Analytical and chromatographic parameters used to quantify flavonols and chlorogenic acid in Solidago raw extracts

Species in the Solidago genus are used worldwide due to the therapeutic activities of their flavonoids and terpenoids. Its anti-inflammatory, vulnerary, antirheumatic, analgesic, diuretic, aquaretic, wound-healing properties, as well as its ability to relieve the burn and insect bites, allow use in a variety of therapeutic applications. This study was carried out to determine the comparative chemical profile, the content of flavonoids (FLV) and chlorogenic acid (CA) in the inflorescence extracts of Solidago chilensis and Solidago canadensis, as well as the biological potential of these species, regarding other Solidago species used in North America and Europe. S. chilensis was cultivated in Itaipava, Tapera Quilombo’s (Rio de Janeiro/Itaboraí Forum - FIT/Fiocruz) and in the Agroecological Platform of Phytomedicines (PAF/Farmanguinhos/Fiocruz). S. canadensis was acquired in Rio de Janeiro, in a popular market. The inflorescences polar extracts were evaluated and standardized by HPLC analytical methodology about the levels of the flavonoids reference standards and CA content and expressed in µg/mL for quantification, using the selectivity analytical parameters, linearity, limit of detection, accuracy, precision, and robustness as defined by national health surveillance agency in Brazil. The HPLC-UV-PDA revealed mainly flavonols (FLV) such as quercetin, glycosides as well as CA. S. canadensis presented the highest concentrations of quercetin (114.46 ± 0.114 µg/mL) and quercitrin (54.40 ± 2.014 µg/mL) but did not present isoquercitrin. However, the S. chilensis (TT0116 extract) presented the highest amount of CA (96.06 ± 2.365 µg/mL) and isoquercitrin (143.88 ± 4.219 µg/mL), and the samples of TB0116 extract presented the highest amount of hyperoside (227.79 ± 3.333 µg/mL and 153.49 ± 4.200 µg/mL). The presented data in this study indicate qualitative similarities and quantitative differences in the CA and FLV contents in the crude extracts of the two Solidago species. These differences are essential to assess the biological activity of each species, confirm its antioxidant and anti-inflammatory actions, and perform quality control of species occurring in Brazil.