Evaluation of Antibacterial and Synergistic/Antagonistic Effect of Some Medicinal Plants Extracted by Microwave and Conventional Methods

The purpose of the study was to evaluate the efficiency of the microwave (MW) extraction method by comparing it with a conventional method through evaluation of antimicrobial and synergism/antagonism activity of each aquatic and ethanolic extracts samples, which were extracted from the dried plants (Ficus sycomorus leaves, Lawsonia inermis leaves and Glycerrhiza glabra Linn.). Nine samples of each plant for both solvents were irradiated with MW at several power outputs (180 w, 360 w, and 540 w) in several interval times (1, 2 and 3 minutes). The antibacterial activities of extracts and the synergistic effect between plants and antibiotics were evaluated using disk diffusion method against clinical isolated Staphylococcus aureus and Escherichia coli. The result revealed that the inhibition zone for more than 50% using aquatic and ethanolic samples results (extracted in two minutes and MW power 180 w) had shown the optimum extract and better antibiotic activity for each plant. Also, the results of ethanolic extracts used against selected microorganisms showed antimicrobial and synergistic effect with most antibiotics better than aquatic extracts. Our results indicate the possibility of using MW apparatus as an extractor to obtain bioactive compounds from plants and thus used in the treatment of bacterial infections, and some results of this study were encouraging. However, the antagonistic reactions of some extracts with some antibiotics and their use in combination should be further studied for in vitro activities. It is clearly a need to be furthermore evaluated, to identify the effective components, the mode of action and the possible toxic effect in-vivo of these ingredients.

水域生态学中生物稳定同位素样品采集、处理与保存

稳定同位素分析技术由于能够刻画复杂的食物网结构并追踪食物网中的能量流而成为水域生态学研究中的重要手段。但是当水生生物样品采集、处理和保存过程中存在不确定性时,营养关系分析中的同位素结果可能会产生误导性解释。文章采用数据模拟分析和文献总结的方法,研究了水域生态系统中样品采集、处理和保存对于稳定同位素的影响,概括性地建议了水域生态系统中适合应用稳定同位素分析技术开展生态学研究的样品采集、处理和保存的注意事项。但今后仍需进一步评估样品采集、处理和保存对稳定同位素比值的影响效果,确定化学动力学在水生生物样品采集、处理和保存中的作用,以进一步完善水生生物样品的采集、处理和保存稳定同位素生态学研究规范。

水蒸气蒸馏与乙醇提取茭白成分的GC-MS分析

运用水蒸气蒸馏和乙醇提取两种方法分别提取茭白中的化学成分,气相色谱-质谱联用技术进行分离鉴定,面积归一法进行定量分析。并对两种方法所得结果进行比较,分析其中的差异之处。结果显示,水蒸气蒸馏提取物中共分离出106种组分(占总峰面积的82.07%),其中棕榈酸(16.89%)、己二酸二(2-乙基己)酯(6.39%)、油酸酰胺(5.64%)、亚油酸(3.84%)和油酸(3.64%)为主要组分。乙醇提取物中共分离出89种组分(占总峰面积的91.75%),其中棕榈酸(33.71%)、油酸(11.24%)、2-羟基-1-(羟甲基)棕榈酸乙酯(6.84%)、反油酸乙酯(4.93%)和亚油酸乙酯(3.88%)为主要成分。还鉴定出香兰素、月桂酸、茉莉酸等香味成分,以及花生四烯酸等活性组分。结果表明,茭白中的化学成分十分丰富,两种方法提取的成分及其总量存在一定差异。