Bioactivity against Bursaphelenchus xylophilus: Nematotoxics from essential oils, essential oils fractions and decoction waters

• Published in: Phytochemistry (Oxford) Vol. 94; pp. 220 - 228
• Main Authors: Faria, Jorge M.S., Barbosa, Pedro, Bennett, Richard N., Mota, Manuel, Figueiredo, A. Cristina
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2013
• Subjects: 2-Undecanone; Animals; Bursaphelenchus xylophilus; Carvacrol; Chemical Fractionation; Cluster Analysis; coniferous forests; Decoction waters; direct contact; Dose-Response Relationship, Drug; environmental impact; Essential oils; Host-Parasite Interactions - drug effects; Hydrocarbon molecules; hydrocarbons; Lamiaceae - chemistry; mortality; Nematoda; Nematoda - drug effects; Nematoda - physiology; Nematotoxic; Oils, Volatile - classification; Oils, Volatile - isolation & purification; Oils, Volatile - pharmacology; Oxygen-containing molecules; pesticides; phytochemicals; Pinus - parasitology; Pinus pinaster; Plant Diseases - parasitology; Plant Extracts - chemistry; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Plant Oils - classification; Plant Oils - isolation & purification; Plant Oils - pharmacology; plant parasitic nematodes; Plants - chemistry; Plants - classification; Ruta - chemistry; Ruta graveolens; Satureja; Satureja - chemistry; Satureja montana; Species Specificity; Thymbra; vascular wilt; Water - chemistry; γ-Terpinene; Pinus pinaster; Nematotoxic; Hydrocarbon molecules; Essential oils; Oxygen-containing molecules; Decoction waters; Carvacrol; γ-Terpinene; Bursaphelenchus xylophilus; 2-Undecanone
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2013.06.005

Ruta graveolens, Satureja montana and Thymbra capitata essential oils showed high nematotoxic activities against Bursaphelenchus xylophilus. Activities from fractions containing hydrocarbon- or oxygen-containing molecules suggested additive and/or synergic relations. •Pine wilt disease (PWD) is caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus.•84 essential oil samples were evaluated against Bursaphelenchus xylophilus.•Ruta graveolens, Satureja montana and Thymbra capitata essential oils showed PWN toxicity.•Essential oils oxygen-containing molecules fractions were more effective in most cases.•In addition, the hydrocarbon fraction also plays an important role in PWN toxicity. The Portuguese pine forest has become dangerously threatened by pine wilt disease (PWD), caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus. Synthetic chemicals are the most common pesticides used against phytoparasitic nematodes but its use has negative ecological impacts. Phytochemicals may prove to be environmentally friendly alternatives. Essential oils (EOs) and decoction waters, isolated from 84 plant samples, were tested against B. xylophilus, in direct contact assays. Some successful EOs were fractionated and the fractions containing hydrocarbons or oxygen-containing molecules tested separately. Twenty EOs showed corrected mortalities ⩾96% at 2 μL/mL. These were further tested at lower concentrations. Ruta graveolens, Satureja montana and Thymbra capitata EOs showed lethal concentrations (LC100)<0.4μL/mL. Oxygen-containing molecules fractions showing corrected mortality ⩾96% did not always show LC100 values similar to the corresponding EOs, suggesting additive and/or synergistic relationships among fractions. Nine decoction waters (remaining hydrodistillation waters) revealed 100% mortality at a minimum concentration of 12.5μL/mL. R. graveolens, S. montana and T. capitata EOs are potential environmentally friendly alternatives for B. xylophilus control given their high nematotoxic properties. Nematotoxic activity of an EO should be taken in its entirety, as its different components may contribute, in distinct ways, to the overall EO activity.