Inhibition of human neutrophil elastase by labdane diterpenes from the fruiting bodies of Ramaria formosa.

Two new labdane diterpenes (1 and 2) were isolated from the fruiting bodies of Ramaria formosa. The structures of these compounds were established by extensive spectroscopic studies and chemical evidence. The inhibitory activity of compounds 1 and 2 against human neutrophil elastase (HNE) was evaluated in vitro. Compounds 1 and 2 inhibited HNE activity moderately. The IC50 values for compounds 1 and 2 were 36.4 ± 1.2 and 40.8 ± 1.5 µM, respectively; the IC50 value for the positive control, EGCG, was 12.5 ± 0.8 µM. In addition, the mechanism by which 2 inhibited HNE was a mixed-type noncompetitive inhibition, with a Ki of 41.5 ± 1.8 µM.

Sesquiterpenes from the fruiting bodies of Ramaria formosa and their human neutrophil elastase inhibitory activity.

Two new sesquiterpene derivatives (1 and 2), ramarin A (1) and ramarin B (2), together with three known compounds (3-5) were isolated from the fruiting bodies of Ramaria formosa. The structures of the two sesquiterpenes were established by extensive spectroscopic studies and chemical evidence. The inhibitory activity of the isolated compounds (1-5) against human neutrophil elastase (HNE) was evaluated in vitro. All compounds tested inhibited HNE by 35-30% at the highest concentration used (100 µM), whereas the positive control, epigallocatechin gallate (EGCG), exhibited 60% inhibition at 100 µM.

Illudins C2 and C3 stimulate lipolysis in 3T3-L1 adipocytes and suppress adipogenesis in 3T3-L1 preadipocytes.

The secondary metabolites illudins C2 (1) and C3 (2), obtained from the culture broth of Coprinus atramentarius, have been shown to possess antimicrobial activity. In the present study, we discovered novel biological activities of 1 and 2 in lipolysis of differentiated 3T3-L1 adipocytes and adipogenesis of 3T3-L1 preadipocytes. Compounds 1 and 2 exhibit a dose-dependent increase in glycerol release and thereby reduce intracellular lipid accumulation. The stimulatory effects of 1 and 2 on lipolysis are prevented by cAMP-dependent protein kinase (PKA) and extracellular signal-regulated kinase (ERK) inhibitors. Compounds 1 and 2 down-regulated perilipin and also affected the mRNA and protein levels of adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL). However, 1 and 2 treatment leads to a significant increase in PKA-mediated phosphorylation of HSL at S563 and S660. In addition, 1 and 2 treatment in 3T3-L1 preadipocytes induces down-regulation of the critical transcription factors, CCAAT/enhancer binding protein α and ß (C/EBPα and C/EBPß), and peroxisome proliferator activated receptor γ (PPARγ), which are required for adipogenesis, and accordingly inhibits adipogenesis. These results suggest that 1 and 2 might be useful for treating obesity due to their modulatory effects on fat by affecting adipocyte differentiation and fat mobilization.

Clitocybin A, a novel isoindolinone, from the mushroom Clitocybe aurantiaca, inhibits cell proliferation through G1 phase arrest by regulating the PI3K/Akt cascade in vascular smooth muscle cells.

Abnormal proliferation of vascular smooth muscle cells (VSMCs) plays an essential role in the pathogenesis of vascular diseases, such as atherosclerosis, hypertension, and restenosis. Clitocybin A, a novel isoindolinone, isolated from the culture broth of mushroom Clitocybe aurantiaca has been reported to possess free radical scavenging activity. However, the antiproliferative effects of clitocybin A on VSMCs are unknown. In the present study, we investigated the effect of clitocybin A on platelet-derived growth factor (PDGF)-BB-induced proliferation of VSMCs and examined the molecular basis of the underlying mechanism. Clitocybin A inhibited DNA synthesis and cell proliferation. In accordance with these findings, clitocybin A blocked the PDGF-BB-inducible progression through G0/G1 to S phase of the cell cycle in synchronized cells and decreased the expression of cyclin-dependent kinase (CDK) 2, CDK4, cyclin D1, cyclin E, and proliferative cell nuclear antigen. In addition, clitocybin A inhibited the PDGF-BB-induced phosphorylation of phosphatidylinositol 3 kinase (PI3K) / Akt kinase. However, clitocybin A did not change the expression levels of extracellular signal-related kinase (ERK) 1/2, phospholipase C-γ1, and PDGF-Rß phosphorylation. These results indicate that clitocybin A may inhibit VSMCs proliferation through G1 phase arrest by regulating the PI3K/Akt pathway.

