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

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