Stability and anti-topoisomerase activity of phenolic compounds of Capsicum annuum "Serrano" after gastrointestinal digestion and in vitro colonic fermentation.

"Serrano" pepper is extensively used in Mexican cuisine. The aim of this study was to identify the bioaccessible phenolic compounds (PC) of "Serrano" pepper as well as short-chain fatty acids (SCFA) produced and PC bioconverted using an in vitro step-wise gastromimetic model of the intestinal digestion and anaerobic fermentation of the isolated indigestible fraction (IF). The anti-topoisomerase activity of the fermented samples was also evaluated. PC bioaccessibility was about 45% in the small intestine. Chlorogenic acid and capsaicin were identified during the intestinal digestion, while quercetin was identified as available to the gut microbiota. After 48-h fermentation, SCFA molar ratio was 77:11:12 for acetic, propionic and butyric acid. The PC identified in IF and after 12 h of fermentation showed anti-topoisomerase activity. A synergistic effect among the PC and gut metabolites mixture was observed, which indicates a possible antiproliferative mechanism that should be tested in further studies.

Bioaccessibility of phenolic compounds in Psidium guajava L. varieties and P. friedrichsthalianum Nied. after gastrointestinal digestion.

Psidium guajava L. and Psidium friedrichsthalianum Nied are part of the Psidium species native to America. Nowadays, it is essential to study the phenolic compound (PC) profile and their changes during digestion and the fractions available for absorption. This study aimed to characterize the PC profile in some Psidium species and their bioaccessibility (BA). Fifty-seven compounds were identified, and forty-six belonged to ten different phenolic classes. PC profiles showed significant differences between the species and the intestinal fraction P. friedrichsthalianum Nied. showed the highest PC content, although it mostly belonged to non-extractable polyphenols. This leads to the lowest BA (37%); P. guajava L. 'Morada' showed the highest (47%). Hydroxycinnamic acids were the most stable PC after gastrointestinal digestion. This study showed relevant differences in the PC content and profile of different Psidium species and changes between the PC in the original matrix and those released in the different stages of gastrointestinal digestion.

Immunomodulatory effect of metabolites from digested and fermented fractions from irradiated pineapple (Annanas comosus L.) snack-bars.

Phenolic compounds (PC), can modulate the immune response. UV-C irradiation, commonly used as a minimal processing method in fresh-foods to reduce the microbial load, increase shelf-life, provide a minimal processing and facilitate the release of PC. This study aimed to evaluate the effect of intestinal (IF) and fermented (FF) fractions of non-irradiated (NIPB) and irradiated (IPB) pineapple snack-bars on the production of nitric oxide (NO), interleukin 6 (IL-6), cyclooxygenase 2 (COX-2), and tumor necrosis factor-alpha (TNF-α) in mice macrophages. IF of NIPB and IPB exerted an immunomodulatory effect by promoting the production of NO (26 pg/mL) in both treatments, COX-2 (438 and 399 pg/mL), and TNF-α (778 and 802 pg/mL) for NIPB and IPB respectively. The TNF-α increased in IF of NIPB and IPB approximately 371 %, and in FF, only increased 132 %. The NO production was not different between IF and FF. COX-2 production was higher in FF.

Gut metabolites produced during in vitro colonic fermentation of the indigestible fraction of a maize-based traditional Mexican fermented beverage, Tejuino.

Tejuino, is a Mexican fermented beverage prepared by germination-fermentation or nixtamalization-fermentation (artisanal and commercial mode respectively) of maize. The aim of this study was to evaluate the gut metabolites, volatile, and phenolic compounds (PC) produced by the indigestible fraction (IF) of Tejuino during an in vitro colonic fermentation. Twenty-six PC in the IF were identified; the hydroxycinnamic acids (30-40 %) were the most abundant. In the IF of Tejuino pyrogallol, and urolithins were identified. Some of the representative PC of maize as maysin derivatives (apimaysin and 3-methoxymaysin) (flavonoids). The quantification of acetic and butyric acid become notable after 6 h of the colonic fermentation of IF of Tejuino. Ninety-seven volatile compounds were found, and the PCA shows the predominant compounds as short chain fatty acids, esters of organic acids and indole derivatives. These results suggest that Tejuino could be an important source of metabolites with high biological value.