Determinação do perfil metabólico das cascas de Citrus aurantium usando CL-EMAR e avaliação do potencial biológico

Abstract

Citrus aurantium, known as bitter orange, is one of the many species of the genus Citrus and is widely used in traditional Chinese medicine as a digestive, anti-inflammatory, anxiolytic, etc. While many studies have described the use of its essential oil in various applications, little is known about the chemical composition and biological potential derived from the fruit peels. This study aims to report the chemical composition and evaluate the antifungal and antioxidant capacities of the decoction obtained from C. aurantium peels. Initially, the extract obtained from the decoction through partitioning with ethyl acetate (EAE-CA) underwent solid-phase extraction (SPE) followed by analysis using high-performance liquid chromatography (HPLC). Then, the EAE-CA extract and the fractions obtained were subjected to biological assays, such as antifungal activity against the phytopathogen Fusarium jinanense and antioxidant activity using the 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) radical scavenging method. The EAE-CA extract and two fractions with antifungal potential, FR3 and FR4, were analyzed by Liquid Chromatography coupled with High-Resolution Mass Spectrometry (LC-HRMS). This data allowed the annotation of 65 secondary metabolites, with 57 substances in positive mode and 8 in negative mode, including flavonoids, coumarins, terpenes, limonoids, aromatic compounds, and nitrogenous compounds. Fractions FR3 and FR4, whose annotated compounds were predominantly polymethoxyflavones and coumarins, showed a 60.97% inhibition of fungal mycelial growth of F. jinanense, a value higher than that achieved by the current commercial antifungal Cercobin® (47.92%). The antioxidant activity showed moderate results with an Inhibitory Concentration at 50% (IC50) of 0.0602 mg/mL for the extract, while the positive control Trolox presented an IC50 of 0.0061 mg/mL. Thus, the search for compounds or fractions enriched with biologically active substances from underexplored industrial waste sources such as peels adds value and maybe an alternative for the control of different phytopathologies.