Allelopathic effect of fatty acid methyl esters from corn and sunflower oils

Abstract

The fatty acid methyl esters (FAMEs) were obtained from vegetable oils by transesterification reaction. In the present work, the vegetable oils and fatty acid methylesters were evaluated for allelopathic activity. The main components of the methylesters were methyl oleate and methyl linoleate, identified by gas chromatography-mass spectrometry (GC-MS). Allelopathic activity against seeds of Lactuca sativa (lettuce) showed that most of the samples stimulated the growth of root and hypocotyl. However, against seeds of Allium cepa (onion), it was revealed that the samples presented higher inhibitory activity for radicle and hypocotyl. Corn oil and its FAME, at a concentration of 1000 microg/mL, showed inhibition greater than 80% for radicle, and percentages higher than 60% for hypocotyl. The corn FAME also inhibited the growth of radicle and hypocotyl more than 50%, at a concentration of 250 microg/mL. For sunflower FAME, the inhibition to the radicle and hypocotyl was inversely proportional to the concentration. The sunflower FAME inhibit radicle and hypocotyl of onion about 60%, at a concentration of 250 microg/mL. Sunflower oil showed greater than 50% inhibition for the radicle, at concentrationsof 250 and 1000 microg/mL, and the hypocotyl, at a concentration of 1000 microg/mL.