Identification of Constituents and Evaluation of Biological Activity of Piptadenia stipulacea (Benth.) Ducke Ethanol Extract

Secondary metabolites such as flavonoids bring a range of biological properties to natural products, making them potential candidates for the pharmaceutical industry. Piptadenia stipulacea (Benth.) Ducke is well known in Brazil as Jurema Branca, and yet few studies have investigated its biological and phytochemical properties. This study aimed to characterize and evaluate the biological properties of ethanolic extract obtained from the bark of Jurema Branca. Characterization was performed by qualitative phytochemistry, HPLC, and mass spectroscopy. The antibacterial properties were investigated by microdilution method, cytotoxicity by MTT method, biocompatibility testing with human erythrocytes was performed, and antioxidant properties were investigated using DPPH and ABTS radical scavenging. The phytochemical tests demonstrated that rhamnetin and luteolin were the main constituents of the extract. This is the first report of these compounds in this species. The extract presented activity against Staphylococcus aureus (MIC = 500 µg/mL) and demonstrated activity against human colorectal adenocarcinoma (HCT-116), prostate adenocarcinoma (PC-3), and acute myeloid leukemia (HL-60) cell lines with IC50 of 37.96, 37.6, and 27.82 µg/mL, respectively, for this Piptadenia genus. Additionally, the extract presented excellent biocompatibility and antioxidant activity (IC50 = 956.7 and 147.2 µg/mL in DPPH and ABTS methods, respectively). These results are novel for the Piptadenia genus and pave the way for further evaluations regarding the biological importance of this species.