Determination of Barbaloin in Aloe vera L. var. chinensis (Haw.) Berger and Aloe barbadensis Miller by HPLC

A reserved-phase HPLC method was developed for the determination of barbaloin in Aloe vera L. var. chinensis (Haw.) Berger and Aloe barbadensis Miller, and whether there was a close relationship between the contents of barbaloin and their environments in which they were growing was decided. A Hypersil ODS column (4.6 mm×200 mm, 5 μm)was used with a mobile phase of methanol-water (40:60, containing 0.1% acetic acid), the flow rate being 1.0 mL·min -1, detection wavelength at 359 nm, and the column temperature being 30℃. The linear range of barbaloin was between 0.0726 and 0.726 μg with a correlation coefficient of 0.9998 and the regression equation being Y=1.9202×10 6X-1801.9. Barbaloin was stable in methanol in 48 h and the instrument precision was 1.2% while the method precision was 4.9%. The contents of barbaloin of 12 samples ranged from 6.160 to 319.1 μg·g -1. The method developed was fast and simple with good reproducibility. There was high correlation between the contents of barbaloin and their growing environments.

库拉索芦荟与中华芦荟抗氧化酶活性比较研究

分别以库拉索芦荟(Aloe barbadensis Mill.)和中华芦荟(Aloe vera L.var.Chinesis)老叶、中叶、嫩叶的整个叶片及叶片中间凝胶部分为样品,比较2种芦荟不同部位的抗氧化酶活性。结果表明,库拉索芦荟、中华芦荟不同部位抗氧化酶间活性差异较大。库拉索芦荟超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性最高部位分别是老叶中间凝胶、中叶整个叶片、老叶整个叶片;中华芦荟SOD、CAT、POD活性最高部位分别是嫩叶中间凝胶、老叶整个叶片、老叶整个叶片。结合生物学产量,开发应用SOD方面,应以2种芦荟中叶中间凝胶为原料;开发应用CAT和POD方面,应以2种芦荟老叶整个叶片为原料。

不同来源的芦荟对酪氨酸酶的抑制作用(英文)

In this study, lyophilized and methanolic extracts of aloe gel from different germplasms were evaluated for their potential to inhibit mushroom tyrosinase activity. The results showed potent inhibitory effect of Aloe vera gel extracts on L-dihydroxyphenylalanine(L-DOPA) oxidation catalyzed by tyrosinase in a dose-dependent manner. Significant differences in % inhibition of tyrosinase among the extraction methods and the germplasms were observed. The relative performance of the germplasms was evaluated with the help of posthoc multicomparison test. The methanolic extract was more effective than the lyophilized crude gel in all the germplasms. The inhibitory effect of the lyophilized gel and methanolic extract tested from five germplasms followed the order: RM > TN > S24 > OR > RJN. The germplasm RM showed the highest tyrosinase inhibition, and the maximum % inhibition noted was 26.04% and 41.18%, respectively for the lyophilized and methanolic extracts at 6 mg·mL–1concentration. Lineweaver-Burk plots of the different concentrations of L-DOPA in the absence and presence of lyophilized gel extract showed competitive inhibition of mushroom tyrosinase in all the germplasms. This study suggests that the germplasm RM could potentially be used for the isolation and identification of the effective tyrosinase inhibitory component, and ascertains the critical role of selecting the best source of germplasm for natural product isolation and characterization.