[A new nor-neolignan compound identified from Itea yunnanensis].

Various separation methods in combination with spectral data analysis, X-ray single crystal diffraction analysis, and litera-ture data comparison were employed to clarify the chemical constituents of Itea yunnanensis. Seven compounds were obtained from I. yunnanensis, which were identified as(S)-3-[1-(4-hydroxyphenyl)propane-2-yl]-4-methoxybenzoate methyl ester(1), iteafuranal B(2), syringaresinol(3), dihydrokaempferol(4), trimethoxybenzene(5), eicosane(6), and nonacosane(7), respectively. Among them, compound 1 was a new nor-neolignan compound named iteanorneoligan A, and the rest of the compounds were identified from I. yunnanensis for the first time. The anti-hepatocellular carcinoma effect of the compound was evaluated based on Sk-hep-1 cells model via MTT assay, and compound 2 showed a significant inhibitory effect on the proliferation of Sk-hep-1 cells with an IC_(50) of 9.4 µmol·L~(-1). The antioxidant capacity was determined via DPPH, ABTS~(·+), and O■ radical scavenging ability, and compound 1 exhibited a significant ABTS~(·+) radical scavenging effect with an IC_(50) of 0.178 mg·mL~(-1).

Study on 2-arylbenzo[b]furans from Itea omeiensis and their fragmentation patterns with Q-Orbitrap mass spectrometry.

One new 2-arylbenzo[b]furan named iteafuranal F (1) as well as two known analogues (2-3) were isolated from the 95% EtOH extract of aerial parts of Itea omeiensis. Their chemical structures were constructed based on extensive analyses of UV, IR, 1D/2D NMR and HRMS spectra. Antioxidant assays revealed significant superoxide anion radical scavenging capacity of 1 with IC50 value of 0.66 mg/mL, which was comparable to the efficiency of positive control of luteolin. In addition, the preliminary MS fragmentation patterns in negative ion mode were established to distinguish 2-arylbenzo[b]furans with C-10 in different oxidation states: the characteristic loss of CO molecule [M-H-28]- was observed for 3-formyl-2-arylbenzo[b]furans, and the loss of CH2O fragment [M-H-30]- for 3-hydroxymethyl-2-arylbenzo[b]furans, and the loss of CO2 fragment [M-H-44]- for 2-arylbenzo[b]furan-3-carboxylic acids.

Establishment and application of the model of islet impaired by NO free radical released from streptozotocin / 生物工程学报

For diabetes mellitus, little research has been done on the tissue-based or cell-based drug screening model, which has advantages over traditional animal diabetic model in high specificity, high screening volume, low cost and simple manipulation. Considering that the maintenance of complete islet tissue structure is the prerequisite for islet cells to perform their functions normally, an in vitro islet-based drug screening model for diabetes mellitus was established and evaluated. Pancreatic islets were isolated from 3 weeks old mice of either sex by collagenase digestion and density gradient centrifugation as prescribed by Ramanadham S. The volume of 0.1% (W/V) collagenase IV, 0.1% (W/V) Hyaluroridase and 0.1% (W/V) DNase I were 4 times, 2 times and 1 times that of the islets to be digested. And a 2 hours' cold digestion at 4 degrees C was followed by a 10 minutes' warm digestion at 37 degrees C. Under the optimized digestion condition, the islet recovery could be increased by 10%. The isolated islets could survive 6 weeks in vitro and show stable insulin secretion in the first 10 days after inoculation. The obtained islets were cultured in RPMI-1640 medium at 37 degrees C with 5% CO2. Then a diabetic model was established by selecting streptozotocin (STZ) as the evocator and nitric oxide (NO) as the responding index. After 1 day's inoculation, islets culture was treated with STZ, whose concentration ranged from 0 to 5.0 mmol/L. NO was measured by a colorimetric assay at 540nm based on the Griess reaction for 10 min with 0.1 mL Griess reagent and 0.1 mL culture supernatants. Insulin secretion was assayed by RIA methods. Due to the islets-related inoculation variations, NO release and insulin content were both expressed as a percentage of the value recorded in basal experiment which was in the only presence of Krebs culture medium. It was testified that the amount of NO released from islet itself remained steady at 30-35 mmol/L regardless of the changes of STZ concentration from 0 to 5.0 mmol/L. However the NO content in the supernatants of islets culture had close relationship with STZ concentration. This indicated that in this STZ-induced islet diabetic model, NO mainly comes from STZ when it dissolves in water. On the other hand, when STZ changed from 0 to 5.0 mmol/L, the dose-dependent relationship between NO content and insulin secretion showed that the increase of NO came along with the decrease of insulin secretion, which is an important symbol of islet function. As a kind of oxidative free radical, NO is capable of impair islet cells. Thus, NO is a reliable responding index of the model. The optimal STZ concentration in the model is finally determined to be 5.0 mmol/L, under which condition the NO content and insulin secretion is 10.81 times and 0.43 times that in the medium before STZ is added. So if anything is effective in lowering the NO content in the culture, it could protect islets cells from the oxidative attacks of NO. Finally, as an application of the model, the scavenging effect of KOSCr on NO was studied. In a series of KOSCr with different chromium content, all had shown better NO scavenging effects than KOS itself, which could give us an enlightenment of the influence of chromium ion on oligosaccharide. And 1 g/mL KOSCr with 3.519% chromium content can significantly inhibit the NO formation. This has lain a theoretic basis for the research of KOSCr bioactivity and quality control. These results suggested that the STZ-induced diabetic islet model which is impaired by NO free radical can be used effectively, fast and conveniently when screening potential diabetes drugs.