Preparation, partial characterization and bioactivity of exopolysaccharides from Lactobacillus casei LC2W

Crude exopolysaccharides (LCP) were isolated from skim milk fermented by Lactobacillus casei LC2W and fractionated into three fractions (LCP1, LCP2 and LCP3) with the ratios of 35.74%, 12.61% and 33.34% (w/w) based on LCP, respectively. The molecular weight, polydispersity, intrinsic viscosity and radius of gyration of three fractions were determined by high-performance size exclusion chromatography, and monosaccharide compositions were analyzed by high-performance anion-exchange chromatography. The antihypertensive effects of exopolysaccharides were evaluated using spontaneously hypertensive rats (SHR). SHR were randomized into four groups (eight rats per group) and fed with the test samples (LCP1, LCP2 and LCP3) at the daily dosage of 15 mg kg−1 (body weight) and saline for 7 days. The results showed only LCP1 could decrease significantly the systolic blood pressure of SHR (P < 0.01), and LCP1, LCP2 and LCP3 had no significant effect on the heart rate of SHR.