Desenvolvimento e otimização de método por HPLC-MS/MS para determinação do ácido caurenoico em extratos, tinturas e xaropes obtidos a partir das folhas de Mikania glomerata (guaco)

Abstract

Natural products have been used for many years for medicinal purposes. The kaurenoic acid (KA) is a secondary metabolite, a diterpene of the cauran class that is widespread among medicinal plants and it is found in Sphagneticola trilobata, Copaifera langsdorffii, Annona glabra, Mikania laevigata, Mikania glomerata, Smallanthus sonchifolius and Xylopia frutescen. The KA is an antioxidant, anti-inflammatory, leishmanicide, has activity against malaria and may present cytotoxic activity. Because it is a substance that contributes synergistically to the pharmacological activity of a new medicine or an important marker for existing medicines, a high performance liquid chromatography coupled to triple quadrupole mass detector with tandem capabilities (HPLC-QqQ-MS/MS) was developed for the detection and quantification of KA in complex matrices. Another method, with a qualitative and verifiable purpose, was developed using the ultra-efficient liquid chromatography technique coupled to a high resolution mass spectrometer of the simple quadrupole type and time of flight (UHPLC-QTOF-MS/MS). The HPLC-QqQ-MS/MS method detected and quantified KA in the samples obtained from extracts of Mikania glomerata (guaco) - a commercial extract used as raw material by the pharmaceutical industry, a tincture prepared with the leaves of the plant and two products purchased in the market (NL syrup and a BT syrup). Quantification was performed by the construction of calibration curves by the standard addition method. Concentrations of KA were 0.191 mg / mL in the commercial extract, 0.930 mg/mL in the tincture, 0.003 mg / mL in the NL syrup and less than the detection limit of the method in the BT syrup. The UHPLC-QTOF-MS/MS method confirms the results obtained and still allows the quantification of the BT syrup. The methods developed are excellent alternatives for agile and efficient analysis of the KA in complex matrices from simple dilution and injection in the equipments.