Anadenanthera colubrina (Vell.) Brenan produces steroidal substances that are active against Alternaria alternata (Fr.) Keissler and that may bind to oxysterol-binding proteins

Abstract

BACKGROUND: In previous studies, the extract from Anadenanthera colubrina was active against Alternaria alternata in vitroand reduced the disease caused by this fungus on Murcott tangor fruits to levels that have been obtained using commercialfungicides. Therefore, the goal of the present work was to isolate and identify the active substances in this extract and identifyin silico their protein target in the fungus.RESULTS: The bioguided fractionation of the methanol extract from the fruits of A. colubrina resulted in the isolation of β-sitosterol and β-sitosteryl linoleate, which had minimal inhibitory concentrations (MICs) of 250 and 500 µgmL−1, respectively,against A. alternata. Under the same conditions, the MICs for two commercial fungicides were 1250 and 19 µgmL−1. In silicostudies showed that these steroidal substances bind well to oxysterol-binding proteins from Saccharomyces cerevisiae.CONCLUSION: β-Sitosterol and β-sitosteryl linoleate, produced by A. colubrina, are active against A. alternata. In silico studiessuggest that these substances may act by binding to oxysterol-binding proteins. Therefore, both substances and these proteinshave potential use in the development of new steroidal structures and analogues to control the disease caused by A. alternata.c 2014 Society of Chemical Industry