Structure of fomitellan A, a mannofucogalactan from the fruiting bodies of Fomitella fraxinea.

Chemical structure of fomitellan A, a polysaccharide with a mitogenic effect isolated from the fruiting bodies of Fomitella fraxinea, has been assigned as a mannofucogalactan with a repeating unit of penta-saccharide, which was composed of a (1 →6)-linked D-galactopyranosyl backbone having a C-2 position substituted with disaccharide units of 3-O-D-mannopyranosyl-L-fucopyranosyl residue. The (1)H and (13)C NMR signals of fomitellan A have been completely assigned by extensive NMR experiments.

Evaluation of human neutrophil elastase inhibitory effect of iridoid glycosides from Hedyotis diffusa.

Five iridoid glycosides were isolated from the MeOH extract of Hedyotis diffusa, and their structures were elucidated as E-6-O-p-methoxycinnamoyl scandoside methyl ester (1), Z-6-O-p-methoxycinnamoyl scandoside methyl ester (2), E-6-O-p-feruloyl scandoside methyl ester (3), E-6-O-p-coumaroyl scandoside methyl ester (4), and Z-6-O-p-coumaroyl scandoside methyl ester (5) by interpretation of their spectroscopic data. All the isolated compounds were evaluated for human neutrophil elastase inhibitory effect, and compound 1 showed potent activity with an IC(50) value of 18.0muM. The molecular docking simulation suggested a structural model for the inhibition of human neutrophil elastase by compound 1.

Hypopigmentary action of dihydropyranocoumarin D2, a decursin derivative, as a MITF-degrading agent.

In this study, the decursin derivative dihydropyranocoumarin D2 (1) was selected for its effects on melanogenesis using a spontaneously immortalized mouse melanocyte cell line (Mel-Ab). The results showed that 1 effectively inhibited melanin synthesis in a concentration-dependent manner, but that it did not inhibit tyrosinase in a cell-free system. In addition, the changes in ERK, Akt, and microphthalmia-associated transcription factor (MITF) in response to treatment with 1 were assessed. The results revealed that ERK was dramatically up-regulated and MITF was down-regulated in response to treatment with 1, but that Akt was unchanged. Therefore, the effects of 1 on melanogenesis were examined in the absence or presence of PD98059 (a specific inhibitor of the ERK pathway). PD98059 restored hypopigmentation and the down-regulation of MITF induced by 1. Finally, MITF down-regulation by 1 was clearly restored by both chloroquine, a lysosomal proteolysis inhibitor, and MG132, a proteasome inhibitor.

Enhancement of osteoblast biocompatibility on titanium surface with Terrein treatment.

Titanium is biocompatible with bodily tissues. However, the formation of ROS on the titanium surfaces might have negative response of the activity of the surroundings cells. Terrein was isolated from Penicullium sp. 20135 and found to reduce the effects of LPS-induced inflammation. This study examined the role of Terrein on the biocompatibility of titanium to determine if it can help improve osseointegration. MC-3T3 E1 cells were grown on titanium surfaces. The biocompatibility of Terrein was examined by adding it directly to the culture media at the indicated concentration. The cells on the titanium surface produced excessive ROS and decreased the activity of Cu/Zn SOD and Mn SOD. Moreover, the cells had higher activity towards oxidative stress molecules, such as MAPK, FAK and iNOS expression. In addition, MC-3T3 E1 osteoblast-like cells promoted osteoclast differentiation but reduced osteoblast differentiation and mineralization on the titanium surface. Interestingly, the cells given the Terrein treatment showed higher resistance towards oxidative stress through the up-regulation of ERK1/2 and FAK activity but the down-regulation of SAPK/JNK and iNOS activity. Moreover, Terrein promoted osteoblast differentiation and bone mineralization to elevate the activity of ALP, SPARC and down-regulate RANKL expression after blocking NF-κB translocation from the cytosol to the nucleus. In conclusion, the presence of Terrein on titanium surfaces increases osteoblast cell growth without inflammation. Moreover, Terrein, as a putative antioxidant agent, may enhance osseointegration by decreasing the level of ROS and having a potentially synergistic effect on osteoblast differentiation.

