Extraction and Identification of Flavonoids from the Leaves of Pilocarpus microphyllus: Focus on Antioxidant Activity and Neuroprotective Profile

This work is based on research aiming to extract and identify flavonoids from jaborandi (Pilocarpus microphyllus) leaves and investigate their antioxidant and acute antinociceptive capacity. Characterization of the constituents of the ethyl acetate fraction (EtOAcF) obtained from the methanolic extract (ME) was performed by UV-Vis spectrophotometry, infrared spectroscopy, high-performance liquid chromatography (HPLC), mass spectrometry (MS), and cyclic voltammetry, demonstrating the possible majority component of this fraction, the flavone chrysin. Its solubility properties in HPLC are very close to those of the flavonol quercetin, revealing the characteristic presence of this group. An MS spectrum of the fraction revealed a major protonated molecule of m/z 254.9 [M+H]+. The EtOAcF fraction showed three oxidation processes at 0.32 V, 0.54 V, and 0.73 V vs. Ag/AgCl. Three reduction processes at the respective potentials: 0.60 V, −0.03 V, and -0.24 V vs. Ag/AgCl, indicating potential antioxidant activity. At DPPH and ABTS antioxidant radical capture assay, The IC50 obtained was 0.5 mg/mL and 0.81 mg/mL, respectively. In vivo test to determine the mechanical nociceptive threshold in the von Frey test, the dose of 100 mg/kg of the EtOAcF was able to cause inhibition of behavioral changes in neuropathy. The results obtained in this study demonstrate the biological potential of an EtOAcF derived from jaborandi leaves.