Development of an analytical method using reversed-phase HPLC-PDA for a semipurified extract of Paullinia cupana var. sorbilis (guaraná)

► Semipurified extract of Paullinia cupana was analyzed by RP-HPLC-PDA for catechin, epicatechin and caffeine. ► The validation method was development and was linear, precise, accurate, and robust, under the conditions employed, for catechin and epicatechin. The results demonstrated the efficiency of the proposed method. ► The quantification of the EPA extractive solution demonstrated that it contained 14.46μgmL−1 of catechin (180.75μg catechinmg−1 of EPA), 22.31μgmL−1 of epicatechin (278.87μg epicatechinmg−1 of EPA), and 24.07μgmL−1 of caffeine (300.87μg caffeinemg−1 of EPA). ► The solutions were stable for a sufficient time (one week) to complete the analytical process. The Neotropical plant ‘guaraná’ has been widely used in medicine, cosmetics, and industry because of its versatile biological activities. These effects are mainly attributed to the presence of polyphenols. An efficient, precise, and reliable method was developed for quantification of the polyphenols catechin and epicatechin in guaraná extract solution, using HPLC-PDA detection. The ideal conditions for the analysis of a semipurified extract of guaraná (EPA), using solutions of 0.05% TFA–water (phase A) and 0.05% TFA in acetonitrile:methanol (75:25, vv−1) (phase B) as mobile phases were established. Gradient reversed-phase chromatography was performed using a guard cartridge (C18, 4.6mm×20mm, 4μm) and column (C18, 250mm×4.6mm, 4μm), flow of 0.5mLmin−1 and detection at 280nm. The main validation parameters of the method were also determined. The method was linear over a range of 18.75–300μgmL−1 for catechin and epicatechin, with detection limits of 0.70 and 0.88μgmL−1 and quantification limits of 2.13 and 2.67μgmL−1, respectively. The method also showed consistent mean recoveries of 91.3±3.8%, 2.14 RSD and 93.4±3.1, 2.74 RSD of catechin and epicatechin respectively. The relative standard deviations were relatively low: intra-day (0.72% and 0.66% for catechin and epicatechin, respectively) and inter-day (0.93% and 0.75% for catechin and epicatechin, respectively). The semipurified extract showed catechin, epicatechin, and caffeine contents of 180.75, 278.87, and 300.87μgmg−1, respectively. The results demonstrated the efficiency, precision, accuracy, and robustness of the proposed method. The solutions remained stable for a sufficient time (one week) to complete the analytical process.