Secondary metabolites of Volvariella bombycina and their inhibitory effects on melanogenesis.

Four compounds were isolated from the broth culture of Volvariella bombycina and they were identified as ergosta-4,6,8(14),22-tetraene-3-one (1), ergosterol peroxide (2), indole-3-carboxaldehyde (3) and indazole (4) by interpretation of spectroscopic data. Among them, compound 2 exhibited melanogenesis inhibitory effect in cultured B16 mouse melanoma cells.

Hydoroxyhibiscone A, a novel human neutrophil elastase inhibitor from Hibiscus syriacus.

In an ongoing investigation of compounds from natural products that exhibit anti-aging properties, hydroxyhibiscone A (1), a new furanosesquiterpenoid, together with hibiscone D (2), was isolated from the root bark of Hibiscus syriacus. Utilizing UV, IR, NMR, and MS spectroscopic analyses, these chemical structures were revealed. Compounds 1 and 2 were found to possess significant anti-aging properties on the human neutrophil elastase (HNE) assay, exhibiting HNE inhibitory activities with IC50 values of 5.2 and 4.6 micronM, respectively.

Long-term suppression of tyrosinase by terrein via tyrosinase degradation and its decreased expression.

Previously, we reported that a fungal metabolite, terrein, decreases melanin synthesis via downregulation of microphthalmia-associated transcription factor (MITF). In the present study, we further investigated the long-term hypopigmenting action of terrein in a spontaneously immortalized mouse melanocyte cell line, Mel-Ab. Treatment with terrein at a concentration of 50 mum strongly decreased melanogenesis in a time-dependent manner. Interestingly, the decreased tyrosinase protein levels lasted for at least 7 days, even though the MITF protein levels were restored after 3 days of treatment. In accordance with the results of Western blot analyses, the tyrosinase mRNA levels were found to be continuously decreased for at least 7 days, even though recovery of the MITF mRNA levels began after 3 days of terrein treatment. Therefore, we evaluated tyrosinase downregulation to determine if it is caused by proteasomal degradation. We found that the reduction in tyrosinase levels that was induced by terrein was clearly recovered by MG-132, a proteasome inhibitor. Moreover, ubiquitination of tyrosinase increased following treatment with terrein in the presence of MG-132. Taken together, these results suggest that terrein decreases melanogenesis through ubiquitin-dependent proteasomal degradation as well as via decreased expression of its mRNA.

Clitocybins, novel isoindolinone free radical scavengers, from mushroom Clitocybe aurantiaca inhibit apoptotic cell death and cellular senescence.

High concentration of intracellular reactive oxygen species (ROS) plays a role in damaging biological systems. We isolated clitocybin A from the culture broth of Clitocybe aurantiaca and then clitocybin B and C derivatives were synthesized from clitocybin A. IMR-90 lung fibroblast cells were pre-treated or post-treated with clitocybin A, B and C to the addition of 100 muM H(2)O(2). These compounds inhibited the level of intracellular reactive oxygen species (ROS) and H(2)O(2)-induced cell death as judged by hypodiploid cell formation. The inhibitory effect of clitocybins on H(2)O(2)-induced cell death was comparable to that with N-acetylcysteine (NAC), a well-known ROS scavenger. The inhibition of H(2)O(2)-induced cell death by clitocybins was mediated by the reduction of caspase 3 and 9 activation, cytochrome c release from mitochondria and the degradation of IkappaB-alpha and IkappaB-beta, which could be resulted in the prevention of cellular senescence. It suggests that clitocybins are novel compounds scavenging ROS and protect cells from apoptosis and cellular senescence.

