ABSTRACT
Strengthening the immune system in order to better withstand the threat of COVID-19 is an important way to ensure the protection of our health against the current pandemic associated with SARS-CoV-2. There are many ways to achieve this, but with current circumstances, certain modalities stand out as being the most valid and are certainly worth greater consideration. Here we review the effects that particular immuno-strengthening activities can have on limiting the severity of COVID-19 disease as well as preventing virus infection. Physical activity, in particular, should not be discounted as an important method of prevention of viral diseases as it triggers many biological processes within the human body which in turn lead to heightened natural defences against viral infections. When exercise is performed in forested areas, these protective health benefits may be increased since many plant species emit biogenic volatile compounds (VOCs) which, when inhaled, have many protective properties. These VOCs have been shown in particular to have immunostimulatory effects on the human body and, thus, they could be of use in the prevention and/or treatment of COVID-19. Being amongst trees may also help to alleviate stress and anxiety, lowering cortisol levels and consequently helping the proper functioning of the immune system. In the following work, we have performed an analysis of the available scientific literature which looks at the effects of physical exercise as well as 'forest-bathing' on the immune system's ability to fight disease, especially of course as it relates to COVID-19. Our review aims at shedding light on the benefits of exercising outdoors in green areas and suggests reforestation as a protective measure against future outbreaks.
ABSTRACT
<b>Background and Objective:</b> Lemongrass (<i>Cymbopogon citratus</i>) and turmeric (<i>Curcuma longa</i>) are widely used by the community for traditional medicinal spices and cooking spices. In the era of the COVID-19 pandemic, people use lemongrass and turmeric to increase immunity and protect the body from infection with the SARS-CoV-2 virus. However, the antiviral mechanisms have not been studied much. This study aims to predict the bioactivity of the phytosterol compounds of lemongrass and turmeric for COVID-19 therapy through inhibition of 3C-like protease (3CLPro) <i>in silico</i>. <b>Materials and Methods:</b> The 3CLPro protein 3D structure was downloaded from the PDB database with the access code 2ZU2 and the phytosterol compounds of lemongrass and turmeric were taken from PubChem. A total of 59 total phytosterol compounds from turmeric and lemongrass were screened for their bioactivity as an antiviral by using online PASS. Compounds with a high activating potential (Pa) were interacted with 3CLPro protein with the PyRx program and analyzed by Discovery Studio version 19.0 and LigPlus. <b>Results:</b> A total of 22 total phytosterol compounds were identified as potential antiviral agents. Based on the Pa value, 15 phytosterol compounds have the potential to act as inhibitor agents for 3CLPro SARS-CoV-2. The phytosterol compounds of lemongrass and turmeric bind to the 3CLPro protein in the N-finger domain region and the A and B domain inhibitors connect residues of the 3CLPro protein. The phytosterols of lemongrass and turmeric show a low binding affinity with 3CLPro SARS-CoV-2, indicating a strong interaction between ligand and protein. The inhibition of phytosterols against 3CLPro protein can be used as a basis for determining candidates for COVID-19 therapeutic agents. <b>Conclusion:</b> The phytosterol compounds contained in lemongrass and turmeric have the potential to act as 3CLPro inhibitors. Further studies both <i>in vitro</i> and <i>in vivo</i> need to be done to prove the inhibitory potential of phytosterol compounds.