Isolation of chemically well-defined semipreparative liquid chromatography fractions from complex mixtures of proanthocyanidin oligomers and polymers

In this study, a semipreparative liquid chromatography method was developed for the isolation of chemically well-defined proanthocyanidin (PA) oligomer and polymer fractions. The aim was to achieve better separation than traditionally achieved for the PAs with other chromatographic methods. The method was tested with eleven PA rich Sephadex LH-20 fractions, which originated from eleven different plant species. The resulting semipreparative fractions were analyzed by both triple quadrupole and high-resolution mass spectrometry assisted by ultrahigh-performance liquid chromatography (UPLC) separation. The results showed remarkable differences in the procyanidin to prodelphinidin ratio, mean degree of polymerization, and specific oligomeric and polymeric content. However, some of these features indicated consistent patterns between species as the function of UPLC retention time. The developed method enables the production of tens of well-defined fractions of PA oligomers and polymers from the unresolved chromatographic PA hump. Accordingly, this allows researchers to explore the most bioactive parts of the complex PA humps of any plant species, which have not been possible earlier.</div

Structure-function analysis of purified proanthocyanidins reveals a role for polymer size in suppressing inflammatory responses

Proanthocyanidins (PAC) are dietary compounds that have been extensively studied for beneficial health effects due to their anti-inflammatory properties. However, the structure-function relationships of PAC and their mode-of-action remain obscure. Here, we isolated a wide range of diverse PAC polymer mixtures of high purity from plant material. Polymer size was a key factor in determining the ability of PAC to regulate inflammatory cytokine responses in murine macrophages. PAC polymers with a medium (9.1) mean degree of polymerization (mDP) induced substantial transcriptomic changes, whereas PAC with either low (2.6) or high (12.3) mDP were significantly less active. Short-term oral treatment of mice with PAC modulated gene pathways connected to nutrient metabolism and inflammation in ileal tissue in a polymerization-dependent manner. Mechanistically, the bioactive PAC polymers modulated autophagic flux and inhibited lipopolysaccharide-induced autophagy in macrophages. Collectively, our results highlight the importance of defined structural features in the health-promoting effects of PAC-rich foods

Fermentation quality of ensiled crimped faba beans using different additives with special attention to changes in bioactive compounds

Faba bean (Vicia faba L.) is a grain legume that provides possibilities to increase local protein self-sufficiency both as feed and food in areas where possibilities for cultivation of other protein crops are limited. However, full ripening may not be achieved and storage of the moist beans by crimping and ensiling provides an economic alternative to drying, and is well suited for animal feeding. The objectives of the current experiment were to evaluate the effects of moisture content and various silage additives on the fermentation quality, aerobic stability and fate of bioactive compounds of ensiled crimped faba beans in a pilot scale ensiling experiment. Faba beans were combine harvested at moisture level of 443 g/kg and crimped prior to ensiling. The following additive treatments were applied using three replicates: 1) control (CON), 2) two commercial lactic acid bacteria inoculants as mixture (LABmix), 3) In-house LAB inoculant (LABLuke), 4) Formic acid based product (FA) and 5) Salt based product (Salt). Further, two of the additive treatments were prepared with additional moisture: 6) Control with tap water addition (CON + w) and 7) LABmix with tap water addition (LABmix + w). The beans ensiled without additive showed elevated pH, butyric acid and ethanol concentrations and proportion of ammonia N in total N. Addition of water further decreased the fermentation quality. The LAB inoculants improved the fermentation quality of the beans compared to CON. The fermentation was effectively restricted when FA was used. Both LAB and chemical additives improved aerobic stability compared to CON and Salt was especially effective in improving aerobic stability. Vicine disappeared totally during the ensiling period and also convicine was effectively degraded. It seems that promoting microbial activity in the silo either by LAB inoculation or increased moisture promoted the degradation of convicine, while chemical additives decreased the degradation of it. Total and particularly soluble proanthocyanidins were also degraded during the ensiling period. Crimping and ensiling is an alternative preservation method for faba beans which eliminates the energy consumption and investments required for drying. In addition, benefits regarding the concentrations of bioactive compounds may be expected

Fermentation quality of ensiled crimped faba beans using different additives with special attention to changes in bioactive compounds

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