Biomedical subjects

Sam Sik Kang

Publications and source records attributed to Sam Sik Kang.

At least 19 recordsLinked to original sources

PubMed2006

Trichotomoside: a new antioxidative phenylpropanoid glycoside from Clerodendron trichotomum.

The structure and antioxidant properties of a new natural glycoside, trichotomoside (1), isolated from Clerodendron trichotomum, were investigated. Trichotomoside was identified as 2-(3-hydroxy-4-methoxyphenyl)ethyl 3-O-(2,3-di-O-acetyl-alpha-L-rhamnopyranosyl)-4-O-[(2E)-3-(3-hydroxy-4-methoxyphenyl)prop-2-enoyl]-beta-D-glucopyranoside. The compound was active towards intracellular reactive oxygen species (ROS) and exhibited DPPH-radical-scavenging effects. The radical-scavenging activity of 1 was found to protect the viability of Chinese hamster lung fibroblasts (V79-4 cells) exposed to H2O2 and gamma-irradiation.

Animals↗

PubMed2006

Chemical constituents of the root of Dystaenia takeshimana and their anti-inflammatory activity.

In our ongoing search for bioactive compounds originating from the endemic species in Korea, we found that the hexane and EtOAc fractions of the MeOH extract from the root of Dystaenia takeshimana (Nakai) Kitagawa (Umbelliferae) showed cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) dual inhibitory activity by assessing their effects on the production of prostaglandin D2 (PGD2) and leukotriene C4 (LTC4) in mouse bone marrow-derived mast cells. By activity-guided fractionation, five coumarins, viz. psoralen (2), xanthotoxin (3), scopoletin (4), umbelliferone (5), and (+)-marmesin (6), together with beta-sitosterol (1), were isolated from the hexane fraction, and two phenethyl alcohol derivatives, viz. 2-methoxy-2-(4'-hydroxyphenyl)ethanol (7) and 2-hydroxy-2-(4'-hydroxyphenyl)ethanol (8), three flavonoids, viz. apigenin (9), luteolin (10), and cynaroside (11), as well as daucosterol (12) were isolated from the EtOAc fraction using silica gel column chromatography. In addition, D-mannitol (13) was isolated from the BuOH fraction by recrystallization. Two of the coumarins, scopoletin (4) and (+)-marmesin (6), the two phenethyl alcohol derivatives (7, 8) and the three flavonoids (9-11) were isolated for the first time from this plant. Among the compounds isolated from this plant, the five coumarins as well as the three flavonoids showed COX-2/5-LOX dual inhibitory activity. These results suggest that the anti-inflammatory activity of D. takeshimana might in part occur via the inhibition of the generation of eicosanoids.

Animals↗

PubMed2006

Naturally occurring biflavonoid, ochnaflavone, inhibits cyclooxygenases-2 and 5-lipoxygenase in mouse bone marrow-derived mast cells.

Ochnaflavone is a medicinal herbal product isolated from Lonicera japonica that inhibits cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D2 (PGD2) generation in bone marrow-derived mast cells (BMMC) in a concentration-dependent manner with IC50 values of 0.6 microM. Western blotting probed with specific anti-COX-2 antibodies showed that the decrease in quantity of the PGD2 product was accompanied by a decrease in the COX-2 protein level. In addition, this compound consistently inhibited the production of leukotriene C4 (LTC4) in a dose dependent manner, with an IC50 value of 6.56 microM. These results demonstrate that ochnaflavone has a dual cyclooxygenase-2/5-lipoxygenase inhibitory activity. Furthermore, this compound strongly inhibited degranulation reaction in a dose dependent manner, with an IC50 value of 3.01 microM. Therefore, this compound might provide a basis for novel anti-inflammatory drugs.

Animals↗

PubMed2006

Constituents from the fruiting bodies of Ganoderma applanatum and their aldose reductase inhibitory activity.

