The effect of Virgin coconut oil in the inhibition of SARS-CoV-2 via direct virus inactivation and regulation of inflammatory response via TLR4 receptor

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection presents a significant number of patients have died till date. Some drug and herbal extracts have been approved for the treatment of coronavirus disease 2019 (COVID-19) in several countries, but its use has not decreased mortality rates. Virgin coconut oil (VCO) is the purest form of coconut oil that consists mainly of medium chain saturated fatty acids. For over many decades, the biological properties of VCO have been widely explored and investigated due to their antimicrobial potentials. In the study, VCO had EC50 of 0.1 ± 0.02 mg/mL against Vero E6 cells. VCO concentrations were capable of blocking protein synthesis. In addition, they significantly decreased virus-induced cytokine release and viral protein/RNA levels in the mice lung epithelial cell line and the LPS-mediated secretion of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-12 p40, but not IL-10 in macrophages. LPS (lipopolysaccharide)-induced activation of mitogen-activated protein kinases [MAPKs; extracellular signal-regulated kinase (ERK) 1/2 and p38] and supreoxide generation, NADPH oxidase activities, and phosphorylation of Ser345 of p47phox, one of the key intracellular events associated with NADPH oxidase was significantly inhibited by pre-treatment with VCO or Dexamethasone in macrophages. Furthermore, VCO inhibited viral replication by inactivating the virion and showed additive-to-synergistic efficacy against SARS-CoV-2 when used in combination with remdesivir. Collectively, these data indicated the first time that VCO regulates LPS-induced inflammatory responses through TLR4 (toll lile receptor 4)-dependent manner and is capable of inhibiting SARSCoV-2 replication by inactivating the virion. Our data may prompt additional investigation on the clinical usefulness of VCO for preventing or treating COVID-19 and suggest novel approaches for excessive inflammatory responses.

Keywords: Covid-19, Virgin coconut oil, inflammation