Effect of heating treatment on stability of two coumarins in Angelica dahurica and activity of tyrosinase / 中国中药杂志

To study the heating treatment of Angelica dahurica under different temperature and time conditions on the stability of coumarins and tyrosinase activity. HPLC method was used to determine the contents of imperatorin and isoimperatorin, and tyrosinase activity was assayed by measuring the oxidation rate of L-DOPA in vitro. After heated, the contents of imperatorin increased. Expect for being heated at 90 ℃ for 2 h, the content of isoimperatorin was higher than crude one. Before and after being heated, A. dahurica showed an activating effect on tyrosinase. In the same temperature and time conditions, the activation rate increased with the rise of concentration of tyrosinase extracts. Heating process for A. dahurica could change the contents of imperatorin and isoimperatorin, mainly increasing their concentrations.

Research progress on chemical compounds and pharmacological effects of Caesalpinia / 中国中药杂志

Consult literature, the chemical composition of the type of system Caesalpinia plants were summarized and discussed in detail its pharmacological effects. The genus contains major chemical components of high isoflavones, chalcones and diterpenoids, pharmacological effects inhibit melanin production, anti-inflammatory, antioxidant, antibacterial, immune regulation, and further research in this genus offer reference.

Simultaneous determination of quercitrin, phloridzin and 3-hydroxyl phloridzin in leaves of Malus halliana by ultrasound-assisted ionic liquid-reversed phase liquid chromatography / 中国中药杂志

To establish a method for the simultaneous determination of phloridzin, 3-hydroxy phloridzin and quercitrin in leaves of Malus halliana by ultrasonic-assisted ionic liquid coupled with RP-HPLC. An Agilent TC-C₁₈ (4.6 mm×250 mm, 5 μm) column was used, with the mobile phase of acetonitrile and 1% phosphoric acid-water (20∶80) by gradient elution at the detection wavelength of 270 nm. The flow rate was 0.8 mL•min⁻¹, and chromatographic column temperature was controlled at the room temperature. Under the optimized conditions, the linear ranges for phloridzin, 3-hydroxy phloridzin and quercitrin were 0.9-112.5 μg (r = 0.999 6), 0.093 2-11.65 μg (r = 0.999 1) and 0.097 2-12.15 μg (r = 0.999 8), respectively. The average recoveries of the three constituents were 99.35%, 98.80% and 98.19%, respectively. The method was environmental friendly, rapid, accurate and highly reproducible, and so suitable for the quantitative analysis of phloridzin, 3-hydroxy phloridzin and quercitrin in leaves of M. halliana.