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

The resinous exudates from <i>Escallonia illinita</i> 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 (<b>1</b>), 4-(5-hydroxy-3,7-dimethoxy-4-oxo-4<i>H</i>-chromen-2-yl)phenyl acetate (<b>2</b>), pinocembrin (<b>3</b>), kaempferol 3-<i>O</i>-methylether (<b>4</b>), (3<i>S</i>,5<i>S</i>)-(<i>E</i>)-1,7-diphenylhept-1-ene-3,5-diol (<b>5</b>) and the new diarylheptanoid (3<i>S</i>,5<i>S</i>)-(<i>E</i>)-5-hydroxy-1,7-diphenylhept-1-en-3-yl acetate (<b>6</b>). The anti-oomycete potential of the resinous exudate, as well as the main compounds, was tested in vitro against <i>Saprolegnia parasitica</i> and <i>Saprolegnia australis</i>. The resinous exudate showed a strong anti-oomycete activity. In addition, the compounds <b>6</b>, <b>1</b> and <b>3</b> demonstrated significant inhibition of <i>Saprolegnia</i> strains development. These findings strongly suggest that <i>E. illinita</i> is a potential biomass that could be used as a natural anti-oomycete product.