Characterization and Antibacterial Activity of Phthalides from the Roots of the Medicinal Herb Levisticum officinale W.D.J. Koch.

A new phthalide, namely 7-methoxy-3-propylidenephthalide (1), along with two known compounds (2, 3) were isolated from the roots of the edible herb Levisticum officinale W.D.J. Koch, commonly known as lovage and well known in traditional medicine for its spasmolytic and diuretic effects. The structure of the new compound was established by HRMS and 1D & 2D NMR (1H 1H COSY, HMQC, and HMBC) spectroscopic analysis. All compounds are reported for the first time from L. officinale. Compounds 1-3 were tested against two Gram negative (Escherichia coli, Pseudomonas aeruginosa) and two Gram positive (Staphylococcus aureus and vancomycin-resistant Enterococcus [VRE] faecium) bacteria strains. Compound 3 was active against S. aureus, E. coli and vancomycin-resistant E. faecium with MIC values of 16, 64, and 128 µg/mL, respectively.

Pectenotoxin-2 represses telomerase activity in human leukemia cells through suppression of hTERT gene expression and Akt-dependent hTERT phosphorylation.

In this study, we found that pectenotoxin-2 (PTX-2) decreased cell viability and inhibited telomerase activity with downregulation of hTERT expression in human leukemia cells. PTX-2 treatment also reduced c-Myc and Sp1 gene expression and DNA binding activity. Further chromatin immunoprecipitation assay demonstrated that PTX-2 attenuated the binding of c-Myc and Sp1 to the regulatory regions of hTERT. We also observed that PTX-2 treatment attenuated the phosphorylation of Akt, thereby reducing the phosphorylation and nuclear translocation of hTERT. We concluded that PTX-2 suppressed telomerase activity through the transcriptional and post-translational suppression of hTERT and this process precedes cellular differentiation of human leukemia cells.

Induction of apoptosis by pectenotoxin-2 is mediated with the induction of DR4/DR5, Egr-1 and NAG-1, activation of caspases and modulation of the Bcl-2 family in p53-deficient Hep3B hepatocellular carcinoma cells.

The tumor suppressor protein p53 restricts proliferation in response to DNA damage or the deregulation of mitogenic oncogenes, by leading to the induction of various cell cycle checkpoints, apoptosis or cellular senescence. Consequently, p53 mutations increase cell proliferation and survival and in some settings promote genomic instability and resistance to certain anti-cancer drugs. It is very important to identify chemotherapeutic agents that activate in a p53-independent manner for the development of treatments for p53-deficient tumors. Pectenotoxin-2 (PTX-2), isolated from marine sponges has been reported to display significant cytotoxicity to p53-deficient cancer cell lines. In this study, we compared the anti-cancer activity of PTX-2 in order to further test the status of p53 using two well-known hepatocarcinoma cell lines, p53-deficient Hep3B and p53-wild-type HepG2. MTT assay indicated that Hep3B cells were highly susceptible, whereas HepG2 cells were more resistant to this compound which was connected with the induction of apoptotic cell death in p53-deficient Hep3B cells, though not in HepG2 cells. The apoptosis induced by PTX-2 in Hep3B cells was associated with the down-regulation of anti-apoptotic Bcl-2 members (Bcl-2 and Bcl-xL) and IAP family proteins, the up-regulation of pro-apoptotic Bax protein and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-receptor 1/receptor 2 (DR4/DR5) and mitochondrial dysfunction. PTX-2 activated caspases (caspase-3, -8 and -9) and the blockade of caspase-3 activity by the caspase-3 inhibitor prevented the PTX-2-induced apoptosis in Hep3B cells. Additionally, the transcription factor early growth response-1 (Egr-1) gene was transcriptionally activated and the levels of non-steroidal anti-inflammatory drugs (NSAID)-activated gene-1 (NAG-1) protein were also elevated in PTX-2-treated Hep3B cells. Although further studies are needed to prove that an increased expression of Egr-1 by PTX-2 directly leads to NAG-1 induction and then apoptosis induction in p53-deficient Hep3B cells, the results of this study suggest that PTX-2 may be a good candidate for the development of a potential anti-tumorigenic agent in p53-deficient tumors.

Antitumor and antioxidant activity of protocatechualdehyde produced from Streptomyces lincolnensis M-20.

