ABSTRACT
Oxalicine B ( 1) is an α-pyrone meroterpenoid with a unique bispirocyclic ring system derived from Penicillium oxalicum. The biosynthetic pathway of 15-deoxyoxalicine B ( 4) was preliminarily reported in Penicillium canescens, however, the genetic base and biochemical characterization of tailoring reactions for oxalicine B ( 1) has remained enigmatic. In this study, we characterized three oxygenases from the metabolic pathway of oxalicine B ( 1), including a cytochrome P450 hydroxylase OxaL, a hydroxylating Fe(II)/α-KG-dependent dioxygenase OxaK, and a multifunctional cytochrome P450 OxaB. Intriguingly, OxaK can catalyze various multicyclic intermediates or shunt products of oxalicines with impressive substrate promiscuity. OxaB was further proven via biochemical assays to have the ability to convert 15-hydroxdecaturin A ( 3) to 1 with a spiro-lactone core skeleton through oxidative rearrangement. We also solved the mystery of OxaL that controls C-15 hydroxylation. Chemical investigation of the wild-type strain and deletants enabled us to identify 10 metabolites including three new compounds, and the isolated compounds displayed potent anti-influenza A virus bioactivities exhibiting IC50 values in the range of 4.0-19.9 μmol/L. Our studies have allowed us to propose a late-stage biosynthetic pathway for oxalicine B ( 1) and create downstream derivatizations of oxalicines by employing enzymatic strategies.
ABSTRACT
Aim To investigate the anti-neuroinflam-matory activities of dehydromiltirone and the underlying mechanisms in LPS-stimulated microglial cell line BV2 cells. Methods BV2 cells were pre-treated with de-hydromiltirone, then stimulated by LPS. The levels of nitric oxide( NO) were measured by Griess assay, and the concentrations of pro-inflammatory cytokines were measured by ELISA assay. Confocal fluorescence mi-croscopy was used to measure the expression of MAC-1, the biomarker of activated BV2 cells. The levels of-inducible nitric oxide synthase ( iNOS ) , cyclooxygen-ase-2 ( COX-2 ) , NF-κB and PI3 K/Akt were deter-mined by Western blot analysis. Results The treat-ment of dehydromiltirone significantly inhibited the pro-duction of NO, TNF-α and IL-6, attenuated the ex-pression of iNOS and COX-2 protein, and dampened the microglial activation in LPS-stimulated BV2 cells. The mechanistic study revealed that dehydromiltirone inhibited the phosphorylation of PI3 K and Akt in LPS-stimulated BV2 cells, and decreased NF-κB activation by suppressing the degradation of IκB. Conclusion dehydromiltirone shows significant anti-neuroinflamma-tory effects through inhibiting PI3 K/Akt phosphoryla-tion and then inhibiting NF-κB signaling pathway.
ABSTRACT
From callus cultures of Stellera chamaejasme, 17 compounds were isolated. Based on their physical and chemical data and spectroscopic analysis, they were identified as syringaresinol (1), medioresinol (2), pinoresinol (3), (1R, 2S, 5R, 6S)- 2-(4- hydroxyphenyl)-6-(3-methoxy-4-hydroxyphenyl)-3, 7-dioxabicyclo [3, 3, 0] octane (4), epipinoresinol (5), caruilignan D (6), 3-oxo-guai-4-ene-11, 12-diol (7), (-) -lariciresinol (8), tetrahydro-2-(4-hydroxy-3-methoxyphenyl)-4-[(4-hydroxyphenyl) methyl]-3-furanmethanol (9), 5'-methoxylariciresinol (10), vladinol D (11), cyclo (L-Pro-L-Val) (12), oxomatairesinol (13), (+) -guayarol (14); acutissimalignan B (15), isolariciresinol (16), and beta-sitosterol (17), respectively. Among these compounds, 12 was a cyclodipeptide, 7 was a sesquiterpene, and the others except 17 were lignans. All compounds were first isolated from callus cultures of S. chamaejasme.
Subject(s)
Lignans , Thymelaeaceae , ChemistryABSTRACT
<p><b>OBJECTIVE</b>To investigate the isoflavones from the vines of Pueraria lobata.</p><p><b>METHOD</b>The compounds were isolated by column chromatography over silica gel and RP-C18, and purified by Sephadex LH-20 column chromatography and preparative TLC. The structures were elucidated on the basis of physico-chemical properties and spectral data.</p><p><b>RESULT</b>Twelve compounds were isolated and identified as: 3'-methoxydaidzein (1), formononetin (2), genistein (3), daidzein (4), daidzin (5), genistin (6), ononin (7), 5-hydroxyl ononin (8), calycosin (9), 6"-O-acetyl genistein (10), 6"-O-acetyl daidzin (11), puerarin (12).</p><p><b>CONCLUSION</b>For the first time, compounds 9-11 were isolated from the genus Pueraria plant, and compounds 1, 3, 6-8 were obtained from the vines of this plant.</p>