title: Identification of two phytotoxins, blumenol A and grasshopper ketone, in the allelopathic Japanese rice variety Awaakamai.
abstract: Aqueous methanol extracts of the traditional rice (Oryza sativa) variety Awaakamai, which is known to have the greatest allelopathic activity among Japanese traditional rice varieties, inhibited the growth of roots and shoots of cress (Lepidium sativum), lettuce (Lactuca sativa), timothy (Phleum pratense), Digitaria sanguinalis, Lolium multiflorum and Echinochloa crus-galli. Increasing the extract concentration increased the inhibition, suggesting that the extract of Awaakamai contains growth inhibitory substances. The extract of Awaakamai was purified and two main growth inhibitory substances were isolated and determined by spectral data as blumenol A and grasshopper ketone. Blumenol A and grasshopper ketone, respectively, inhibited the growth of cress shoots and roots at concentrations greater than 10 and 30 μmol/L. The concentrations required for 50% growth inhibition on cress roots and shoots were 84 and 27 μmol/L, respectively, for blumenol A, and 185 and 76 μmol/L, respectively, for grasshopper ketone. These results suggest that blumenol A and grasshopper ketone may contribute to the growth inhibitory effect of Awaakamai and may play an important role in the allelopathy of Awaakamai.
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan. hisashi@ag.kagawa-u.ac.jp
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kato-Noguchi
authors.forename: Kazuya
authors.initials: K
authors.lastname: Tamura
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sasaki
authors.forename: Kiyotake
authors.initials: K
authors.lastname: Suenaga
mesh_terms: D000466:Alkadienes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D001681:Biological Assay; D003511:Cyclohexanols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D003512:Cyclohexanones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D031747:Echinochloa / Q000187:drug effects / Q000254:growth & development; D007659:Ketones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D031220:Lepidium sativum / Q000187:drug effects / Q000254:growth & development; D012275:Oryza / Q000737:chemistry* / Q000145:classification; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification; D010937:Plant Growth Regulators / Q000302:isolation & purification* / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development; D018547:Plant Stems / Q000737:chemistry; D058728:Weed Control
chemical_list: D000466:Alkadienes; D003511:Cyclohexanols; D003512:Cyclohexanones; D007659:Ketones; D010936:Plant Extracts; D010937:Plant Growth Regulators; C000589723:blumenol A; C000589724:grasshopper ketone