Broccoli Leaves Attenuate Influenza A Virus Infection by Interfering With Hemagglutinin and Inhibiting Viral Attachment

Abstract

Broccoli (Brassica oleracea L. var. Italica) leaves are a byproduct of broccoli and could be used as a food source. The study aimed to evaluate the effect of broccoli leaves on influenza A virus (IAV) infection. We investigated the effect of ethanol extract of Broccoli leaves (EBL) on IAV infection using green fluorescent protein (GFP)–tagged Influenza A/PR/8/34 virus (PR8-GFP IAV). When EBL and PR8-GFP IAV were cotreated to RAW 264.7 cells, the fluorescence microscopy and fluorescence-activated cell sorting (FACS) analysis showed that EBL significantly reduced the levels of GFP expression by influenza viral infection dose-dependently. Immunofluorescence (IF) analysis confirmed that EBL decreased the expression of IAV proteins. EBL exhibited a strong inhibitory effect of IAV binding on the cells and moderate virucidal impact. Consistently, EBL potently suppressed the hemagglutination by IAV infection. These results indicate that EBL prevents IAV attachment via the inhibition of HA upon viral infection. Finally, EBL as an HA inhibitor of IAV could be used as the natural antiviral source to protect against influenza viral infection.

The antiviral activity of Thuja orientalis folium against Influenza A virus

“…HA of IAV is responsible for viral binding on the cells and main target for antiviral therapies. There are several reports on natural herbal extracts such as broccoli leaves ( Cho et al., 2022a ), Eupatorium perfoliatum ( Derksen et al., 2016 ), cranberry ( Luganini et al., 2018 ), and jatropha curcas Linn. leaf ( Patil et al., 2013 ), which inhibited HA activity and viral attachment into the cells.…”

Thuja orientalis folium protects against Influenza A virus via inhibition of hemagglutinin and viral binding at early stage

“…The virucidal effects of EKN are due to speci c components of the extract which have the ability to directly interact with the virus, and this inhibits viral particles from adhering to the cells. There are several recent reports on nature extracts such as Broccoli leaves ethanol extract [23], Eupatorium Perfoliatum [24], cranberry extract [25], and jatropha curcas Linn. Leaf extracts [26], which were shown to have inhibit HA activity and viral attachment into the cells.…”

Diagnostic Tools for Zoonotic Infections

“…Numerous viral families' virions attach to red blood cells to hemagglutinate them. Hemagglutination is suppressed if antibodies and viruses are combined before the inclusion of red blood cells (Cho et al 2022). Dissociating the virions using detergents can boost the hemagglutination level of some viruses, such as the canine distemper virus (Suarez et al 2020).…”