Correlation between Plant Secondary Metabolites and Their Antifungal Mechanisms–A Review

Abstract

The search for new antifungal drugs often involves secondary metabolites from plants because of their pharmacological activity against foreign pathogens. Among the modern drugs in use today about 40% are of natural origin. To distinguish the secondary metabolites they can be divided into groups based on their structure or biosynthetic origin. When searching for new antifungal agents it is crucial to search for a mechanism of action for which unwanted side effects can be avoided. This can be done if the mechanism of action only involves fungal cells and not mammalian cells. For that reason it is interesting to investigate a relation between the biosynthetic origin of the antifungal compound and it’s mode of action against fungi. This correlation could limit the search to those natural compounds, which only interferes with the target of interest. This review is based on a comprehensive literature search for existing knowledge about antifungal mechanisms of different secondary metabolites from plants. The secondary metabolites have been grouped into three major groups according to their biosynthetic origin, and into subgroups according to their structure. There seems to be a correlation between the biosynthetic group of terpenes and their antifungal mechanisms of action, all of them exhibiting their antifungal action through cell membrane disruption, although some of the terpenes also seemed to work through mitochondrial dysfunction. A clear correlation has not been demonstrated between the two other biosynthetic groups of secondary metabolites; the phenolic compounds and the nitrogen containing compounds. Despite this there are correlations between some of the subgroups and their antifungal mechanism of actions.