HCQ is urgently needed to ascertain its potency against the virus as this is the current available treatment option. There is still a need to find other innovative drug candidates as other possible candidate to go into clinical evaluation and testing.