[Correlation between intrahepatic triglyceride content quantified by proton magnetic resonance spectroscopy and glucose metabolism].

Objective: To investigate the correlation between intrahepatic triglyceride content (IHTC) and glucose metabolism in patients with non-alcoholic fatty liver disease (NAFLD) diagnosed by proton magnetic resonance spectroscopy (1H-MRS). Methods: A total of 239 subjects without diabetes mellitus were previously enrolled and underwent 1H-MRS scans. Anthropometric indexes including height, weight, waist and blood pressure, and laboratory findings as plasma glucose (PG), insulin (INS), C-peptide (CP), liver enzymes [alanine aminotransferase (ALT), aspartate transaminase (AST), γ-glutamyl transpeptidase (GGT)] and lipid profiles were collected. According to IHTC levels, participants were divided into three groups: the non-NAFLD group (IHTC<5.56%), the mild NAFLD group (IHTC 5.56%-<33%), and the moderate and severe NAFLD group (IHTC ≥ 33%). The clinical characteristics of each group were analyzed, and the correlation between IHTC and glucose metabolism were assessed. Results: Compared with those in the non-NAFLD group, male proportion, waist, 120 min postprandial PG (PG120), CP, liver enzymes and total cholesterol (TC) levels were greater in the NAFLD group, whereas insulin sensitivity index-Cederholm (ISI-Cederholm) and high density lipoprotein cholesterol (HDL-C) levels were lower in the NAFLD groups. Subjects in the moderate and severe NAFLD group had higher levels of 120 min postprandial INS (INS120) and Stumvoll indexes, and lower ISI-Cederholm than those in the mild NAFLD group [80.37 (57.68, 112.70) mU/L vs.110.50(71.78, 172.80)mU/L, 1453(1178, 1798)vs.1737(1325, 2380), 358(297, 446) vs.441(318, 594), 2.27(2.01, 2.53) vs.2.06(1.81, 2.39), respectively, all P<0.05]. Correlation analyses showed that IHTC was significantly positively correlated with waist hip ratio (WHR), PG120, INS120, HOMA insulin resistance (HOMA-IR), Stumvoll 1st-insulin secretion, Stumvoll 2nd-insulin secretion, ALT, AST, GGT and TC (r=0.197, 0.274, 0.334, 0.162, 0.199, 0.211, 0.406, 0.361, 0.215, and 0.196, respectively, all P<0.05), and negatively correlated with ISI-Cederholm and HDL-C (r=-0.334, and-0.237, respectively, all P<0.05). Furthermore, a multiple linear stepwise regression analysis indicated that ISI-Cederholm (Standardized ß =-0.298, P<0.001) and Stumvoll 1st insulin secretion (Standardized ß = 0.164, P = 0.024) were independent factors of IHTC. Conclusions: Peripheral insulin resistance occurs in the early stage of NAFLD and becomes worse with the progression of the disease. IHTC was independently associated with insulin sensitivity and first-phase insulin secretion.

Full-field fabric stress mapping by micro Raman spectroscopy in a yarn push-out test.

The full-field stress distribution of a two-dimensional plain fabric was mapped using micro Raman spectroscopy (MRS) through a novel yarn push-out test, simulating a quasi-static projectile impact on the fabric. The stress-strain relationship for a single yarn was established using a digital image correlation method in a single-yarn tensile test. The relationship between Raman peak shift and aramid Kevlar 49 yarn stress was established using MRS in a single-yarn tensile test. An out-of-plane loading test was conducted on an aramid Kevlar 49 plain fabric, and the yarn stress was measured using MRS. From the full-field fabric stress distribution, it can be observed that there is a cross-shaped distribution of high yarn stress; this result would be helpful in further studies on load transfer on a fabric during a projectile impact.

Study on fragmentation behavior of 5/7/6-type taxoids by tandem mass spectrometry.

