Obtenção e caracterização de extratos de folhas de Momordica charantia L. utilizando líquidos pressurizados

Abstract

Momordica charantia L., also known as bitter melon, is a non-conventional food plant that is commonly used in folk medicine. It originates from Asia and is included in the National List of Medicinal Plants of Interest to the SUS (Brazil's Unified Health System) for future studies. Authors highlight the antioxidant potential and the presence of phenolics in this species as the reason for its vast therapeutic list. The use of pressurized liquids in extraction processes offers advantages over conventional methods, including time and solvent savings and the preservation of thermosensitive compounds. The objective was to determine the content of bioactive compounds such as phenolic compounds, flavonoids and chlorophyll, as well as the antioxidant capacity of the extracts. This study focused on obtaining extracts from the leaves of the São Caetano melon using pressurized liquids, specifically ethanol, a 50:50 hydroalcoholic mixture, and water. The extracts were obtained at different temperatures (40, 50, and 60 ºC) and flow rates (1, 2, and 3 g/min) at a fixed pressure of 12 MPa. The study examined the extraction of bioactive compounds from Momordica charantia L. leaves using pressurized liquid extraction (PLE). The best results in terms of bioactive compounds were achieved with different conditions for phenolics, flavonoids, and chlorophyll. Specifically, phenolics were extracted using water at a flow rate of 2 g/min and a temperature of 60 ºC, resulting in 2185 ± 14 mg of gallic acid/100 g. Flavonoids were extracted using ethanol at a flow rate of 1 g/min at the highest temperature, yielding 999 ± 18 mg of quercetin/100 g. Chlorophyll extraction was most effective at a flow rate of 3 g/min and a temperature of 60 ºC, resulting in concentrations of chlorophyll a (404 ± 5 mg/100 g), b (175 ± 1 mg/100 g) and ab (579 ± 6 mg/100 g). Antioxidant capacity was also evaluated, and the highest values were obtained at a temperature of 60 ºC, to ABTS (21896 ± 1200 µmol Trolox/100 g) and DPPH (31989 ± 587 µmol Trolox/100 g) using ethanol and water as solvents, respectively. The study concludes that PLE extraction is a viable option for obtaining bioactive compounds and antioxidants from Momordica charantia L. leaves, with factors such as flow rate, temperature, and solvent choice impacting the concentrations of these compounds.