We characterized the biological functions of protocatechualdehyde (PA) isolated from the butanol extract of culture supernatant from Streptomyces lincolnensis M-20. Following butanol extraction, it was purified by silica gel and Sephadex LH-20 column chromatography. PA was analyzed by Furier Transform Infrared Spectroscopy (FT-IR), Gas chromatograph-Mass Spectrometer (GC-MS), and Nuclear Magnetic Resonance (NMR). PA had potent antioxidant activity, as measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Antitumor activity against MCF-7 human breast cancer cells was evaluated by the 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium-bromide (MTT) assay. PA treatment (0 approximately 150 muM) dose-dependently blocked apoptosis, as shown by improved cell viability and inter-nucleosomal DNA fragmentation. Our findings suggest that Streptomyces lincolnensis M-20, a lincomycin producer, also produces protocatechualdehyde.

Novel ß-phenylacrylic acid derivatives exert anti-cancer activity by inducing Src-mediated apoptosis in wild-type KRAS colon cancer.

Many stress conditions including chemotherapy treatment is known to activate Src and under certain condition Src can induce the apoptotic signal via c-Jun N-terminal kinase (JNK) activation. Here we report that the newly synthesized ß-phenylacrylic acid derivatives, MHY791 and MHY1036 (MHYs), bind to epidermal growth factor receptor (EGFR) tyrosine kinase domains and function as EGFR inhibitors, having anti-cancer activities selectively in wild-type KRAS colon cancer. Mechanistically, MHYs-induced Src/JNK activation which enhanced their pro-apoptotic effects and therefore inhibition of Src by the chemical inhibitor PP2 or Src siRNA abolished the response. In addition, MHYs generated reactive oxygen species and increased ER stress, and pretreatment with antioxidant-inhibited MHY-induced ER stress, Src activation, and apoptosis. Furthermore, the irreversible EGFR inhibitor PD168393 also activated Src while the reversible EGFR inhibitor gefitinib showed the opposite effect, indicating that MHYs are the irreversible EGFR inhibitor. Collectively, Src can play a key role in apoptosis induced by the novel EGFR inhibitor MHYs, suggesting that activation of Src might prove effective in treating EGFR/wild-type KRAS colon cancer.

Petrotetrayndiol A induces cell cycle arrest and apoptosis in SK-MEL-2 human melanoma cells through cytochrome c-mediated activation of caspases.

We investigated the possible mechanisms by which petrotetrayndiol A, a polyacetylene from the sponge Petrosia sp., exerts its anti-proliferative activity in cultured SK-MEL-2 human melanoma cells. Petrotetrayndiol A-treated SK-MEL-2 cells showed growth inhibition and induction of apoptosis in a dose-dependent manner as measured by MTT assay, fluorescent microscopy and flow cytometric analysis. Flow cytometric analysis revealed that petrotetrayndiol A resulted in G2/M arrest in the cell cycle progression which was associated with a marked decrease in the protein expression of cyclin B1 and its activating partner Cdc2 with concomitant inductions of p21WAF1/CIP1. The increase in apoptosis was associated with a dose-dependent up-regulation of cytosolic factor, such as Bax and release of cytochrome c, and down-regulation of Bcl-2. We also observed activation of caspase-9 and caspase-3, DNA ladder formation, proteolytic degradation of poly(ADP-ribose)-polymerase (PARP), and selective down-regulation of cIAP-1. The apoptotic manifestations, such as PARP cleavage and DNA fragmentation, were abolished in the presence of the tripeptide caspase inhibitor z-VAD-fmk and a caspase-3-specific inhibitor Ac-DEVD-cho. Our data thus demonstrate that petrotetrayndiol A-induced apoptosis and growth inhibition of SK-MEL-2 cells is dependent on caspase activation.

Effects of Paecilomyces tenuipes cultivated in egg yolk on lipid metabolism in rats on a high fat-cholesterol diet.

We investigated the effects of the fruiting bodies of cultivated Paecilomyces tenuipes grown on egg yolk (PTE) on lipid and antioxidant metabolisms. Forty 8-week-old male Sprague-Dawley rats were fed a high fat/high cholesterol diet (control) or a high fat/high cholesterol diet with 1%, 3%, or 5% PTE for 5 weeks. PTE was found to significantly lower plasma total lipid, total cholesterol, low-density lipoprotein cholesterol, and the atherogenic index, compared with the control. Hepatic total lipid and total cholesterol were also significantly lower than in the control group. The hypolipidemic activity of PTE was increased with increasing concentrations, and plasma lipid peroxidation was significantly lower in the 3% and 5% PTE groups than in the control or 1% PTE group. Plasma total radical trapping antioxidant potential, erythrocytic antioxidant enzyme, and leukocytic DNA damage were not significantly different among the groups. Our results indicate that P. tenuipes cultivated on egg yolk can improve lipid profiles and lipid peroxidation in rats fed a high fat/high cholesterol diet.

