Dong-Ung Lee

4-Hydroxybenzaldehyde from Gastrodia elata B1. is active in the antioxidation and GABAergic neuromodulation of the rat brain.

Ether fraction of G. elata methanol extract significantly inhibited the recovery time and severity induced by pentylenetetrazole (PTZ) treatment. Pretreatment of ether fraction of G. elata methanol extract successfully prevented diminution of brain GABA level in subconvulsive dose of PTZ-treated rats. 4-Hydroxybenzaldehyde, an analogue of p-hydroxybenzyl alcohol, showed an inhibitory effect on the GABA transaminase, and its inhibitory activity was higher than that of valproic acid, a known anticonvulsant. In the brain of PTZ-treated rats, brain lipid peroxidation was significantly increased, while it recovered to the control level after treatment with 4-hydroxybenzaldehyde. It may be concluded that antioxidation and positive modulation of GABAergic neuromodulation of 4-hydroxybenzaldehyde partially contribute to an antiepileptic and anticonvulsive activity of G. elata B1.

Ferulic acid protects against carbon tetrachloride-induced liver injury in mice

Ferulic acid (FA), isolated from the root of Scrophularia buergeriana, is a phenolic compound possessing antioxidant, anticancer, and antiinflammatory activities. Here, we have investigated the hepatoprotective effect of FA against carbon tetrachloride (CCl(4))-induced acute liver injury. Mice were treated intraperitoneally with vehicle or FA (20, 40, and 80mg/kg) 1h before and 2h after CCl(4) (20μl/kg) injection. The serum activities of aminotransferases and the hepatic level of malondialdehyde were significantly higher after CCl(4) treatment, while the concentration of reduced glutathione was lower. These changes were attenuated by FA. The serum level and mRNA expression of tumor necrosis factor-α significantly increased after CCl(4) treatment, and FA attenuated these increases. The levels of inducible nitric oxide synthase and cyclooxygenase-2 protein and mRNA expression after CCl(4) treatment were significantly higher and FA reduced these increases. CCl(4)-treated mice showed increased nuclear translocation of nuclear factor-κB (NF-κB), and decreased levels of inhibitors of NF-κB in cytosol. Also, CCl(4) significantly increased the level of phosphorylated JNK and p38 mitogen-activated protein (MAP) kinase, and nuclear translocation of activated c-Jun. FA significantly attenuated these changes. We also found that acute CCl(4) challenge induced TLR4, TLR2, and TLR9 protein and mRNA expression, and FA significantly inhibited TLR4 expression. These results suggest that FA protects from CCl(4)-induced acute liver injury through reduction of oxidative damage and inflammatory signaling pathways.

Alantolactone suppresses inducible nitric oxide synthase and cyclooxygenase-2 expression by down-regulating NF-κB, MAPK and AP-1 via the MyD88 signaling pathway in LPS-activated RAW 264.7 cells.

Several sesquiterpene lactones are the active components of several medicinal plants and have been demonstrated to perform various pharmacological functions. In this study, we investigated the anti-inflammatory effects of alantolactone, a sesquiterpene lactone isolated from the root of Aucklandia lappa, in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and peritoneal macrophages. Alantolactone inhibited inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) protein and mRNA transcription, as well as the downstream products, nitric oxide (NO), prostaglandin E(2) (PGE(2)) and tumor necrosis factor-α (TNF-α). Investigation of the effects on nuclear factor κB (NF-κB) signaling showed that alantolactone inhibits the phosphorylation of inhibitory κB (IκB)-α and IκB kinase (IKK) and the subsequent translocation of the p65 and p50 NF-κB subunits to the nucleus. Moreover, inhibition of mitogen-activated protein kinases (MAPKs), including c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and p38 MAPK, and activator protein-1 (AP-1) was also observed. A further study indicated that alantolactone attenuated the phosphorylation of Akt and inhibited the expression of MyD88 and Toll-interleukin 1 receptor domain-containing adaptor protein (TIRAP), an upstream signaling molecule required for IKK and MAPKs activation. Taken together, these results suggest that alantolactone exerts its anti-inflammatory effect in LPS-stimulated RAW 264.7 cells by suppressing NF-κB activation and MAPKs phophorylation via downregulation of the MyD88 signaling pathway. Thus, alantolactone may provide a useful therapeutic approach for inflammation-associated diseases.

