Triterpenoid Saponins from a Siberian Chemorace of the Thalictrum Genus

Abstract

Plants of the Thalictrum genus (Ranunculaceae family) grow in the temperate zones of the both hemispheres of the globe. Many of these species are met worldwide. Thalictrum minus, for example, is known in Europe, Asia, and North America. However, secondary metabolism in this species is variable. Thus, in the Bulgarian population of the plant a bisbenzylisoquinoline alkaloid, thalicarpin, has been isolated as a major secondary metabolite [1], whereas the Moldavian chemorace met hereabout produces a secoprotoberberine base, β-allocryptopine [2]. In general, all the Thalictrum species were thought to serve as producers of diverse isoquinoline and, on rare occasions, of diterpene alkaloids. T. minus widely spreads from east to west over the whole territory of Russia and is involved in the Siberian biocenoses. That is why 15 years ago we tried to assess its potential as a producer of alkaloids. However any tertiary bases have not been detected. Instead, we have found a fairly large amount of saponins. This seemed strange, since earlier in the literature there were only scarce and unreliable data on the presence of saponins of unidentified structure in the representatives of this genus. Therefore, we decided to concentrate all research efforts on the elucidation of the chemical nature of the glycosides found.