• Journal of Nutrition and Health
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• v.55 no.3
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• pp.330-347
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• 2022

Folate, a water-soluble vitamin, acts as a coenzyme for one-carbon metabolism in nucleic acid synthesis and amino acid metabolism. Adequate folate nutritional status during the periconceptional period is known to prevent neural tube defects. In addition, insufficient folate intake is associated with various conditions, such as anemia, hyperhomocysteinemia, cardiovascular disease, cancer, cognitive impairment, and depression. This review discusses the rationale for the revision of the 2020 Korean dietary reference intakes for folate, and suggestions for future revisions. Based on the changes in the standard body weight in 2020, the adequate intake (AI) for infants (5-11 months) and the estimated average requirements (EARs) for 15-18 years of age were revised, but there were no changes in the recommended nutrient intakes (RNIs) and tolerable upper intake levels (ULs) for all age groups. Mean folate intake did not reach RNI in most age groups and was particularly low in women aged 15-29 years, according to the results of the 2016-2018 Korea National Health and Nutrition Examination Survey (KNHANES). The percentages of folate intake to RNI were lower than 60% in pregnant and lactating women, but serum folate concentrations were higher than those in other age groups, presumably due to the use of supplements. Therefore, total folate intake, from both food and supplements, should be evaluated. In addition, the database of folate in raw, cooked, and fortified foods should be further expanded to accurately assess the folate intake of Koreans. Determination of the concentrations of erythrocyte folate and plasma homocysteine as well as serum folate is recommended, and quality control of the analysis is critical.

• Clinical and Experimental Reproductive Medicine
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• v.51 no.2
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• pp.135-141
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• 2024

Objective: Recently, oral antioxidants in combined forms have been used to treat men with idiopathic infertility. This study aimed to evaluate the effects of treatment with vitamin C, vitamin E, selenium, zinc, arginine, L-carnitine, and coenzyme Q10 on sperm quality parameters, DNA integrity, reproductive hormones, and pregnancy rates in men with infertility and idiopathic oligoasthenoteratozoospermia (OAT). Methods: A prospective study was conducted on 420 men with infertility and idiopathic OAT who took an oral supplement of antioxidant SP-Power tablets twice daily for 6 months. Semen quality, reproductive hormones, and the DNA fragmentation index (DFI) were evaluated at baseline and at 3 and 6 months after supplementation, using the World Health Organization 2021 guidelines. Results: No significant difference was observed in volume or the percentage of typical morphology during treatment. A significant improvement in sperm concentration was observed after supplementation (8.67±1.41, 12.17±1.91, and 19.01±0.86 at baseline, 3, and 6 months respectively, p<0.01). The total motility, progressive motility, and total motile sperm count also increased significantly (p<0.01), whereas the DFI decreased after 6 months. There was an increase in normal FSH levels and testosterone levels after 6 months of supplementation of antioxidant SP-Power but these differences were not statistically significant (p=not significant and p=0.06, respectively). Conclusion: Supplementation with SP-Power tablets improved sperm quality parameters, sperm DFI, some reproductive hormones, and pregnancy rates in men with infertility and idiopathic OAT, which could be attributed to the supplement's synergistic antioxidant action. Further studies are needed to determine the effects of supplementation on oxidative stress markers.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.24 no.1
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• pp.1-9
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• 2024

Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episode (MELAS) is a rare maternally inherited disorder primarily caused by mutations in mitochondrial DNA, notably the m.3243A>G mutation in the MT-TL1 gene. This mutation impairs mitochondrial function crucial for cellular energy production, particularly in high-energy-demanding organs such as the brain and muscles. MELAS manifests as recurrent stroke-like episodes, seizures, diabetes mellitus, cardiomyopathy, and other multisystemic symptoms that are often present in childhood. The diagnosis combines genetic testing, clinical evaluation, and neuroimaging, with elevated lactate levels and characteristic magnetic resonance imaging (MRI) findings as key indicators. Treatment focuses on symptomatic management and enhancement of mitochondrial function through L-arginine, coenzyme Q10, high-dose vitamins, and taurine supplementation. Studies have identified additional genetic variants linked to MELAS, including mutations in POLG and other mitochondrial genes, further complicating the genetic landscape. Emerging therapies, particularly gene therapy and mitochondria-targeting drugs, offer promising avenues for addressing the underlying genetic defects and improving mitochondrial functioning. Furthermore, ongoing studies continue to enhance our understanding and management of MELAS, with the aim of reducing its burden and improving patient outcomes and quality of life. This review summarizes the current knowledge on the genetics, clinical features, diagnosis, and treatment of MELAS, highlighting the latest advancements and future directions for therapeutic interventions.

