Introduction - Vaccines and antiviral drugs are the most widely used methods of preventing or treating Influenza virus infection. The role of sea buckthorn (SBT) bud dry extract as a natural antiviral drug against Influenza was investigated.Methods - Influenza virus was cultured in the MDCK cell line, with or without SBT bud extract, and virus growth was assessed by HA and TCID50 virus titration in terms of cytopathic effect on cells. Several concentrations of extract were tested, the virus titer being measured on day 4 after infection.Results - After infection, the virus titer in the control sample was calculated to be 2.5 TCID50/ml; treatment with SBT bud extract reduced the virus titer to 2.0 TCID50/ml at 50 µg/ml, while the HA titer was reduced from 1431 (control) to 178. Concentrations lower than 50 µg/ml displayed an inhibitory effect in the HA assay, but not in the TCID50 virus titration; however, observation of the viral cultures confirmed a slowdown of viral growth at all concentrations.Discussion - Natural dietary supplements and phytotherapy are a growing market and offer new opportunities for the treatment of several diseases and disorders. These preliminary experiments are the first to show that SBT bud extract is able to reduce the growth of the Influenza A H1N1 virus in vitro at a concentration of 50 µg/ml. This discovery opens up the possibility of using SBT bud extract as a valid weapon against Influenza and, in addition, as the starting-point for the discovery of new drugs
