Ferns: From traditional uses to pharmaceutical development, chemical identification of active principles

Abstract

Many fern species are used in traditional medicine in many countries to treat different ailments. For example, ferns belonging to the Microsorum genus such as Metuapua'a represent major medicinal plants in the pharmacopoeia of Pacific islands. These pharmacological effects concern very different diseases, but the major effects are in purgative, antibacterial, gastric and renal infection treatment, diuretic, pain killer (to treat headache, stomachaches, gastrointestinal aches), and anti-inflammatory areas. In contrast to their widespread use, ferns have not been widely investigated by phytochemical analyses, which in many cases are not directly related with the described pharmacological properties. Several classes of phytochemicals have been investigated, including both large families of secondary metabolites (e.g., steroid or phenolic compounds), as well as more specific compounds responsible for toxic/carcinogenic effects. In practice, there are only a few examples where the active principles expected to be responsible for the pharmacological effects have been identified. This is the case for ecdysteroids, which are also present in many other medicinal plants other than ferns, and also several anti-inflammatory compounds. The isolation and the identification of active principles require a combination of efficient separation methods and suitable bioassays, and in this respect, ferns should deserve more efforts in order to understand the chemical basis of their numerous pharmacological properties.