Acrodontiolamide, a rare chlorinated fungal metabolite, and five bioactive α-Pyrones from an endophytic Nigrospora sp.

Endophytic microorganisms are recognized as potential sources of novel bioactive compounds for pharmaceutical applications. This study [ 1 ] investigated the secondary metabolites produced by an endophytic Nigrospora sp. isolated from the Nigerian plant, Gongronema latifolium . Standard procedures were used for fungal isolation, taxonomic identification, fermentation, and extraction of secondary metabolites. Chromatographic and spectroscopic techniques were used to isolate and characterize compounds from the fungal extract. The fungal extract yielded a rare chlorinated metabolite, acrodontiolamide ( 1 ), and five α-pyrone derivatives: hydroxypestalopyrone ( 2 ), pestalopyrone ( 3 ), pestalotiopyrone D ( 4 ), cis -4-hydroxymellein ( 5 ), and trans -4-hydroxymellein ( 6 ) ([ Fig. 1 ]). Acrodontiolamide, like many fungal secondary metabolites, has a nitro group attached to an aromatic ring. However, unlike typical fungal secondary metabolites where chlorination occurs on the aromatic ring, chlorination in acrodontiolamide occurs on its aliphatic moiety. Few natural product compounds have been reported with monochlorination on the aliphatic C3 chain, making this type of halogenation uncommon. Notably, this study marks only the second report of acrodontiolamide in nature, following its initial discovery in 1993 [ 2 ]. Acrodontiolamide and the five α-pyrone derivatives have been reported to possess various pharmacological activities, including antimicrobial, cytotoxic, anticancer, and antimalarial properties [ 2 ] [ 3 ] [ 4 ] [ 5 ], highlighting their potential in drug development and the value of endophytic microorganisms as sources of new bioactive compounds. Fig. 1 Acrodontiolamide ( 1 ) and five α-pyrone derivatives: hydroxypestalopyrone ( 2 ), pestalopyrone ( 3 ), pestalotiopyrone D ( 4 ), cis -4-hydroxymellein ( 5 ), and trans -4-hydroxymellein ( 6 ) isolated from an endophytic Nigrospora sp. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany