E.I. Filippova - Post-graduate Student, State Research Center of Virology and Biotechnology «Vector», Koltsovo, Novosibirsk region
E.V. Makarevich - Post-graduate Student, State Research Center of Virology and Biotechnology «Vector», Koltsovo, Novosibirsk region. E-mail: makarevich@vector.nsc.ru
V.A. Kostikova - Junior Research Scientist, Central Siberian Botanical Garden SB RAS, Novosibirsk

Currently, for the purposes of a specific influenza therapy using drugs adamantane series, do not allow the virus to enter the cell, and neuraminidase inhibitors that prevent budding of viral particles. Both groups of compounds have drawbacks, namely adamantane derivatives is - a narrow specificity, relatively high toxicity and rapid development of resistance strains to drugs and to neuraminidase inhibitors - a somewhat lower clinical efficacy, the formation of resistant variants and the high cost of synthesis [1, 2]. Therefore, the search for new, more effective means for the prevention and treatment of influenza, including those of medicinal plants, is extremely important. We have previously [3] shown that extracts of Alchemilla vulgaris, Salvia officinalis, Agrimonia pilosa, Monarda fistulosa, Hyssopus officinalis, Lathyrus vernus and Spiraea salicifolia inhibit the reproduction of the human influenza virus A/Aichi/2/68 (H3N2) and avian A/chicken/Kurgan/05/2005 (H5N1) in cell culture MDCK (neutralization indices (NI) these strains under the influence of plant extracts comprised from 2.0 to 5.5 lg, a selectivity index of 10 to > 200). In this paper we have investigated the virucidal effect of extracts of these plants on the influenza virus. It is established that ethanol extracts of Alchemilla vulgaris, Spiraea salicifolia, Agrimonia pilosa, Monarda fistulosa and Lathyrus vernus showed virucidal activity against influenza virus А/H3N2, a similar activity against influenza virus А/H5N1 showed extracts of Hyssopus officinalis and Lathyrus vernus (IN from 3.0 to 3.7 lg). The study of the protective action of plant extracts in mice infected with ten 50 % lethal dose (10 LD50) of the virus A/Aichi/2/68(H3N2) showed that the protective effect detected extracts of Alchemilla vulgaris and Agrimonia pilosa (the number of surviving after infection animals when the data extracts was 20 and 40 %, and the average life span of mice was 9.4 ± 2.1 and 10.6 ± 3.0, respectively, for a commercial anti-influenza drug Tamiflu® figures were 60 % and 11.4 ± 3.4, respectively). Thus the ethanol extracts of Alchemilla vulgaris and Agrimonia pilosa are promising for further study in order to create drugs with anti-influenza activity.