Herbs for boosting immunity 

Turmeric, also known as ""Indian saffron"," is collected from the roots of the turmeric plant (Curcuma longa) and contains curcumin as an active ingredient. Curcumin is ""generally recognized as safe"" by the Food and Drug Administration (FDA).¹ The medicinal properties of turmeric are mainly due to the three main active ingredients: curcuminoids-curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Curcumin demonstrates various pharmacological activities, including antioxidant, anti-inflammatory, anti-bacterial, antiviral, and immunomodulatory activity.² Different toxicological studies have shown that  doses up to 12 g in humans are quite safe.³

Different studies in animal models disclosed that curcumin supplementation might help in interrupting cough, sore throat, to several respiratory diseases, more specifically, acute respiratory distress syndrome (ARDS), acute lung injury, pneumonia, pulmonary fibrosis, and sepsis, by modulating inflammation and oxidative stress ². Various research has shown that it can directly interact with numerous signaling biomolecules and has therapeutic potential against a wide range of inflammatory and infectious diseases caused byfungi, bacteria, and viruses. It is active against both RNA and DNA viruses¹. Because of the easy availability and potential antioxidant property, wound healing properties, anti-inflammatory, antiviral, and anti-bacterial nature, the use of turmeric has increased in the present world scenario, which is facing the pandemic of Coronavirus disease 19 (COVID-19/2019-nCoV) caused due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Majority of the infected population experiences mild to moderate respiratory infection.  The major risk factors associated with greater severity and mortality caused by COVID-19 include hypertension, diabetes mellitus, cardiovascular disease (CVD), advanced age, and obesity.

Various drugs have been approved by the FDA for patients with COVID-19, and the process is still ongoing. Many existing drug moieties, both synthetic and natural been virtually screened to discover a potential antiviral agent against SARS-CoV-2. Clinical studies have demonstrated the effects of nano-encapsulated curcumin in patients with COVID-19. Studies have shown a significant reduction in clinical manifestations like fever, cough, dyspnea in patients with mild and severe COVID-19 when treated with nanocurcumin⁴.

Wen et al. revealed that curcumin inhibited viral replication at concentrations of 3–10 µMin vitro analyses against the SARS-CoV virus in Vero-E6 cells. Based on such data regarding antiviral activity, researchers worldwide are using in silico prediction models to evaluate curcumins efficacy against the binding proteins of SARS-CoV-2 and its cellular receptors. 

Patients with a more severe infection of COVID-19 develop acute respiratory distress syndrome (ARDS). It was observed that ARDS arises in 42% of COVID‐19 patients with pneumonia and 61–81% of those requiring intensive care⁵. Studies have shown that inadequate MV and inappropriate setting of mechanical ventilation caused  lung damage, also known as  ventilator-induced lung injury (VILI)) in patients suffering from acute respiratory distress syndrome (ARDS).⁶ Ventilator-induced lung injury (VILI) causes lung expansion conversion into biochemical signals, resulting in increased activation of inflammatory cells^7,8. Wang et al. experimentally showed that curcumin inhibited the inflammatory cells and oxidative stress, causing lung damage due to VILI, reducing edema and lung injury partly through the NF-κB pathway and also through the reestablishment of the redox balance from the recovery of total antioxidative capacity.^9,10 Also curcumin shows anti-inflammatory effect which is mediated through the induction of PPAR-γ up-regulation and represses the inflammatory process by reducing cytokine production. Hence curcumin present in turmeric may further help protect against lung injury associated with VILI in COVID¹¹. Hence; turmeric is the most common household remedy for different diseases, including cough, sore throat, and respiratory ailments.

References

1. Parks, M. R. J. a. R. J. Curcumin as an Antiviral Agent. Viruses;2020 12, 1242.
2. Kumar Mudnakudu Nagaraju, Chandan Shivamallub, K.J. Thirumalai, Subramaniamd, Arun Radhakrishna, ND Suresh Bhojrajc, Gowthamarajan Kuppusamy, R. K. T. Antiviral and immunomodulatory activity of curcumin: A case for prophylactic therapy for COVID-19. Heliyon; 2021, 7.
3. Christopher D Lao, M. T. R., Daniel Normolle, Dennis D Heath, Sandra I Murray, Joanne M Bailey, Martha E Boggs, James Crowell, Cheryl L Rock, and Dean E Brenner. Dose escalation of a curcuminoid formulation. BMC Complement Altern Med; 2006, 6, 1-4.
4. Bruna A. C. Rattis, G. R. a. R. N. C. Curcumin as a Potential Treatment for COVID-19. Front. Pharmaco 2021, 12, 1-14.
5. Peter G Gibson, c. a. L. Q., 2 and Ser Hon Puah 3. COVID‐19 acute respiratory distress syndrome (ARDS): clinical features and differences from typical pre‐COVID‐19 ARDS. Med J Aust. 2020.
6. Giacomo Grasselli, E. C., Gaetano Florio, Mariachiara Ippolito, Alberto Zanella, Andrea Cortegiani, Jianbo Huang, Antonio Pesenti & Sharon Einav Mechanical ventilation parameters in critically ill COVID-19 patients: a scoping review. Critical Care 2021, 25, 1-11.
7. Jeremy R. Beitler, A. M., and B. Taylor Thompson,. Ventilator-Induced Lung Injury. Clin Chest Med.  2016, 37, 633–646.
8. Pedro Leme Silva , D. N., Patricia Rieken Macêdo Rocco Mechanisms of ventilator-induced lung injury in healthy lungs. Best Pract Res ClinAnaesthesiol., 2015, 29, 301-313.
9. XunWang, X. A., Xiaocen Wang, ChenBa, Jing Li, DongYang, Chunxue Bai. Curcumin ameliorated ventilator-induced lung injury in rats. Biomedicine & Pharmacotherapy., 98, 754-761.
10. Bruna A. C. Rattis, G. R. a. N. C. Curcumin as a Potential Treatment for COVID-19. Front. Pharmacol., 2021, 12, 1-14.
11. Carmen Ciavarella 1, I. M., Sabrina Valente 1, Gianandrea Pasquinelli 1. Pharmacological (or Synthetic) and Nutritional Agonists of PPAR-γ as Candidates for Cytokine Storm Modulation in COVID-19 Disease. Molecules., 2020, 25, 1-15.