The mass spectrometric behaviors of seven compounds, namely four 4beta(20),5-oxetane 5/7/6-type taxoids (i.e. taxayuntin A, taxayuntin B, taxayuntin and taxayuntin C) and three 4(20)-methylene 5/7/6-type taxoids (i.e. brevifoliol, taxchinin A and 7-acetyl-10-deacetyl-7-debenzoylbrevifoliol) have been investigated by the positive ion FAB-MS/MS technique. The fragmentation has been correlated with the types and positions of substituents of these compounds. It has been found that with the OH group at the C-10 position, taxayuntin A, taxayuntin B and 7-acetyl-10-deacetyl-7-debenzoylbrevifoliol are dominated by the loss of H2O, while with the BzO group at the C-10 position, taxayuntin, taxayuntin C, brevifoliol and taxchinin A preferentially eliminate the BzO group. In addition, C-2 is an active site, and neutral loss from the C-2 position readily occurs. The four 4beta(20),5-oxetane 5/7/6-type taxoids produce the terminal product ion with a stable conjugated system at m/z 311, while the 4(20)-methylene 5/7/6-type taxoids brevifoliol and 7-acetyl-10-deacetyl-7-debenzoylbrevifoliol produce this ion at m/z 237, and taxchinin A at m/z 253. Interestingly, characteristic fragment ions involving the loss of a 118 u group were observed for taxayuntin, and a possible fragmentation mechanism is given. The major fragmentation pathways and mechanisms of ion formation for the compounds are proposed on the basis of CID spectra and accurate mass measurements. The results of this paper will be helpful for structural analysis of analogs.

[Isoquinoline alkaloids from Corydalis thyrsiflora prain].

From the whole plant of Corydalis thyrsiflora Prain, an herbal medicine used in Tibet, 12 isoquinoline alkaloids were isolated and identified as protopine, dl-tetrahydrocoptisine, l-sinactine, l-cavidine, d-bicuculline, d-corlumine, sibiricine, ochotensine, dihydrosanguinarine, 8-acetonydihydrosanguinarine, d-adlumidine, and fumaramine. The structure determination was based on spectral analysis and on the comparison of physical and spectral data with those of authentic standards or those published in literature. In addition, the structure of fumaramine was confirmed by chemical transformation from bicuculline.

[Application of high speed countercurrent chromatography for the isolation of natural products--preparative isolation of taxane-diterpenoids and diterpene alkaloids].

High speed countercurrent chromatography (HSCCC) based on the fundamental principle of liquid-liquid partition is a newly developed technique for isolation. It utilizes a particular combination of coil orientation and planetary motion to produce a unique hydrodynamic phenomenon in the unilateral phase distribution of two immiscible solvents in a coiled column. In recent years HSCCC has gained increasing popularity in the isolation of bioactive natural products. This paper reports its application in the preparative separation of taxol (1), cephalomannine (2) and baccatin-III (3) from the alcoholic extract of Taxus yunnanensis. These 3 ingredients are first obtained from this plant.

[Isolation and identification of four new tetracyclic-atxanes from Taxus yunnanensis].

Four new minor toxoids, named as taxayuntin A, B, C and D, have been isolated from the ethanolic extract of the bark of Taxus yunnanensis Cheng et L. K. Fu. Their structures were identified as the new taxane diterpenoids with 5/7/6/4 membered ring system by spectral means and 2D NMR shift correlation experiments.

Two New Oleanane Saponins from Anemone flaccida.

Two new oleanane saponins, named flaccidoside II and III, were isolated from the rhizome of ANEMONE FLACCIDA Fr. Schmidt. On the basis of spectroscopic analysis and chemical transformation their structures were elucidated as 3- O-[alpha- L-rhamnopyranosyl-(1-->2)-beta- D-xylopyranosyl]-oleanolic acid 28- O-[alpha- L-rhamnopyranosyl-(1-->4)-beta- D-glucopyranosyl-(1-->6)-beta- D-glucopyranoside] and 3- O-[beta- D-glucopyranosyl-(1-->2)-beta- D-xylopyranosyl]-oleanolic acid 28- O-[alpha- L-rhamnopyranosyl-(1-->4)-beta- D-glucopyranosyl-(1-->6)-beta- D-glucopyranoside].

