title: (1)H and DOSY NMR spectroscopy analysis of Ligusticum porteri rhizome extracts.
abstract: The presence of dimeric phthalides and other constituents in extracts of the vegetal species Ligusticum porteri was established by NMR spectroscopy. In comparative qualitative (1)H NMR analyses of acetone extracts of rhizomes from fresh and dried L. porteri samples, we found that the dimeric phthalides tokinolide B (3), diligustilide (4) and riligustilide (5) were naturally produced by the plant and not post-harvest products. We also obtained DOSY (1)H NMR data that provided both virtual separation and structural information for the phthalides present in a dry acetone extract of L. porteri. In addition, we developed a protocol for the quantification of dimeric phthalides, which is performed by calculating the relative ratio of the peak area of selected proton signals for some compounds with respect to the known signal of the internal standard, 4-dimethylaminopyridine. The protocol allows the rapid and direct quantification of dimeric phthalides and others constituents in fresh L. porteri rhizomes.
authors.affiliation: Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Coyoacán, 04510, México, D.F.
authors.forename: Alejandra
authors.initials: A
authors.lastname: León
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Chávez
authors.forename: Guillermo
authors.initials: G
authors.lastname: Delgado
mesh_terms: D015761:4-Aminopyridine / Q000031:analogs & derivatives; D000096:Acetone; D001572:Benzofurans / Q000302:isolation & purification*; D030004:Ligusticum / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry*; D011522:Protons; D012015:Reference Standards; D027343:Rhizome / Q000737:chemistry; D012997:Solvents
chemical_list: D001572:Benzofurans; D010936:Plant Extracts; D011522:Protons; D012997:Solvents; C517987:riligustilide; C574260:tokinolide B; D000096:Acetone; D015761:4-Aminopyridine; C003885:4-dimethylaminopyridine