Optimized extraction conditions for carqueja (Baccharis articulata) and orange (Citrus sinensis) for maximal antioxidant activity: cytotoxicity of these infusions

GUALDIERI F; GUERRA LN; MONTALDO L; ROCHA GF

Sevilla

Congreso; XIII Reunión del Grupo Español de Investigación en Radicales Libres (GEIRLI),; 2022

Grupo Español de Investigación en Radicales Libres

Antioxidants are commonly used as dietary supplements, they are known as agents that could reduce the risk of chronic diseases related to oxidative stress. However, uncontrolled consumption of antioxidants compounds may cause cytotoxicity. In our laboratory, we developed infusions from natural sources with potential antioxidant activity. We used Baccharis articulata (carqueja) and Citrus sinensis (orange) leaves for experiments, based on a central composite rotatable design (CCRD), to optimize the extraction conditions for best antioxidant activity. This CCRD was performed at five levels of three extracting parameters: Temperature (50 ? 90°C), incubation time (2-30 min) and concentration (6-30 mg leave powder/mL). We demonstrated that only concentration was relevant in the obtained model. We prepared infusions from 30 mg leaves powder/mL at 70°C, for 14 min; we determined antioxidant capacity by inhibition of DPPH: 71.6 ± 2.2 % (orange) and 51.5 ± 1.3 % (carqueja). Protein and polyphenols concentration were assessed; orange infusion: 39 ± 3 µg/mL and 54.2 ± 1.6 µg/mL, respectively; carqueja infusion: 526 ± 12 µg/mL and 42.7 ± 0.5 µg/mL, respectively. We evaluated these infusions toxicity in vitro, on Hep-G2 cells, by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Dilution 1:10 of these infusions were not significantly toxic to hepatic Hep-G2 cells compared to control not treated cells (1.08 ± 0.12 [orange treated cells] vs 1.00 ± 0.13 [control], p= 0.96; 0.94 ± 0.25 [carqueja treated cells] vs control, p= 0.99). Our results suggested that dilution of these infusions could be a possible source for antioxidants, without cytotoxicity effects, for developing healthy food.