Eight compounds were isolated from the fruiting bodies of Ganoderma applanatum, and were identified as 2-methoxyfatty acids (1), 5-dihydroergosterol (2), ergosterol peroxide (3) 3beta,7beta, 20,23xi-tetrahydroxy-11,15-dioxolanosta-8-en-26-oic acid (4), 7beta,20,23xi-trihydroxy-3,11,15-trioxolanosta-8-en-26-oic acid (5), cerevisterol (6), 7beta,23xi-dihydroxy-3,11,15-trioxolanosta-8,20E (22)-dien-26-oic acid (7), and 7beta-hydroxy-3,11,15,23-tetraoxolanosta-8,20E(22)-dien-26-oic acid methyl ester (8) by spectral analysis. All compounds were isolated for the first time from this fruiting bodies, and their effect on rat lens aldose reductase (RLAR) activity was tested. Among these eight compounds, ergosterol peroxide (3) was found to exhibit potent RLAR inhibition, its IC50 value being 15.4 microg/mL.

Aldehyde Reductase↗

PubMed2006

Inhibition of chronic skin inflammation by topical anti-inflammatory flavonoid preparation, Ato Formula.

Flavonoids are known as natural anti-inflammatory agents. In this investigation, an anti-inflammatory potential of new topical preparation (SK Ato Formula) containing flavonoid mixtures from Scutellaria baicalensis Georgi roots and Ginkgo biloba L. leaves with an extract of Gentiana scabra Bunge roots was evaluated in an animal model of chronic skin inflammation. Multiple 12-O-tetradecanoylphorbol-13-acetate treatments for 7 consecutive days on ICR mouse ear provoked a chronic type of skin inflammation: dermal edema, epidermal hyperplasia and infiltration of inflammatory cells. When topically applied in this model, this new formulation (5-20 microL/ear/treatment) reduced these responses. Furthermore, it inhibited prostaglandin E2 generation (17.1-33.3%) and suppressed the expression of proinflammatory genes, cyclooxygenase-2 and interleulin-1beta in the skin lesion. Although the potency of inhibition was lower than that of prednisolone, all these results suggest that Ato Formula may be beneficial for treating chronic skin inflammatory disorders such as atopic dermatitis.

Administration, Topical↗

PubMed2006

Expression profiling of lipopolysaccharide target genes in RAW264.7 cells by oligonucleotide microarray analyses.

In inflammatory responses, induction of cytokines and other immune regulator genes in macrophages by pathogen-associated signal such as lipopolysaccharide (LPS) plays a crucial role. In this study, the gene expression profile changes by LPS treatment in the macrophage/monocyte lineage cell line RAW264.7 was investigated. A 60-mer oligonucleotide microarray of which probes target 32381 mouse genes was used. A reverse transcription-in vitro translation labeling protocol and a chemileuminescence detection system were employed. The mRNA expression levels in RAW264.7 cells treated for 6 h with LPS and the control vehicle were compared. 747 genes were up-regulated and 523 genes were down-regulated by more than 2 folds. 320 genes showing more than 4-fold change by LPS treatment were further classified for the biological process, molecular function, and signaling pathway. The biological process categories that showed high number of increased genes include the immunity and defense, the nucleic acid metabolism, the protein metabolism and modification, and the signal transduction process. The chemokine-cytokine signaling, interleukin signaling, Toll receptor signaling, and apoptosis signaling pathways involved high number of genes differentially expressed in response to LPS. These expression profile data provide more comprehensive information on LPS-target genes in RAW264.7 cells, which will be useful in comparing gene expression changes induced by extracts and compounds from anti-inflammatory medicinal herbs.

Animals↗

PubMed2006

Alkaloids from the roots of Aconitum pseudo-laeve var. erectum.

One new quinazoline (1) and two new norditerpenoid (2 and 3) alkaloids along with 10 known compounds were isolated from the roots of Aconitum pseudo-laeve var. erectum. The new alkaloids were assigned as 2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoic acid methyl ester (1), 18-O-2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoyllycoctonine (2), and 14-O-acetyl-8-O-methyl-18-O-2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoylcammaconine (3). The structures of the new alkaloids were established by spectroscopic methods. This is the first report of the 2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoyl ester group being found as an acyl substituent in norditerpenoid alkaloids (compounds 2 and 3).

Aconitine↗

PubMed2006

Effects of anti-inflammatory biflavonoid, ginkgetin, on chronic skin inflammation.

