Biomedical subjects

Moonkyu Kang

Publications and source records attributed to Moonkyu Kang.

12 recordsLinked to original sources

PubMed2006

Survey and mechanism of skin depigmenting and lightening agents.

The type and amount of melanin synthesized by the melanocyte, and its distribution pattern in the surrounding keratinocytes, determines the actual color of the skin. Melanin forms through a series of oxidative reactions involving the amino acid tyrosine in the presence of the enzyme tyrosinase. Tyrosinase catalyses three different reactions in the biosynthetic pathway of melanin in melanocytes: the hydroxylation of tyrosine to l-DOPA and the oxidation of l-DOPA to dopaquinone; furthermore, in humans, dopaquinone is converted by a series of complex reactions to melanin. Among the skin-lightening and depigmenting agents, magnesium-l-ascorbyl-2-phosphate (MAP), hydroxyanisole, N-acetyl-4-S-cysteaminylphenol, arbutin (hydroquinone-beta-d-glucopyranoside) and hydroquinone (HQ) are the most widely prescribed worldwide. However, with reports of potential mutagenicity and epidemics of ochronosis, there has been an increasing impetus to find alternative herbal and pharmaceutical depigmenting agents. A review of the literature reveals that numerous other depigmenting or skin-lightening agents are either in use or in investigational stages. Some of these, such as kojic, glycolic and azelaic acids, are well known to most dermatologists. Others have been discovered and reported in the literature more recently. Several depigmentation and lightening agents are discussed, including their historical background, biochemical characteristics, type of inhibition and activators from various sources. In addition, the clinical importance of mushroom tyrosinase as a recent prospect is discussed in this paper.

Biological Products↗

PubMed2006

Effects of Nelumbinis Semen on contractile dysfunction in ischemic and reperfused rat heart.

Nelumbinis Semen (NS), or lotus seed, is one of the most well-known traditional herbal medicines and is frequently used to treat cardiovascular symptoms in Korea. The anti-ischemic effects of NS on ischemia-induced isolated rat heart were investigated through analyses of changes in blood pressure, aortic flow, coronary flow, and cardiac output. The subjects in this study were divided into two groups: a control, untreated ischemia-induced group, and an ischemia-induced group treated with NS. There were no significant differences in perfusion pressure, aortic flow, coronary flow and cardiac output between the groups before ischemia was induced. The supply of oxygen and buffer was stopped for ten minutes to induce ischemia in isolated rat hearts, and NS was administered during ischemia induction. NS treatment significantly prevented decreases in perfusion pressure, aortic flow, coronary flow and cardiac output under ischemic conditions (p < 0.01). In addition, the mechanism of the anti-ischemic effects of NS was also examined through quantitation of intracellular calcium content in rat neonatal cardiomyocytes. NS significantly prevented intracellular calcium increases induced by isoproterenol (p < 0.01). These results suggest that NS has distinct anti-ischemic effects through calcium antagonism.

Animals↗

PubMed2006

Effects of Yukmijihwang-tang derivatives (YMJd) on ibotenic acid-induced amnesia in the rat.

The present study investigates the effects of Yukmijihwang-tang Derivatives (YMJd) on learning and memory through the Morris water maze task and the central cholinergic system of rats with excitotoxic medial septum (MS) lesion. In the water maze test, the animals were trained to find a platform in a fixed position for 6 d and then received a 60-s probe trial in which the platform was removed from the pool on the 7th day. Ibotenic lesion of the MS showed the impaired performance in the Morris water maze test and severe cell losses in the MS, as indicated by decreased choline acetyltransferase-immunoreactivity in the medial septum. Daily administrations of YMJd (100 mg/kg, i.p.) for 21 consecutive days produced significant reversals of ibotenic acid-induced deficit in learning and memory. These treatments also reduced the loss of choline acetyltransferase (ChAT) immunoreactivity in the MS induced by ibotenic acid. These results suggest that impairments of spatial learning and memory might be attributable to the degeneration of septohippocampal cholinergic (SHC) neurons and that YMJd treatment ameliorated learning and memory deficits partly due through neuroprotective effects on the central acetylcholine system. Our studies suggest that YMJd might be useful in the treatment of Alzheimer's disease.

Amnesia↗

PubMed2006

Effect of Acori graminei Rhizoma on contractile dysfunction of ischemic and reperfused rat heart.