In vitro and in vivo anti-Vibrio vulnificus activity of psammaplin A, a natural marine compound.

Vibrio vulnificus is known to induce severely fulminant and fatal septicemia in susceptible hosts. In the present study, the antimicrobial activity of natural marine product-derived compounds against V. vulnificus, were investigated in vitro and in vivo. Twelve pure compounds were isolated from natural marine products and their inhibitory effects on V. vulnificus-induced cytotoxicity were determined in INT­407 cells. Among the 12 pure compounds tested, treatment with psammaplin A significantly suppressed V. vulnificus­induced cytotoxicity in INT­407 cells. Notably, treatment with psammaplin A (5-50 µg) had improved survival rates compared with that in the untreated mice, when the mice were infected with V. vulnificus intraperitoneally. In addition, the bacterial load of V. vulnificus in several tissues (spleen, liver and small intestine) was significantly lower in psammaplin A­treated mice than in untreated mice. Furthermore, psammaplin A treatment significantly suppressed the growth of V. vulnificus. Taken together, these results indicate that psammaplin A may be a potential agent for the prevention and treatment of V. vulnificus infections.

Ginsenoside fractions regulate the action of monocytes and their differentiation into dendritic cells.

BACKGROUND: Panax ginseng (i.e., ginseng) root is extensively used in traditional oriental medicine. It is a modern pharmaceutical reagent for preventing various human diseases such as cancer. Ginsenosides-the major active components of ginseng-exhibit immunomodulatory effects. However, the mechanism and function underlying such effects are not fully elucidated, especially in human monocytes and dendritic cells (DCs). METHODS: We investigated the immunomodulatory effect of ginsenosides from Panax ginseng root on CD14(+) monocytes purified from human adult peripheral blood mononuclear cells (PBMCs) and on their differentiation into DCs that affect CD4(+) T cell activity. RESULTS: After treatment with ginsenoside fractions, monocyte levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 increased through phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and c-Jun N-terminal kinase (JNK), but not p38 mitogen-activated protein kinase (MAPK). After treatment with ginsenoside fractions, TNF-α production and phosphorylation of ERK1/2 and JNK decreased in lipopolysaccharide (LPS)-sensitized monocytes. We confirmed that DCs derived from CD14(+) monocytes in the presence of ginsenoside fractions (Gin-DCs) contained decreased levels of the costimulatory molecules CD80 and CD86. The expression of these costimulatory molecules decreased in LPS-treated DCs exposed to ginsenoside fractions, compared to their expression in LPS-treated DCs in the absence of ginsenoside fractions. Furthermore, LPS-treated Gin-DCs could not induce proliferation and interferon gamma (IFN-γ) production by CD4(+) T cells with the coculture of Gin-DCs with CD4+ T cells. CONCLUSION: These results suggest that ginsenoside fractions from the ginseng root suppress cytokine production and maturation of LPS-treated DCs and downregulate CD4(+) T cells.

First detection and seasonal variation of lipophilic toxins okadaic acid, dinophysistoxin-1, and yessotoxin in Korean gastropods.

Okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2, and yessotoxin (YTX) are classes of lipophilic toxins found in marine animals. OA and DTX1 accumulation causes diarrhetic shellfish poisoning, a worldwide public health problem. Diarrhetic shellfish poisoning has not previously been reported in gastropods, which are widely consumed in Korea. Seasonal variation in marine lipophilic toxins in gastropods was investigated using liquid chromatography-tandem mass spectrometry. Eighty specimens of Neptunea cumingii, 65 specimens of Rapana venosa, and 95 specimens of Batillus cornutus were collected at the Tongyeong fish market on the southern coast of Korea between May 2009 and December 2010. OA, DTX1, and YTX were detected in meat and digestive glands in all gastropod species studied. Pectenotoxin-2 was not found in any sample tested. Lipophilic toxins were detected in the digestive glands of gastropods; no lipophilic toxin was detected in the salivary glands of the carnivorous gastropods, N. cumingii and R. venosa. The highest concentrations of OA (21.5 ng/g) and DTX1 (8.4 ng/g) were detected in the digestive glands of R. venosa, and the maximum concentration of YTX (13.7 ng/g) was found in the digestive glands of N. cumingii. The maximum toxicities in gastropod tissues were lower than the European standard for acceptable levels. The concentrations of lipophilic toxins in carnivorous gastropods showed a high degree of seasonal variation; lipophilic toxins in carnivorous gastropods were found predominantly in spring and summer. This is the first report of the occurrence of lipophilic toxins in Korean gastropods.

Pectenotoxin-2 induces G1 arrest of the cell cycle in synovial fibroblasts of patients with rheumatoid arthritis.

