Unrevealing the in vitro impacts of Cereus jacamaru DC. cladodes flour on potentially probiotic strains, selected bacterial populations, and metabolic activity of human intestinal microbiota.

This study investigated the potential impacts of the flour from Cereus jamacaru cactus cladodes (CJF), a cactus native to the Brazilian Caatinga biome, on the growth and metabolism of different potentially probiotic strains, as well as on the abundance of selected intestinal bacterial populations and microbial metabolic activity during in vitro colonic fermentation with a pooled human fecal inoculum. Cultivation of the probiotics in a medium with C. jamacaru cladodes flour (20 g/L) resulted in viable cell counts of up to 9.8 log CFU/mL, positive prebiotic activity scores (0.73-0.91), decreased pH and sugar contents, and increased lactic, acetic, and propionic acid production over time, indicating enhanced probiotic growth and metabolic activity. CJF overall increased the relative abundance of Lactobacillus spp./Enterococcus spp. (2.12-3.29%) and Bifidobacterium spp. (4.08-4.32%) and decreased the relative abundance of Bacteroides spp./Prevotella spp. (8.35-6.81%), Clostridium histolyticum (6.91-3.59%), and Eubacterium rectale/Clostridium coccoides (7.70-3.95%) during 48 h of an in vitro colonic fermentation using a pooled human fecal inoculum. CJF stimulated the microbial metabolic activity, with decreased pH, sugar consumption, lactic and short-chain fatty acid production, alterations in overall metabolic profiling and phenolic compound contents, and maintenance of high antioxidant capacity during colonic fermentation. These results show that CJF stimulated the growth and metabolic activity of distinct potential probiotics, increased the relative abundance of beneficial intestinal bacterial groups, and stimulated microbial metabolism during in vitro colonic fermentation. Further studies using advanced molecular technologies and in vivo experimental models could forward the investigation of the potential prebiotic properties of CJF.

Antibacterial and hemolytic activity of a new lectin purified from the seeds of Sterculia foetida L.

The aim of this study was to isolate, characterize, and verify possible antibacterial and hemolytic activity for a lectin found in the seeds of Sterculia foetida L. Purification of the lectin from S. foetida (SFL) was realized with ion exchange chromatography DEAE-Sephacel coupled to HPLC. The purity and the molecular weight was determined by SDS-PAGE. The isolated SFL was characterized as to its glycoprotein nature, and sugar specificity, as well as resistance to pH, temperature, denaturing agents, reduction, oxidation, and chelation. A microdilution method was used to determine antibacterial activity, and hemolytic activity was observed in human erythrocytes. The SFL has a molecular weight of 17 kDa, and a carbohydrate content of 53 µg/mL, specific for arabinose and xylose, and is resistant to treatment with urea, sensitive to treatment with sodium metaperiodate and ß-mercaptoethanol, and in the presence of EDTA lost its hemagglutinating activity (HA). However, in the presence of divalent cations (Ca(2 +) and Mn(2 +)) the HA was increased. The SFL remained active even after incubation at 80 °C, and, within pH values of between 5 and 11. The SFL inhibited the bacterial growth of all the tested strains and caused little hemolysis in human erythrocytes when compared to the positive control Triton X-100.