Campus Units

Food Science and Human Nutrition, Kinesiology, Veterinary Pathology

Document Type

Article

Publication Version

Published Version

Publication Date

2013

Journal or Book Title

PLOS ONE

Volume

8

Issue

9

First Page

e76491

DOI

10.1371/journal.pone.0076491

Abstract

Hypericum perforatum (H. perforatum) ethanol extract has been found to inhibit lipopolysaccharide-induced production of inflammatory mediators and cytokines in cultured macrophages. Therefore, it may be able to protect the host from excessive inflammation during viral infection. In the current study, the immune-regulatory effect of H. perforatum extract was evaluated in A549 lung epithelial cells and BALB/c mice exposed to Influenza A/PR/8/34 H1N1 virus. In A549 cells, the extract (30 µg/mL) significantly inhibited influenza virus induced monocyte chemotactic protein (MCP)-1 and interferon-γ induced protein 10 kD (IP-10), but dramatically increased interleukin-6 (IL-6). In mice inoculated intranasally with 107.9 EID50 of Influenza A/PR/8/34 H1N1 (high dose), daily oral treatment of H. perforatum extract at a rate of 110 mg/kg of body weight increased lung viral titer, bronchoalveolar lavage (BAL) proinflammatory cytokine and chemokine levels, and the infiltration of pro-inflammatory cells in the lung 5 days postinoculation, as compared to ethanol vehicle treated mice. Transcription of suppressor of cytokine signaling 3 (SOCS3) was increased by H. perforatum extract both in A549 cells and BALB/c mice, which could have interrupted anti-viral immune response and thus led to the inefficient viral clearance and increased lung inflammation. H. perforatum treatment resulted in minor reduction in viral titer without affecting body weight when mice were inoculated with a lower dose (~105.0 EID50) and H. perforatum was applied in the later phase of infection. Mice challenged intranasally with high dose of influenza virus (107.9 EID50) suffered from a higher mortality rate when dosed with H. perforatum extract. In conclusion, the current study showed that SOCS3 elevation by H. perforatum may cause impaired immune defense against influenza virus infection and lead to higher mortality.

Comments

This article is published as Huang N, Singh N, Yoon K, Loiacono CM, Kohut ML, et al. (2013) The Immuno-Regulatory Impact of Orally-Administered Hypericum perforatum Extract on Balb/C Mice Inoculated with H1n1 Influenza A Virus. PLoS ONE 8(9): e76491. doi:10.1371/journal.pone.0076491

Copyright Owner

Huang et al.

Language

en

File Format

application/pdf

Share

COinS