title: Identification and phytotoxicity of a new glucosinolate breakdown product from Meadowfoam (Limnanthes alba) seed meal.
abstract: Meadowfoam (Limnanthes alba Hartw. ex Benth.) is an oilseed crop grown in the Willamette Valley of Oregon. Meadowfoam seed meal (MSM), a byproduct after oil extraction, contains 2-4% glucosinolate (glucolimnanthin). Activated MSM, produced by adding freshly ground myrosinase-active meadowfoam seeds to MSM, facilitates myrosinase-mediated formation of glucosinolate-derived degradation products with herbicidal activity. In the activated MSM, glucolimnanthin was converted into 3-methoxybenzyl isothiocyanate ("isothiocyanate") within 24 h and was degraded by day three. 3-Methoxyphenylacetonitrile ("nitrile") persisted for at least 6 days. Methoxyphenylacetic acid (MPAA), a previously unknown metabolite of glucolimnanthin, appeared at day three. Its identity was confirmed by LC-UV and high resolution LC-MS/MS comparisons with a standard of MPAA. Isothiocyanate inhibited lettuce germination 8.5- and 14.4-fold more effectively than MPAA and nitrile, respectively. Activated MSM inhibited lettuce germination by 58% and growth by 72% compared with the control. Results of the study suggest that MSM has potential uses as a pre-emergence bioherbicide.
authors.affiliation: Department of Crop and Soil Science, Oregon State University , 109 Crop Science Building, Corvallis, Oregon 97331, United States.
authors.forename: Suphannika
authors.initials: S
authors.lastname: Intanon
authors.forename: Ralph L
authors.initials: RL
authors.lastname: Reed
authors.forename: Jan F
authors.initials: JF
authors.lastname: Stevens
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Hulting
authors.forename: Carol A
authors.initials: CA
authors.lastname: Mallory-Smith
mesh_terms: D001673:Biodegradation, Environmental; D001681:Biological Assay; D002853:Chromatography, Liquid; D005961:Glucosinolates / Q000737:chemistry* / Q000494:pharmacology*; D006026:Glycoside Hydrolases / Q000378:metabolism; D006540:Herbicides / Q000494:pharmacology; D017879:Isothiocyanates / Q000378:metabolism; D019684:Magnoliopsida / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*; D053719:Tandem Mass Spectrometry; D013861:Thiocyanates / Q000494:pharmacology; D013863:Thioglucosides / Q000494:pharmacology
chemical_list: D005961:Glucosinolates; D006540:Herbicides; D017879:Isothiocyanates; D013861:Thiocyanates; D013863:Thioglucosides; C055576:glucolimnanthin; C055578:3-methoxybenzyl isothiocyanate; D006026:Glycoside Hydrolases; C022739:thioglucosidase