Caracterização e avaliação das propriedades físico-químicas e bioativas de óleos de semente e de folhas de Moringa oleifera

Abstract

Moringa oleifera is a plant widely recognized for its bioactive properties and for the potential extraction of vegetable oils from its seeds and leaves, which have promising applications in the food, cosmetic, and pharmaceutical industries. However, its physicochemical characteristics, bioactive properties, and cytotoxicity remain poorly studied. Therefore, this study aimed to evaluate the physicochemical characteristics and bioactive properties of seed and leaf oils from M. oleifera. Analyses were performed using Proton Nuclear Magnetic Resonance (¹H NMR), Fourier Transform Infrared Spectroscopy (FTIR), and Gas Chromatography coupled with Mass Spectrometry (GC-MS), in addition to thermogravimetric and physicochemical characterization (TG/DTA). The cytotoxicity of the oils was evaluated in vitro using Chinese hamster ovary (CHO) cells and human hepatocarcinoma (HepG2) cells through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Different fractions of the seed and leaf oils were used to determine Total Phenolic Content (TPC) and other bioactive properties. TPC was determined using the FolinCiocalteu method. Antioxidant activity was assessed through scavenging assays of the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical, ABTS (2,2′-azino-bis(3- ethylbenzothiazoline-6-sulfonic acid)) radical cation, and by the Total Antioxidant Capacity (CAT) assay. Antifungal and antibacterial activities were tested through Minimum Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC), and Minimum Bactericidal Concentration (MBC). The in vitro inhibition of glucose metabolism enzymes was evaluated for α-amylase, α-glucosidase, and amyloglucosidase. The oils showed high levels of unsaturated fatty acids (70.9% in seed oil and 70.6% in leaf oil), with linoleic acid as the predominant component. Both oils demonstrated no cytotoxicity, maintaining cell viability above 70%. The methanolic fraction of the leaf oil exhibited the highest TPC (173.18 µg GAE·g⁻¹) and superior antioxidant capacity in all three assays. According to the methodology applied, no antibacterial activity was observed against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Salmonella typhimurium, but both oils showed antifungal activity against Candida albicans, with MIC and MFC values of 10 mg/mL. Lastly, the methanolic, integral, and insoluble precipitate fractions showed in vitro enzyme inhibition activity, with the integral fraction being the most effective. This fraction exhibited the highest inhibition percentages, reaching 97.94% for α-glucosidase and 95.32% for amyloglucosidase in seed oil. For the leaf oil, inhibition values were 94.79% and 85.96%, respectively. These results demonstrate the potential of both oils for applications in the food, cosmetic, and pharmaceutical industries.