Some species of lactic acid bacteria (LAB) are called probiotics around the world. They especially are normal residents of the complex ecosystem of the gastrointestinal tract and constitute an important part of the indigenous microflora. Their distribution is influenced by several environmental fact...
Some species of lactic acid bacteria (LAB) are called probiotics around the world. They especially are normal residents of the complex ecosystem of the gastrointestinal tract and constitute an important part of the indigenous microflora. Their distribution is influenced by several environmental factors, including pH, oxygen availability, level of specific substrates, presence of secretions and bacterial interactions. Lactobacilli are in general characterized as gram-positive, non-sporeforming, and non-flagellated rods or coccobacilli. Also, they are proposed to exert health promoting in humans and animals. Thus, they could not only improve our health or defend pathogenic bacterial infections in a number of ways but could also help in real disease management and treatment. In particular, Lactobacillus species are beneficial bacteria that have several probiotic effects in humans and animals, such as alleviation of acute diarrhea and allergy of inflammatory bowel disease, and antibiotic-associated gastrointestinal symptoms as well as a reduction in the number of potentially pathogenic bacteria and immunomodulatory effects. In addition, they reduce serum cholesterol and blood pressure, alleviate symptoms of lactose intolerance, have a resistance to antibiotics, suppress tumors and protect against colon and bladder cancer risk. Recently, LAB has attracted attention as potential cholesterol-lowering additives in the milk. Lactobacillus strains induce resistance to diet-induced body weight gain and increased plasma cholesterol and triglyceride levels. Therefore, this study investigated the properties of probiotics isolated from kimchi in vitro and the effect of probiotics on the cholesterol reduction in vivo.
Kimchi, a traditional Korean food is manufactured by fermenting vegetables with lactic acid bacteria (LAB). The isolated strains from kimchi were confirmed to have characteristics of probiotics including KOH and catalase negative, and gram stain positive. Also, potential strains were selected via acid and bile acid tolerances.
Ten strains of lactobacilli selected in our previous study were investigated probiotics properties, such as acid resistance, bile tolerance, cholesterol assimilation activity, and adherence to HT-29 cells. Lactobacillus sp. JNU 8829, L. acidophilus KU41, L. brevis CH7, L. fermentum NS2, L. plantarum M13, and L. sakei CH8 were the most acid tolerant strains, with more than 106 CFU/mL of bacteria present after incubation at pH 2.5 for 2 h. Lactobacillus sp. JNU 8829, L. acidophilus M23, L. casei MB3, and L. sakei MA9 were found to have full tolerance to 0.3% bile. Some of strains showed the survival at pH 2.5 in the presence of pepsin, and 0.3% bile. Lactobacillus sp. JNU 8829, L. acidophilus KU41, L. acidophilus M23, L. fermentum NS2, L. plantarum M13, and L. plantarum NS3 were found to reduce cholesterol levels by >50% in vitro test. In particular, Lactobacillus sp. JNU 8829 showed high viable cell counts compared to the other strains after 2 h in the adhesion assays to intestinal cell. These results indicate that the Lactobacillus sp. JNU 8829 of lactic acid bacteria could be better candidates for reducing the risk of cardiovascular disease. Thus, animal models to study the effects of cholesterol-lowering by Lactobacillus strains was used.
In an animal study, seven-week-old male C57BL/6 mice were fed with the normal diet (ND), high fat diet (HFD) and HFD and Lactobacillus sp. JNU 8829 (ca. 1.0×108 CFU/mL) (HFD-JNU 8829) for 10 weeks. HFD-JNU 8829 mice showed the reduction of both body weight and adipocyte size, compared with the HFD. Total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol levels were significantly lower in mice fed with the HFD with Lactobacillus sp. JNU 8829 than in those fed with the HFD only, while high-density lipoprotein (HDL) cholesterol levels were similar between these two groups. To understand the mechanism of the cholesterol-lowering effect of Lactobacillus sp. JNU 8829 on the HFD-mediated increase in plasma cholesterol levels, mRNA levels of genes involved in cholesterol homeostasis were investigated in the liver. Expression of sterol regulatory element-binding protein 2 (SREBP2) and LDL receptor (LDLR) in the liver was dramatically reduced in mice fed with the HFD compared to those fed with the ND. When Lactobacillus sp. JNU 8829 was administered orally to HFD-fed mice, a HFD-induced suppression of SREBP2 and LDLR expression in the liver was abolished. These results suggest that the oral administration of Lactobacillus sp. JNU 8829 to mice fed with the HFD increased the expression of SREBP2 and LDLR in the liver, which was inhibited by high-fat intake, thus leading to a decrease in plasma cholesterol levels. Therefore, Lactobacillus sp. JNU 8829 could be utilized probiotic microorganism for cholesterol-lowering dairy products and the improvement of hypocholesterolemic and hepatic lipid metabolism.
