Abstract:

Lactobacillus fermentum Zhao (LFZ), a novel strain of Lactobacillus isolated from naturally fermented
yak yogurt in the Qinghai-Tibet Plateau in western Sichuan, has been found to have good viability in simulated gastric
fluid and stronger cholate resistance than Streptococcus thermophilus (ST). This study aimed to compare the gastric
ulcer-preventive activity of LFZ-fermented soybean milk with the commercial ST-fermented sample when orally
administered to mice. By using reserpine-induced gastric ulcer mice model as a control group, IL-6, IL-12, TNF-α and IFN-γ
cytokine levels of the mice in LFZ group were lower than those of the mice in ST group. The serum SS (somatostatin) and
VIP (vasoactive intestinal peptide) levels of LFZ mice were higher than those of ST mice, and the MOT (motillin) and SP
(substance P) levels were lower than those of ST mice. The gastric ulcer area of LFZ mice was also smaller than that of ST
mice. These results suggest that LFZ-fermented soybean milk shows better quality and gastric ulcer-preventive activity
than the ST-fermented one.

Key words: soybean milk, Lactobacillus, amino nitrogen, isoflavone, gastric ulcer