This review, covering the literature from 1844 to present (end 2017), probes questions concerning small molecule metabolites derived from lichens (lichenized fungi) and their impact in terms of providing compounds with significant promise in oncology. The review gives an overview of lichenized fungi and summarizes the classes of compounds obtained as metabolites from these organisms. A definition of what characteristics an actual “promising” anticancer compound should possess is also delineated. The review reports a brief overview on human cancer and then goes into depth in listing compounds with so-called “anticancer properties” that have been isolated from lichenized fungi, according to their small molecule structural classes. Five “most promising” compounds are discussed in-depth, also considering the possibility of obtaining sufficient amounts for further investigations.
