Biomedical subjects

Young Choong Kim

Publications and source records attributed to Young Choong Kim.

At least 19 recordsLinked to original sources

PubMed2006

Inhibitory activity of phenolic glycosides from the fruits of Idesia polycarpa on lipopolysaccharide-induced nitric oxide production in BV2 microglia.

Two new phenolic glycosides characterized as idesin salicylate (1) and 2-hydroxyphenol-1-O-beta-D-glucopyranosyl-(6-->1)- alpha-L-rhamnopyranoside (2) were isolated with four known compounds, idescarpin (3), idesin (4), 1-hydroxy-6-oxocyclohex-2-enecarboxylic acid methyl ester (5) and salirepin (6), from the fruits of IDESIA POLYCARPA. All six compounds significantly inhibited lipopolysaccharide-induced nitric oxide production in BV2 microglia at concentrations from 1 microM to 100 microM.

Animals↗

PubMed2006

Osteoblast differentiation stimulating activity of biflavonoids from Cephalotaxus koreana.

Six amentoflavone-type biflavonoids, bilobetin (1), ginkgetin (2), 4',7''-di-O-methyl-amentoflavone (3), 7-O-methyl-isoginkgetin (4), sciadopitysin (5), and 7,4',7'',4'''-O-methyl-amentoflavone (6), were isolated from the EtOAc fraction of Cephalotaxus koreana Nakai (Cephalotaxaceae) by bioactivity-guided fractionation technique using primary cultures of mouse osteoblasts as an in vitro assay system. Among the six biflavonoids isolated, bilobetin (1), sciadopitysin (5), and 7,4',7'',4'''-O-methyl-amentoflavone (6) significantly increased osteoblast differentiation as assessed by alkaline phosphatase activity, collagen synthesis, and mineralization. Considering structure-activity relationship, methoxyl groups at 4' and 4''' in the B rings in amentoflavone-type biflavonoid might be important in osteoblast differentiation. Taken together, our present study suggests therapeutic potential of biflavonoids against bone diseases such as osteoporosis.

Animals↗

PubMed2006

Acteoside and its aglycones protect primary cultures of rat cortical cells from glutamate-induced excitotoxicity.

We have previously reported that acteoside isolated from the leaves of Callicarpa dichotoma has significant neuroprotective activity against glutamate-induced neurotoxicity in primary cultured rat cortical cells. To determine the essential structural moiety within this phenylethanoid glycoside needed to exert neuroprotective activity, acteoside was hydrolyzed with acid into its aglycones, caffeic acid and 3',4'-dihydroxylphenylethanol. Caffeic acid and 3',4'-dihydroxylphenylethanol also showed significant neuroprotective activities. Acteoside and its aglycones inhibited glutamate-induced intracellular Ca2+ influx resulting in overproduction of nitric oxide and reduced the formation of reactive oxygen species. These compounds preserved the mitochondrial membrane potential and the activities of antioxidative enzymes, such as superoxide dismutase, glutathione reductase and glutathione peroxidase reduced by glutamate. It was followed by the preservation of the level of glutathione and finally the inhibition of membrane lipid peroxidation.

Animals↗

PubMed2006

15-Methoxypinusolidic acid from Biota orientalis attenuates glutamate-induced neurotoxicity in primary cultured rat cortical cells.

15-Methoxypinusolidic acid (15-MPA), a pinusolide derivative isolated from Biota orientalis (Cupressaceae) leaves prevented glutamate-induced excitotoxicity in primary cultured rat cortical cells in vitro. 15-MPA had more selectivity in protecting neurons against N-methyl-D-aspartate (NMDA)-induced neurotoxicity than that induced by kainic acid (KA). The glutamate-induced increase of intracellular calcium ([Ca2+]i) in cortical cells was effectively reduced by 15-MPA. Moreover, 15-MPA could successfully reduce the subsequent overproduction of nitric oxide (NO) and the level of cellular peroxide, and inhibit glutathione (GSH) depletion and lipid peroxidation induced by glutamate in our cultures. Collectively, these results suggested that 15-MPA attenuated glutamate-induced excitotoxicity via stabilization of [Ca2+]i homeostasis and suppression of oxidative stress possibly through the actions on the NMDA receptors.

Animals↗

PubMed2006

meso-Dihydroguaiaretic acid attenuates the neurotoxic effect of staurosporine in primary rat cortical cultures.

