Abstract

This study investigated the anti-hypertensive effect of gamma-aminobutyric acid (GABA)-rich Chingshey purple sweet potato (CPSP) fermented-milk with three different lactic acid bacteria (LAB) strains including Lactobacillus acidophilus BCRC 14065, Lactobacillus delbrueckii ssp. lactis BCRC 12256, and Lactobacillus gasseri BCRC 14619. In a chronic administration study, the results showed that both systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly decreased (P < 0.05) in spontaneously hypertensive rats (SHR) after receiving CPSP fermented-milk for 8 weeks. Blood pressure-lowering effects were typically measured after 5 weeks of treatment. Maximum blood pressure reductions were approximately 37 (SBP) and 22 mmHg (DBP) when compared with the control group. There was no significant difference in SBP and DBP before and after the 8 weeks of feeding CPSP fermented-milk to the normotensive Wistar Kyoto rats. In a single administration study, treatment with 100% CPSP fermented-milk elicited a significant decrease (P < 0.05) in SBP as compared to the control group. In SHR’ feces, consumption of CPSP fermented-milk significantly increased the fecal populations of Bifidobacterium spp. numbers (1 to 2 log CFU/g feces) (P < 0.05) andLactobacillus spp. numbers (~0.5 log CFU/g feces) (P < 0.05) as compared to the control group, and decreased Clostridium perfringens numbers (1 to 1.5 log CFU/g feces) (P <0.05). These findings demonstrated that oral administration of GABA-rich CPSP fermented-milk had antihypertension and improved the intestinal microflora balance.

Key words: Gamma-aminobutyric acid, Chingshey purple sweet potato, Lactobacillus, spontaneously hypertensive rats, anti-hypertension