Ginkgetin, a biflavonoid from Ginkgo biloba leaves (Ginkgoaceae), was previously demonstrated to inhibit phospholipase A2 and to suppress proinflammatory gene expression such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase. In this study, the effects of ginkgetin were examined on an animal model of chronic skin inflammation and proinflammatory gene expression. When topically applied to ICR mouse ear, ginkgetin (20-80 microg/ear/treatment) inhibited ear edema (22.8-30.5%) and prostaglandin E2 production (30.2-31.1%) induced by multiple treatment of 12-O-tetradecanoylphorbol-13-acetate (TPA) for 7 consecutive days. By histological comparison, ginkgetin was also found to reduce epidermal hyperplasia. The expression of proinflammatory gene, interleukin-1beta, was suppressed by ginkgetin. From the results, it is suggested that ginkgetin may be beneficial against chronic skin inflammatory disorders like atopic dermatitis.

Administration, Topical↗

PubMed2006

Flavonols inhibit sortases and sortase-mediated Staphylococcus aureus clumping to fibrinogen.

Sortases are a family of Gram-positive transpeptidases responsible for anchoring surface protein virulence factors to the peptidoglycan cell wall layer. In Staphylococcus aureus, deletion of the sortase isoforms results in marked reduction in virulence and infection potential, making it an important antivirulence target. We examined the effects of naturally occurring flavonols on recombinant sortase A (SrtA) and B (SrtB) prepared from S. aureus ATCC6538p and found that these compounds inhibited the activity of sortases, without exhibiting antibacterial activities. Among the flavonols tested, morin, myricetin, and quercetin exhibited strong sortase inhibitory activities (SrtA IC50: 37.39-52.70 microM, SrtB IC50: 8.54-36.89 microM). The fibrinogen cell-clumping activity data highlight the potential of flavonols for the treatment of S. aureus infections via inhibition of sortase.

Base Sequence↗

PubMed2006

Anti-asthmatic activity of an ethanol extract from Saururus chinensis.

As an attempt to find bioactive medicinal herbs exerting anti-asthmatic activity, the effects of an ethanol extract from the parts of Saururus chinensis were evaluated in both in vitro and in vivo. The ethanol extract of S. chinensis (ESC) inhibited generation of the cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D(2) in bone marrow-derived mast cells in a concentration-dependent manner with an IC(50) value of 14.3 microg/ml. ESC also inhibited leukotriene C(4) production with an IC(50) value of 0.3 microg/ml. This demonstrates that ESC has COX-2/5-lipoxygenase dual inhibitory activity. In addition, this compound inhibited degranulation reaction in a dose dependent manner, with an IC(50) value of 1.3 microg/ml. An ovalbumin induced mouse asthmatic animal model was used to determine its in vivo anti-asthmatic activity. The oral administration (50-200 mg/kg) of ESC reduced the number of infiltrated eosinophil in a bronchoalveolar lavage fluid. Furthermore, ESC (100 mg/kg) inhibited the eotaxin and IL-4 mRNA expression levels. These results suggest that the anti-asthmatic activity of S. chinensis might in part occur via the inhibition of eicosanoid generation, degranulation as well as the down regulation of IL-4 and eotaxin mRNA expression.

Animals↗

PubMed2006

Ochnaflavone, naturally occurring biflavonoid, inhibits phospholipase A2 dependent phosphatidylethanolamine degradation in a CCl4-induced rat liver microsome.

This study investigated the protective effects of a group IIA secretory phospholipase A2 (sPLA2-IIA) inhibitor, ochnaflavone, on the progression of carbon tetrachloride (CCl4)-induced acute liver injury in rat liver microsomes in vitro. When rat liver was incubated at 37 degrees C in the presence of CCl4, the level of phosphatidylethanolamine (PE) degradation increased markedly compared with the control. The rat 14 kDa platelet PLA2 antibody, R377, suppressed the degradation of PE. Pretreating the microsome with ochnaflavone (2-16 microM) reduced the level of PE degradation in a dose dependent manner. In addition, p-bromophenacy bromide (p-BPB), which is a PLA2 inhibitor, also inhibited PE degradation. However, the inhibitory activity was weaker than that of ochnaflavone. Further investigation showed that ochnaflavone not only inhibited the purified rat platelet sPLA2 activity in a dose dependent manner with an IC50 value of 3.45 microM, when arachidonyl PE was used as a substrate, but also inhibited lipid peroxidation in a dose dependent manner with an IC50 value of 7.16 microM. This result suggests that ochnaflavone prevents the progression of CCl4-induced PE hydrolysis by inhibiting the endogenous sPLA2 activity.