The effect of meso-dihydroguaiaretic acid (MDGA) on the staurosporine-induced neuronal apoptosis and its potential mechanism were investigated using primary cultures of rat cortical cells as an assay system. Treatment of MDGA at the concentrations of 0.1, 1.0 and 10 microM significantly protected neuronal cells against Staurosporine-induced apoptosis. The neuroprotective activity of MDGA was the most potent at the concentration of 1.0 microM and was not increased at higher concentration. MDGA reduced apoptotic characteristics induced by STS; MDGA reduced the condensed nuclei in staurosporine-injured rat cortical cells. MDGA diminished the calcium influx that accompanies the staurosporine-induced apoptosis, and inhibited the subsequent overproduction of reactive oxygen species and peroxide to the level of control cells. It also preserved cellular activity of superoxide dismutase, an antioxidative enzyme reduced by staurosporine insult. In addition, MDGA significantly inhibited caspase-3/7 activation and cytochrome c release. Taken together, these results suggested that MDGA protected neuronal cells against staurosporine-induced apoptosis through the inhibition of Ca(2+) influx, cellular oxidation, cytochrome c release and caspase-3/7 activation.

Analysis of Variance↗

PubMed2006

Cytotoxic terpene hydroperoxides from the aerial parts of Aster spathulifolius.

Three new sesquiterpene hydroperoxides, 1-[3-(2-hydroperoxy-3-methylbut-3-en)-4-hydroxyphenyl]ethanone (2), 7beta-hydroperoxy-eudesma-11-en-4-ol (3), and 7alpha-hydroperoxymanool (4), together with three known compounds, germacrone (1), ent-germacra-4(15),5,10(14)-trien-1alpha-ol (5) and teucdiol A (6) were isolated from the aerial parts of Aster spathulifolius (Compositae). Their structures were characterized using chemical and spectroscopic methods. The isolated compounds were tested for their cytotoxicity against five human tumor cell lines in vitro using a SRB method. The two new compounds, 3 and 4, showed moderate cytotoxicity against human cancer cells with ED50 values ranging from 0.24 to 13.27 microg/mL.

Aster Plant↗

PubMed2006

Neuroprotective 2-(2-phenylethyl)chromones of Imperata cylindrica.

Bioactivity-guided fractionation of the methanolic extract of the rhizomes of Imperata cylindrica afforded a new compound, 5-hydroxy-2-(2-phenylethyl)chromone (1), together with three known compounds, 5-hydroxy-2-[2-(2-hydroxyphenyl)ethyl]chromone (2), flidersiachromone (3), and 5-hydroxy-2-styrylchromone (4). Among these four compounds, 1 and 2 showed significant neuroprotective activity against glutamate-induced neurotoxicity in primary cultures of rat cortical cells.

Adrenal Cortex↗

PubMed2006

Neuroprotective bibenzyl glycosides of Stemona tuberosa roots.

Three new bibenzyl glycosides characterized as stilbostemin B 3'-beta-D-glucopyranoside (1), stilbostemin H 3'-beta-D-glucopyranoside (2), and stilbostemin I 2"-beta-D-glucopyranoside (3) were isolated from the roots of Stemona tuberosa. All three bibenzyl glycosides significantly protected human neuroblastoma SH-SY5Y cells from 6-hydroxydopamine-induced neurotoxicity.

Bibenzyls↗

PubMed2006

A new neuroprotective compound of Ligustrum japonicum leaves.

A new secoiridoid glycoside characterized as (8 Z)-nuezhenide A along with five known glycosides, (8 E)-nuezhenide, (8 Z)-nuezhenide, oleonuezhenide, osmanthuside B and osmanthuside D, were isolated from the n-BuOH fraction of Ligustrum japonicum leaves. All six compounds significantly protected human neuroblastoma SH-SY5Y cells from 6-hydroxydopamine-induced neurotoxicity.

Cell Line, Tumor↗

PubMed2006

Acteoside of Callicarpa dichotoma attenuates scopolamine-induced memory impairments.

