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Background:Plantago major L. leaves have been used for centuries by the traditional medicine in the treatment of infectious disorders of the respiratory, urinary and digestive tracts. Researchers have reported that hot water extracts of Plantago major possess a broad-spectrum of anticancer, antioxidant and antiviral activities, as well as activities which modulate cell-mediated immunity. Their beneficial properties may be due to the significant content of polysaccharides. The polysaccharides that have been isolated from the leaves of Plantago major L. have different structures – pectic substances, galactans, arabinogalactans, glucomannans.

The aim of the present study was to evaluate the prebiotic potential of Plantago major L. leaves water-extractable polysaccharide (PWPs) and its lower molecular fractions. The structure of PWPs was investigated by high pressure anion exchange chromatography (HPAEC), size exclusion chromatography coupled with multi-angle laser light scattering detector (SEC-MALLS) and Fourier-transform infrared (FTIR) spectroscopy. The chemical composition and monosaccharide analyses showed that galacturonic acid was the main monosaccharide of PWPs followed by glucose, arabinose, galactose, rhamnose and xylose. FTIR study indicated a strong characteristic absorption peak at 1550 cm−1 corresponding to the vibration of COO− group of galacturonic acid. The PWPs was subjected to hydrolysis using commercial enzymes to obtain P. major low molecular fraction (PLM) which was successively separated by size exclusion chromatography on Biogel P2. PWPs and PLM were examined for in vitro prebiotic activity using various assays. Results gave evidence for changes in optical density of the bacteria cells and pH of the growth medium. A heterofermentative process with a lactate/acetate ratio ranged from 1:1 to 1:5 was observed. The ability of PLM to stimulate the production of certain probiotic bacteria glycohydrolases and to be fermented by Lactobacillus sp. strains was successfully proved. [ABSTRACT FROM AUTHOR]

The leaves of Plantago species have been known as a rich source of polysaccharides, polyphenols, and iridoids. In the recent years, some authors have examined the relative influence of carbohydrate compositions and polyphenols on their antioxidant and prebiotic activity. In this study enzymatic hydrolysis of Plantago major, Plantago lanceolata, and Plantago media leaves with hemicellulase and xylanase was carried out. The chemical composition of the enzyme‐derived hydrolysis products was determined. Their antioxidant activity was evaluated using 2,2‐diphenyl‐2‐picryl‐hydrazyl‐hydrate, ferric reducing antioxidant power, and cupric reducing antioxidant capacity assays. The utilization of the carbohydrate complex from the obtained hydrolysates to stimulate the production of certain glycohydrolases from Lactobacillus plantarum probiotic strains was investigated. The HPLC analysis of the hydrolysis products showed the presence of galactose and arabinose in 1:3 and 1:4 ratios. The highest concentration of total sugars was determined in P. major hydrolysates with hemicellulase (386.71 mg/g dry weight). The antioxidant activity according to the three methods was the highest in P. media hydrolysates, which correlated with their total phenolic concentration. L. plantarum S27 showed the highest values of α‐galactosidase activity at the 24‐h fermentation process when it was cultivated in a broth with the presence of P. major hydrolysates with hemicellulase and xylanase (0.129 U/mg and 0.133 U/mg, respectively). [ABSTRACT FROM AUTHOR]