Synthesis of novel Schiff base analogues of 4-amino-1,5-dimethyl-2-phenylpyrazol-3-one and their evaluation for antioxidant and anti-inflammatory activity

4-Aminoantipyrine (4-amino-1,5-dimethyl-2-phenylpyrazole-3-one) and its analogues have been found to be compounds of interest for their anti-inflammatory, analgesic, antiviral, antipyretic, antirheumatic and antimicrobial activities. In the present study, Schiff base analogues of 4-aminoantipyrine were synthesized by the condensation reaction with substituted benzaldehydes and then evaluated for their antioxidant and anti-inflammatory activities. From among the synthesized compounds (3a-m, 4 and 5), 3 k and 3f exhibited the highest antioxidant activity followed by 3g, 3l, 3c, 3i, 5, 3m and 3h. The IC(50) values for compounds 3 k and 3f were found to be 0.44 and 0.93 μM, respectively, comparable to that of ascorbic acid (IC(50) 0.41 μM), a standard antioxidant agent. From the comparisons between the hydroxylated and methoxylated compounds, the rank order of antioxidant activity for the products resulting from benzylidene phenyl ring substitution was 2,4,6-OH>3,4-OH>3-OMe-4-OH>3,5-OMe-4-OH>2,4-OH>3-Me-4-OMe>3,4-OMe>4-OMe>4-OH. The structure-activity relationship study revealed that the position and nature of the substituted group on the benzylidene phenyl ring of the Schiff base analogues of 4-aminoantipyrine play an important role in their antioxidant activity. The anti-inflammatory activity of 3f, which also exhibited excellent antioxidant activity, was evaluated in terms of its inhibition of NO production, an inflammatory modulator, in LPS pretreated RAW 264.7 cells using the Griess method. We also examined whether or not this compound had effect on iNOS and COX-2 mRNA expression in RAW 264.7 cells. It was observed that compound 3f significantly reduced NO production and inhibited LPS-stimulated iNOS and COX-2 mRNA levels in a dose-dependent manner. Overall, 3f showed promising antioxidant and anti-inflammatory activities and may be used as the lead compound in a future study.

Antimalarial activity and structure-activity relationships of protoberberine alkaloids

The thirty-nine protoberberine derivatives including berberine 1 and palmatine 2 were tested for antimalarial activity in vitro against Plasmodium falciparum and structure-activity relationships are proposed. The activity of the protoberberine alkaloids was influenced by the type of the quaternary nitrogen atom, the nature and the size of the substituents at the C-13 position, and the type of O-alkyl substituents on rings A and D. The activity of the quaternary protoberberinium salts with an aromatic ring C such as berberine was higher than that of the quaternary salts such as the N-metho salts or the N-oxides of tetrahydro and dihydro derivatives as well as tertiary tetrahydroprotoberberines. Of the 13-alkyl derivatives of 1 and 2, the activity did not always increase as the length of the aliphatic chain rose in the order methyl, ethyl, propyl, butyl, and hexyl group. 13-Butylberberine (1Bu) and 13-propylpalmatine (2Pr) were the most active compounds among the 13-alkylberberines and 13-alkylpalmatines, respectively. 13-Hydroxyberberine 3 possessed the same level of activity as 1. Of 1 and 2 with different substituents types on Ring A, the activity of 1 was significantly higher than that of 2. Among berberrubines 4 and 5 and their C-9-O-alkyl derivatives 6 and 7, the activity of 9-O-ethylberberrubine 6 was the highest. Of the potent protoberberinium salts, the activity decreased in the order: 1, 3 > 2Pr > 6 > 1Bu. A positive effect on the activity might be exerted by the introduction of a more hydrophilic function into the C-13 position of the protoberberinium salts.

