Foods rich in antioxidants play an essential role in the prevention of diseases. The present study compared contents of phenolics, vitamin C, anthocyanin and antioxidant activity of 11 fresh exotic fruits, cultivated in the northeastern part of Brazil. The antioxidant activities were evaluated using two antioxidant systems 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), expressed as TEAC (Trolox Equivalent Antioxidant Capacity) and VCEAC (Vitamin C Equivalent Antioxidant Capacity) values. The results indicated that the above fruits, such as murici and mangaba, were good sources of antioxidants. The phenolic contents showed positive correlations with total antioxidant by ABTS (R = 0.94, P ≤ 0.001) and DPPH (R = 0.88, P ≤ 0.001) assays. However, this correlation was not noticed when examining vitamin C and anthocyanins contents. The 11 fruits studied had comparable antioxidant activity in both, ABTS and DPPH assays. These methods are recommended as useful tools for the evaluation of the total activity antioxidant in fruits. Our results indicated promising perspectives for the development and usage of fruits species studied with considerable levels of antioxidant activity.

Ursolic acid, an important bioactive compound, was isolated from ethanol extract of aerial parts of Sambucus australis. In order to develop bioactive ursolic acid derivatives, two semi-synthetic compounds were obtained through modification at C-3. The antibacterial activity of the ursolic acid and its derivatives was investigated. The microdilution method was used for determination of the minimal inhibitory concentration (MIC), against twelve bacterial strains. The influence of ursolic acid and its derivatives on the susceptibility of some bacterial pathogens to the aminoglycosides antibiotics neomycin, amikacin, kanamycin and gentamicin was evaluated. The most representative synergistic effect was observed by 3β-formyloxy-urs-12-en-28-oic acid at the concentration of 64 μg/mL in combination with kanamycin against Escherichia coli (27), a multidrugresistant clinical isolate from sputum, with reduction of MIC value from 128 μg/mL to OPEN ACCESSMolecules 2014, 19 1318 8 μg/mL. Ursolic acid and its derivatives were examined for their radical scavenger activity using the DPPH assay, and showed significant activity.

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Dos frutos dePterodon polygalaeflorus (Leguminosae) foram isolados o novo diterpeno 6α-hidroxivouacapano e os conhecidos diterpenóides 6α,7β,14β,19-tetraidroxivouacapano, 6α,7β-diidroxivouacapan-17β-oato de metila e o flavonóide taxifolina. As estruturas foram determinadas com base em análise espectroscópica, inclusive RMN bidimensional, transformação química do novo diterpeno e comparação com dados da literatura.From fruits of Pterodon polygalaeflorus (Leguminosae) the new diterpene 6a-hydroxyvouacapane, the known diterpenoids vouacapane-6α,7β,14β,19-tetraol and methyl 6α,7β-dihydroxyvouacapan-17β-oate and the flavonoid taxifolin were isolated. Structural determinations were accomplished by spectroscopic analysis, including two-dimensional NMR, chemical transformation of the new diterpene and comparison with literature data.

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