Acori graminei Rhizoma is one of the best-known traditional herbal medicines frequently used for the treatment of cardiovascular symptoms in Asian countries. The anti-ischemic effect of Acori graminei Rhizoma on ischemia-induced isolated rat heart was investigated through analysis of changes in perfusion pressure, aortic flow, coronary flow, and cardiac output. The subjects in this study were divided into two groups, an ischemia-induced group without any treatment (I), and an ischemia-induced group with Acori graminei Rhizoma treatment (I+AGR). There were no significant differences in perfusion pressure, aortic flow, coronary flow, or cardiac output between the two groups before ischemia was induced. The supply of oxygen and buffer was stopped for 10 min to induce ischemia in isolated rat hearts, and Acori graminei Rhizoma was administered while inducing ischemia. The data showed that Acori graminei Rhizoma treatment significantly prevented decreases in perfusion pressure, aortic flow, coronary flow, and cardiac output under an ischemic condition. In addition, hemodynamics (except heart rate) of the AGR-treated group was significantly recovered 60 min after reperfusion compared to the control group, (systolic aortic pressure: 85.5% vs. 62.5%, aortic flow volume: 68.1% vs. 49.4%, coronary flow volume: 86.8% vs. 60.1%, and cardiac output: 73.1% vs. 54.1%, p<0.01). These results suggest that Acori graminei Rhizoma has distinct anti-ischemic effects.

Animals↗

PubMed2005

Inhibition of lipopolysaccharide and interferon-gamma-induced expression of inducible nitric oxide synthase and tumor necrosis factor-alpha by Lithospermi radix in mouse peritoneal macrophages.

Lithospermi radix (LR, root of Lithospermum erythrorhizon Siebold. et Zuccarinii) has been used to treat various conditions, such as septic shock, eczema and burns. In this study, the effect of LR on lipopolysaccharide (LPS) and recombinant interferon-gamma (rIFN-gamma)-induced production of nitric oxide (NO) and tumor necrosis factor (TNF)-alpha were examined using mouse peritoneal macrophages. At 0.01-1 mg/ml, LR inhibited the LPS/rIFN-gamma-induced expression of inducible nitric oxide synthase (iNOS) and TNF-alpha release. To clarify the mechanism involved, the effect of LR on the activation of nuclear factor (NF)-kappaB was examined. The LPS/rIFN-gamma-induced activation of NF-kappaB was almost completely blocked by LR at 1mg/ml without cytotoxicity. These findings demonstrate that the inhibition of the LPS/rIFN-gamma-induced production of NO and TNF-alpha by LR involves the inhibition of NF-kappaB activation.

Animals↗

PubMed2005

Yukmijihwang-tang derivatives enhance cognitive processing in normal young adults: a double-blinded, placebo-controlled trial.

Yukmijihwang-tang (YMJ), also known as Luweidihuang-tang in China, has been widely used as a general herbal tonic for hundreds of years in many Asian countries. This study examines whether YMJ derivatives (YMJd) enhance cognitive ability in normal human subjects and discusses its potential as treatment for dementia patients with deficient cognitive ability. Subjects were divided into two groups, the placebo-treated group (n = 15) and the YMJd-treated group (n = 20). K-WAIS tests, a Korean version of an individual intelligence quotient (IQ) test, and a P300 latency assessment of event-related potential (ERP) were conducted in order to measure changes in cognitive ability before and after 6 weeks of YMJd treatment. The K-WAIS mean scores of the group treated with YMJd were significantly higher than those of the placebo group (p < 0.05), and their mean P300 latency was substantially shorter (p < 0.005). These results suggest that YMJd treatment accelerates the speed of information processing and enhances cognitive ability. YMJd treatment may help dementia patients or the elderly recover from cognition deficiencies or degeneration in clinic.

Adolescent↗

PubMed2005

The anti-depressant effect of Nelumbinis semen on rats under chronic mild stress induced depression-like symptoms.

Nelumbinis Semen is a well-known traditional herbal medicine frequently used in treatment of depression in many Asian countries. In this study, its anti-depression effects in rats were investigated by comparing the test results of those treated with Nelumbinis Semen to those treated with other herbal anti-depressants, including Rehmanniae Radix Preparat, Corni Fructus, Lycii Fructus, Pinelliae Rhizoma and Hypericum Perforatum. In order to induce depression-like symptoms, the animals were placed under chronic mild stress in the form of overnight illumination for 2 consecutive days. They were treated with the respective herbal extract and forced swimming tests were conducted afterwards. The anti-depression effects of each extract were then evaluated based on a measured index, which consisted of struggling time, first latency and first rest duration. These test results show that Nelumbinis Semen provides greater anti-depression effects than the other herbal extracts. Specifically, only the rats treated with Nelumbinis Semen showed significant increases in struggling time (43.9%, p < 0.005, p = 0.0037) and in first latency time (90.2%, p < 0.05, p = 0.0116). However, the first rest duration for Nelumbinis Semen treated rats was not significantly different from the other rats. It appears that Nelumbinis Semen provides even greater anti-depression effects than Hypericum Perforatum (commonly referred to as St. John's Wort, perhaps the most widely used natural antidepressant today). The anti-depression effects of Nelumbinis Semen might be due to the modulation of the amount of neurotransmitters involved in depression.

