ABSTRACT
Fourteen cassane-type diterpenoids, echinalides H-U, were isolated from the stem of Caesalpinia echinata Lam. (Leguminosae). The structures of the echinalides were elucidated by spectroscopic investigation, including 2D NMR spectroscopic analysis. The structures of echinalide H and echinalide T were further confirmed by single-crystal X-ray diffraction. The absolute configurations of echinalides H, I, J and K were determined by CD spectroscopy. Additionally, the absolute configurations of echinalide L and M were determined by chemical conversion from echinalide H. These compounds were evaluated for inhibitory activity against nuclear factor κB (NF-κB). Echinalide M showed the most potent inhibitory activity (47±11% at 5µM) toward NF-κB-responsive gene expression.
Subject(s)
Caesalpinia/chemistry , Diterpenes/isolation & purification , Diterpenes/pharmacology , NF-kappa B/antagonists & inhibitors , Brazil , Crystallography, X-Ray , Diterpenes/chemistry , HeLa Cells , Humans , I-kappa B Proteins , Molecular Conformation , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Plant Stems/chemistry , Seeds/chemistry , Signal Transduction/drug effectsABSTRACT
Two new clerodane diterpenoids, gaudichanolides A (1) and B (2), were isolated from the dried twigs of Baccharis gaudichaudiana, together with 7-oxo-16,19-dihydroxy-3,4-dehydroclerodan-15,20-diacid dilactone, spathulenol, 4,10-aromadendranediol, kobusone, trans-cosanyl ferulate, and defuscin. The structures and relative stereochemistry of 1 and 2 were elucidated by detailed 2D NMR spectroscopic experiments, and the absolute stereochemistry of 1 was determined by X-ray crystallographic analysis.
Subject(s)
Baccharis/chemistry , Diterpenes, Clerodane/isolation & purification , Plants, Medicinal/chemistry , Brazil , Crystallography, X-Ray , Diterpenes, Clerodane/chemistry , Molecular Conformation , Molecular StructureABSTRACT
In a continuing study to isolate novel antitumor agents from rainforest plants, three new isopropenylfurano-beta-naphthoquinones, designated lantalucratins A (1), B (2), and C (3), and three new isoprenyl-alpha-naphthoquinones, designated lantalucratins D (4), E (5), and F (6), were isolated from Lantana involucrata. Their structures were determined on the basis of NMR and X-ray crystallographic analyses. Compounds 1 and 2 showed cytotoxic activities against various human tumor cell lines, including drug-resistant variants, with IC50 values of 1.0-4.9 microM.
Subject(s)
Antineoplastic Agents, Phytogenic/isolation & purification , Lantana/chemistry , Naphthoquinones/isolation & purification , Plants, Medicinal/chemistry , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Drug Resistance, Neoplasm , Drug Screening Assays, Antitumor , Humans , Inhibitory Concentration 50 , Molecular Structure , Naphthoquinones/chemistry , Naphthoquinones/pharmacology , Nuclear Magnetic Resonance, Biomolecular , Puerto Rico , Tumor Cells, CulturedABSTRACT
As part of a study on antitumor agents from rainforest plants, two new flavanones, buceracidin A (1), 5,2'-dihydroxy-3-methoxy-6,7-(2' ',2' '-dimethylchromene)flavanone, and buceracidin B (2), 5,2'-dihydroxy-6,7-(2' ',2' '-dimethylchromene)flavanone, were isolated together with four known prenylated flavanones, minimiflorin (3), 3-hydroxyminimiflorin (4), 3-methoxyminimiflorin (5), and mundulinol (6), from Bucida buceras. The structures of buceracidins A and B were elucidated from detailed 2D NMR analyses. Among the six flavanones, 3, 5, and 6 were marginally cytotoxic in a human tumor cell line panel.