Fungal infections are difficult to control in plants, animals and humans. Especially in immunocompromised patients fungal infections cause major problems. There is an increasing resistance by several fungi against some fungicides. It appears that the last new antifungal framework molecule was identified 60 years ago. Since then new antifungals were mainly derivative compounds. Searching for new antifungal compounds based on traditional use has been counterproductive probably because traditional healers generally have only water available as an extractant. The antimicrobial compounds we isolated from plants were all relatively non-polar. We consequently determined the activity acetone leaf extracts of 537 South African tree species against eight important bacterial and fungal pathogens including Candida albicans. In addition to finding extracts of species with high activity, we investigated whether predictions could be made which taxa had high activity. [1]. One of the species with high activity against Candida albicans, Ptaeroxylon obliquum (Ptaeroxylaceae ) a tree occurring mainly in southern Africa was investigated in depth. A novel compound obliquumol closely related to eranthin was isolated. The compound had higher activity against Candida albicans than amphotericin B. Many natural products have high activity but may be too toxic for general use obliquumol had higher cellular safety against several cell lines than amphotericin B. It occurs in high concentrations in the tree leaves and we developed a procedure to isolate relatively large quantities. The compound also had good activity against other fungi and other promising biological activities. The low water solubility causes difficulties and derivatives have to be synthesized to overcome this problem. A preliminary docking study indicates that it targets different sites than amphotericin B. The information has been patented in Europe and the United States.
1 Pauw and Eloff BMC Complementary and Alternative Medicine 2014, 14:317