Rapid Identification of Chemical Composition in Aloe Barbadensis Mill by Liquid Chromatography-Mass Spectrometry-Ion Trap-Time-of-Flight / 世界科学技术-中医药现代化

This article was aimed to rapidly analyze chemical composition in A loe Barbadensis Mill, and to compare the chemical composition of commercial aloe vera medicinal materials with that of fresh aloe yellow exudate. An opti-mized liquid chromatography-mass spectrometry-ion trap-time-of-flight (LCMS-IT-TOF) method was applied for the analysis of commercial aloe vera medicinal materials and fresh aloe yellow exudates. The Agilent TC-C18 column (4.6 í 250 mm, 5 m) was used. The gradient elution was a solvent system of water(A)-methanol(B). ESI source was operated in both positive and negative ion modes. The results showed that chromones, pyrones, naphthalene deriva-tive, anthrones and anthraquinones were separated successfully, 30 compounds were characterized by the comparison of characteristic MS/MS fragment ions data with the literature. The diagnostic fragmentation patterns of different chemical compositions were also discussed on the basis of EST-IT-TOF MS data. It was concluded that the chemical composition of commercial aloe vera medicinal materials were significantly different from that of fresh aloe yellow ex-udate in terms of types and contents: the former one mainly contains isoaloeresin D and aloin, and few aloesin; but the latter is mainly composed of aloesin and aloin, and the content of aloesin is the highest. The LCMS-IT-TOF analysis can be used to rapidly obtain rich structural information of different chemical compositions, which improves the efficiency of qualitative analysis of chemical composition, and is of great significance to the quality control, eval-uation and the utilization of A loe Barbadensis Mill.

A novel naphthalene derivative from Aloe barbadensis / 药学学报

To investigate the chemical constituents of A. barbadensis, aqueous extract of the plant was subjected to preparative medium pressure liquid chromatography (MPLC). The chemical structures were mainly determined by spectroscopic evidences (UV, IR, HR-MS, 1H NMR, 13C NMR, HSQC, 1H-1H COSY and HMBC) and chemical methods. A new O, O, O-triglucosylated naphthalene derivative, together with two known 6-phenyl-2-pyrone derivatives and four 5-methylchromones, were isolated and identified as 1-((3-((4- O-beta-D-glucopyranosyl)-beta-D-xylopyranosyloxymethyl)-1-hydroxy-8-alpha-L-rhamnopyranosyloxy)naphthalene-2-y])-ethanone (1), 10-O-beta-D-glucopyranosyl aloenin (2), aloenin B (3), aloesin (4), 8-C-glucosyl-(R)-aloesol (5), 8-C-glucosyl-7-O-methyl-(S)-aloesol (6), and isoaloeresin D (7). Compound 1 is a novel naphthalene derivative and named as aloveroside B, compounds 2-3 are isolated from this Aloe species for the first time.

Isolation and Purification of Isoaloeresin D and Aloin from Aloe vera by High-speed Counter-current Chromatography / 中草药·英文版

Objective To develop an efficient method to isolate and purify the main components isoaloeresin D and aloin from Aloe vera for its industrial production. Methods High-speed counter-current chromatography was used to isolate isoaloeresin D and aloin in a one-step separation from dried crude extract ofA. vera. The biphasic solvent system the lipophilic phase was selected as the mobile phase and the apparatus was rotated at 840 r/min. The effluent was detected at 254 nm. Results Isoaloeresin D (53.1 mg) and aloin (106.9 mg) were separated from the crude extract (384.7 mg) with the purities of 98.6% and 99.5%, respectively. Conclusion HSCCC is a powerful technique for isolation and separation of chemical composition from aloe.

Simultaneous isolation and purification of gallic acid and brevifolincarboxylic acid from Polygonum capitatum by high-speed counter-current chromatography / 中国中药杂志

<p><b>OBJECTIVE</b>To isolate and purify gallic acid and brevifolincarboxylic acid simultaneously by high-speed counter-current chromatography (HSCCC) from a crude extract of Polygonum capitatum.</p><p><b>METHOD</b>The biphasic solvent system composed of ethyl acetate-n-butanol-0.44% acetic acid (3:1:5) was used at a flow rate of 2.0 mL x min(-1), while the aqueous phase was selected as the mobile phase and the apparatus was rotated at 860 r x min(-1). The effluent was detected at 272 nm.</p><p><b>RESULT</b>51.5 mg of gallic acid and 5.9 mg of brevifolincarboxylic acid were separated from 1.07 g of the crude extract with the purities of 99.7% and 97.5%, respectively, while brevifolincarboxylic acid was obtained firstly from the genus Polygonum. The structures of the compounds were identified by ultraviolet spectrometry (UV), infra-red spectrometry (IR), liquid chromatography/mass spectrometry (LC/MS), time-of-flight mass spectrometry( TOF-MS), 1H-nuclear magnetic resonance (NMR) and 13C-NMR.</p><p><b>CONCLUSION</b>This method is feasible and rapid for isolation and purification of gallice acid and brevifolincarboxylil acid.</p>

Factors Affecting the Clinical Probation Teaching and the Countermeasures / 中华医学教育探索杂志

The status of current clinical probation teaching is not satisfactory,so it is essential to establish and perfect clinical teaching mode based on laws and guide students to properly handle the relationship among the internship,employment and preparation for the examination for postgraduates,reform the clinical teaching system,strengthen the training and education of medical ethics and quality,integrate the clinical teaching resources and make full use of clinical cases,as well as strengthen the internship management so as to ensure the quality of teaching of clinical internship.

Diagnosis and treatment of acute acalculous cholecystitis / 临床外科杂志

Objective To investigate the cause, diagno sis and treatment of acute acalculous cholecystitis(AAC).Method 32 cases of AAC which were treated from 1990 to 2000 were analyzed retrosp ective ly.Results 25 cases were diagnosed by B-ultrasonograph ,th e positive rate of diagnosis was 88.0%(22/25),7 cases were diagnosed by CT,6 c ases were definitely diagnosed(85.7%).All of them underwent operations, cholec ystectomy was performed in 29 patients,cholecystostomy in 2, subtotal cholecyste ctomy in 1 .Of them 31 were cured and one died.Conclusions The cause of AAC is very complication, the preoperative diagnosis is difficult, it is easy to be misdiagnosed. Surgeon should pay more attention to AAC. B-ultra sonograph is the first choice of the diagnosis of AAC,CT can give a hand to diag nosis. The early operation resection is the most effective method.