Biological activity of optimized phenolic extracts of quince (Cydonia oblonga Miller) parts before and after simulated in vitro gastrointestinal digestion

In this study, the phenolic extracts of Eşme quince parts (pulp, peel, seed, juice, and leaf) were obtained under optimized extraction conditions. Then, the total phenolic content (TPC), the quantities of main phenolic compounds, antioxidant, and antimicrobial activity and the change in bioactivity properties (TPC, antioxidant capacity, and antimicrobial activity on the same sixteen microorganisms) after in vitro digestion of each quince part were evaluated. The order of TPC and antioxidant activity was determined as leaf > peel > juice > pulp > seed. After in vitro gastrointestinal digestion, a decrease was observed for the TPC (average 5-fold reduction) and antioxidant activity (more than 2.5-fold reduction) in all quince parts except quince seed than their extract forms. The quince leaf extract exhibited the highest antibacterial activity. Overall, this study exhibited that the quince leaf was considered a promising, cheap, and natural source for nutritional or pharmaceutical applications with biological activity properties.

Ultrasound-assisted extraction optimization and validation of ultra-performance liquid chromatographic method for the quantification of miquelianin in Cuphea glutinosa leaves

Cuphea glutinosa is a medicinal species abundant in South of Brazil, known because of its flavonoids, which have pharmacological properties as antioxidant, anti-hypertensive, diuretic, and antimicrobial. The present study aimed to optimize the extraction and validate an ultra-performance liquid chromatographic method coupled to a photodiode array detector (UPLC-PDA) method for the quantification of a chemical marker miquelianin in C. glutinosa leaves. The optimum conditions for the extraction of miquelianin from leaves of C. glutinosa were determined using a fractional factorial design (FFD) and a central composite design (CCD). An UPLC-PDA method was validated, following the ICH guidelines and RDC 166/2017 of ANVISA (Brazil). The extraction-optimization methodology was obtained with the following parameters: plant:solvent 1:60 (w/v), percentage solvent 38% ethanol, 60 min time, five extractions and particle size ≤ 180 μm. The validation parameters of the quantification method were satisfactory. The results revealed a method with excellent selectivity, linearity, precision (repeatability and intermediate precision were below 2.18 and 1.40%, respectively) and accuracy (mean recovery 90.6%). The average content of miquelianin was 1.03%. Briefly, the optimization of the extractive method in the leaves of C. glutinosa increased the concentration of miquelianin in the crude extract and the method was validated according to the current legislation.