The identification of the ability of imanin to inhibit the multiplication of plant and animal viruses has raised the task of determining which components of the drug determine its antiviral properties. In this connection, flavonoids and tannins of imanine were obtained and investigated, their effect on plant and animal viruses was studied (Derbentseva et al., 19726).
The basis of the scheme adopted for the preparation of these substances is the principle of exhaustive extraction of the material under study by various solvents – ether, ethyl acetate, acetone and water, aimed at isolating groups of substances with different degrees of polymerization.Thus, ether extracts contain monomolecular polyphenolic compounds, ethyl acetate extracts – easily hydrolysed tannins, acetone extracts – hardly hydrolyzed tannins, hot water extracts – water-soluble tannins and free carbohydrates, and finally a water-insoluble residue, which is highly condensed substances – flobophrenes.
Identification of the substances that make up each fraction was carried out by chromatographic analysis on paper, qualitative reactions to flavonoids and tannins, and removal of absorption spectra in the UV region. The hydrolysable tannins present in the ethyl acetate and acetone fractions underwent acid hydrolysis, resulting in the production of polyoxyflavone aglycones: quercetin, 7-hydroxyflavone and 2,4-dioxiflavone, as well as free fructose, glucose, galactose and rhamnose sugars. Catechins are found in the water-soluble portion of the ethyl acetate fraction and in hot water extraction. When comparing the content of tannins in the herb of St. John’s wort and imanin, it was found that the composition of all fractions extracted by organic solvents, aqueous alkali and water is not the same. For example,
The study of the antiviral activity of the obtained imanin fractions was carried out on the influenza virus in vitro by a contact method. The fractions that showed the greatest activity in these experiments were tested in in ovo experiments on chick embryos. In contact experiments, the influenza virus type A strain PR-8 was used; in experiments in ovo, influenza virus type A2 strain 2226. Virulicidal activity is most pronounced in the ether-soluble fraction comprising monomeric polyphenols, in the acetone fraction and in the water-soluble portion of the ethyl acetate fraction containing catechins and flavonoid agglucones, and in the fraction recovered by hot water, which also has catechins are found.These substances in vitro inactivate the virus group by 95-100% to the same extent as the imanin itself. The activity of the remaining fractions is less and their inactivation of the virus does not exceed 50-70%. In experiments in ovo on chicken embryos, the same fractions containing catechins and flavonoid aglycons are most active, which, like Imanin itself, completely inhibit the accumulation of viral agglutinins. The ability to inactivate the influenza virus in similar fractions obtained from the herb of St. John’s wort is somewhat weaker (50-70%).