类叶牡丹果实超临界提取物成分分析及其抗菌活性研究

目的:超临界提取黑龙江类叶牡丹果实中脂溶性性化学成分,GC-MS分析其组成,并对其进行抗菌活性研究。方法:应用超临界-CO2法提取类叶牡丹果实,采用气质联用(GC-MS)技术进行成分分析测定,对类叶牡丹果实超临界提取物采用微量二倍连续梯度稀释法测定最小抑菌浓度(MIC),平板转种法测定最小杀菌浓度(MBC)。结果:利用峰面积归一化法,共鉴定出了40个化学成分,相对百分含量占总离子流成分的94.24%,脂肪酸酯类占38.707%,其中甲酸异戊酯(isopentyl formate)相对含量最高,达到了22.536%,脂肪酸类化合物占36.88%,脂肪醇占8.005%,烷烃占5.51%,尚含醚、酮类、烯烃类、生物碱类和芳香族化合物。类叶牡丹果实超临界提取物对各菌株均有很好的抗菌活性。结论:类叶牡丹果实超临界-CO2提取的脂溶性成分脂肪酸酯和脂肪酸含量较高。本方法为类叶牡丹果实脂溶性成分的提取分析提供了一种选择,且提取物对4种菌株均有抑制和灭活作用。     

Amateur endurance cycling practice and adult’s physical and psychosocial health: a cross-sectional study of the influence of training volume

ABSTRACT

This study aimed to analyse the association between amateur cycling training volume and physical and psychosocial health. A cross-sectional study was developed, via self-reported survey, among 1669 cyclists and 1039 controls, where analysis of variance and hierarchical multiple linear regression test were developed. Independent of gender, high volumes of amateur endurance cycling practice benefited cyclists’ body mass index and male cyclists’ physical conditioning, while psychosocial health did not differ among the training volume groups. Hierarchical multiple linear regression analysis highlighted the contribution of training volume to lower cyclists’ body mass index and better male cyclists’ physical conditioning. All cyclist groups presented better physical and psychosocial health than controls. High volumes of amateur endurance cycling training were associated with better physical health without jeopardizing psychosocial health. The practice of amateur endurance cycling, both in low and high volumes, was associated with better physical and psychosocial health compared with inactivity.     

The activity prediction of indole inhibitors against HCV NS5B polymerase

Non‐structural viral protein 5B (NS5B) is a viral protein in hepatitis C virus. Although various inhibitors against NS5B have been found, the activity prediction of similar untested inhibitors is still highly desirable. In this respect, the Tchebichef moments (TMs) calculated from the images of molecular structures were regarded as the independent variables while the inhibitory activity (pIC₅₀) was the dependent variable, and the predictive model was established by means of stepwise regression. The R‐squared of leave‐one‐out cross‐validation (Q²) for the training set and the R‐squared of prediction () for external independent test set were 0.919 and 0.927, respectively. The obtained model was also evaluated strictly. Compared with the multivariate curve resolution with alternating least squares (MCR‐ALS) and the QSAR approaches derived from the literature, the proposed method is more accurate and reliable. This study not only provides an effective approach to predict the biological activity of RNA replication's inhibitors, but also extends the QSAR modeling technique.     

Antimicrobial Activity and Biocompatibility of Antibiotic-Loaded Chitosan Hydrogels as a Potential Scaffold in Regenerative Endodontic Treatment

IntroductionThe objective of this study was to determine the effectiveness of several antibiotic-loaded hydrogel scaffolds against Enterococcus faecalis, as well as their ability to stimulate proliferation and mineralization of dental pulp stem cells.MethodsFibrin (Fg) or chitosan-fibrin hydrogels (Ch) were prepared using 12.5 mg/mL fibrinogen and 0.4% (w/v) chitosan. Triple antibiotics, clindamycin-modified triple antibiotic paste, or double antibiotics were loaded in gels (1 mg/mL). Antibacterial effect against E. faecalis biofilm was determined by using colony-forming units (CFUs) and confocal laser scanning microscope (CLSM). Cell viability and morphology were determined by loading cells into different gels at 7 and 14 days using the water-soluble tetrazolium salt-1 cell viability assay and Live & Dead cell analysis. Mineralization was detected by using alkaline phosphatase and alizarin red staining activity.ResultsAntibiotic-loaded Fg gel and Ch gel alone without antibiotics resulted in a significant reduction in CFUs compared with the positive control (P < .05). When antibiotics were loaded in Ch gel, there were no CFUs detected in any groups (P < .05). CLSM images showed dense red areas with mostly dead bacteria on the dentin surface in antibiotic-loaded Ch groups, which showed significantly less live bacteria compared with the other groups (P < .05). Triple antibiotic-loaded Fg and Ch gels resulted in a dramatic decrease in the mineralized nodule formation compared with all other gel groups (P < .05). Ch hydrogels resulted in round cell morphology up to 7 days. Ch alone or with double antibiotic paste showed more cell spreading with spindle-shaped morphology at 14 days and higher alkaline phosphatase activity compared with other antibiotic-loaded Ch groups (P > .05).ConclusionsDouble antibiotic-loaded Ch gel appears to enhance the antibacterial properties while maintaining higher cell viability, cell spreading, and mineralization activity, compared with all the other scaffolds investigated.     

白及多糖超声提取工艺及其抗氧化活性研究

目的：优化白及多糖的超声提取工艺，比较不同产地白及多糖含量差异，考察白及多糖稳定性和抗氧化活性。方法：以多糖得率为考察指标，料液比、超声温度、超声时间为考察因素设计L9（34）正交试验优化白及多糖超声波提取工艺；以苯酚-硫酸法测定白及多糖含量，考察陕西汉中、云南普洱、湖南洪江及四川绵阳白及多糖含量产地差异；以化学方法考察白及多糖稳定性，并比较白及多糖对1,1-二苯基-2-苦肼基自由基（DPPH·）和羟基自由基（·OH）的清除率以评价其体外抗氧化活性。结果：最佳超声提取工艺条件为：料液比1:25（g/mL）、超声温度80 ℃、超声时间10 min；四川绵阳白及多糖含量最高，达到60.81%，湖南洪江次之，云南普洱最低；白及多糖在柠檬酸及中性溶液中的稳定性较好，在苯甲酸钠、过酸性或过碱性溶液中的稳定性较差；白及多糖能有效地清除DPPH和羟基自由基，具有潜在的体外抗氧化活性。结论：白及多糖超声波提取工艺的优化及其抗氧化活性研究，可为白及多糖提取及综合利用提供借鉴。