• Journal of Microbiology
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• v.41 no.3
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• pp.189-195
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• 2003

To enhance the reductive dechlorination of polychlorinated biphenyls (PCBs) under anaerobic conditions, we examined the adjunctive effects of cobalt (Co) and nickel (Ni), which are the central metals of transition-metal cofactors of coenzyme F$\_$430/ and vitamin B$\_$12/, respectively, on the dechlorination of Aroclor 1248. After 32 weeks of incubation, the average numbers of chlorines per biphenyl in culture vials supplemented with 0.2, 0.5, and 1.0 mM of Co reduced from 3.88 to 3.39, 2.92, and 3.28, respectively. However, the numbers of chlorine after supplementing with Ni decreased from 3.88 to 3.43, regardless of the Ni concentrations. The observed congener distribution patterns of all vials with different conditions were similar to the pattern produced by the dechlorination process of H' after 21 weeks of incubation, and these patterns were unchanged up to week 32, except for vials supplemented with 0.5 and 1.0 mM of Co. In vials containing 0.5 mM of Co, meta-rich congeners, such as 25/ 25-,24/25-, and 25/23-chlorobiphenyls (CBPs), which were found as accumulated products of dechlorination in other conditions, were further dechlorinated, and 25/2-, 24/2-, and 2/2-CBPs were concomitantly increased after 32 weeks of incubation. In this case, the congener distribution was similar to the dechlorination pattern of process M. From these results, we suggested that the enrichment of cultures with Co might stimulate the growth of specific populations of meta-dechlorinators, and that populations might promote a change in the dechlorination process from H' to M, which is known to be less effective on the dechlorination of the more highly chlorinated congeners of PCBs.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.258-264
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• 2011

Glutathione (GSH) has important roles in cellular defense against oxidative stress, 1) direct scavenging of reactive oxygen species (ROS), and 2) coenzyme of ROS scavenging enzyme like glutathione peroxidases (GPx). GSH peroxidase reduces free hydrogen peroxide to water using 2GSH. $N$-acetyl-L-cysteine (NAC), one of the antioxidants, is used as a precursor for intracellular GSH. In this study, relation of GSH, NAC, and GSH peroxidase was investigated through transcriptional expression of $GPX1$ and $GPX2$, which are GSH peroxidase encoding genes, in yeast cells treated with 0 mM to 20 mM of NAC or in combination with 100 Gy gamma-rays. The transcriptional expression of $GPX1$ and $GPX2$ was induced by NAC and 100 Gy gamma-rays. The gene expression of both GSH peroxidases was decreased with increasing concentrations of NAC in irradiated yeast cells. These results suggest that elevation of intracellular GSH by NAC and oxidative stress and ROS generated from gamma-rays induces expression of GSH peroxidase genes, and that NAC can protect the yeast cells against ROS generated from gamma-rays through direct scavenging of ROS and transcriptional activation of GSH peroxidase.

