Suk-Heung Oh

Effects of Germinated Brown Rice Extracts with Enhanced Levels of GABA on Cancer Cell Proliferation and Apoptosis

In the present work we investigated the effects of brown rice extracts on proliferation and apoptosis of cancer cells. Brown rice extracts were prepared using nongerminated brown rice versus germinated brown rices. Mouse leukemia L1210 cells, human acute lymphoblastic leukemia Molt4 cells, and human cervical cancer HeLa cells were treated with either nongerminated brown rice extract (N ex), water-germinated extract (W ex), chitosan-germinated extract (C ex), glutamic acid-germinated brown rice extract (G ex), or chitosan/glutamic acid-germinated brown rice extract (CG ex). The concentrations of gamma-aminobutyric acid (GABA) in the G ex and CG ex were three and 3.3 times higher than the GABA concentration in the N ex, respectively. The G ex and CG ex retarded significantly the proliferation rates of L1210 and Molt4 cells, and the highest retardation rate was with CG ex. In addition, the G ex and CG ex enhanced significantly apoptosis of the cultured L1210 cells, but no significant apoptosis was seen with the other extracts, which have lower concentrations of GABA than G ex and CG ex. These results show that brown rice extracts with enhanced levels of GABA have an inhibitory action on leukemia cell proliferation and have a stimulatory action on the cancer cell apoptosis.

Germinated brown rice extract shows a nutraceutical effect in the recovery of chronic alcohol-related symptoms.

Chronic ethanol abuse can cause liver damage and unfavorable lipid profiles in humans and rodents. Phytonutrients have the potential to partially reverse some of the adverse effects of alcoholism. In this study, a germinated brown rice grown under conditions that favor high concentrations of gamma-aminobutyric acid (GABA) was evaluated for protective effects against the toxic consequences of chronic ethanol use. Serum and hepatic lipid concentrations and enzymes indicative of liver damage were determined in mice chronically administered ethanol. Balb/c mice were fed with either AIN-76 diet (control), control diet plus ethanol, or control diet plus ethanol and supplemental brown rice extract for 30 days. The extract naturally contained 841 nmol GABA per milliliter and was prepared from germinated brown rice. Serum low-density lipoprotein cholesterol (LDL-C), liver aspartate aminotransferase, and liver alanine aminotransferase levels were increased in mice administered ethanol, but not in mice given ethanol and brown rice extract. The brown rice extract significantly increased serum and liver high-density lipoprotein cholesterol (HDL-C) concentrations. Furthermore, administration of the extract prevented ethanol-induced increases in liver triglyceride and total cholesterol concentrations. These findings raise the possibility that brown rice extracts containing a high level of GABA may have a nutraceutical role in the recovery from and prevention of chronic alcohol-related diseases.

Anti-obesity effect of kimchi fermented with Weissella koreensis OK1-6 as starter in high-fat diet-induced obese C57BL/6J mice.

In this study, we investigated the anti‐obesity effects of kimchi (Korean traditional fermented vegetable) fermented either without starter culture or with a specific starter culture, Weissella koreensis OK1‐6.

Expression of Rice Glutamate Decarboxylase in Bifidobacterium Longum Enhances γ-Aminobutyric Acid Production

Bifidobacteria are important for the production of fermented dairy products and probiotic formulas but have a low capacity for γ-aminobutyric acid (GABA) production. To develop a Bifidobacterium strain with an enhanced GABA production, we transformed Bifidobacterium longum with a rice glutamate decarboxylase (OsGADC−) gene by electroporation. When the transformed strain was cultured in medium containing monosodium glutamate, the amount of GABA increased significantly compared with those of untransformed Bifidobacterium. Thus, by introducing a plant derived GAD gene, a Bifidobacterium strain has been genetically engineered to produce high levels of GABA from glutamate.

Changes in the Levels of γ-Aminobutyric Acid and Glutamate Decarboxylase in Developing Soybean Seedlings

The changes in the levels of 7-aminobutyric acid (GABA), glutamic acid (Glu), calcium ions, and calmodulin as well as glutamate decarboxylase (GAD) activities were investigated in developing soybean seedlings. The GABA level determined was 12.3% of total free amino acids in the apical regions of roots, whereas it was only 4.2% of total free amino acid in cotyledons. The apical regions of roots also contained significantly higher levels of GAD, compared with cotyledons and mature base tissues. The Glu level was 13% of total free amino acids in the cotyledons, whereas it was only about 0.2% of total free amino acids in the apical regions. Calcium and calmodulin were found higher in cotyledons and the apical regions, compared with other parts of the seedlings. These data indicate that in develop ing soybean seedlings the levels of GABA and GABA synthesis activity are highest in the youngest tissues.

