Assay of amino acids in leaves of Eucommia ulmoides under arbor forest mode and leaf-oriented cultivation mode by pre-column derivatization HPLC / 中国中药杂志

This study aims to develop the pre-column derivatization high performance liquid chromatography(HPLC) method for the determination of 16 kinds of amino acids in Eucommia ulmoides leaves, and compare the content of amino acids in the leaves harvested at different time and under leaf-oriented cultivation mode(LCM) and arbor forest mode(AFM). The HPLC conditions are as below: phenyl isothiocyanate(PITC) as pre-column derivatization agent, Agilent ZORBAX C_(18 )column(4.6 mm×250 mm, 5 μm), mobile phase A of acetonitrile-water(80∶20), mobile phase B of 0.1 mol·L~(-1) sodium acetate solution-acetonitrile(94∶6), gradient elution, flow rate of 1.0 mL·min~(-1), injection volume of 5 μL, column temperature of 40 ℃, and detection wavelength of 254 nm. The HPLC profile indicated well separation of 16 kinds of amino acids and the amino acid content in E. ulmoides leaves was up to 16.26%. In addition, the amino acid content in leaves of E. ulmoides under LCM was higher than under AFM. The amino acid content varied with the harvesting time. Through orthogonal partial least squares discriminant analysis, the amino acids of E. ulmoides under LCM and AFM were compared, which can distinguish the leaves under LCM from those under AFM. Principal component analysis was applied to comprehensively score the amino acids of E. ulmoides leaves. The results showed that the score of leaves under LCM was higher than that under AFM. Nutritional evaluation results indicated that the proteins in E. ulmoides leaves belonged to high-quality vegetable proteins. The established method for the determination of amino acid content is reliable. With the amino acid content as index, the leaf quality of E. ulmoides under LCM is better than that under AFM. This study lays a theoretical basis for the promotion of LCM for E. ulmoides and the development of medicinal and edible products from E. ulmoides leaves.

Simultaneous Determination of Contents of 8 Components in Eucommia ulmoides Leaves by HPLC / 中国药房

OBJECTIVE： To establish content determination method for simultaneously determining aucubin，geniposidic acid，catechin，chlorogenic acid，asperuloside，rutin，isoquercitrin and astragalin in Eucommia ulmoides leaves. METHODS：HPLC method was adopted. The determination was performed on Agilent ZORBAX SB-C18 column with the mobile phase consisted of acetonitrile-0.1％ phosphoric acid（gradient elution） at the flow rate of 1.0 mL/min. The detection wavelength was set at 203 nm for aucubin and catechin，239 nm for geniposidic acid and asperuloside，220 nm for chlorogenic acid，354 nm for rutin and isoquercitrin，and 266 nm for astragalin. The sample size was 5 μL. RESULTS： The linear range of aucubin， geniposidic acid， catechin， chlorogenic acid， asperuloside， rutin， isoquercitrin and astragalin were 0.812-6.090 μg（r＝0.999 3），0.438-3.285 μg（r＝0.999 2），0.045-0.336 μg（r＝0.999 2），0.882-6.615 μg（r＝0.999 3），0.097-0.726 μg（r＝0.999 1），0.064-0.483 μg（r＝0.999 3），0.048-0.360 μg（r＝0.999 1） and 0.014-0.108 μg（r＝0.999 7），respectively. RSDs of precision， stability and reproducibility tests were all lower than 3.5％（n＝6）. The average recovery rates were 101.60％，103.06％，99.77％，96.93％，98.17％，96.75％，98.97％ and 99.60％，with RSDs of 1.42％，2.65％，2.78％，2.05％，2.26％，0.93％，2.79％ and 3.08％，respectively（n＝6）. The contents of aucubin， geniposide， catechin， chlorogenic acid， plantain， rutin， isoquercetin and astragaloside in 12 batches of E. ulmoides leaves from different collection time and planting varieties were 10.903-17.245， 5.578-7.892， 0.198-0.440， 13.890-19.782， 1.008-1.547， 1.102-2.396， 0.267-0.701， 0.150-0.412 mg/g， respectively. The content fluctuated greatly. The contents of aucubin， geniposide， catechin， chlorogenic acid， rutin and pinoresinol diglucoside in cortex of E. ulmoides were 0.299， 0.123， 0.580， 0.112， 0.026，1.961 mg/g， respectively. CONCLUSIONS： The method is simple， reproducible and accurate. It can be used to evaluate the quality of E. ulmoides leaves. There are obvious differences in composition and content of components in different medicinal parts （cortex， leaves） of E. ulmoides.

Research on Characteristics of Eucommia ulmoides Leaf from Different Producing Areas by ;IR and TLC / 中国中医药信息杂志

Objective To analyze and compare the Eucommia ulmoides leaves from different producing areas by IR;To establish a TLC method for identification of Eucommia ulmoides leaves;To provide a reference for its quality control. Methods The characteristic absorption peaks were identified and the positions and intensities of Eucommia ulmoides leaves from 6 producing areas were compared by IR and second derivative spectrum, including clustering analysis; Separation and identification of the active components in Eucommia ulmoides leaves were conducted by TLC. Results There a difference exited in the characteristic absorption peaks in peakshapes, positions and intensities. And the samples from 6 producing areas could be divided into one category. Results found 6 batches of sample spots of consistent by TLC, but between samples of different producing areas trace components spots existed differences. Conclusion The two methods are direct, simple, fast and convenient, which can provide a reliable evidence for identification and quality control of the Eucommia ulmoides leaves.