Isolation and identification of compounds from the resinous exudate of Escallonia illinita Presl. and their anti-oomycete activity

The resinous exudatesfrom Escalloniaillinita by products was characterized by FT-IR, NMR and HRMS. Six compounds were isolated and identified as follows: 1,5-diphenylpent-1-en-3-one (1), 4-(5-hydroxy-3,7-dimethoxy-4-oxo-4H-chromen-2-yl) phenyl acetate(2), pinocembrin(3), kaempferol3-O-methylether (4), (3S,5S)-(E)-1,7-diphenylhept-1-ene-3,5-diol (5) and the new diarylheptanoid(3S,5S)-(E)-5-hydroxy-1,7-diphenylhept-1-en-3-yl acetate (6). The anti- oomycetepotential of the resinous exudate, as well as the main compounds, was tested in vitro against Saprolegniaparasitica and Saprolegniaaustralis. The resinous exudateshowed a strong anti- oomyceteactivity. In addition, the compounds 6, 1 and 3 demonstrated significant inhibition of Saprolegniastrains development. These findings strongly suggest that E. illinita is a potential biomass that could be used as a natural anti- oomyceteproduct.