Attenuation of influenza virus infectivity with herbal-marine compound (HESA-A): an in vitro study in MDCK cells

Abstract

Abstract Background The influenza virus is still one of the most important respiratory risks affecting humans which require effective treatments. In this case, traditional medications are of interest. HESA-A is an active natural biological compound from herbal-marine origin. Previous studies have reported that the therapeutic properties of HESA-A are able to treat psoriasis vulgaris and cancers. However, no antiviral properties have been reported. Methods This study was designed to investigate the potential antiviral properties of HESA-A and its effects in modulating TNF-α and IL-6 cytokine levels. HESA-A was prepared in normal saline as a stock solution (0.8 mg/ml, pH = 7.4). Percentages of cell survival when exposed to different concentrations of HESA-A at different time intervals was determined by MTT assay. To study the potential antiviral activity of HESA-A, Madin-Darby Canine Kidney (MDCK) cells were treated with the effective concentration (EC50) of HESA-A (0.025 mg/ml) and 100 TCID50/0.1 ml of virus sample under different types of exposure. Results Based on the MTT method and hemagglutination assay (HA), HESA-A is capable of improving cell viability to 31% and decreasing HA titre to almost 99% in co-penetration exposures. In addition, based on quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA), it was found that HESA-A causes decrements in TNF-α and IL-6 cytokine expressions, which was significant for TNF-α (p ≤ 0.05) but not for IL-6. Conclusion In conclusion, HESA-A was effective against influenza infection through suppressing cytokine expression.