Bicyclic taxoids from needles of Taxus chinensis.

A new bicyclic taxoid, 5-deacetyltaxachitriene B (2) together with a known bicyclic taxoid (1) were isolated from needles of Taxus chinensis. Spectral characteristics for these bicyclic taxoids were discussed.

Triterpenoid Saponins from Anemone flaccida.

From the rhizome of ANEMONE FLACCIDA Fr. Schmidt, used in Chinese folk medicine, four saponins of oleanolic acid-A,B,C,D were isolated. By means of spectroscopy and chemical transformation, saponins A, B, and D were identified as 3- O-[alpha- L-rhamnopyranosyl-(1-->2)-alpha- L-arabinopyrasyl]-oleanolic acid, 3- O-[alpha- L-rhamnopyranosyl-(1-->2)-beta- D-xylopyranosyl]-oleanolic acid, and 3- O-[alpha- L-rhamnopyranosyl-(1-->2)-beta- D-glucopyranosyl]-oleanolic acid. These three saponins are known compounds but isolated from ANEMONE plants for the first time. Saponin C was elucidated as 3- O-[beta- D-glucopyranosyl-(1-->2)-beta- D-xylopyranosy1]-oleanolic acid, which has not been reported in the literature before, and is named as flaccidoside I.

Chemical Study on the Alkaloids of Corydalis hsuchowensis.

Ten alkaloids were isolated from the bulb of CORYDALIS HSUCHOWENSIS W. Y. Lian nov. ined. Among them nine alkaloids are known, identified as (-)-stylopine ( 1), cheilanthifoline ( 2), (+)-adlumidine ( 3), (+)-bicuculline ( 4), sibiricine ( 5), humosine A ( 6), (+)-bulbocapnine ( 7), (-)-scoulerine ( 8), and protopine ( 10), respectively. The other one is a new isoquinoline alkaloid. The structure was deduced as 9 based on spectroscopic analysis and chemical reactions. It was named coryximine.

Preliminary applications of cross-axis synchronous flow-through coil planet centrifuge for large-scale preparative counter-current chromatography.

The cross-axis synchronous flow-through coil planet centrifuge with a 20-cm revolutional radius and a total capacity of 1600 ml was successfully applied to preparative counter-current chromatography of various biological samples, which include sea buckthorn extract, steroid reaction mixture, indole plant hormones, and dinitrophenylamino acids. The present system offers advantages of stable balance of the centrifuge, a large column capacity, and high resolution.

Rearranged taxoids from Taxus yunnanensis.

Two rearranged 2(3-->20)abeotaxanes were isolated from the leaves and stems of Taxus yunnanensis, and designated as taxin B and 2-deacetyltaxin B. The structure of taxin B with a unique 6/10/6 skeleton was deduced on the basis of 1H-NMR, 13C-NMR, 1H-1H COSY, DEPT, NOE, and mass spectra and confirmed by X-ray crystallographic analysis. The structure of 2-deacetyltaxin B is elucidated by analog.

Application of countercurrent chromatography/thermospray mass spectrometry for the identification of bioactive lignans from plant natural products.

The versatility and resolving power of countercurrent chromatography (CCC) has been demonstrated with a newly developed analytical high-speed planet centrifuge system. Interfacing countercurrent chromatography with mass spectrometry (MS) provides a new analytical methodology that integrates the advantages of countercurrent chromatography with the low detection limit and identification capability of mass spectrometry. In this paper the capability of thermospray CCC/MS is demonstrated in identifying and validating the bioactive and structurally known lignans from a crude extract of Schisandra rubriflora Rhed et Wils, a traditional Chinese herbal medicine for treatment of hepatitis.