RESUMO
Sterile bracts can represent 80% of Araucaria angustifolia pinecone and are a rich source of phenolic compounds. This study aimed to optimize the extraction of the phenolic compounds from Araucaria angustifolia bracts using response surface methodology; the bioactivity properties were also investigated. The effects of the ethanol concentration, solute/solvent ratio, and temperature in relation to the phenolic composition and antioxidant activity were evaluated. The quantification and identification of the individual phenolic compounds (using high-performance liquid chromatography) and their bioactivity were evaluated. The optimized extraction conditions, which detected gallic acid, catechin, epicatechin, quercetin, and kaempferol, were obtained using 60% ethanol at a ratio of 1:38 (w/v) and a temperature of 80 °C. The extract showed high levels of phenolic classes and antioxidant activity. The extract also showed an inhibitory activity for pathogenic (approximately 80%, 10,000 µg/mL) and lactic acid (27.9%, 15,000 µg/mL) bacteria strains. The α-glucosidase inhibitory activity was approximately ten times greater than acarbose, demonstrating its high antiglycemic potential. No antioxidant and anti-inflammatory cellular activity were determined; however, a high cytotoxicity for non-tumor cells and the antiproliferative activity against the tumor cells were observed. Overall, the phenolic extract showed promising action in relation to the fight against the diseases related to oxidative stress and, hopefully, the application of the safe concentrations of the extract, based on bioavailability assays, can be verified.
RESUMO
The extraction of phenolic compounds from apples was optimised using response surface methodology (RSM). A Box-Behnken design was conducted to analyse the effects of solvent concentration (methanol or acetone), temperature and time on the extraction of total phenolic content, total flavonoids and antioxidant capacity (FRAP and DPPH). Analysis of the individual phenolics was performed by HPLC in optimal extraction conditions. The optimisation suggested that extraction with 84.5% methanol for 15 min, at 28 °C and extraction with 65% acetone for 20 min, at 10 °C were the best solutions for this combination of variables. RSM was shown to be an adequate approach for modelling the extraction of phenolic compounds from apples. Most of the experiments with acetone solutions extracted more bioactive compounds, and hence they had more antioxidant capacity, however, chlorogenic acid and phloridzin had higher yields (32.4% and 48.4%, respectively) in extraction with methanol.
Assuntos
Fracionamento Químico/métodos , Malus/química , Fenóis/isolamento & purificação , Antioxidantes/análise , Antioxidantes/isolamento & purificação , Flavonoides/análise , Flavonoides/isolamento & purificação , Fenóis/análiseRESUMO
This study evaluated the phenols of the Gala, Fuji and Golden Delicious varieties, which make up 95% of Brazilian production. The phenolic profiles (whole fruit) were determined by high pressure liquid chromatography, total phenols were determined using the Folin-Ciocalteau method and antioxidant capacity by the FRAP method (whole fruit, skin, pulp and centre). The Golden Delicious had the highest phenol content (408 mg/fruit) compared to Fuji (194 mg/fruit) and Gala (162 mg/fruit), and the antioxidant capacity of the Golden Delicious was 2.5 and 3.6 times higher than that found in the Fuji and Gala, respectively. The phenolic profile for the three varieties showed 5-caffeoylquinic acid, ( - )-epicatechin, procyanidin B2 and phloridzin as major components with procyanidins as the predominant class and quercetin as the minority. The consumption of apple pulp may provide 48-78% of the antioxidant capacity; however, if the peel is ingested, it may increase to 79-89%. The type of apple variety and the parts ingested are factors that must be taken into consideration in consumption.