Secondary metabolites from endangered Gentiana, Gentianella, Centaurium, and Swertia species (Gentianaceae): promising natural biotherapeutics

Gentianaceae have a long history of use as traditional remedies for the treatment of various ailments. The medicinal properties of crude herbal drug are attributed to bitter glycosides, flavonoids, and xanthones, the main plant secondary metabolites. These plant-derived molecules, especially naturally occurring xanthones, possess a broad spectrum of bioactivity, being anticarcinogenic, antimicrobial, neuroprotective, antidiabetic, and cardioprotective. Most Gentianaceae species are rare and endangered by uncontrolled overharvesting and influences of various environmental factors (habitat loss, climate change, and invasive species spreading). The decline of Gentianaceae species poses a high risk to the loss of an enormous diversity of potentially bioactive compounds. In this chapter we will summarize the pharmacological activities of identified secondary metabolites from endangered species belonging to four Gentianaceae genera (Gentiana, Gentianella, Centaurium, and Swertia), as well as the importance of biodiversity conservation in the context of their biotherapeutic potential.