科研之友
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摘要
The problem of standardization of propolis is a complex issue that has been approached by different researchers based on the elucidation of chemical composition and its correlation with biological activity. Due to variability of the matrix and the particular characteristics of the various types of propolis, this work is complex and time consuming, requires the availability of several analytical techniques, and generally leaves out the interactions between the different compounds that constitute the matrix. A complete analysis of the matrix together with the selective determination of some compounds with relevant biological activity could establish a quality parameter of the samples that helped us to develop a control system that facilitates their standardization. Caffeic acid phenethyl ester (CAPE) is a derivative of caffeic acid that has been extensively studied, because it has various types of biological activity beneficial to human health. In addition, it is present in different proportions in all the samples studied. In this work, a new method based on near-infrared spectroscopy (NIR) to estimate equivalents of CAPE in propolis samples is proposed. Simultaneously, a new method for estimating antioxidant activity expressed as EC50 is also presented. A multivariate partial least squares (PLS) method was used for calibration. These models were previously calibrated by measuring the content of CAPE by HPLC-EC, and antioxidant activity by UV-vis spectroscopy with the high-performance microplate reader method. PLS models were studied by cross-validation and external validation. The NIR methods developed proved to be a non-destructive, simple, fast, and inexpensive to use. This study model can be used as a quality parameter of in situ raw propolis samples, without any preprocessing, and contributes to solve the problem of standardization of propolis.
- 出版日期2016