Animals↗

PubMed2006

Anti-complementary activity of ursane-type triterpenoids from Weigela subsessilis.

A new ursane-type triterpenoid, weigelic acid (1), and seven known compounds, ursolic acid (2), ilekudinol A (3), corosolic acid (4), ilekudinol B (5), esculentic acid (6), pomolic acid (7), and asiatic acid (8) were isolated from the leaf and stem of Weigela subsessilis. The structure of the new triterpenoid was established as 1beta,2alpha,3alpha,23-tetrahydroxyurs-12-en-28-oic acid on the basis of spectroscopic analyses. In addition, the isolated compounds were evaluated for their anti-complement activity against the classical pathway of the complement system. Of these, compounds 1-2 and 4-8 exhibited anti-complement activity with IC50 values of 152, 90, 130, 51, 56, 4, and 163 microM, respectively, whereas 3 was inactive. This shows that a carboxylic group of ursane-type triterpenoids seems to play an important role in inhibiting the hemolytic activity of human serum against erythrocytes.

Animals↗

PubMed2006

Anti-inflammatory activity of Ailanthus altissima in ovalbumin-induced lung inflammation.

As part of an ongoing investigation to find bioactive medicinal herbs exerting anti-inflammation activity, the effect of an ethanol extract from the parts of Ailanthus altissima (Simaroubaceae) was evaluated in both in vitro and in in vivo system. The ethanol extract of A. altissima (EAa) inhibited generation of the cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D2 in bone marrow-derived mast cells (BMMC) in a concentration-dependent manner with an IC50 value of 214.6 microg/ml. However, this compound did not inhibit COX-2 protein expression up to a concentration of 400 microg/ml in the BMMC, indicating that EAa directly inhibits COX-2 activity. In addition, EAa inhibited leukotriene C4 production with an IC50 value of 25.7 microg/ml. Furthermore, this compound inhibited degranulation reaction in a dose dependent manner, with an IC50 value of 27.3 microg/ml. Ovalbumin (OVA)-sensitized mice were orally pretreated with EAa before aerosol challenges. EAa reduced the eosinophil infiltration into the airway and the eotaxin, IL-4, and IL-13 mRNA expression levels. These results suggest that the anti-inflammation activity of A. altissima in OVA-induced lung inflammation may occur in part via the down regulation of T(H)2 cytokines and eotaxin transcripts as well as the inhibition of inflammatory mediators.

Ailanthus↗

PubMed2005

Polyphenol amentoflavone affords neuroprotection against neonatal hypoxic-ischemic brain damage via multiple mechanisms.

Flavonoids are naturally occurring polyphenolic compounds that have many biological properties, including antioxidative, anti-inflammatory and neuroprotective effects. Here, we report that amentoflavone significantly reduced cell death induced by staurosporine, etoposide and sodium nitroprusside in neuroblastoma SH-SY5Y cells. In post-natal day 7 rats, hypoxic-ischemic (H-I) brain damage induced by unilateral carotid ligation and hypoxia resulted in distinct features of neuronal cell death including apoptosis and necrosis. In this model, a systemic administration of amentoflavone (30 mg/kg) markedly reduced the H-I-induced brain tissue loss with a wide therapeutic time window up to 6 h after the onset of hypoxia. Amentoflavone blocked the activation of caspase 3, characteristic of apoptosis, and the proteolytic cleavage of its substrates following H-I injury. Amentoflavone also reduced the excitotoxic/necrotic cell death after H-I injury in vivo and after oxygen/glucose deprivation in mouse mixed cultures in vitro. Treatment of mouse microglial cells with amentoflavone resulted in a significant decrease in the lipopolysaccharide-induced production of nitric oxide and induction of inducible nitric oxide synthase and cyclo-oxygenase-2. Furthermore, amentoflavone decreased the inflammatory activation of microglia after H-I injury when assessed by the microglial-specific marker OX-42. These data demonstrate for the first time that amentoflavone strongly protects the neonatal brain from H-I injury by blocking multiple cellular events leading to brain damage.

Animals↗

PubMed2005

Neuroprotective effects of naturally occurring biflavonoids.

