A recently published study showed that bromelain or bromelain rich pineapple stem could be effective against COVID-19. Currently, infected patients are being treated with different anti-inflammatory, antiviral and antimalarial drugs. This research studied the effect of bromelain on ACE-2 and TMPRSS2 expression. African green monkey kidney epithelial cells (Vero E6) were chosen as the primary cell line utilized in this study. SARS-CoV-2 S-protein ectodomain that contains insect cell secretion signal was expressed.
Surface plasmon resonance technology and Luminex assay were used to determine the interaction between purified S-Ectodomain and human recombinant ACE-2. SARS-CoV-2 S-Ectodomain was tagged with a green fluorescent protein. The results revealed that bromelain (isolated from pineapple stem) diminishes the expression of TMPRSS2 and ACE-2 in VeroE6 cells and lowers the expression of S-Ectodomain in a dose-dependent manner. Bromelain’s cysteine proteolytic activity was higher in ACE-2. SARS-CoV-2 spike glycoprotein has highly sialylated N-and O-linked glycans, and bromelain managed to cleave it. These results suggest that bromelain rich pineapple stem could be used as an antiviral against COVID-19.
Ref Link: https://www.biorxiv.org/content/10.1101/2020.09.16.297366v1