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

Won-Kyung Cho; Nam-Hui Yim; Myong-Min Lee; Chang-Hoon Han; Jin Yeul Ma

doi:10.3389/fphar.2022.899181

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

Front Pharmacol. 2022 Jun 30:13:899181. doi: 10.3389/fphar.2022.899181. eCollection 2022.

Authors

Won-Kyung Cho¹, Nam-Hui Yim¹, Myong-Min Lee¹, Chang-Hoon Han², Jin Yeul Ma¹

Affiliations

¹ Korean Medicine Application Center, Korea Institute of Oriental Medicine, Daegu, South Korea.
² College of Veterinary Medicine, Jeju National University, Jeju, South Korea.

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.

Keywords: broccoli leaf ethanol extract; hemagglutinin; influenza A virus; viral attachment; virucidal effect.