Determination of polyphenols in Schinus terebinthifolius Raddi bark extracts and chemometric analysis

Abstract

This work describes a comparison of HPLC and spectrophotometric methods to determine the variation of the polyphenolics catechin, gallic acid, epicatechin, rutin, quercetin and chlorogenic acid in bark extracts of Schinus terebinthifolius Raddi (Anacardiaceae). This plant is a well-known medicinal plant that occurs in South and Central America and it is employed in folk medicine mainly as an antimicrobial, anti-inflammatory and antipyretic, and it is also commercialized as herbal medicine. Samples of S. terebinthifolius were collected from different habitats of the Brazilian semi-arid region and commercial samples were bought from local drugstores. The samples were submitted to ethanol : H₂O extraction and the extracts were submitted to HPLC-DAD for the best separation of compounds. Besides, a validation method for quantification of the above chemical markers was obtained and the concentration of compounds was determined in all samples, including the reference sample and commercial herbal medicines. In the same way, a methodology based on simple UV-VIS spectrophotometric analysis was also developed and the concentration data of the chemical markers were obtained for all samples. Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were carried out, and the six active compounds were determined and analyzed. The chromatograms showed similar chemical profiles but some differences in intensities were observed. HCA and PCA permitted us to group the samples with similar chemical composition, and paired multivariate analyses of the obtained sample compositions from HPLC/DAD and UV-VIS analyses showed that both methods are similar, and they permitted us to indicate the main chemical markers responsible for the quality of the herbal medicines.