Lactobacillus plantarum LG42 isolated from gajami sik-hae decreases body and fat pad weights in diet-induced obese mice.

This study investigated the antiobesity effect of lactic acid bacteria (Lactobacillus plantarum LG42) isolated from gajami sik‐hae.

Enhancement of γ-aminobutyric acid production in Chungkukjang by applying a Bacillus subtilis strain expressing glutamate decarboxylase from Lactobacillus brevis

For a foreign glutamate decarboxylase (GAD) to be expressed in Bacillus host system, a recombinant DNA (pLip/LbGAD) was constructed by ligating an LbGAD gene from Lactobacillus brevis OPK-3 into Escherichia coli–Bacillus shuttle vector, pLip. The pLip/LbGAD construct was then transformed into Bacillus subtilis. The culture of the transformed Bacillus strain with the pLip/LbGAD construct had higher GAD activity and γ-aminobutyric acid (GABA) concentration than those of untransformed Bacillus counterpart. In addition, Chungkukjang, a traditional Korean fermented soybean product prepared by the transformed Bacillus subtilis, contained a significantly higher level of GABA than conventional ones. Thus, by introducing a foreign GAD gene, Bacillus strains have been genetically engineered to produce high levels of GAD and GABA.

Intracellular lipid accumulation inhibitory effect of Weissella koreensis OK1‐6 isolated from Kimchi on differentiating adipocyte

To investigate the intracellular lipid accumulation inhibitory effect of spent culture medium extract and the cytoplasmic fraction of Weissella koreensis OK1‐6 cells isolated from kimchi in differentiating 3T3‐L1 cells.

Effects of Kimchi Lactic Acid Bacteria Lactobacillus sp. OPK2-59 with High GABA Producing Capacity on Liver Function Improvement

This study investigated the effect of improved liver function in rats administered with ethanol by kimchi lactic acid bacteria with high GABA producing capacity. Sprague-Dawley male rats were divided into four groups; normal diet control (NC), ethanol control (EC), ethanol＋Lactobacillus sp. OPK2-59 normal powder (EL1), ethanol＋Lactobacillus sp. OPK2-59 GABA powder (EL2) and fed for 6 weeks. Analysis showed that there were no significant differences in body weight and feed consumption among the groups during the experimental period. Also, there were no significant differences in organ weight among the groups. The test results showed total cholesterol and triglyceride in the blood concentration that were increased by ethanol administration were significantly lowered in EL2 group. Liver triglyceride was also significantly lowered in the EL2 group compared with the EC group. Serum GOT and GPT, and liver GOT levels were significantly lower in the EL2 group compared with the EC group. Serum ethanol concentration was lower in the EL1 and EL2 groups compared with the EC group. SOD activities in liver were significantly increased in the EL1 and EL2 groups compared with the EC group. These results suggest that Lactobacillus sp. OPK2-59 GABA powder improves lipid and enzyme profiles of rats administered with ethanol.

Lactobacillus plantarum LG42 Isolated from Gajami Sik-Hae Inhibits Adipogenesis in 3T3-L1 Adipocyte

We investigated whether lactic acid bacteria isolated from gajami sik-hae (GLAB) are capable of reducing the intracellular lipid accumulation by downregulating the expression of adipogenesis-related genes in differentiated 3T3-L1 cells. The GLAB, Lactobacillus plantarum LG42, significantly decreased the intracellular triglyceride storage and the glycerol-3-phosphate dehydrogenase (GPDH) activity in a dose-dependent manner. mRNA expression of transcription factors like peroxisome proliferator-activated receptor (PPAR) γ and CCAAT/enhancer-binding protein (C/EBP) α involved in adipogenesis was markedly decreased by the GLAB treatment. Moreover, the GLAB also decreased the expression level of adipogenic markers like adipocyte fatty acid binding protein (aP2), leptin, GPDH, and fatty acid translocase (CD36) significantly. These results suggest that the GLAB inhibits lipid accumulation in the differentiated adipocyte through downregulating the expression of adipogenic transcription factors and other specific genes involved in lipid metabolism.