Analogues of the Quararibea metabolite chiral enolic-γ-lactone from (2S,3S)- and (2S,3R)-tetrahydro-3-hydroxy-5-oxo-2,3-furandicarboxylic acids

Reaction of dialkyl (2S,3S)- or (2S,3R)-tetrahydro-3-hydroxy-5-oxo-2,3-furandicarboxylates with POCl₃ in pyridine followed by diazomethane resulted in the isolation of dialkyl 2S-4-methoxy-5-oxo-2,5-dihydro-2,3-furandicarboxylates, which are analogues of the Quararibea metabolite chiral enolic-γ-lactone (3-hydroxy-4,5-(R)-dimethyl-2(5H)-furanone). An unusual α-hydroxylation of γ-butyrolactone takes place involving POCl₃ in pyridine. When the dehydration was facilitated with methanesulfonyl chloride in triethylamine, instead of POCl₃, aromatic dialkyl 5-[(methylsulfonyl)oxy]-2,3-furandicarboxylates were obtained.     

Terpenoids with a new skeleton and novel triterpenoids with anti-inflammatory effects from Garcinia subelliptica

Three novel phloroglucinol derivatives, garcinielliptones F (1), H (3), and I (4), and two novel terpenoids, garcinielliptones G (2) and J (5), with a new skeleton have been isolated from the seeds of Garcinia subelliptica. Their structures, including relative configurations, were elucidated by spectroscopic methods and computer-generated molecular modeling. Compound 1 showed potent inhibitory effects on the release of beta-glucuronidase and lysozyme from rat neutrophils that had been stimulated with formyl-Met-Leu-Phe (fMLP)/cytochalasin B (CB). This effect was concentration-dependent with IC(50) values of 26.9+/-2.6 and 20.0+/-1.3 microM, respectively. Compound 1 also showed a potent concentration-dependent inhibitory effect on superoxide anion generation in rat neutrophils stimulated with fMLP/CB, with an IC(50) value of 17.0+/-0.9 microM. Compound 4 showed a potent inhibitory effect on NO production in culture media of N9 cells in response to lipopolysaccharide (LPS)/interferon-gamma (IFN-gamma) in a concentration-dependent manner with an IC(50) value of 7.4+/-0.2 microM.     

藤黄化学成分的研究

传统中药藤黄通过各种色谱方法分离纯化, 得到15个化合物, 根据其理化性质和光谱方法鉴定其结构分别为: 2α-羟基-3β-乙酰氧基白桦酯酸(1), 10α-羟基表藤黄酸(2), 藤黄酸(3), 异藤黄酸(4), gambogin (5), gambogoic acid B (6), desoxymorellin (7), isomorellin (8), gambogenic acid (9), isogambogenin (10), gambogellic acid (11), desoxygambogenin (12), morellic acid (13), isomorellic acid (14), 30-hydroxygambogic acid (15). 其中化合物1和2为新化合物.     

New Biphenyl Constituents from Garcinia oblongifolia

Four new biphenyl derivatives, oblongifoliagarcinines A–D ( 1 – 4 ), were isolated on the chemical investigation of the stems and leaves of Garcinia oblongifolia. The structures of 1 – 4 were established on the basis of 1D‐ and 2D‐NMR and other spectroscopic analyses.     

A novel polyprenylated phloroglucinol, garcinialone, from the roots of Garcinia multiflora

A novel polyprenylated phloroglucinol garcinialone (1) along with a known compound isoxanthochymol (2) have been isolated from the roots of Garcinia multiflora. The structures of 1 and 2 were elucidated spectroscopically, by 1D and 2D NMR and mass spectrometry.