Determinação de 1,2-benzopirona em xaropes de guaco empregando cromatografia líquida de alta eficiência

Abstract

The use of herbal medicines in Brazil has increased due to the creation of national incentive policies, in addition to presenting great biodiversity, providing conditions for the development of their production chain. Among the most diverse herbal medicines mentioned in the standards, the Mikania glomerata species popularly known as "guaco" is the one with the most records among those marketed in Brazil, the syrup is widely used for its expectorant and bronchodilator activity due to the presence of 1.2 -benzopyrone (coumarin). Among the methods used to quantify coumarins present in herbal medicines, High Performance Liquid Chromatography stands out. Given the above, this study aimed to validate an analytical methodology using HPLC for the quantification of 1,2-benzopyrone in eleven commercialized guaco syrup samples. The preparation of working solutions was carried out by diluting the mobile phase with acetonitrile and water (40:60 v/v). The guaco syrup samples were diluted with the same proportion of acetonitrile and water. Subsequently, the analyzes were carried out using an equipment for HPLC-DAD evaluating two wavelengths, 275 nm and 310 nm. During the validation of the method, the selectivity was evaluated, which demonstrated the absence of interfering peaks in the study range. Linearity was evaluated and attested by the ANOVA results, in addition to indicating analytical accuracy and the repeatability of the method. The limits of detection and quantification obtained from the parameters of the analytical curve, being for LOD 0.0041 and 0.0160 mg.L-1 and LOQ of 0.0124 and 0.0485 mg.L-1 in the ranges 275 and 310 nm respectively, being values considered satisfactory for the analyzed analytes. Among the eleven samples evaluated, two had 1,2-benzopyrone levels well below the values mentioned on the syrup labels, which can occur due to several factors associated with the various stages of production of a herbal medicine, drying method that alters the composition chemical and storage conditions. Therefore, the methodology used is an alternative for quantifying coumarins in guaco syrups.