New antioxidant C-geranylated flavonoids from the fruit peels of Paulownia catalpifolia T. Gong ex D.Y. Hong

Three new geranylated flavonoids, including two geranylflavones (1, 2) and one geranylflavonol (3), named as paucatalinone C–E, were isolated from the fruit peel of P. catalpifolia T. Gong ex D.Y. Hong. Their structures were determined by means of UV, IR, MS, and NMR techniques. To our known, geranylflavone or geranylflavonol was the first isolation from the genus Paulownia. These isolated geranylated flavonoids displayed good antioxidant effects on DPPH and the senescent human embryonic lung diploid fibroblasts cells (2BS cells) induced by H₂O₂. The geranyl substituent may be an important factor for the cellular radical-scavenging effect because of its lipophilic character.     

Monocyte-macrophage membrane possesses free radicals scavenging activity: stimulation by polyphenols or by paraoxonase 1 (PON1)

Abstract

In the current study, we analysed free radicals scavenging activity of monocytes-macrophages in the absence or presence of antioxidants such as polyphenols or paraoxonase 1 (PON1). THP-1 human monocytic cell line, murine J774A.1 macrophages, as well as human primary monocytes have the capability to scavenge free radicals, as measured by the 1-diphenyl-2-picryl-hydrazyl (DPPH) assay. This effect (which could be attributed to the cell's membrane) was cell number and incubation time dependent. Upon incubation of J774A.1 macrophages with acetylated LDL (Ac-LDL), with VLDL, or with the radical generator, AAPH, the cells’ lipid peroxides content, and paraoxonase 2 (PON2) activity were significantly increased. While non-treated cells decreased DPPH absorbance by 65%, the Ac-LDL-, VLDL- or AAPH-treated cells, decreased it by only 33%, 30%, or 45%, respectively. We next analysed the effect of J774A.1 macrophage enrichment with antioxidants, such as polyphenols or PON1 on the cells’ free radicals scavenging activity. Non-treated cells decreased DPPH absorbance by 50%, whereas vitamin E-, punicalagin- or PJ-treated cells significantly further decreased it, by 75%. Similarly, in PON1-treated cells DPPH absorbance was further decreased by 63%, in association with 23% increment in PON1 catalytic activity. In cells under oxidative stress [treated with AAPH-, or with oxidized LDL], PON1 activity was decreased by 31% or 40%, as compared to the activity observed in PON1 incubated with non-treated cells. We conclude that monocytes-macrophages possess free radicals scavenging activity, which is decreased under atherogenic conditions, and increased upon cell enrichment with potent antioxidants such as nutritional polyphenols, or PON1.     

2-Ketogluconate Reductase Inhibition by Oxalate

The active site of α-glucosidase from Mucor javanicus IFO 4570 was investigated by kinetic studies. Competition between maltose and soluble starch, and linearity of Lineweaver-Burk plots for the mixed substrates were observed. The dependence of the apparent maximum velocities agreed with those predicted for a single active site mechanism. These results suggest that the enzyme hydrolyzes maltose and soluble starch at a single active site.     

Flavonolacyl glucosides from the aril of Schotia brachypetala Sond. and their antioxidant,antibacterial and antimalarial activities

Two new flavonolacyl glucosides, 3-O-methylquercetin 7-O-[β-D-6″-(E-p-coumaroyl) glucopyranoside] (1) and 3,4′-di-O-methylquercetin 7-O-[β-D-6″-(E-p-coumaroyl) glucopyranoside] (2), four known flavonol glycosides (3–5, 7) and one known dihydroflavonolglucoside (6) were isolated from the aril part of Schotia brachypetala with high-speed countercurrent chromatography (HSCCC) as the primary chromatographic technique. The structures of the isolated compounds were elucidated with spectroscopic and spectrometric methods and acid hydrolysis. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) antioxidant, antibacterial and antimalarial activities of selected isolates were evaluated. Strong to moderate antioxidant activity (lowest IC₅₀ of 15.2 μM), moderate to weak antibacterial activity (lowest MIC of 0.13 mg/mL) and moderate antimalarial activity (lowest IC₅₀ of 5.18 μg/mL) compared to the positive controls were observed.     

