Elayne Cristina Gomes de Souza Barbosa, Wliana Alves Viturino da Silva, Janaína Carla Barbosa Machado, Magda Rhayanny Assunção Ferreira*, Luiz Alberto Lira Soares
The activities reported for Cinnamomum verum may be associated with the presence of flavonoids and the quantification of these compounds has an important role in the evaluation of the quality of the species. The study aimed to validate a spectrophotometric methodology for the quantification of flavonoids in C. verum leaves. The extracts were obtained by reflux (0.25-1.25 g of the herbal drug; 40-80% ethanol) and the samples were analyzed after scanning (200-500 nm) and complexed with aluminum chloride (2.5-7.5%; AlCl3) evaluated by reaction kinetics (0-60 min). Finally, the method was validated according to RDC 166/2017 of the National Health Surveillance Agency. The extraction was optimized using 0.5 g of the herbal drug and ethanol 80% (v/v) as a solvent, at 412 nm, 2.5% AlCl3 with 30 min of reaction. The method was considered linear (R² > 0.99), with detection and quantification limits equal to 0.096 and 0.292 µg/mL, respectively. The specificity was evidenced by the parallelism between the curves obtained. In precision, a total flavonoid content of 1.25 g% (repeatability) and 1.19 g% (intermediate precision), expressed in rutin, was observed. The recovery values remained between 92-102% and the robustness presented a relative standard deviation < 5%. Thus, the analytical suitability of the method for the proposed purpose was demonstrated. Keywords: Cinnamomum verum. Phytochemical screening. Spectrophotometry. Validation.