Human Immune Response to COVID-19 Infection and Potential Role of Chloroquine Family of Drugs: A Review

Currently, world is witnessing a massive morbidity and mortality due to COVID-19 pandemic.  A novel strain of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). The virus enters inside the body and infect the cells through angiotensin-converting enzyme 2 (ACE2) receptor. The S1 protein of SARS-CoV-2 binds to the ACE2 receptor which results in endocytosis and transfer of virus into endosomes of body cells. Entry of SARS-CoV-2 results in activation of innate immune responses first followed by adaptive immune responses. The effective host immune responses are crucial to control and prevent viral infection. However, excessive production of proinflammatory cytokines and decrease in number of T-lymphocytes are the major reasons associated with severity of COVID-19. Therapies and drugs that can modulate the immune responses appropriately may play a crucial role to control and prevent the progression of disease. Chloroquine (CQ) and hydroxychloroquine (HCQ) have anti-inflammatory, immunomodulatory, antitumor, antimicrobial and antithrombotic effects. These drugs have already been registered in many countries to treat arthritis, lupus and malaria. The treatment responses of COVID-19 patients to these drugs have been found positive in some cases and clinical studies are underway for evaluating these drugs for the same. However, there are some serious side effects and health hazards associated. Many regulatory bodies are demanding more conclusive data on efficacy and safety from the clinical studies. Moreover, some regulatory bodies such as Food and Drug Administration (FDA) and European Medicines Agency (EMA) have recommended to use these drugs in emergency and chronic situation to treat critically ill COVID-19 patients under doctor’s supervision with all issued guidelines. The national task force (NTF) set up by Indian Council of Medical Research has recommended high risk individuals to take HCQ for prophylaxis. This review summarizes human immune response and various aspects of CQ and HCQ with special reference to COVID-19

Therapeutic Potential of Olive’s Bioactive Compounds in COVID-19 Disease Management: A Review

In this present time the world is continuously discovering effective treatment strategies for controlling the Coronavirus disease - 2019 (COVID-19). Many researchers have focused on designing drugs which can affect replication or protease activity of coronavirus. The clinical testing and regulatory approvals for these drugs will take time. However, currently there is an urgent requirement of treatment strategies which are safe, effective and can be implemented through readily available products in market. Many plant derived products rich in secondary metabolites having potential health benefits and antimicrobial properties. The olive plant leaf extracts and olive oil are rich sources of secondary metabolites such as phenols (oleuropein and hydroxytyrosol) and terpenoids (oleanolic, maslinic and ursolic acid). These compounds have been used as an effective antiviral agents in the past. The phenolics affect the virus attachment and replication. Whereas, the terpenoids mainly affects the membrane fluidity of the virus. In the recent molecular docking studies, it was found that, these compounds effectively bound to Mpro and 3CLpro protease sites of SARS-CoV-2 and were predicted to affect the replication of the SARS-CoV-2. Apart from antiviral properties, these bioactive compounds possess various other pharmacological properties such as anti-inflammatory, anti-modulatory, anti-thrombotic and anti-oxidative. The olive oil is consumed as a source of dietary fat and is the secret behind the good health in Mediterranean people. The consumption of olive oil is safe and is believed to increase the immunity against various infectious microbes. Hence olive products can be explored in management of COVID-19. In this review the various properties of phenolic and terpenoid compounds found in olives were discussed in the context of COVID-19