Abstract:
Invasive and weedy species such as Pseudognaphalium luteoalbum may serve as a source of biologically active
extracts or compounds with application in crop and ornamental plant protection, among other uses. The acetone
crude extract of P. luteoalbum leaves had strong antifungal activity when tested against a selection of plant
pathogenic fungi in vitro. Fractionation of the crude extract to isolate, characterize and evaluate the antifungal
constituents afforded two compounds. Structure elucidation of the isolated compounds was carried out
using spectroscopic techniques: mass spectrometry and NMR (1D and 2D). The compounds were identified
as: 5,4′-dihydroxy-6-methoxy-7-O-β-glucopyranosideflavone (hispidulin-7-O-glucopyranoside) (1) and
stigmasterol-3-O-β-glucopyranoside (2). These compounds are reported from P. luteoalbum for the first
time. The crude extract and isolated compounds were moderately to highly active against a selection of phytopathogenic
fungal organisms with MIC values ranging from 0.02 to 1.25 mg/mL. No cytotoxicity of the isolated
compounds against Vero kidney cells was observed at 200 μg/mL, the highest concentration tested.