• Molecules and Cells
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• v.38 no.4
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• pp.318-326
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• 2015

We previously reported that the SbROMT3syn recombinant protein catalyzes the production of the methylated resveratrol derivatives pinostilbene and pterostilbene by methylating substrate resveratrol in recombinant E. coli. To further study the production of stilbene compounds in E. coli by the expression of enzymes involved in stilbene biosynthesis, we isolated three stilbene synthase (STS) genes from rhubarb, peanut, and grape as well as two resveratrol O-methyltransferase (ROMT) genes from grape and sorghum. The ability of RpSTS to produce resveratrol in recombinant E. coli was compared with other AhSTS and VrSTS genes. Out of three STS, only AhSTS was able to produce resveratrol from p-coumaric acid. Thus, to improve the solubility of RpSTS, VrROMT, and SbROMT3 in E. coli, we synthesized the RpSTS, VrROMT and SbROMT3 genes following codon-optimization and expressed one or both genes together with the cinnamate/4-coumarate:coenzyme A ligase (CCL) gene from Streptomyces coelicolor. Our HPLC and LC-MS analyses showed that recombinant E. coli expressing both ScCCL and RpSTSsyn led to the production of resveratrol when p-coumaric acid was used as the precursor. In addition, incorporation of SbROMT3syn in recombinant E. coli cells produced resveratrol and its mono-methylated derivative, pinostilbene, as the major products from p-coumaric acid. However, very small amounts of pterostilbene were only detectable in the recombinant E. coli cells expressing the ScCCL, RpSTSsyn and SbROMT3syn genes. These results suggest that RpSTSsyn exhibits an enhanced enzyme activity to produce resveratrol and SbROMT3syn catalyzes the methylation of resveratrol to produce pinostilbene in E. coli cells.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.826-833
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• 2002

This study was conducted to investigate the effects of YK-209 mulberry leaves on HMG-CoA reductase activity and lipid composition of liver in streptozotocin-induced diabetic rats. Sprague-Dawley male rats weighing 100 $\pm$ 10 B were randomly assigned as a normal group and four STZ-induced diabetic groups according to the level of dietary mulberry leaves supplement. The experimental diets were fed ad libidum, so that diabetes was experimentally induced by intravenous injection of STZ 55 mg/kg of body weight after feeding for 3 weeks. Animals were sacrificed on the 9th day of diabetic states. The levels of serum triglyceride, total-cholesterol and LDL-cholesterol in DM group were higher than mulberry leaves supplemented groups and normal group, but those of the mulberry leaves supplemented groups were significantly decreased to normal level. In contrast, the leavels of serum HDL-cholesterol in DM group was significantly reduced than that of normal group, but mulberry leaves supplemented groups were increased to normal level. Atherogenic index in DM group was higher about 3 fold than the normal group but the DM-0.1Y and DM-0.2Y groups were maintained the normal level. Contents of total lipid and triglyceride of liver in DM group were significantly lower than that of normal group, but the mulberry Leaves supplemented groups increased than that of DM group. The contents of hepatic cholesterol in DM group was 160% higher than that of normal group, but the mulberry leaves supplementation groups maintained the normal level. The activity of hepatic 3-hydroxy -3-methylglutaryl Coenzyme A (HMG-CoA) reductase in DM group was 43% lower than that of normal group, but had no significant difference between DM-0.1Y, DM-0.2Y and normal groups. In conclusion, YK-209 mulberry loaves has improving effect of the lipid metabolism in STZ-induced diabetic rats through hepatic HMG-CoA reductase activity, and the change of lipids contents in serum and liver.

• Analytical Science and Technology
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• v.23 no.6
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• pp.531-536
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• 2010

A quantitative analytical method has been established for the measurement of inosine 5'-monophosphate dehydrogenase (IMPDH) activity in human peripheral blood mononuclear cells (PBMCs) by ion-pair reversed-phase high performance liquid chromatography equipped with ultraviolet detection (HPLC/UV). IMPDH is a ${\beta}$-nicotinamide adenine dinucleotide hydrate (NAD+)-dependent dehydrogenase in which the enzyme converts inosine 5'-monophosphate (IMP) into xanthosine 5'-monophosphate (XMP). Its activity was measured by quantifying a HPLC chromatogram corresponding to XMP produced during the incubation of lysed PBMCs with IMP as a substrate and $NAD^+$ as a coenzyme. XMP produced was detected at a wavelength of 260 nm. The mobile phase was composed of a mixture of 37 mM potassium dihydrogen phosphate containing 7 mM tetra-n-butylammonium hydrogen sulfate adjusted to pH 5.5 and methanol (85:15, v/v) with a flow rate of 1 mL/min. The calibration curve was linear ($r^2$=0.999999) in the range of $0.2-50.0\;{\mu}M$ and the limit of quantification (LOQ) was $0.2\;{\mu}M$. The intra- and inter-day precisions were between 0.88-1.47% and 0.85-5.24%, respectively. The intra- and inter-day accuracies were between 98.74-99.99% and 99.95-101.65%, respectively. IMPDH activity in 11 Korean healthy volunteers ranged from 18.29 to 36.60 nmol/h/mg protein (mean = $27.70{\pm}6.28\;nmol/h/mg$ protein).