Antimicrobial activity of 8-alkyl- and 8-phenyl-substituted berberines and their 12-bromo derivatives

The 8-alkyl- (3-6), 8-phenyl- (7), 12-bromo- (8), 8-alkyl-12-bromo- (9-12), and 12-bromo-8-phenyl- (13) berberine derivatives were prepared and tested for their antimicrobial activity in vitro to evaluate structure-activity relationships. Introduction of the alkyl or phenyl group and the bromine atom into the C-8 and C-12 positions of berberine (1), respectively, led to significant increases of the antimicrobial activity. In both the 8-alkyl- and 8-alkyl-12-bromo-berberines (3-6 and 9-12, respectively), the antibacterial activity increased as the length of the aliphatic chain increased. The exception was the activity against Candida albicans and Escherichia coli, which did not always increase as the alkyl side chain lengthened. Among the compounds tested, 12-bromo-8-n-hexylberberine (12) was 64, 256, 128, 16, and 32 times more active against Staphylococcus aureus, Bacillus subtilis, Salmonella enteritidis, E. coli, and C. albicans, respectively, in comparison to the clinically used berberine. Compound 12 was also found to be 8, 16, and 128 times more active against S. aureus, S. enteritidis, and C.albicans, respectively, than kanamycin sulfate, but was of the same order of activity against B. subtilis, and only one-fourth as active against E. coli.

Genipin protects lipopolysaccharide-induced apoptotic liver damage in d-galactosamine-sensitized mice

This study examined the effects of genipin, isolated from Gardenia jasminoides Ellis, on d-galactosamine (GalN) and lipopolysaccharide (LPS)-induced hepatic apoptosis and liver failure. Mice were given an intraperitoneal injection of genipin (25, 50, 100 and 200mg/kg) 1h before GalN (700mg/kg)/LPS (10microg/kg) administration. The survival rate of the genipin group was significantly higher than that of the control. Genipin markedly reduced the increases in serum aminotransferase activities and lipid peroxidation. The glutathione content decreased in GalN/LPS group, and this decrease was attenuated by genipin. Increases in serum tumor necrosis factor-alpha (TNF-alpha), which were observed in GalN/LPS-treated mice, were significantly reduced by genipin. Genipin attenuated the GalN/LPS-induced apoptosis of hepatocytes, as estimated by the caspase-3 and -8 activity assay, TNF-R1 associated death domain (TRADD) protein measurement and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) method. Moreover, increased cytosolic cytochrome c protein was reduced by genipin. After 3h of GalN/LPS injection, nuclear phosphorylated c-Jun (p-c-Jun) level was significantly increased, whereas it was attenuated by genipin. Also, the increased nuclear level of nuclear factor-kappaB and the decreased cytosolic level of IkappaB-alpha protein were significantly attenuated by genipin. Our results suggest that genipin offers marked hepatoprotection against damage induced by GalN/LPS related with its antioxidative, anti-apoptotic activities, and inhibition of NF-kappaB nuclear translocation and nuclear p-c-Jun expression.

