Bryophytes, phylogenetically placed between algae and pteridophytes, are divided into three classes, mosses, liverworts, and hornworts. Bryophytes are a source of traditional medicines throughout the world. Bryophyte phytochemistry is a fascinating research niche as some compounds - such as secondary metabolites - from these sources have been found to have bioactive properties. Liverworts and other bryophytes have yielded a rich array of secondary metabolites. Many of these compounds are characterized by unprecedented structures, and some have not been found in any other plants, fungi, or marine organisms. Among the bryophytes, the chemical constituents of liverworts and their biological activity have been studied in the most detail. In this article, Agnieszka Ludwiczuk (Medical University of Lublin, Poland) and Yoshinori Asakawa (Tokushima Bunri University, Japan) review the chemistry of the liverworts, mosses, and hornworts. The researchers highlight medicinal properties of different compounds such as the neuroprotective activity of dimeric herbertane-type sesquiterpenoids, mastigophorenes and secoaromadendrane-type sesquiterpenoids, marchantin-type cyclic bisbibenzyls with muscle-relaxant activity, or ent-longipinane-type sesquiterpenoids with acetylcholinesterase inhibitory activity, among others.
