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Phenolics including flavonoids are suggested to be the major bioactive compounds contributing to the health benefits of fruits and vegetables. The objective of the study was to determine the total phenolic and flavonoid contents, oxygen radical absorbance capacity (ORAC), peroxyl radical scavenging capacity (PSC), cellular antioxidant activity (CAA) and antiproliferative properties of selected cerrado fruits named gabiroba (Campomanesia cambessedeana Berg), murici (Byrsonoma verbascifolia Rich) and guapeva (Pouteria guardneriana Radlk). Gabiroba fruit showed the highest amount of total phenolics (851.0±40.7mg/100g fruit) and the highest antioxidant activity for both the performed assays (ORAC 8027.5±378.6μmol TE/100g fruit and PSC 2342.5±48.1μmol AAE/100g fruit). Gabiroba fruit and the pulp of guapeva had the highest antiproliferative capacity with the lowest EC50 40.7±4.8mg/mL and 37.9±2.2mg/mL, respectively. The results for the analyzed fruits for CAA were not significantly different from each other (p<0.05) (murici 41.3±17.8; gabiroba 33.9±18.8 and the pulp of guapeva 23.3±4.2μmol quercetin/100g fruit). More than 30 phenolic compounds in the pulp of guapeva, gabiroba and murici extracts were identified in the present study using ESI–TOF-MS. These results characterized for the first time the functional activity of selected Brazilian fruits and demonstrated the importance of these fruits from cerrado biome. [ABSTRACT FROM AUTHOR]

• Quantitative analysis of 21 microbial metabolites of (epi)catechin was performed. • The antioxidant activities of 12 metabolites were evaluated. • C-ring opened significantly increased the antioxidant activities of (epi)catechin. • Dehydroxylation at the C-3′ or C-4′ mostly deprived their antioxidant activity. The changes in DPPH radical-scavenging capability of catechin and epicatechin during 24 h incubation with fecal microbiota in vitro and the targeted analysis of the characteristic metabolites by using UPLC-Q-TOF indicated that increase in antioxidant activity was synchronous with the accumulation of C-ring cleavage metabolites. Therefore, C-ring cleavage metabolite, 1-(3′,4′-Dihydroxyphenyl)-3-(2′′,4′′,6′′-trihydroxyphenyl)propan-2-ol (3,4-DHPP-2-ol), was separated from incubation liquid. The antioxidant activities of this metabolite and other 11 metabolites were examined through DPPH and ABTS free radical scavenging capacity and ferric reducing antioxidant capability (FRAC). The results indicated that all metabolites with the structure of 3′,4′-dihydroxylated had high antioxidant activity, especially 3,4-DHPP-2-ol, whose EC 50 was 5.97 μM in DPPH assay, 2 times as high as that of catechin, and 1.8 times as high as that of epicatechin. But the metabolites with the structure of monohydroxylated or unhydroxylated on the benzene ring hardly exhibited antioxidant activity. [ABSTRACT FROM AUTHOR]