In vitro inhibitory activity of Alpinia katsumadai extracts against influenza virus infection and hemagglutination.
BACKGROUND
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.


RESULTS
In 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.


CONCLUSIONS
These 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.
Eco-Friendly Biomaterial Research Center and AI Control Material Research Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup 580-185, Republic of Korea.
Hyung-Jun
HJ
Kwon
Ha-Hyun
HH
Kim
So Young
SY
Yoon
Young Bae
YB
Ryu
Jong Sun
JS
Chang
Kyoung-Oh
KO
Cho
Mun-Chual
MC
Rho
Su-Jin
SJ
Park
Woo Song
WS
Lee
D032429:Alpinia / Q000737:chemistry*; D000818:Animals; D000998:Antiviral Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002645:Chickens; D006384:Hemagglutination / Q000187:drug effects*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects*; D053127:Influenza A Virus, H9N2 Subtype / Q000187:drug effects*; D020128:Inhibitory Concentration 50; D007723:Korea; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D053585:Virus Attachment / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
D000998:Antiviral Agents; D010936:Plant Extracts