We previously reported that ten phenylethanoid glycosides including acteoside isolated from the leaves and twigs of Callicarpa dichotoma significantly attenuated glutamate-induced neurotoxicity. In the present study, we examined anti-amnesic activity of acteoside using scopolamine-induced (1 mg/kg body weight, s.c.) amnesic mice with both passive avoidance and Morris water maze tests. Acute oral treatment (single administration prior to scopolamine treatment) of mice with acteoside (1.0, 2.5 mg/kg body weight) significantly mitigated scopolamine-induced memory deficits in the passive avoidance test. It is interesting to note that prolonged oral daily treatment of mice with much lower amount (0.1 mg/kg body weight) of acteoside for 10 d reversed the scopolamine-induced memory deficits. In the Morris water maze, prolonged oral treatment with acteoside (prolonged daily administration of 1.0 mg/kg body weight for 10 d) significantly ameliorated scopolamine-induced memory deficits showing the formation of long-term and/or short-term spatial memory. We suggest, therefore, that acteoside has anti-amnesic activity that may ultimately hold significant therapeutic value in alleviating certain memory impairment observed in Alzheimer's disease.

Animals↗

PubMed2005

Idesolide: a new spiro compound from Idesia polycarpa.

[structure: see text]. Idesolide, a new spiro compound possessing tetrahydrobenzodioxole structure, was isolated from the fruits of Idesia polycarpa Maxim. Its structure was established by NMR and MS spectroscopic analysis with single-crystal X-ray experiments. Idesolide significantly reduced nitric oxide production induced by lipopolysaccharide in BV2 microglial cells.

Anti-Inflammatory Agents↗

PubMed2005

Protective activities of stilbene glycosides from Acer mono leaves against H2O2-induced oxidative damage in primary cultured rat hepatocytes.

In our previous study, we isolated two new hepatoprotective stilbene glycosides, 5-O-methyl-(E)-resveratrol 3-O-beta-D-glucopyranoside (MRA) and 5-O-methyl-(E)-resveratrol 3-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (MRAG), from the methanolic extract of Acer mono leaves. Thereby, we have attempted to elucidate the hepatoprotective mechanism of these compounds, focusing on antioxidative effects, using hydrogen peroxide (H2O2)-injured primary cultures of rat hepatocytes. Both MRA and MRAG showed potent hepatoprotective activities in pretreatment but showed little effects in posttreatment. In addition, they increased the glutathione (GSH) level in the normal control cultures and significantly prevented the depletion of GSH in H2O2-injured primary cultured rat hepatocytes. Moreover, these compounds significantly restored the level of GSH depleted by buthionine sulfoximine or diethylmaleate in the presence or absence of H2O2. Furthermore, these compounds preserved the activities of antioxidant enzymes such as superoxide dismutase, glutathione reductase, and glutathione peroxidase reduced by H2O2 insults. Meanwhile, MRA and MRAG showed moderate scavenging effects with IC50 values of 103.6 and 80.5 microM, respectively, as determined by 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging activity. Taken together, these results suggest that MRG and MRAG exert significant hepatoprotective activities against H2O2-induced hepatotoxicity by maintaining the antioxidative defense system rather than scavenging free radicals.

Acer↗

PubMed2005

ESP-102, a standardized combined extract of Angelica gigas, Saururus chinensis and Schizandra chinensis, significantly improved scopolamine-induced memory impairment in mice.

We assessed the effects of oral treatments of ESP-102, a standardized combined extract of Angelica gigas, Saururus chinensis and Schizandra chinensis, on learning and memory deficit. The cognition-enhancing effect of ESP-102 was investigated in scopolamine-induced (1 mg/kg body weight, s.c.) amnesic mice with both passive avoidance and Morris water maze performance tests. Acute oral treatment (single administration prior to scopolamine treatment) of mice with ESP-102 (doses in the range of 10 to 100 mg/kg body weight) significantly reduced scopolamine-induced memory deficits in the passive avoidance performance test. Another noteworthy result included the fact that prolonged oral daily treatments of mice with much lower amounts of ESP-102 (1 and 10 mg/kg body weight) for ten days reversed scopolamine-induced memory deficits. In the Morris water maze performance test, both acute and prolonged oral treatments with ESP-102 (single administration of 100 mg/kg body weight or prolonged daily administration of 1 and 10 mg/kg body weight for ten days, respectively, significantly ameliorated scopolamine-induced memory deficits as indicated by the formation of long-term and/or short-term spatial memory. In addition, we investigated the effects of ESP-102 on neurotoxicity induced by amyloid-beta peptide (Abeta25-35) or glutamate in primary cultured cortical neurons of rats. Pretreatment of cultures with ESP-102 (0.001, 0.01 and 0.1 mug/ml) significantly protected neurons from neurotoxicity induced by either glutamate or Abeta25-35. These results suggest that ESP-102 may have some protective characteristics against neuronal cell death and cognitive impairments often observed in Alzheimer's disease, stroke, ischemic injury and other neurodegenerative diseases.

