Medium-Chain Fatty Acids from <i>Eugenia winzerlingii</i> Leaves Causing Insect Settling Deterrent, Nematicidal, and Phytotoxic Effects

• Main Authors: Angel Cruz-Estrada, Esaú Ruiz-Sánchez, Jairo Cristóbal-alejo, Azucena González-Coloma, María Fe Andrés, Marcela Gamboa-Angulo
• Format: Article
• Language: English
• Published: MDPI AG 2019-05-01
• Series: Molecules
• Subjects: Bemisia tabaci; decanoic acid; dodecanoic acid; Eugenia winzerlingii; Lolium perenne; Meloidogyne; Myzus persicae; Solanum lycopersicum; undecanoic acid
• Online Access: https://www.mdpi.com/1420-3049/24/9/1724

<i>Eugenia winzerlingii</i> (Myrtaceae) is an endemic plant from the Yucatan peninsula. Its organic extracts and fractions from leaves have been tested on two phloem-feeding insects, <i>Bemisia tabaci</i> and <i>Myzus persicae</i>, on two plant parasitic nematodes, <i>Meloidogyne incognita</i> and <i>Meloidogyne javanica</i>, and phytotoxicity on <i>Lolium perenne</i> and <i>Solanum lycopersicum</i>. Results showed that both the hexane extract and the ethyl acetate extract, as well as the fractions, have strong antifeedant and nematicidal effects. Gas chromatography-mass spectrometry analyses of methylated active fractions revealed the presence of a mixture of fatty acids. Authentic standards of detected fatty acids and methyl and ethyl derivatives were tested on target organisms. The most active compounds were decanoic, undecanoic, and dodecanoic acids. Methyl and ethyl ester derivatives had lower effects in comparison with free fatty acids. Dose-response experiments showed that undecanoic acid was the most potent compound with EC₅₀ values of 21 and 6 nmol/cm² for <i>M. persicae</i> and <i>B. tabaci</i>, respectively, and 192 and 64 nmol for <i>M. incognita</i> and <i>M. javanica</i>, respectively. In a phytotoxicity assay, medium-chain fatty acids caused a decrease of 38&#8722;52% in root length and 50&#8722;60% in leaf length of <i>L. perenne</i>, but no effects were observed on <i>S.</i> <i>lycopersicum</i>. This study highlights the importance of the genus <i>Eugenia</i> as a source of bioactive metabolites for plant pest management.