Parkia pendula pod exudate polysaccharide: structural characterization and impact on human gut microbiota.

A polysaccharide from the exudate of Parkia pendula (PePp) was obtained by aqueous extraction and precipitation with ethanol, and its chemical and structural properties, as well as its in vitro fermentation by gut microbiota, were evaluated. Chemical analysis revealed a high percentage of total carbohydrates (80%), with a predominance of arabinose (78%), uronic acid (12%), and galactose (10%). In the methylation analysis, the main linkages were 5-Araf (31.9%), terminally-linked-Araf (26.8%), 2,5-Araf (17.6%), 3,6-Galp (6.1%), 3,4,6-Galp (2.0%), and 3,4-Galp (1.3%) indicating an arabinogalactan. The molecular weight was estimated at 70.8 kDa. PePp was metabolized by the gut microbiota, leading to increased biomass, a reduction in pH, and the production of short-chain fatty acids, including acetic, propionic, and isobutyric acids. This arabinogalactan rich in 5-linked arabinose residues stimulated the proliferation of beneficial bacteria belonging to the genera Bacteroides, Bifidobacterium, Prevotella, and Enterococcus. These findings highlight the prebiotic potential of the P. pendula pod exudate and its relevance for supporting gut health.