Fermentation and dry fractionation increase bioactivity of cloudberry (Rubus chamaemorus).

Phenolic composition and bioactivity of cloudberry was modified by bioprocessing, and highly bioactive fractions were produced by dry fractionation of the press cake. During fermentation polymeric ellagitannins were partly degraded into ellagic acid derivatives. Phenolic compounds were differentially distributed in seed coarse and fine fractions after dry fractionation process. Tannins concentrated in fine fraction, and flavonol derivatives were mainly found in coarse fraction. Ellagic acid derivatives were equally distributed between the dry fractions. Fermentation and dry fractionation increased statistically significantly anti-adhesion and anti-inflammatory activity of cloudberry. The seed fine fraction showed significant inhibition of P fimbria-mediated haemagglutination assay of uropathogenic Escherichia coli. The seed coarse fraction significantly reduced NO and IL-6 production and iNOS expression in activated macrophages. Fermentation did not affect antimicrobial activity, but slight increase in activity was detected in dry fractions. The results indicate the potential of cloudberry in pharma or health food applications.

Flavonoids, proanthocyanidins, vitamin C, and antioxidant activity of Theobroma grandiflorum (Cupuassu) pulp and seeds.

The ascorbic acid, flavonoids, and proanthocyanidins content and in vitro antioxidant activity of fresh pulps and seeds of cupuassu, harvested at three different times of the year, and in commercial frozen pulps were evaluated. Lipids, total phenolics contents, and antioxidant activities were the highest in the seeds, followed by fresh and commercial frozen pulps, respectively. The latter also showed a lower content of ascorbic acid (9-13 mg/100 g DW) when compared to fresh pulps (96-111 mg/100 g DW). The 8-O-ß-D-glucuronides and the corresponding 3″-sulfates of isoscutellarein (5,7,8,4'-tetrahydroxyflavone), hypolaetin (5,7,8,3',4'-pentahydroxyflavone), and 8-hydroxychrysoeriol (5,7,8,4'-tetrahydroxy-3'-methoxyflavone), also known as hypoaletin 3'-methyl ether, were identified and quantified (31 mg/g DW) in cupuassu seeds. The same flavonoid profile was present in pulps although in much lower concentrations (0.5 to 2 mg/g DW). The two 8-hydroxychrysoeriol glycosides had not been previously reported in cupuasssu. The content of proanthocyanidin oligomers in seeds (23 mg/g DW), mainly of the epicatechin type, and the mean degree of polymerization (5.5) were calculated. No discernible effect of the harvesting period on the evaluated chemical aspects could be identified. Commercial frozen pulps contained a smaller amount of all these compounds than the fresh pulp, suggesting that these compounds were potentially degraded during processing/storage.

Inhibition of quorum sensing (QS) in Yersinia enterocolitica by an orange extract rich in glycosylated flavanones.

Flavanones, flavonoids abundant in Citrus , have been shown to interfere with quorum sensing (QS) and affect related physiological processes. We have investigated the QS-inhibitory effects of an orange extract enriched in O-glycosylated flavanones (mainly naringin, neohesperidin, and hesperidin). The QS-inhibitory capacity of this extract and its main flavanone components was first screened using the bacteriological monitoring system Chromobacterium violaceum . We next examined the ability of the orange extract and of some of the flavanones to (i) reduce the levels of the QS mediators produced by Y. enterocolitica using HPLC-MS/MS, (ii) inhibit biofilm formation, and (iii) inhibit swimming and swarming motility. Additionally, we evaluated changes in the expression of specific genes involved in the synthesis of the lactones (yenI, yenR) and in the flagellar regulon (flhDC, fleB, fliA) by RT-PCR. The results showed that the orange extract and its main flavanone components inhibited QS in C. violaceum, diminished the levels of lactones secreted by Y. enterocolitica to the media, and decreased QS-associated biofilm maturation without affecting bacterial growth. Among the tested compounds, naringin was found to inhibit swimming motility. Exposure to the orange extract and (or) to naringin was also found to be associated with induction of the transcription levels of yenR, flhDC, and fliA. This work shows the in vitro QS-inhibitory effects of an orange extract enriched in flavanones against a human enteropathogen at doses that can be achieved through the diet and suggests that consumption of these natural extracts may have a beneficial antipathogenic effect.

Inhibition by chestnut honey of N-Acyl-L-homoserine lactones and biofilm formation in Erwinia carotovora, Yersinia enterocolitica, and Aeromonas hydrophila.

Bacteria are able to communicate and coordinate certain processes using small secreted signaling molecules called autoinducers. This phenomenon, known as "quorum sensing" (QS), may be essential for the synchronization of virulence factors as well as biofilm development. The interruption of bacterial QS is acknowledged to attenuate virulence and considered to be a potential new therapy to treat infections caused by pathogenic bacteria. N-Acyl-L-homoserine lactones (AHLs) have been identified as the main bacterial signaling molecules in Gram-negative bacteria. This study evaluates the capacity of chestnut honey and its aqueous and methanolic extracts to inhibit bacterial AHL-controlled processes in Erwinia carotovora , Yersinia enterocolitica , and Aeromonas hydrophila . This study is the first in applying liquid chromatography coupled with tandem mass spectrometry to determine the QS inhibitory activity of honey against pathogenic bacteria. The tandem mass spectrometry analysis of culture supernatants confirmed the presence of three main AHLs: N-(3-oxohexanoyl)-L-homoserine lactone (3-oxo-C6-HSL) and N-hexanoyl-L-homoserine lactone (C6-HSL) in E. carotovora and Y. enterocolitica and N-butanoyl-L-homoserine lactone (C4-HSL) in A. hydrophila. The effect of chestnut honey and its aqueous and methanolic extracts (0.2 g/mL) on AHL concentration and biofilm formation in bacterial cultures was determined. The obtained results revealed their potential use as QS inhibitors or regulators of the degradation of QS signals, with the methanolic extract showing less inhibitory capacity. Thus, the QS inhibitory activity of chestnut honey seems to be related to the aqueous phase, suggesting that the carbohydrate fraction contains an antipathogenic substance responsible for the inhibitory activity.