title: Screening and identification of phytotoxic volatile compounds in medicinal plants and characterizations of a selected compound, eucarvone.
abstract: Screening and identification of phytotoxic volatile compounds were performed using 71 medicinal plant species to find new natural compounds, and the characterization of the promising compound was investigated to understand the mode of action. The volatile compounds from Asarum sieboldii Miq. showed the strongest inhibitory effect on the hypocotyl growth of lettuce seedlings (Lactuca sativa L.cv. Great Lakes 366), followed by those from Schizonepeta tenuifolia Briquet and Zanthoxylum piperitum (L.) DC.. Gas chromatography-mass spectrometry (GC/MS) identified four volatile compounds, α-pinene (2,6,6-trimethylbicyclo[3.1.1]hept-2-ene), β-pinene (6,6-dimethyl-2-methylenebicyclo[3.1.1]heptane), 3-carene (3,7,7-trimethylbicyclo[4.1.0]hept-3-ene), and eucarvone (2,6,6-trimethy-2,4-cycloheptadien-1-one), from A. sieboldii, and three volatile compounds, limonene (1-methyl-4-(1-methylethenyl)-cyclohexene), menthone (5-methyl-2-(propan-2-yl)cyclohexan-1-one), and pulegone (5-methyl-2-propan-2-ylidenecyclohexan-1-one), from S. tenuifolia. Among these volatile compounds, eucarvone, menthone, and pulegone exhibited strong inhibitory effects on both the root and shoot growth of lettuce seedlings. Eucarvone-induced growth inhibition was species-selective. Cell death, the generation of reactive oxygen species (ROS), and lipid peroxidation were induced in susceptible finger millet seedlings by eucarvone treatment, whereas this compound (≤158 μM) did not cause the increase of lipid peroxidation and ROS production in tolerant maize. The results of the present study show that eucarvone can have strong phytotoxic activity, which may be due to ROS overproduction and subsequent oxidative damage in finger millet seedlings.
authors.affiliation: Graduate school of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan, sunohara.yukari.gp@u.tsukuba.ac.jp.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Sunohara
authors.forename: Yohei
authors.initials: Y
authors.lastname: Baba
authors.forename: Shigeru
authors.initials: S
authors.lastname: Matsuyama
authors.forename: Kaori
authors.initials: K
authors.lastname: Fujimura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsumoto
mesh_terms: D000470:Alkaloids / Q000378:metabolism; D030023:Asarum / Q000378:metabolism*; D000081008:Bicyclic Monoterpenes; D001643:Bridged Bicyclo Compounds / Q000378:metabolism; D000081005:Cyclohexane Monoterpenes; D008401:Gas Chromatography-Mass Spectrometry; D018545:Lactuca / Q000378:metabolism; D015227:Lipid Peroxidation / Q000502:physiology; D039821:Monoterpenes / Q000378:metabolism; D010946:Plants, Medicinal / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000378:metabolism
chemical_list: D000470:Alkaloids; D000081008:Bicyclic Monoterpenes; D001643:Bridged Bicyclo Compounds; D000081005:Cyclohexane Monoterpenes; D039821:Monoterpenes; D017382:Reactive Oxygen Species; C039648:pulegone; C010789:beta-pinene; C030218:3-carene; C005451:alpha-pinene