We examined neuroprotective effects of naturally occurring biflavonoids on oxidative stress-induced and amyloid beta peptide-induced cell death in neuronal cells. Among the nine biflavonoids tested, amentoflavone, ginkgetin, and isoginkgetin exhibited strong neuroprotection against cytotoxic insults induced by oxidative stress and amyloid beta, suggesting their therapeutic potential against neurodegenerative diseases, including ischemic stroke and Alzheimer's disease.

Alzheimer Disease↗

PubMed2005

Inhibition of inducible nitric oxide synthase and cyclooxygenase II by Platycodon grandiflorum saponins via suppression of nuclear factor-kappaB activation in RAW 264.7 cells.

Saponins are glycosidic compounds present in many edible and inedible plants. They exhibit potent biological activities in mammalian systems, including several beneficial effects such as anti-inflammation and immunomodulation. In this study, we investigated the effects of seven platycodin saponins on the activities of inducible nitric oxide synthase (iNOS) and cyclooxygenase II (COX-2) in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. We found that 2"-O-acetyl polygalacin D (S1), platycodin A (S2), platycodin D (S3), and polygalacin D (S6) inhibited LPS-induced NO production in a concentration-dependent manner. Furthermore, these compounds inhibited the expression of LPS-induced iNOS and COX-2 protein and mRNA without an appreciable cytotoxic effect on RAW 264.7 macrophages, and could suppress induction by LPS of pro-inflammatory cytokines such as prostaglandin E2 (PGE2). Treatment with these compounds of RAW 264.7 cells transfected with a reporter construct indicated a reduced level of LPS-induced nuclear factor-kappaB (NF-kappaB) activity and effectively lowered NF-kappaB binding as measured by electrophoretic mobility shift assay (EMSA). The suppression of NF-kappaB activation appears to occur through the prevention of inhibitor kappaB (IkappaB) degradation. In vivo, platycodin saponin mixture (PS) and S3 protected mice from the lethal effects of LPS. The 89% lethality induced by LPS/galactosamine was reduced to 60% and 50% when PS and S3, respectively, were administered simultaneously with LPS. These results suggest that the main inhibitory mechanism of the platycodin saponins may be the reduction of iNOS and COX-2 gene expression through blocking of NF-kappaB activation.

Animals↗

PubMed2005

Antioxidant activity of isoacteoside from Clerodendron trichotomum.

The antioxidant properties of isoacteoside, isolated from Clerodendron trichotomum (Verbenaceae), were investigated. This compound scavenged intracellular reactive oxygen species (ROS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and prevented lipid peroxidation. This radical scavenging activity of isoacteoside protected cell viability of Chinese hamster lung fibroblast (V79-4) cells exposed to hydrogen peroxide (H2O2). Furthermore, isoacteoside reduced the apoptotic cells formation induced by H2O2, as demonstrated by the decreased number of sub-G1 hypo-diploid cells and apoptotic cell body formation. However, isoacteoside increased the activities of cellular antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT). Taken together, these findings suggest that isoacteoside, isolated from C. trichotomum, possesses antioxidant properties.

Animals↗

PubMed2005

Inhibitory effects of Ganoderma applanatum on rat lens aldose reductase and sorbitol accumulation in streptozotocin-induced diabetic rat tissues.

Aldose reductase, the key enzyme of the polyol pathway, is known to play important roles in diabetic complications. Therefore, inhibitors of aldose reductase would be potential agents for the prevention of diabetic complications. To evaluate the inhibitory potential of aldose reductase from Ganoderma applanatum (Polyporaceae), methanol (MeOH) and water extracts were tested for their effects on rat lens aldose reductase (RLAR). The effects of both extracts on streptozotocin (STZ)-induced diabetes in rats were also investigated. The MeOH extract exhibited a potent rat lens aldose reductase (RLAR) inhibition in vitro, and showed a significant inhibition, of not only serum glucose concentrations, but also of sorbitol accumulations in the lens, red blood cells (RBC) and sciatic nerves in STZ-induced diabetic rats. Associated with a reduction in serum glucose concentration in STZ-induced diabetic rats, this extract was found to cause a significant glucose tolerance effect. These results suggested that G. applanatum might possess constituents with antidiabetic and inhibitory effects on diabetic complications.

Aldehyde Reductase↗