Animals↗

PubMed2005

Nelumbinis Semen reverses a decrease in hippocampal 5-HT release induced by chronic mild stress in rats.

Depression is associated with a dysfunctional serotonin system. Recently, several lines of evidence have suggested that a very important evoking factor in depression may be a serotonin deficit in the hippocampus. This study assessed the antidepression effects of Nelumbinis Semen (NS) through increasing serotonin concentrations under normal conditions and reversing a decrease in serotonin concentrations in rat hippo-campus with depression-like symptoms induced by chronic mild stress (CMS). Using an in-vivo microdialysis technique, the serotonin-enhancing effect of NS on rat hippocampus was investigated and its effects compared with those of two well-known antidepressants, Hypericum perforatum (St John's wort) and fluoxetine (Prozac). Rats were divided into five groups: saline-treated normal, without CMS; saline-treated stress control; NS-, St John's wort- and fluoxetine-treated rats under CMS for 8 weeks or no stress treatment. NS and fluoxetine significantly increased serotonin in normal conditions and reversed a CMS-induced decrease in serotonin release in the hippocampus (P<0.05 compared with normal group or control group under CMS). These results suggest that NS increases the serotonin levels normally decreased in depression, resulting in an enhancement of central serotonergic transmission and possible therapeutic action in depression. It is suggested that NS may present an antidepressant effect through enhancement of serotonin.

Animals↗

PubMed2005

Inhibition of production of reactive oxygen species and gene expression profile by treatment of ethanol extract of Moutan Cortex Radicis in oxidative stressed PC12 cells.

Moutan Cortex Radicis (MCR) is one of the most widely used Oriental medicines. In this study, we assessed the reducing effect of ethanol extract of MCR on hydrogen peroxide-induced reactive oxygen production, the main cause of cell damage or death in PC12 cells. The viability of cells treated with 1 mg/ml of MCR was significantly restored from that of oxidative-stressed PC12 cells. Measurement of intracellular reactive oxygen species (ROS) generation was determined using the H(2)DCFDA assay. MCR at 1-0.01 mg/ml concentration inhibited ROS production in oxidative-stressed cells. To identify candidate genes responsible for the anti-oxidative effects of MCR on PC12 cells, an oligonucleotide microarray analysis was performed. The result of gene expression profiles showed that 10 genes were up-regulated and 7 were down-regulated in MCR plus hydrogen peroxide treated cells compared with hydrogen peroxide treated cells. Among them, heme oxygenase (HO) and cathechol-O-methyltransferase (COMT) are related to regulation of ROS generation and the others are known to regulate cell survival and progression. Subsequently, we performed real-time RT-PCR to quantify the ROS related gene. MCR treatment increased the expression of HO by 370% and COMT by 280% at the concentration of 1 mg/ml. These findings suggest that MCR inhibits the production of ROS and cytotoxicity by oxidative-stressed PC12 cells through over-expression of HO and COMT.

Animals↗

PubMed2005

Effects of Yukmijihwang-tang derivatives (YMJd), a memory enhancing herbal extract, on the gene-expression profile in the rat hippocampus.

The herbal extract Yukmijihwang-tang (YMJ) has been widely used for centuries as an anti-aging herbal medicine in Asian countries. Among the various modified prescriptions of YMJ, YMJ derivatives (YMJd) were formulated to enhance memory retention. This study has three goals: 1) to quantitatively evaluate the memory-enhancing effect of YMJd using behavior tasks; 2) to use cDNA micro-array tools to identify candidate genes responsible for enhancing memory; and 3) to statistically evaluate the specific gene expression patterns using Real-time PCR. Memory retention abilities are addressed by the passive avoidance task with SD male rat. The retention time of the YMJd group was significantly delayed (ca. 100%), whereas with Ginkgo biloba and Soya lecithin treatment, this was only delayed 20% and 10%, respectively. The cDNA from the hippocampi of YMJd and rat control groups were applied to an Incyte rat GEM2 cDNA microarray. The microarray results showed that transthyretin and PEP-19 were abundantly expressed in the YMJd treated group. Importantly, PEP-19 is a neuron-specific protein that inhibits apoptotic processes. On the other hand, neuronal genes involved in neuronal death or neurodegeneration, such as pentraxin and spectrin, were abundantly expressed in the control group. The list of differentially expressed genes may provide further insight into the action and mechanism behind the memory-enhancing effect of herbal extracts of YMJd.