Acetylcholinesterase↗

PubMed2005

Potentially hepatoprotective glycolipid constituents of Lycium chinense fruits.

Further investigation of Lycium chinense fruits gave a mixture of (6'-O-palmitoyl)- and (6'-O-stearoyl)-beta-sitosterol-3-O-beta-D-glucopyranoside (1) and two glycolipids, 1-O-(9Z,12Z, 15Z-octadecatrienoyl)-2-O-(9Z, 12Z, 15Z-octadecatrienoyl)-3-O-beta-D-galactopyranosyl glycerol (2) and 1-O-(9Z, 12Z-octadecadienoyl)-2-O-(9Z, 12Z, 15Z-octadecatrienoyl)-3-O-beta-D-galactopyranosyl glycerol (3). These compounds were newly isolated as constituents of L. chinense.

Animals↗

PubMed2005

Four new neuroprotective dihydropyranocoumarins from Angelica gigas.

Four new dihydropyranocoumarins were isolated from Angelica gigas roots through neuroprotective activity-guided isolation and were characterized as decursinol derivatives 4"-hydroxytigloyldecursinol (1), 4"-hydroxydecursin (2), (2"S,3"S)-epoxyangeloyldecursinol (3), and (2"R,3"R)-epoxyangeloyldecursinol (4), respectively. All four new dihydropyranocoumarins and major coumarin derivatives of A. gigas, decursinol and decursin, exhibited significant protective activity against glutamate-induced neurotoxicity when added to primary cultures of rat cortical cells at concentrations ranging from 0.1 to 10 microM.

Angelica↗

PubMed2005

Two new hepatoprotective stilbene glycosides from Acer mono leaves.

Two new stilbene glycosides, 5-O-methyl-(E)-resveratrol 3-O-beta-d-glucopyranoside (1) and 5-O-methyl-(E)-resveratrol 3-O-beta-D-apiofuranosyl-(1-->6)-beta-d-glucopyranoside (2), were isolated from the leaves of Acer mono, along with seven known compounds. Among these compounds, 1, 2, and quercetin (3) showed significant hepatoprotective activities against H(2)O(2)-induced toxicity in primary cultures of rat hepatocytes.

Acer↗

PubMed2005

Labdane diterpenes from Aster spathulifolius and their cytotoxic effects on human cancer cell lines.

Three new labdane diterpenes (1-3), together with eight known diterpenoids, were isolated from a methanol extract of the aerial parts of Aster spathulifolius. The structures of 1-3 were determined as (13R)-labda-7,14-diene 13-O-beta-d-(4'-O-acetyl)fucopyranoside (1), (13R)-labda-7,14-diene 13-O-beta-d-(3'-O-acetyl)fucopyranoside (2), and (13R)-labda-14(15)-en-8,13-diol 13-O-beta-d-fucopyranoside (3), on the basis of spectroscopic and chemical methods. Compounds 1, 2, and four of the known compounds exhibited generally nonspecific cytotoxicity against human A549, SK-OV-3, SK-MEL-2, XF498, and HCT15 tumor cells.

Antineoplastic Agents, Phytogenic↗

PubMed2005

Meso-dihydroguaiaretic acid and licarin A of Machilus thunbergii protect against glutamate-induced toxicity in primary cultures of a rat cortical cells.

1 We previously reported that four lignans isolated from the bark of Machilus thunbergii Sieb. et Zucc. (Lauraceae) protected primary cultures of rat cortical neurons from neurotoxicity induced by glutamate. 2 Among the lignans, meso-dihydroguaiarectic acid (MDGA) and licarin A significantly attenuated glutamate-induced neurotoxicity when added prior to or right after the excitotoxic glutamate challenge. 3 The neuroprotective activities of two lignans appeared to be more effective in protecting neurons against neurotoxicity induced by NMDA than that induced by kainic acid. 4 MDGA and licarin A diminished the calcium influx that routinely accompanies with the glutamate-induced neurotoxicity, and inhibited the subsequent overproduction of cellular nitric oxide and peroxide to the level of control cells. They also preserved cellular activities of antioxidative enzymes such as superoxide dismutase, glutathione peroxidase and glutathione reductase reduced in the glutamate-injured neuronal cells. 5 Thus, our results suggest that MDGA and licarin A significantly protect primary cultured neuronal cells against glutamate-induced oxidative stress, via antioxidative activities.

Animals↗