Silymarin inhibits melanin synthesis in melanocyte cells.

OBJECTIVES: The aim was to search for inhibitors of melanogenesis from natural resources. METHODS: The inhibitory effect of silymarin on melanogenesis in a spontaneously immortalized mouse melanocyte cell line, Mel-Ab, was studied. KEY FINDINGS: Silymarin significantly prevented melanin production in a dose-dependent manner with an IC50 value (concentration producing 50% maximal inhibition) of 28.2 microg/ml, without effects on cell viability. Also, silymarin inhibited L-DOPA oxidation activity of tyrosinase, the rate-limiting melanogenic enzyme, in cell based-systems but it did not directly affect cell-free tyrosinase activity. Furthermore, Western blot analysis indicated that silymarin decreased the expression of tyrosinase protein. CONCLUSIONS: This study suggests that the depigmenting effect of silymarin might be attributable to inhibition of tyrosinase expression and that silymarin may be useful as a natural skin-lightening agent.

Free radical scavenging and antielastase activities of flavonoids from the fruits of Thuja orientalis.

Bioassay-guided fractionation of the MeOH extract of Thuja orientalis fruits using a DPPH (2,2-diphenyl-1-picrylhydrazyl) assay led to the isolation of 9 flavonoids: cupressuflavone (1), amentoflavone (2), robustaflavone (3), afzelin (4), (+)-catechin (5), quercitrin (6), hypolaetin 7-O-beta-xylopyranoside (7), isoquercitrin (8) and myricitrin (9). Their chemical structures were determined by spectroscopic analyses. The free radical scavenging and human neutrophil elastase (HNE) inhibitory activities were evaluated for the isolated compounds. By DPPH scavenging assay, compounds 5, 6, 7, 8 and 9 showed anti-oxidant activities with IC(50) values of 28.66, 31.19, 18.30, 26.63 and 15.10 microM, respectively. By ABTS [2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] scavenging assay, these compounds also exhibited potent anti-oxidant activities with IC(50) values of 6.77, 13.96, 6.97, 22.79 and 9.96 microM, respectively. Of note, compounds 1, 2 and 3 showed significant HNE inhibitory activities with IC(50) values of 8.09, 1.27 and 1.33 microM, respectively.

Chemical constituents from the leaves of Ilex paraguariensis inhibit human neutrophil elastase.

Human neutrophil elastase (HNE), a serine protease with broad target specificity, is the only enzyme responsible for the degradation of elastin which is an insoluble elastic fibrous protein in animal connective tissue. Biologically, elastase activity significantly increased with age, which results in a reduced skin elasticity and in the appearance of wrinkles or stretchmarks. In the course of our screening program for HNE inhibitors from natural source, the MeOH extract of Ilex paraguariensis leaves showed strong HNE inhibitory effect. Bioassay-guided fractionation led to the isolation of a new pyrrole alkaloid (1), along with seventeen known compounds (2-18) from the MeOH extract of Ilex paraguariensis leaves, and their chemical structures were elucidated on the basis of spectroscopic analysis. All isolated compounds were evaluated for HNE inhibitory activity, and the result demonstrated that dicaffeoylquinic acid derivatives (12, 13, 14, 15 and 16) and flavonoids (8 and 17) exhibited potent HNE inhibitory activity with IC50 values ranging from 1.4 to 7.3 microM.

Reticulone, a novel free radical scavenger produced by Aspergillus sp.

Bioassay-guided fractionation of the culture broth of Aspergillus sp. FN070449 (KCTC 26428) using a DPPH (2,2-diphenyl-1-picrylhydrazyl) assay led to the isolation of two compounds: reticulone (1) and reticulol (2). Their chemical structures were elucidated on the basis of UV, IR, NMR, and MS spectroscopic analysis. Compound 1 exhibited more potent free radical scavenging activity on ABTS.+ (2,2'-azino-bis [3-ethylbenzthiazoline-6-sulphonic acid]) and DPPH radicals than did butylated hydroxyanisole (BHA) and caffeic acid.

