Biology, Phytochemistry, Pharmacology, and Biotechnology of European Ferns, Club Mosses, and Horsetails: A Review

Abstract

Pteridophytes found in Europe have been used for centuries for a variety of ailments but compared to angiosperms they constitute a relatively small group of medicinal plants. The term pteridophytes refer to a polyphyletic group of taxa that consists of club mosses, horsetails, psylophytes and ferns. Now, according to the Peridophyte Phylogeny Group they are members of the monophyletic class of Lycopodiopsida comprising some 1388 species and of the Polypodiopsida class which includes most of all pteridophytes (some 10,597 species). This review presents historical and updated information on pteridophyte taxonomy, secondary metabolites isolated from species screened for medicinal properties, their pharmacological activities, and the use of in vitro plant tissue culture techniques for the conservation of pteridophyte biodiversity and for the biosynthesis of their secondary metabolites. The analysis is based on a comprehensive review of the literature with the relevant papers retrieved from online databases (PubMed, Web of Science, Wiley, Science Direct, Elsevier’s Scopus, Google Scholar) and print sources (ACS Publications, SpringerLink and Elsevier journals). The analysis demonstrates that numerous pteridophyte species are a source of popular and valued herbal medicines used for the treatment of a variety of health problems and diseases. The major secondary metabolites isolated from pteridophytes and reported for their medicinal properties include alkaloids, polyphenols and flavonoids, although secondary metabolites belonging to other compound classes also may have a therapeutic value or they may modify the pharmacological activity of the major secondary metabolites. Numerous studies have demonstrated that pteridophyte extracts and their isolated secondary metabolites have a broad spectrum of pharmacological activity including anti-inflammatory, anticancer, cytotoxic, antibacterial, antiparasitic, antifungal, antiviral, and acetyl- and butyrylcholinesterase inhibitory effects. Importantly, of the 205 European pteridophyte species, only some 40 species have been investigated phytochemically and/or biologically. For some, protocols for in vitro micropropagation have been developed to aid ex-situ species conservation. Further studies are necessary to determine the composition of secondary metabolites and investigate biologically and pharmacologically the remaining 80% of the European pteridophyte flora.