Some species of lactic acid bacteria (LAB) are called probiotics around the world. They especially are normal residents of the complex ecosystem of the gastrointestinal tract and constitute an important part of the indigenous microflora. Their distribution is influenced by several environmental factors, including pH, oxygen availability, level of specific substrates, presence of secretions and bacterial interactions. Lactobacilli are in general characterized as gram-positive, non-sporeforming, and non-flagellated rods or coccobacilli. Also, they are proposed to exert health promoting in humans and animals. Thus, they could not only improve our health or defend pathogenic bacterial infections in a number of ways but could also help in real disease management and treatment. In particular, Lactobacillus species are beneficial bacteria that have several probiotic effects in humans and animals, such as alleviation of acute diarrhea and allergy of inflammatory bowel disease, and antibiotic-associated gastrointestinal symptoms as well as a reduction in the number of potentially pathogenic bacteria and immunomodulatory effects. In addition, they reduce serum cholesterol and blood pressure, alleviate symptoms of lactose intolerance, have a resistance to antibiotics, suppress tumors and protect against colon and bladder cancer risk. Recently, LAB has attracted attention as potential cholesterol-lowering additives in the milk. Lactobacillus strains induce resistance to diet-induced body weight gain and increased plasma cholesterol and triglyceride levels. Therefore, this study investigated the properties of probiotics isolated from kimchi in vitro and the effect of probiotics on the cholesterol reduction in vivo.
Kimchi, a traditional Korean food is manufactured by fermenting vegetables with lactic acid bacteria (LAB). The isolated strains from kimchi were confirmed to have characteristics of probiotics including KOH and catalase negative, and gram stain positive. Also, potential strains were selected via acid and bile acid tolerances.
Ten strains of lactobacilli selected in our previous study were investigated probiotics properties, such as acid resistance, bile tolerance, cholesterol assimilation activity, and adherence to HT-29 cells. Lactobacillus sp. JNU 8829, L. acidophilus KU41, L. brevis CH7, L. fermentum NS2, L. plantarum M13, and L. sakei CH8 were the most acid tolerant strains, with more than 106 CFU/mL of bacteria present after incubation at pH 2.5 for 2 h. Lactobacillus sp. JNU 8829, L. acidophilus M23, L. casei MB3, and L. sakei MA9 were found to have full tolerance to 0.3% bile. Some of strains showed the survival at pH 2.5 in the presence of pepsin, and 0.3% bile. Lactobacillus sp. JNU 8829, L. acidophilus KU41, L. acidophilus M23, L. fermentum NS2, L. plantarum M13, and L. plantarum NS3 were found to reduce cholesterol levels by >50% in vitro test. In particular, Lactobacillus sp. JNU 8829 showed high viable cell counts compared to the other strains after 2 h in the adhesion assays to intestinal cell. These results indicate that the Lactobacillus sp. JNU 8829 of lactic acid bacteria could be better candidates for reducing the risk of cardiovascular disease. Thus, animal models to study the effects of cholesterol-lowering by Lactobacillus strains was used.
In an animal study, seven-week-old male C57BL/6 mice were fed with the normal diet (ND), high fat diet (HFD) and HFD and Lactobacillus sp. JNU 8829 (ca. 1.0×108 CFU/mL) (HFD-JNU 8829) for 10 weeks. HFD-JNU 8829 mice showed the reduction of both body weight and adipocyte size, compared with the HFD. Total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol levels were significantly lower in mice fed with the HFD with Lactobacillus sp. JNU 8829 than in those fed with the HFD only, while high-density lipoprotein (HDL) cholesterol levels were similar between these two groups. To understand the mechanism of the cholesterol-lowering effect of Lactobacillus sp. JNU 8829 on the HFD-mediated increase in plasma cholesterol levels, mRNA levels of genes involved in cholesterol homeostasis were investigated in the liver. Expression of sterol regulatory element-binding protein 2 (SREBP2) and LDL receptor (LDLR) in the liver was dramatically reduced in mice fed with the HFD compared to those fed with the ND. When Lactobacillus sp. JNU 8829 was administered orally to HFD-fed mice, a HFD-induced suppression of SREBP2 and LDLR expression in the liver was abolished. These results suggest that the oral administration of Lactobacillus sp. JNU 8829 to mice fed with the HFD increased the expression of SREBP2 and LDLR in the liver, which was inhibited by high-fat intake, thus leading to a decrease in plasma cholesterol levels. Therefore, Lactobacillus sp. JNU 8829 could be utilized probiotic microorganism for cholesterol-lowering dairy products and the improvement of hypocholesterolemic and hepatic lipid metabolism.
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