Antioxidant and Enzyme Inhibitory Activities of Blueberry Anthocyanins Prepared Using Different Solvents

Abstract

We compared the biological activities of anthocyanins prepared from whole blueberries or pomace and extracted with acetone, ethanol, and methanol. Crude Amberlite extracts (CAE) and rehydrated powders of freeze-dried anthocyanins were used. Ethanolic CAE yielded the highest total monomeric anthocyanin content [TMAC] (160 ppm), ferric reducing antioxidant power [FRAP] (3.4 mM Fe(2+)), total phenolics content [TPC] (382 ppm gallic acid equivalents [GAE]), and α-amylase inhibitory activity (36.8%). The rehydrated powder from acetonic extract gave the greatest FRAP (5.19) and TPC (422.7). α-Amylase (26.1%) and α-glucosidase (91.5%) inhibitory activities were also sustained. Methanolic CAE yielded values intermediate between ethanolic and acetonic extracts. Comparison of mass spectra between Amberlite extracts and rehydrated preparations revealed putative degradation and dimerization products in the rehydrated powders, which could account for loss in biological activities for rehydrated methanolic and ethanolic powders. Results of this study provide useful information in optimizing anthocyanin preparation methods for improved biological activity.

Evaluation of the in vitro α‐glucosidase inhibitory activity of green tea polyphenols and different tea types

“…The α ‐glucosidase inhibitory assay was conducted using the method of Flores et al . Fifty‐microliter serial two‐fold dilutions of green TPs solution (1.95, 3.91, 7.81, 15.63, 31.25, 62.50, 125 and 250 µg mL −1 ) or the above tea extracts and 20 µL of α ‐glucosidase (0.5 U mL −1 ) in 200 mmol L −1 potassium phosphate buffer (pH 6.8) were respectively added to 96‐well plates and pre‐incubated at 37 °C for 15 min.…”

“…The -glucosidase inhibitory assay was conducted using the method of Flores et al 15 Fifty-microliter serial two-fold dilutions of green TPs solution (1.95, 3.91, 7.81, 15.63, 31.25, 62.50, 125 and 250 μg mL −1 ) or the above tea extracts and 20 μL of -glucosidase (0.5 U mL −1 ) in 200 mmol L −1 potassium phosphate buffer (pH 6.8) were respectively added to 96-well plates and pre-incubated at 37 ∘ C for 15 min. Then, 50 μL of pNPG (3.0 mmol L −1 ) in 200 mmol L −1 potassium phosphate buffer (pH 6.8) was added and incubated for an additional 15 min at 37 ∘ C. The reaction was terminated by the addition of 70 μL of 1 mol L −1 sodium carbonate.…”

“…The ferric reducing antioxidant power (FRAP) assay was carried out according to the method of Flores et al 15 Briefly, the FRAP reagent was freshly prepared daily by adding 1.0 volume of 2,4,6-tris(2-pyridyl)-s-triazine solution (10 mmol L −1 in 40 mmol L −1 HCl), 1.0 volume of ferric chloride hexahydrate solution (20 mmol L −1 ), and 10 volumes of acetate buffer (300 mmol L −1 , pH 3.6), and was warmed to 37 ∘ C prior to use. One hundred microliters of the sample was pipetted in a cuvette, and 1 mL of the FRAP reagent was added.…”

Metabolic Engineering of the Phenylpropanoid Pathway Enhances the Antioxidant Capacity of Saussurea involucrata

“…6 and 7). Anthocyanins are well-documented potent antioxidant, which has been intensively investigated in various plant species [32], [33], [34]. The chlorogenic acid and cynarine in snow louts including S. involucrata showed good correations with their antioxidant activities [4].…”

O extrato etanólico das folhas de Baccharis dracunculifolia (Asteraceae) modula funções efetoras de neutrófilos: um promissor agente fitoterápico para o tratamento de processos inflamatórios mediados por estas células

“…Neste contexto, os produtos naturais têm recebido grande destaque nos últimos anos, uma vez que diversos estudos têm buscado substâncias naturais com efeito sobre o metabolismo oxidativo dos neutrófilos (Simões et al, 2004;Zekonis et al, 2008;Amaral et al, 2009;Paula et al, 2009;Simões-Ambrosio et al, 2010;Andrade et al, 2013;Barioni et al, 2013;Figueiredo-Rinhel et al, 2013;Flores et al, 2013;Kabeya et al, 2013;Denev et al, 2014;Figueiredo-Rinhel et al, 2014;Ren et al, 2014;Santos et al, 2014;Wang et al, 2014;Wickramasinghe et al, 2014;Liao et al, 2015).…”