Antioxidant activity and mechanism of commercial Rama Forte persimmon fruits (Diospyros kaki)
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2018
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This study aimed to characterize the antioxidant properties of Rama Forte persimmon,
a tannin-rich fruit variety produced in Brazil. Extracts prepared with lyophilized
pulps from fruits obtained in local markets were analyzed individually to evaluate
the extent of antioxidant protection and investigate the antioxidant mechanism.
Iron-mediated hydroxylation of 5,5-dimethyl-1-pirrolidine-N-oxide, determined by
electron paramagnetic resonance (EPR), and oxidative degradation of 2-deoxyribose
(2-DR) were inhibited by fruit extracts in a dose-dependent manner. There was a
considerable individual variability in inhibition of 2-DR degradation by individual
fruits. Higher protection of 2-DR degradation (by the extracts) was observed in
Fe(III)-citrate/ascorbate in comparison with Fe(III)-EDTA/ascorbate system; however,
antioxidant effectiveness of fruit extracts was not diminished by increasing EDTA
concentration by 10-fold. Other competition experiments using the 2-DR assay (varying
pre-incubation time and 2-DR concentration) indicated that protection comes mainly
from free radical scavenging, rather that metal chelation antioxidant activity. Persimmon
extracts prevented iron-mediated lipid peroxidation in rat liver homogenates,
which correlated significantly with the inhibition of 2-DR oxidation. Finally, sugar
content of individual fruits correlated inversely with inhibition of 2-DR degradation,
which could indicate that maturation decreases soluble antioxidant concentration or
efficiency. In conclusion, lipid peroxidation, 2-DR and EPR experiments indicated that
extracts from commercial fruits showed mainly radical-scavenger activity and relevant
antioxidant activity.
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Fruit maturation, Tannin, Oxidative stress, Lipid peroxidation, Polyphenol
Citação
DALVI, Luana T.; MOREIRA, Daniel C.; ALONSO, Antonio; AVELLAR, Isa G.J. de; HERMES-LIMA, Marcelo. Antioxidant activity and mechanism of commercial Rama Forte persimmon fruits ( Diospyros kaki ). PeerJ, Corte Madera, v. 6, e5223, 2018. DOI: 10.7717/peerj.5223. Disponível em: https://www-ncbi-nlm-nih.ez49.periodicos.capes.gov.br/pmc/articles/PMC6064204/pdf/peerj-06-5223.pdf. Acesso em: 14 abr. 2023.