Helleborus caucasifcus and Helleborus abchasicus: An Integrative Review of Taxonomy, Ecology, Phytochemical Diversity, and Conservation

Helleborus caucasicus and Helleborus abchasicus are two Caucasian taxa of the family Ranunculaceae with considerable botanical, pharmacognostic, and phytochemical interest. However, knowledge of these plants remains fragmented across historical and contemporary publications, including a substantial body of literature published in Russian and Georgian, which limits its accessibility to the international scientific community. This narrative review synthesizes available evidence on their taxonomy, morphology, anatomical characteristics, distribution, ecology, phytochemical composition, biological activities, traditional uses, toxicity, and conservation. Attention is given to taxonomic uncertainties, intraspecific anatomical variability, and differences in research coverage between the two taxa. H. caucasicus has been more extensively investigated for steroidal constituents, including furostanol and spirostanol glycosides, caucasicosides A–M, ecdysteroids, and bufadienolides, whereas the phytochemistry of H. abchasicus remains comparatively underexplored. Studies of both species have also revealed complex lipid profiles influenced by plant organ, lipid class, and cultivation conditions. Available experimental evidence indicates cytotoxic and apoptosis-related effects of certain constituents of H. caucasicus, together with anti-inflammatory and wound-healing activities of lipid preparations from both species. Nevertheless, these findings remain predominantly preclinical, and species-specific toxicological evidence is insufficient. Conservation studies further reveal declining natural populations and variable outcomes of ex situ cultivation and reintroduction.