INTERSPECIFIC AND INTRASPECIFIC VARIATION OF PHENOLICS IN THE GENUS EQUISETUM SUBGENUS EQUISETUM

The patterns of phenolics in methanolic extracts from the overground sporophytes of all species of the subgenus Equisetum are given. From the interspecific variation in the accumulated flavonoid glycosides and other phenolics, all taxa of the subgenus can be distinguished. The retention characteristics in a standard HPLC method and maxima of the on-line UV spectra of all compounds detected are given. The HPLC method allows the quantification of phenolics in herbal remedies containing Equisetum, as well as in the crude drug material and therefore could be useful for both quality control and chemotaxonomic studies. All species show quantitative and qualitative variations during plant development. As an example, we present chromatograms of different developmental stages of E. arvense and accumulation dynamics of some phenols in that species. Phenolics accumulating in different organs of the plant are distinct. Apart from the spores, only diploid tissues are able to accumulate flavonoids. The haploid vegetative gametophytes accumulate caffeic acid esters and styrylpyrones in high contents. The rhizomes are also free of flavonoids, but contain various styrylpyrones, besides hydroxycinnamoyl esters. Styrylpyrones seem to replace flavonoids in gametophytes and sporophytic rhizomes of Equisetum species.