芦丁-锗配合物及其自由基清除活性研究

芦丁是存在于多种植物中的天然多羟基黄酮苷,能与多种金属离子形成配合物。本文采用紫外分光度法考察了芦丁与锗离子的配位作用,并研究了芦丁-锗配合物清除超氧自由基和DPPH自由基的作用。结果显示在KH2PO4-NaOH(pH6．70)的缓冲液中,芦丁与锗离子能形成1：1的配合物,其K稳=10^7.46,同时配合物显示有较好的自由基清除活性。     

Release,Regeneration and Mutant Induction of Pleurotus cornucopiae (‘Tamogitake’) Protoplasts

Both enantiomers of aliphatic and aromatic cyanohydrins were hydrolyzed with the aid of Rhodococcus butanica ATCC 21197 to afford optically active α-hydroxy acids. The usefulness of this reaction is demonstrated by the synthesis of optically pure (R)-4-dodecanolide, a defensive secretion of rove beetles, starting from (R)-2-hydroxydecanenitrile.     

Distribution and Association Form of Polynuclear Aromatic Hydrocarbons in Sediments from Tokyo Bay

Polynuclear aromatic hydrocarbons (PAH), including fluoranthene, pyrene, benzo(a)-anthracene, chrysene, benzo(a)pyrene (benzo(e)pyrene), dibenzo(a,h)anthracene and benzo(ghi)perylene, were identified and determined in sediments from Tokyo Bay. Their concentrations were proved to be in a range from several tens to several hundreds µg/kg of dry samples. This seems to suggest that the smaller are the average particle sizes of sediments and the higher are the total amounts of PAH concentrations.

Statistically significant positive correlations were observed between the following pairs: total amount of PAH vs. clay content; total amount of PAH vs. the sum of (clay + silt) contents; total amount of PAH vs. ignition loss. In addition, significant positive correlations were statistically found between ignition loss and clay content as well as the sum of (clay + silt) contents.     

Induction of Catalase Activity by Hydrocarbons in Candida tropicalis рK 233

1. The catalase activity of Candida tropicalis pK 233 was induced by hydrocarbons but not by glucose, galactose, ethanol, acetate or lauryl alcohol.

2. The induction of the catalase activity depending upon hydrocarbons was sensitive to cycloheximide but not to chloramphenicol.

3. Glucose repressed strongly the induction of the catalase activity by hydrocarbons but galactose did not affect seriously.

4. When C. tropicalis was incubated with hydrocarbons, the appearance of microbodies was observed electronmicroscopicaliy.

     

不同产地生漆中漆酚清除自由基及构效关系的初步研究

为更好地开发和利用生漆资源,探寻生漆中主要有效成分漆酚的抗氧化性能,为生漆的深加工提供理论依据和参数。分别应用丙酮提取中国和越南生漆,对得到的漆酚粗提物中的漆酚含量进行测定,建立了阳性对照组Vc和二丁基羟基甲苯(BHT)基础的DPPH、ABTS及O2-.法,对提取物抗氧化性能进行测试;在此基础上,结合紫外光谱分析了中国和越南生漆中漆酚含量及结构差异性,并初步分析其抗氧化的构效关系。结果显示,各地生漆中漆酚提取物具有强的抗氧化活性:中国毛坝生漆提取物抗氧化活性最强,其次是越南红漆和中国小木漆;紫外光谱分析亦表明毛坝生漆中含有丰富的不饱和键可能与其较强的抗氧化性相关。     

A new fused tetracyclic heterocyclic antioxidant from Serratia sp. PAMC 25557

A new fused tetracyclic heterocyclic compound, (4bR,10bR)-4b-hydroxy-10b,12-dihydrodibenzo[c,h][2,6]naphthyridine-5,11(4bH,6H)-dione (1), and a known compound, butyl 2-[(benzoyloxy)methyl]benzoate, spatozoate 2, were isolated from the broth culture of Serratia sp. PAMC 25557. The structure of 1 was determined by analyzing spectroscopic data. Compound 1 did not exhibit antimicrobial activity against Escherichia coli, Staphylococcus aureus, or Candida albicans. In addition, up to 100 μg/ml compound 1 did not show any toxicity against Artemia salina larvae. However, compound 1 showed DPPH free radical scavenging activity (IC₅₀ = 16.7 ± 0.34 μg/ml). This was the first report of spatozoate isolation from bacterial sources.