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This is the first study to assess antiviral activity against human influenza virus A/Aichi/2/68 and bird influenza virus A/chicken/Kurgan/05/2005 and phytochemical characteristics of an ethanol extract of Cacalia hastata L. from wild populations growing in the vicinity of Tomsk, Russia (mixed forest). A log10 neutralization index—an indicator of inhibition of virus replication by the extract from C. hastata leaves—was ≤2 lg for each influenza virus. The extract reduced the infectivity of the human influenza virus by 1.5-fold and that of the avian influenza virus by 1.7-fold. The phytochemical characterization of C. hastata (its various organs) showed that the largest amount of the tested biologically active substances is present in leaves and rhizomes.

The hairy root culture of halophyte Nitraria schoberi was obtained by transforming seedlings' primary leaves with a wild strain of Agrobacterium rhizogenes 15834 SWISS (transformation frequency was 78.7%). The roots' transgenic status was confirmed by PCR analysis using rolB-, rolC-, virC-, virD1-specific primers. There was a significant increase in the biosynthesis of flavonoids, hydroxycinnamic acids, pectins, protopectins and saponins in hairy roots as compared to intact plant roots. The сatechin content in ethanol extracts of transformed roots' exceeded this factor 3.8 times in plant roots, but the compound composition of catechin nature in the latter was more diverse. The high antiviral activity of N. schoberi hairy root ethanol extracts against influenza virus subtypes A(H5N1), A(H3N2) was revealed, which manifested itself in the effective inhibition of infectivity both in vitro-in MDCK cell culture-and in vivo increasing survival of mice infected with them.