Carboline derivatives based on natural pityriacitrin as potential antifungal agents

Abstract

Carboline alkaloids are a class of important heterocyclic natural products, which usually present extensive bioactivities. During the course of our research for active compounds from natural products, the pityriacitrin and pityriacitrin B belonged carboline alkaloids have been isolated from a Chinese Burkholderia sp. NBF227, which indicated potential antifungal activities. So, in order to develop these carboline alkaloids as potential fungicidal agents, a series of pityriacitrin derivatives were investigated for their antifungal activities against Phytophthora capsici , Sclerotinia sclerotiorum , Botrytis cinerea and Rhizoctonia solani , and the results demonstrated that compounds 4 , 10 and 19 displayed broad-spectrum antifungal activities. In addition, in vivo bioassay also indicated that compounds 4 and 10 could protect the pepper leaves and grape fruits against infection by P . capsici and B . cinerea , respectively. The possible mechanism of antifungal action for these compounds was also explored. • Carboline derivatives displayed broad-spectrum in vitro fungicidal activities. • Compounds 4 and 10 could protect the pepper leaves against infection by P. capsici. • Compounds 4 could protect the grape fruits against infection by B. cinerea. • The possible mechanism of antifungal action for compound 4 has also been explored.