Identification of Spices Promoting the Growth of Lactic Acid Bacteria and Modulation of Tight Junction Protein at mRNA Level by the Fermented Product of Red Pepper (Capsicum annuum L.) in HT-29 Cell

Abstract

Spices are known to possess antibacterial activity against pathogens. In contrast, they also promote probiotic bacterial growth, such as Lactobacillus and Bifidobacterium. In the current study, 10 strains isolated from Korean human feces and kimchi were screened for bacterial growth in the presence of spices mainly used in Korean foods, including garlic, onion, ginger, red pepper, and Chungyang pepper. Majority of the strains showed maximum growth in red pepper. In order to investigate properties of the candidate strains as probiotics, we evaluated the adhesion ability to intestinal epithelial HT-29 cells, acid and bile tolerance, and inhibition activity of gelatinase and urease. The functionality of the fermented product was subsequently studied, as most strains grew well in the presence of spices. The antioxidant activity was determined using DPPH (1,1-diphenyl-2-picrylhydrazyl). Fermented products of ginger and red pepper with strains showed higher free radical scavenging activity than the spices themselves. In addition, subsequent to lipopolysaccharides-induced impairment, the fermented products of red pepper with selected strains also exhibited increased mRNA expression of tight junction protein in HT-29 cells. Taken together, the results of this study indicate that strains isolated from Korean human feces and kimchi have a high growth rate in the presence of spices, and their fermented products exert increased anti-oxidant activity, thereby indicating the potential functionality in improving gut barrier functions.