Confirmation of potential herbicidal agents in hulls of rice, Oryza sativa.
An ethyl acetate extract of Oryza sativa (rice) hulls yielded seven compounds: hentriacontane, 1-tetratriacontanol, beta-sitosterol, momilactone A, momilactone B, tricin (a flavonoid), and beta-sitosterol-3-O-beta-D-glucoside. The structures of these compounds were elucidated with 500 MHz nuclear magnetic resonance (NMR), using 1D and 2D spectral methods, aided by electron ionization mass spectrometry (EI-MS), fast atom bombardment mass spectrometry (FAB-MS), infrared (IR), and ultraviolet (UV) spectrophotometry. The complete 1H NMR assignments for momilactone A and B and 13C NMR assignments for tricin are discussed. To the best of our knowledge, hentriacontane, 1-tetratriacontanol, and beta-sitosterol-3-O-beta-D-glucoside were identified for the first time in rice hulls. In biological activity tests using these identified compounds, momilactone A and B showed potent inhibitory activity against duckweed (Lemna paucicostata). 1-Tetratriacontanol and beta-sitosterol-3-O-beta-D-glucoside also showed about 13-20% inhibitory activity based on chlorophyll reduction. Hentriacontane and beta-sitosterol did not show any herbicidal activity. In a germination assay of three weed species (Leptochloa chinenesis L., Amaranthus retroflexus L., and Cyperus difformis L.) in culture tubes both momilactones A and B had high inhibitory effects. Momilactone B completely inhibited germination of all three weed species at 20 ppm. Germination of L. chinensis L. was completely inhibited by a 4 ppm solution of momilactone B.
Chung
Ill-Min
IM
Department of Applied Life Science, College of Life and Environment Science, Konkuk University, KwangJinKu HwaYangDong, Seoul, 143-701, South Korea.
Hahn
Sang-Joon
SJ
Ahmad
Ateeque
A
D027721:Amaranthus / Q000187:drug effects / Q000254:growth & development; D029786:Cyperus / Q000187:drug effects / Q000254:growth & development; D004224:Diterpenes / Q000302:isolation & purification / Q000494:pharmacology; D005233:Fatty Alcohols / Q000302:isolation & purification / Q000494:pharmacology; D005419:Flavonoids / Q000302:isolation & purification / Q000494:pharmacology; D018525:Germination / Q000187:drug effects*; D006540:Herbicides / Q000737:chemistry / Q000494:pharmacology*; D006838:Hydrocarbons / Q000302:isolation & purification / Q000494:pharmacology; D007783:Lactones / Q000302:isolation & purification / Q000494:pharmacology; D012275:Oryza / Q000187:drug effects* / Q000254:growth & development; D063245:Plant Development; D010944:Plants / Q000187:drug effects*; D012855:Sitosterols / Q000302:isolation & purification / Q000494:pharmacology; D013057:Spectrum Analysis
D004224:Diterpenes; D005233:Fatty Alcohols; D005419:Flavonoids; D006540:Herbicides; D006838:Hydrocarbons; D007783:Lactones; D012855:Sitosterols; C477203:momilactone B; C116023:momilactone A; C025473:gamma-sitosterol; C049203:hentriacontane; C047578:1-triacontanol; C017769:tricin; C011015:lyoniside