Ethnobotanical, historical and histological evaluation of Helleborus L. genetic resources used in veterinary and human ethnomedicine

Abstract

The use of hellebore ( Helleborus ) species for medical purposes has a long-standing tradition. Our work aimed at providing a historical survey of their medicinal application in Europe, and data on current ethnobotanical use of H. purpurascens Waldst. et Kit. in Transylvania (Romania), compared with earlier records of this region and other European countries. While the chemistry and pharmacology of hellebores have been researched extensively, little is known about their anatomical traits. Thus, we intended to provide a detailed histological analysis of Helleborus odorus Waldst. et Kit., H. purpurascens , and H. niger L., based on transverse sections of aerial parts and root. Our survey revealed that H. purpurascens is known for immunotherapy, wounds, and as antiemetic drug in ethnoveterinary medicine, but not in human therapy in the study area. Distinctive histological characters included diverse stele structure in the root; sclerenchymatous bundle caps around compound vascular bundles in the stem and the main leaf veins of H. odorus ; and amphistomatic leaves in H. purpurascens . Quantitative vegetative traits also revealed significant differences among species, but they may reflect environmental influences, too. In all three species the sepal was hypostomatic with mesomorphic stomata, while the modified petal comprised a proximal nectar-producing and a distal non-secretory part. Distinctive floral traits included shape of modified petal, presence of papillae and thickness of non-secretory part; as well as ornamentation of tricolpate pollen grains. Our findings suggest that the anatomy of various plant parts varies slightly with each species, including ethnomedicinally known H. purpurascens , even though the basic structure is the same within the genus.

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