In Vitro inhibitory activity of Alpinia katsumadai extracts against influenza virus infection and hemagglutination

Woo Song Lee,Hyung-Jun Kwon,Ha-Hyun Kim,Jong Sun Chang,So Young Yoon,Young Bae Ryu,Kyoung-Oh Cho,Mun-Chual Rho,Su-Jin Park

doi:10.1186/1743-422x-7-307

Woo Song Lee, Hyung-Jun Kwon + Show 7 more

Open Access

https://doi.org/10.1186/1743-422x-7-307

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Abstract

BackgroundAlpinia katsumadai (AK) extracts and fractions were tested for in vitro antiviral activities against influenza virus type A, specially human A/PR/8/34 (H1N1) and avian A/Chicken/Korea/MS96/96 (H9N2), by means of time-of-addition experiments; pre-treatment, simultaneous treatment, and post treatment.ResultsIn pre-treatment assay, the AK extracts and AK fractions did not show significant antiviral activity. During the simultaneous treatment assay, one AK extract and five AK fractions designated as AK-1 to AK-3, AK-5, AK-10, and AK-11 showed complete inhibition of virus infectivity against A/PR/8/34 (H1N1) and A/Chicken/Korea/MS96/96 (H9N2). The 50% effective inhibitory concentrations (EC50) of these one AK extracts and five AK fractions with exception of the AK-9 were from 0.8 ± 1.4 to 16.4 ± 4.5 μg/mL against A/PR/8/34 (H1N1). The two AK extracts and three AK fractions had EC50 values ranging from <0.39 ± 0.4 to 2.3 ± 3.6 μg/mL against A/Chicken/Korea/MS96/96 (H9N2). By the hemagglutination inhibition (HI) assay, the two AK extracts and five AK fractions completely inhibited viral adsorption onto chicken RBCs at less than 100 μg/mL against both A/PR/8/34 (H1N1) and A/Chicken/Korea/MS96/96 (H9N2). Interestingly, only AK-3 was found with inhibition for both viral attachment and viral replication after showing extended antiviral activity during the post treatment assay and quantitative real-time PCR.ConclusionsThese results suggest that AK extracts and fractions had strong anti-influenza virus activity that can inhibit viral attachment and/or viral replication, and may be used as viral prophylaxis.

Highlights

Alpinia katsumadai (AK) extracts and fractions were tested for in vitro antiviral activities against influenza virus type A, specially human A/PR/8/34 (H1N1) and avian A/Chicken/Korea/MS96/96 (H9N2), by means of time-of-addition experiments; pre-treatment, simultaneous treatment, and post treatment
Cytotoxicity of Alpinia katsumadai extracts in Madin-Darby canine kidney (MDCK) cells The cytotoxicity of two AK extracts and five AK fractions was evaluated by the MTT assay for 50% cytotoxic concentration (CC50)
Confluent MDCK cells were incubated with essential medium (EMEM) media in the absence or presence of two-fold diluted AK extracts (0.39-200 μg/mL) for 72 h, and the MTT reagents were treated onto the cells

Summary

Introduction

Alpinia katsumadai (AK) extracts and fractions were tested for in vitro antiviral activities against influenza virus type A, specially human A/PR/8/34 (H1N1) and avian A/Chicken/Korea/MS96/96 (H9N2), by means of time-of-addition experiments; pre-treatment, simultaneous treatment, and post treatment. There are only four antiviral agents, approved by the FDA to treat influenza virus infection and these can be divided into two groups. Nausea and vomiting are frequent among adults receiving oseltamivir [9,10]. Besides these two major groups of anti-influenza drugs, several other approaches including inhibition of viral RNA transcription (RNA polymerase), small interfering RNA, inhibition of viruscell fusion and proteolytic processing of hemagglutinin (HA) are existing; all of these alternative methods has not yet been licensed [7,11]. The need for a new drug and their market are greatly emphasized

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