高效液相色谱法测定杜仲叶中的绿原酸

 采用高效液相色谱法测定杜仲叶中绿原酸的含量。所用色谱柱为Shim-packCLC-ODS柱,以巯嘌呤为内标,以甲醇-0.01mol/L磷酸二氢钾缓冲液(体积比为25∶75;pH3.9)为流动相,UV检测波长为328nm。在上述色谱条件下,当绿原酸质量浓度为25～300mg/L时,以绿原酸对照品溶液与内标液的峰面积比为纵坐标(Y),绿原酸的质量浓度为横坐标(X),二者呈良好的线性关系,线性方程为Y=8.0368X+1.275×10-3,r=0.9999;平均回收率为99.89%,RSD=1.45%(n=6)。     

外源性加硒法增加枣中硒含量的研究

以不同深度硒溶液对枣树进行不同次数的叶面喷施,得到了不同硒含量的枣样品,用荧光光度法测定了样品中硒的含量。结果表明,与对照组相比,用外源性加硒法可明显提高枣中硒的含量;并且可通过调节喷施液浓度和喷施次数,得到硒含量适宜的成熟小枣。     

毛细管电泳法测定桑叶中的黄酮类成分──芦丁和槲皮素

 采用高效毛细管电泳法分离测定了新疆不同地区、不同采集期、不同品种的桑叶中的黄酮类成分芦丁、槲皮素的含量。以含有体积分数为 15 %甲醇的 10mmol/L的磷酸二氢钠 2 0mmol/L的硼砂溶液 (pH 8 6 2 )为电泳缓冲液 ,采用压力进样方式 ,在 2 5℃ ,2 0kV恒压下进行电泳分离 ,并在 2 45nm波长处检测。结果表明 ,桑叶中的两种目标组分在 12min内完全分离 ,且有良好的线性关系 ;芦丁和槲皮素的加样回收率分别为 95 6 4%和99 36 % ,其RSD分别为 2 2 5 %和 1 79% (n =6 )。方法简单、准确、快速。     

Regulation of Cytokines and Dihydrotestosterone Production in Human Hair Follicle Papilla Cells by Supercritical Extraction-Residues Extract of Ulmus davidiana

This study was conducted to examine the anti-hair loss mechanism of the supercritical fluid extraction-residues extract of Ulmus davidiana by the regulation of cytokine production and hormone function in human dermal follicle papilla cells (HDFPCs). To investigate the modulatory effects on H₂O₂-induced cytokines, we measured transforming growth factor-beta and insulin-like growth factor 1 secreted from HDFPCs. To investigate the regulatory effects of supercritical extraction-residues extract of Ulmus davidiana on dihydrotestosterone hormone production, cells were co-incubated with high concentrations of testosterone. The supercritical extraction-residues extract of Ulmus davidiana significantly inhibited the secretion of transforming growth factor-beta but rescued insulin-like growth factor 1 in a dose-dependent manner. The supercritical extraction-residues extract of Ulmus davidiana markedly reduced dihydrotestosterone production. These results suggest that the supercritical fluid extract residues of Ulmus davidiana and their functional molecules are candidates for preventing human hair loss.     

Antimicrobial Activities of Plant Extracts against Solanum tuberosum L. Phytopathogens

The purpose of the study was to select an environmentally friendly plant biopesticide to protect seed potatoes against phytopathogens. The scope included the evaluation of the antimicrobial activities of 22 plant water extracts, 22 water-glycol extracts, and 3 subcritical carbon dioxide extracts using the agar diffusion method against 10 potato phytopathogens. For the most effective extracts, minimal inhibitory concentration (MIC), chemical composition analysis by gas chromatography–mass spectrometry and in situ assays on seed potatoes were performed. Garlic water extract was finally selected as the most effective in phytopathogen growth inhibition, both in vitro and in situ, with MIC values ranging between 6.3–25 mg/mL. 5-Hydroxymethylfurfural was determined to be the main component of this extract (33.24%). Garlic water extract was proposed as a potential biopesticide against potato phytopathogens.     