Aspochalasin I, a melanogenesis inhibitor from Aspergillus sp.

In the course of screening for the melanogenesis inhibitors, aspochalasin I was isolated from solid-state culture of Aspergillus sp. Fb020460. Its structure was determined by spectroscopic analysis including mass spectroscopy and NMR analysis. Aspochalasin I potently inhibited melanogenesis in Mel-Ab cells with an IC50 value of 22.4 microM without cytotoxicity.

Clitocybin D, a novel human neutrophil elastase inhibitor from the culture broth of Clitocybe aurantiaca.

Clitocybin D, a novel human neutrophil elastase inhibitor, was isolated from the culture broth of Clitocybe aurantiaca. This compound was purified by solvent extraction, silica gel column chromatography, Sephadex LH-20 column chromatography, and preparative HPLC. The compound was determined to be 4-(4,6-dihydroxy-3-methoxy-3H-isoindol-1-yl)-benzoic acid on the basis of 1D and 2D NMRs and MS spectroscopic analysis. Analysis of the human neutrophil elastase (HNE) inhibitory activity of the isolated compound revealed that it showed significant HNE inhibitory activity with an IC(50) value of 17.8 micronM.

Etoposide-resistant HT-29 human colon carcinoma cells during glucose deprivation are sensitive to piericidin A, a GRP78 down-regulator.

Glucose deprivation, a pathophysiological cell condition, causes up-regulation of GRP78 and induction of etoposide resistance in human cancer cells. The induction of drug resistance can be partly explained by the fact that GRP78 can block activation of caspase-7 induced by treatment with etoposide. Therefore, downregulating GRP78 expression may be a novel strategy anticancer drug development. Based on that premise, we established a screening program for anticancer agents that exhibit preferential cytotoxic activity for etoposide-resistant cancer cells under glucose-deprived conditions. We recently isolated an active compound, AR-054, from the culture broth of Streptomyces sp., which prevents stress-induced etoposide resistance in vitro. AR-054 was identified as piericidin A, a prototypical compound, by ESI-MS analysis and various NMR spectroscopic methods. Here, we showed that piericidin A suppressed the accumulation of GRP78 protein and was also highly toxic to etoposide-resistant HT-29 cells, with IC50 values for colony formation of 6.4 and 7.7 nM under 2-deoxyglucose supplemented and glucose-deprived conditions, respectively. Interestingly, piericidin A had no effect under normal growth conditions. Therefore, we suggest that piericidin A prevents up-regulation of GRP78, and exhibits cytotoxicity in glucose-deprived HT-29 cells that are resistant to etoposide.

Terrein inhibits keratinocyte proliferation via ERK inactivation and G2/M cell cycle arrest.

Terrein, a fungal metabolite, has been recently shown to have a strong antiproliferative effect on skin equivalents. In the present study, we further investigated the effects of terrein on the possible signalling pathways involved in the growth inhibition of human epidermal keratinocytes by examining the regulations of extracellular signal-regulated protein kinase (ERK) and of the Akt pathway by terrein. It was observed that ERK was inactivated by terrein and that keratinocyte proliferation was inhibited, whereas Akt was unaffected. The inhibition of the ERK pathway by U0126 (a specific ERK inhibitor) also had a dose-dependent antiproliferative effect on human keratinocytes. These results indicate that ERK inhibition is involved in keratinocyte growth inhibition by terrein. Moreover, flow cytometric analysis showed that terrein inhibits DNA synthesis, as evidenced by a reduction in the S phase and an increase in the G2/M phase of the cell cycle. Thus, we next examined changes in the expressions of G2/M cell cycle-related proteins. Terrein was found to downregulate cyclin B1 and Cdc2 without Cdc2 phosphorylation, but upregulated p27(KIP1) (p27), a known inhibitor of cyclin-dependent kinase. These results suggest that terrein reduces human keratinocyte proliferation by inhibiting ERK and by decreasing the expressions of cyclin B1 and Cdc2 complex.