title: PSII inhibitory activity of resorcinolic lipids from Sorghum bicolor.
abstract: Resorcinolic lipids were isolated from the root extracts of Sorghum bicolor and identified as 4,6-dimethoxy-2-[(8'Z,11'Z)-8',11',14'-pentadecatriene]resorcinol (4), 4-methoxy-6-ethoxy-2-[(8'Z,11'Z)-8',11',14'-pentadecatriene]resorcinol (5), and 4-hydroxy-6-ethoxy-2-[(10'Z,13'Z)-10',13',16'-heptadecatriene]resorcinol (6). Compounds 4 and 5 inhibited photosynthetic oxygen evolution (IC50 0.09 and 0.20 microM, respectively). Compound 4 could not be enzymatically converted to a quinone, suggesting that the quinone moiety is not required for its photosystem II inhibitory activity. Compounds 5 and 6 are reported for the first time.
authors.affiliation: USDA-ARS, Natural Products Utilization Research Unit, P.O. Box 8048, University, Mississippi 38677, USA. arimando@ars.usda.gov
authors.forename: Agnes M
authors.initials: AM
authors.lastname: Rimando
authors.forename: Franck E
authors.initials: FE
authors.lastname: Dayan
authors.forename: Jens C
authors.initials: JC
authors.lastname: Streibig
mesh_terms: D000465:Algorithms; D002734:Chlorophyll / Q000378:metabolism; D018525:Germination / Q000187:drug effects; D020128:Inhibitory Concentration 50; D018545:Lactuca / Q000187:drug effects; D045342:Light-Harvesting Protein Complexes; D008055:Lipids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010788:Photosynthesis / Q000187:drug effects*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000378:metabolism*; D045332:Photosystem II Protein Complex; D018517:Plant Roots / Q000737:chemistry; D006109:Poaceae / Q000737:chemistry*; D011809:Quinones / Q000378:metabolism; D012118:Resorcinols / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013237:Stereoisomerism
chemical_list: D045342:Light-Harvesting Protein Complexes; D008055:Lipids; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D011809:Quinones; D012118:Resorcinols; D002734:Chlorophyll