Nanopartículas contendo óleo de quinoa (Chenopodium quinoa Willd.): síntese, caracterização físico química, avaliação in vitro da toxicidade e do potencial bioativo

Abstract

Quinoa oil (Chenopodium quinoa Willd.) is rich in unsaturated fatty acids and vitamin E. However, like most vegetable oils, it suffers from problems of lipid oxidation instability. The nanoencapsulation of lipophilic components has shown promising strategies for promoting the solubilization of oil in an aqueous matrix, preserving bioactive compounds, improving incorporation in industrial products, increasing bioavailability, and preserving the bioactive properties of the oil. The objective of this study was to encapsulate quinoa oil, characterize the obtained formulations, and evaluate the effect of encapsulation on the bioactive potential of the oil. Nanoemulsions were produced using the oil-in-water emulsification technique using porcine gelatin (OG) and isolated whey protein (OPG) as encapsulating agents and Tween 20 as a surfactant. Characterization of the nanoparticles was performed using techniques such as Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FTIR), encapsulation efficiency (%), Thermogravimetry (TG), and Differential Scanning Calorimetry (DSC), evaluation of Zeta Potential at different pH values, and water dispersibility. The cytotoxicity of free and nanoencapsulated quinoa oil was evaluated in vitro using Chinese Hamster Ovary (CHO) and human hepatocellular carcinoma (HepG2) cells, through the 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Additionally, cell viability tests were performed on epithelial cells using the neutral red assay with HaCaT and NIH-3T3 cells. The antioxidant capacity was determined by Total Antioxidant Capacity (TAC) in neutral and acidic media and iron chelation test. The antibacterial activity was evaluated by determining the Minimal Inhibitory Concentration (MIC) against Gram-negative and Gram-positive bacteria. Inhibition of enzymes related to glucose metabolism was investigated through α-amylase and amylase glucosidase inhibition tests. The results show that OG and OPG particles had smooth surfaces without cracks, with an average size ranging from 160 to 264 nm, with a polydispersity index of 0.11 and 0.130, respectively. The encapsulation efficiencies obtained were 74.137% and 83.085% for OPG and OG nanoformulations, respectively. Cytotoxicity analysis revealed that free and nanoencapsulated quinoa oil did not have cytotoxic effects on CHO-K1 and HepG2 cells, with cell viability higher than 70%. Regarding antioxidant activity, the nanoformulations showed higher activity than crude oil. In a neutral medium, crude oil exhibited an activity of 25.64 mg AA/g of sample, while OG and OPG nanoparticles demonstrated results of 38.61 and 41.81 mg AA/g of sample, respectively. This result was even more significant in an acidic medium, as crude oil did not show antioxidant activity. Still, OG and OPG nanoparticles exhibited 153.48 and 96.08 mg AA/g of sample, respectively. There was no inhibition of bacterial growth in the tested strains. Regarding inhibiting glucose metabolism enzymes, OG and OPG demonstrated a higher capacity to inhibit α- amylase and amylase glucosidase compared to crude oil. The inhibition value for α- amylase was 87.22 for crude oil, while OG and OPG presented values of 93.51 and 91.85, respectively. For amylase glucosidase, crude oil had a value of 8.39, while OG and OPG showed values of 79.03 and 48.34, respectively. The results indicate that encapsulating quinoa oil improves its biological properties, enhances its bioactive effect, and presents potential for future use in pharmaceutical, food, or cosmetic industries.