• Food Science and Preservation
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• v.13 no.5
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• pp.634-642
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• 2006

This study was performed to investigate the effects of lotus root ethanol extinct (LRE) on 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity in vitro, and lipid metabolism in the serum and liver of rate fed normal or high cholesterol diet in vivo. LRE (200 mg/kg/day and 400 mg/kg/day) was administered only to rats with fed high cholesterol diet for 6 week. We divided into 6 groups: normal diet group (NC), high cholesterol diet group (1% cholesterol and 0.25% sodium cholate)(HC), LRE 200 mg/kg treated group (NC-LREL), LRE 400 mg/kg teated group (NC-LREH), high cholesterol diet and LRE 200 mg/kg treated group (HC-LREL), and high cholesterol diet and LRE 400 mg/kg teated group (HC-LREH). LRE significantly inhibited the HMG-CoA reductase activity in a concentration-dependent manner in vitro. The body weight gain and liver weight of the high cholesterol diet group were higher than the normal diet group whereas the groups administered LRE were gradually decreased. The high cholesterol diet group increased serum triglyceride, total cholesterol, free cholesterol and LDL-cholesterol levels, and decreased atherogenic index, HDL-cholesterol and phospholipid levels as compared with the normal diet group. LRE administrated groups were increased in serum HDL-C/T-C, HDL-cholesterol and phospholipid levels, and decreased serum triglyceride, total cholesterol, free cholesterol, and LDL-cholesterol levels as compared with the high cholesterol diet group. These effect of LRE within the high cholesterol diet groups were concentration-dependent manners. There were no differences in the levels of serum triglyceride, total cholesterol, phopholipid, HDL-cholesterol and free cholesterol between normal diet groups. The hepatic LRE administrated groups than in the high cholesterol diet group. Teken together, it is suggested that LRE exerts hypocholesterolemic effect by reducing serum cholesterol concentration in rats with high cholesterol diet-induced hypercholesterolemia.

• Journal of Life Science
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• v.29 no.12
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• pp.1337-1344
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• 2019

Osteoporosis is characterized by a reduction in bone mass and typically manifests as an increase in fractures. Because this disease is common in elderly populations and lifespans are rapidly increasing, the incidence of osteoporosis has also grown. Most drugs currently used for osteoporosis treatment target osteoclasts in the bone tissue to prevent absorption. However, these medications also cause certain side effects and, furthermore, cannot increase bone mass. Thus, in order to control osteoporosis, regenerative medicine that utilizes adult stem cells and osteoblasts has been extensively studied. Statins, also known as 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, are cholesterol-lowering drugs that have been widely prescribed for cardiovascular diseases. Interestingly, recent studies have reported the beneficial effects of various statins on bone formation via the activation of osteoblasts. Thus, the current study investigated the effects of seven statin-family drugs on osteoblast activity during osteogenic differentiation using adult stem cells from human periosteal tissue. Specifically, statin effects on alkaline phosphatase activity, an early marker of bone cell differentiation, and on calcium deposit, a late marker of bone cell differentiation, were assessed. The results demonstrate that some statins (for example, pitavastatin and pravastatin) have a weak but positive effect on bone formation, and the findings therefore suggest that statin treatments can be a novel modulator for osteogenic differentiation and regenerative medicine using periosteal stem cells.