Antiplatelet effects of Cyperus rotundus and its component (+)-nootkatone

ETHNOPHARMACOLOGICAL RELEVANCE Cyperus rotundus, a well-known oriental traditional medicine, has been reported to exhibit wide spectrum activity in biological systems including the circulatory system, however, little information is available on its antiplatelet activity. This study was undertaken to investigate the antiplatelet effects of Cyperus rotundus EtOH extract (CRE) and its constituent compounds. MATERIALS AND METHODS The antiplatelet activities of CRE and its eight constituent compounds were evaluated by examining their effects on rat platelet aggregations in vitro and ex vivo, and on mice tail bleeding times. RESULTS During the in vitro platelet aggregation study, CRE showed significant and concentration-dependent inhibitory effects on collagen-, thrombin-, and/or AA-induced platelet aggregation. Of its eight components, (+)-nootkatone was found to have the most potent inhibitory effect on collagen-, thrombin-, and AA-induced platelet aggregation. In addition, CRE- and (+)-nootkatone-treated mice exhibited significantly prolonged bleeding times. Furthermore, (+)-nootkatone had a significant inhibitory effect on rat platelet aggregation ex vivo. CONCLUSIONS This study demonstrates the antiplatelet effects of CRE and its active component (+)-nootkatone, and suggests that these agents might be of therapeutic benefit for the prevention of platelet-associated cardiovascular diseases.

Structure-activity relationships of quaternary protoberberine alkaloids having an antimalarial activity.

Abstract Seventeen quaternary protoberberine alkaloids related to berberine 1 were tested for antimalarial activity in vitro against Plasmodium falciparum and structure-activity relationships are proposed. The activity of the protoberberine alkaloids was influenced by the type of the oxygen substituents on rings A, C and D and the position of the oxygen functions on ring D. The position of the oxygen functions on ring D and the type of the oxygen substituents at the C-13 position (ring C) strongly influenced the activity. Shifting the oxygen functions at C-9 and C-10 to C-10 and C-11 on ring D resulted in a significant increase in the activity. Compounds bearing a methylenedioxy function at C-2 and C-3 (ring A) or C-9 and C-10 (ring D) showed higher activity than those which have methoxy groups at the same positions. Introduction of a methoxy group into the C-1 position (ring A) decreased the activity. Replacement of a hydroxy group at C-2 or C-3 (ring A) by a methoxy group led to a reduction in the activity. Displacement of a hydroxy function at C-13 (ring C) by the oxygen substituents such as OMe, OEt, OCOOEt, and OCON(Me) 2 reduced the activity. In the same replacement at C-9 (ring D), the activity depended upon the type of the oxygen function. Six protoberberines displayed more potent activity than berberine 1 . The activity decreased in the order: 10 , 11 , 17 and 18 > 7 and 8 > 1 .

Induction of HO-1 through p38 MAPK/Nrf2 signaling pathway by ethanol extract of Inula helenium L. reduces inflammation in LPS-activated RAW 264.7 cells and CLP-induced septic mice.

High mobility group box 1 (HMGB1) plays a crucial mediator in the pathogenesis of many inflammatory diseases. We recently proposed that heme oxygenase-1 (HO-1) negatively regulates HMGB1 in inflammatory conditions. We investigated whether ethanol extract of Inula helenium L. (EIH) activates p38 MAPK/Nrf2/HO-1 pathways in RAW264.7 cells and reduces inflammation in CLP-induced septic mice. EIH induced expression of HO-1 protein in a time- and concentration-dependent manner. EIH significantly diminished HO-1 expression in siNrf2 RNA-transfected cells. As expected, the inhibited expression of iNOS/NO, COX-2/PGE2, HMGB1 release by EIH in LPS-activated RAW264.7 cells was significantly reversed by siHO-1RNA transfection. Furthermore, EIH not only inhibited NF-κB luciferase activity, phosphorylation of IκBα in LPS-activated cells but also significantly suppressed expression of adhesion molecules (ICAM-1 and VCAM-1) in TNF-α activated human umbilical vein endothelial cells. The induction of HO-1 by EIH was inhibited by SB203580 but not by SP600125, PD98059, nor LY294002. Most importantly, administration of EIH significantly reduced not only increase in blood HMGB1, ALT, AST, BUN, creatinine levels but also decrease macrophage infiltrate in the liver of septic mice, which were reversed by ZnPPIX, a HO-1 inhibitor. We concluded that EIH has anti-inflammatory effect via the induction of p38 MAPK-dependent HO-1 signaling pathway.