Use of Ruta graveolens L. vegetable extract standardised by furanocoumarin content to control Magnaporthe oryzae in rice plants

Blast, caused by the fungus Magnapor the oryzae, is one of the most widespread diseases affecting the rice crop. The use of fungicides to combat phyto pathogenic fungi causes great environmental problems. Plant extracts have been studied as an alternative method of plant pathogen control. Ruta graveolens has compounds with antifungal activity, such as furanocoumarins. The objective of this study was to test the effects of various concentrations of the standardised plant extract of R. graveolens as well as its fractions and furanocoumarins (psoralen and bergapten) on reducing M. oryzaemycelial growth. The aerial part of R. graveolens was grinded and subjected to a characterisation process, percolation, concentration, and furanocoumarin standardisation. The standardised extract was fractionated and the fractions were subjected to high-performance liquid chromatography (HPLC) to quantify furanocoumarins. The effects of the extract, fractions, and standards against mycelial growth ofM.oryzaewere tested in vitro. The plant material was handled in accordance with the guidelines established by the general methods of the Brazilian Pharmacopoeia. The furanocoumarin content was the highest in the ethyl acetate fraction. The best results for the mycelial growth test were observed using the extract and the hexane and ethyl acetate fractions. The standardised herbal extract of R. graveolens showed antifungal activity against M.oryzae.