UHPLC–MS/MS determination and pharmacokinetic study of plantamajoside in rat plasma after oral administration of single plantamajoside and Plantago asiatica extract

A sensitive and reliable ultra‐high performance liquid chromatography coupled with tandem quadrupole mass spectrometry (UHPLC–MS/MS) method was developed for quantitation of plantamajoside in rat plasma. First, this study compared the pharmacokinetic properties of plantamajoside after oral administration of Plantago asiatica extract and pure plantamajoside in rat plasma with approximately the same dosage of 8.98 mg/kg. Second, chromatographic separation was performed on an Acquity HSS C₁₈ column (50 × 2.1 mm, p.d.1.7 μm) with isocratic elution using methanol–water (80:20, v /v) as mobile phase at a flow rate of 0.25 mL/min. The calibration curves were linear over the range of 0.1–100 ng/mL for plantamajoside. At different time points (0, 0.083, 0.167, 0.25, 0.5, 0.75, 1, 2, 3, 4, 5, 6 and 8 h) after administration, the concentrations of plantamajoside in plasma were measured and the main pharmacokinetic parameters were estimated. The study indicates that the pharmacokinetics of plantamajoside in rat plasma have significant differences between two groups.     

Discovery of structurally diverse natural product antagonists of chemokine receptor CXCR3

The chemokines (CXCL9, CXCL10 and CXCL11) and associated CXCR3 receptor are expressed during the inflammatory process from multiple sclerosis, atherosclerosis or organ transplantation resulting in the recruitment of lymphocytes leading to tissue damage. It is hypothesized that blocking of the ligand/CXCR3 receptor interaction has potential to provide opportunity for development of agents that would block tissue rejection. In this paper, four classes of natural product inhibitors (IC₅₀ ranging 0.1–41 M) have been described that block the CXCR3 receptor interaction of IP-10 ligand. These include a cyclic thiopeptide (duramycin), polyketide glycosides (roselipins), steroidal glycosides (hypoglausin A and dioscin) and a novel alkyl pyridinium alkaloid that were isolated by bioassay-guided fractionation of the organic extracts derived from actinomycete, fungal, plant and marine sources and discovered using ¹²⁵ I IP-10/CXCR3 binding assay. Duramycin was the most potent with an IC₅₀ of 0.1 M. Roselipins 2A, 2B and 1A showed IC₅₀ values of 14.6, 23.5, and 41 M, respectively. Diosgenin glycosides dioscin, hypoglaucin A and kallstroemin D exhibited IC₅₀ values of 2.1, 0.47 and 3 M, respectively. A novel cyclic 3-alkyl pyridinium salt isolated from a sponge displayed a binding IC₅₀ of 0.67 M.     

Ellipticity of the Linearly Polarized He-Ne Laser Radiation Reflected by the Leaves of Plants

The phenomenon of elliptical polarization of the linearly polarized radiation reflected near the Brewster angle by the leaves of plants has been investigated. It has been shown that the appearance of ellipticity is associated with the complex structure of the cuticle.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 2, pp. 236–240, March–April, 2005.     

Ultrasound-assisted microencapsulation of jackfruit extract in eco-friendly powder particles: characterization and antiproliferative activity

The aim of the article was to develop stable and safe eco-friendly microcapsules and evaluate their physicochemical properties and their efficiency to protect a jackfruit extract. Eco-friendly microcapsules were produced by ultrasound and spray drying using only three safe ingredients: sucrose ester (SE), miglyol and maltodextrin (DE = 10). Some physicochemical properties, particle morphology, FT-IR, differential scanning calorimetry and antiproliferative activity were determined for microcapsules loaded or not with the jackfuit extract. The results revealed that the encapsulation process by spray drying produced stable microcapsules, with adequate physicochemical and fluid properties for a powder product. The cell viability on the proliferation of M12.C3.F6 cell line was not affected by powder microcapsules without jackfruit extract, indicating that capsules are not toxic for these cells. However, microcapsules with jackfruit extract (100 μg/ml) were able to inhibit significantly the proliferation of M12.C3.F6 cells. These microcapsules can be used for the protection of different compounds sensitive to light, oxygen and/or heat and displaying a very low aqueous solubility.