Animals↗

PubMed2004

Anti-obesity effect of PM-F2-OB, an anti-obesity herbal formulation, on rats fed a high-fat diet.

PM-F2-OB is one of the most well-known traditional herbal medicines that are frequently used for the treatment of obesity in Korea. The anti-obesity effect of PM-F2-OB on rats fed a high-fat diet was investigated through analyses of changes in body weight, kidney fat weight, and blood biochemicals including cholesterol, free fatty acid, BUN, creatinine, HDL, LDL, phospholipids, SGOT, SGPT, total lipids, and triglycerides. The subjects in this study were divided into four groups: a normal group with a standard diet (N); a PM-F2-OB treatment group fed a standard diet (N+PM-F2-OB); a control group fed a high-fat diet (C); and a PM-F2-OB treatment group fed a high-fat diet (C+PM-F2-OB). There were no significant differences in body weight change between the N and N+PM-F2-OB treatments. Also, there was no significant difference in the amount of food intake between the C and C+PM-F2-OB treatments. These results suggest that PM-F2-OB has no significant toxicity and does not induce a dislike for that diet due to its smell or taste. Rats were administered a high-fat diet (20% (w/w)) for six weeks to induce obesity. The study shows that PM-F2-OB significantly prevented increases in body weight, cholesterol, LDL and total lipids that resulted from the high-fat diet. PM-F2-OB also decreased kidney fat weight and free fatty acid, phospholipid, and triglyceride concentrations induced by the high-fat diet to level equals or below the normal diet group. It was concluded from the results that PM-F2-OB has a distinct anti-obesity effect.

Adipose Tissue↗

PubMed2004

Nelumbinis Semen reverses a decrease in 5-HT1A receptor binding induced by chronic mild stress, a depression-like symptom.

Depression is associated with a dysfunctional serotonin (5-hydroxytryptamine; 5-HT) system. More recently, several lines of evidence suggest that an important factor in the development of depression may be a deficit in the function and expression of 5-HT1A receptors. The present study assessed if Nelumbinis Semen (N.s.) had an anti-depression effect through reversing a decrease in 5-HT1A receptor binding in rats with depression-like symptoms induced by chronic mild stress. Using a 5-HT1A receptor binding assay, with a specific 5-HT1A receptor agonist, 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino) tetralin), the mechanism of the anti-depression effect of N.s. on rats was investigated, and the effects compared with two well-known antidepressants, Hyperium Perforatum (St. Johns Wort) and fluoxetine (Prozac). Animals were divided into five groups: the normal (N) group without chronic mild stress (CMS), the control (C) group under CMS for 8 weeks, the Nelumbinis Semen (N.s.) treatment group under CMS for 8 weeks, the Hyperium Perforatum (H.p.) treatment group under CMS for 8 weeks and finally, the fluoxetine (F) treatment group under CMS for 8 weeks. Each treatment was administered to rats during the last 4 weeks of the 8-week CMS. A sucrose intake test was performed to test the anti-depression effect of N.s. The N.s. treatment significantly reversed the decreased sucrose intake under CMS (P < 0.05 compared to control group under CMS). In the CA2 and CA3 regions of the hippocampus, both N.s. and H.p. reversed the CMS-induced decrease in 5-HT1A receptor binding. In the I to II regions of the frontal cortex, N.s. and H.p. also reversed the CMS-induced decrease in 5-HT1A receptor binding, and even showed a significant increase in 5-HT1A receptor binding compared to the F treatment group (N.s. vs. P, p < 0.05, H.p. vs. P, p < 0.05). However, in the hypothalamus, all treatments reversed the CMS-induced decrease in 5-HT1A receptor binding. This reversal effect of N.s. on the decrease in 5-HT1A receptor binding in the frontal cortex, hippocampus and hypothalamus of rat brains was very similar to that of H.p, but different from that of F. It is concluded that N.s. presents an anti-depression effect through enhancing 5-HT1A receptor binding.

8-Hydroxy-2-(di-n-propylamino)tetralin↗