Rheumatoid arthritis (RA), a chronic inflammatory disease, is characterized by hyperplasia of the synovial fibroblasts, due in part to increased cell growth. This study investigated the mechanisms underlying the anti-proliferative action of pectenotoxin-2 (PTX-2), isolated from marine sponges, in synovial fibroblasts obtained from RA patients. PTX-2 concentration-dependently inhibited the growth of synovial fibroblasts, arresting them in the G1 phase of their cell cycle. The G1 arrest was correlated with down-regulation of cyclin D1 and cyclin-dependent kinase (Cdk) 6, with a concomitant up-regulation of the tumor suppressor, p53, and the Cdk inhibitor, p21 (WAF1/CIP1). Following PTX-2 treatment of synovial fibroblasts, an increased binding of p21 with Cdk2 and Cdk6 was paralleled by a significant decrease in retinoblastoma protein (pRB) phosphorylation and in the protein levels of E2F transcription factors. Thus, PTX-2 might help identify new therapeutic agents against RA-mediated hyperplasia of synovial fibroblasts.

Geographical and annual variation in lipophilic shellfish toxins from oysters and mussels along the south coast of Korea.

To better understand critical aspects of diarrhetic shellfish poisoning (DSP) occurrence in a chief producing region of bivalves in Korea, the geographical and annual variation of DSP toxins and other lipophilic toxins in mussels (Mytilus galloprovincialis) and oysters (Crassostrea gigas) were investigated by liquid chromatography-tandem mass spectrometry in an area on the south coast of Korea from 2007 to 2009. The total lipophilic shellfish toxin (LST) levels in bivalves showed geographical and annual variations. LSTs were detected mostly in the hepatopancreas of mussels from Jinhae Bay throughout the entire year, except in November and December of 2007, but were almost undetectable in all samples during the entire year in 2009. The peak DSP toxin (okadaic acid plus dinophysistoxin 1) levels in the hepatopancreas of mussels from Jinhae Bay and the Tongyeong region were 945.3 and 37.6 ng/g, respectively. The DSP toxin content was about 10 times higher in mussels than in oysters collected from the same region. The major toxins in bivalves were okadaic acid and dinophysistoxin 1; however, pectenotoxin 2 or yessotoxin was occasionally detected as a major component. The results of a quantitative analysis of phytoplankton showed that Dinophysis acuminata was the most probable source of the LSTs, with the exception of yessotoxin. When the highest DSP toxin level was measured (945.3 ng/g in the hepatopancreas of mussels from Jinhae Bay), the toxin concentration in whole mussel tissue was calculated to be 114.0 ng/g. The calculated highest DSP toxin level in whole oyster tissue from both regions was 15.0 ng/g. The calculated maximum toxicities in whole mussel and oyster tissues were lower than the regulatory limit (160 to 200 ng/g) in Korea, the European Union, and the United States. Korean oysters (242 samples) and mussels (214 samples) were thus deemed safe for consumption. But because such variation was detected in a relatively small area of the coast, it is possible that at some locations or during a specific period LST levels could exceed the standard and a few consumers could be at risk of experiencing DSP.

New cerebrosides from a marine sponge Haliclona (Reniera) sp.

A chemical investigation of the MeOH extract of a marine sponge Haliclona (Reniera) sp., collected off the coast of Ulleung Island, Korea, led to the isolation of thirteen new cerebrosides (1--3, 5--14), along with a known analogue (4). Their structures were elucidated on the basis of 1D and 2D NMR spectroscopy, MS spectrometry, and chemical method. The major new features of these glucocerebrosides are C15 and C19 acyl chains, long (C24-C28) acyl chains, or the S-configuration of the acyl chains. It is noteworthy that both R- and S-configurations of the acyl chains were observed in the same specimen.

Pectenotoxin-2 abolishes constitutively activated NF-kappaB, leading to suppression of NF-kappaB related gene products and potentiation of apoptosis.

Although pectenotoxin-2 (PTX-2) is known to modify the actin cytoskeleton, very little is known about its apoptosis mechanism. In this study, we investigated whether PTX-2 induces apoptotic effects through suppression of the NF-kappaB signaling pathway in several leukemia cell types. PTX-2 significantly induced growth inhibition and apoptosis in a dose-dependent manner. Treatment with PTX-2 also significantly increased caspase-3 activity and poly (ADP-ribose) polymerase (PARP) cleavage, however caspase-3 inhibitor z-DEVD-fmk significantly inhibited PTX-2-induced cell death. These data suggest that the activation of caspase-3 is associated with PTX-2-induced apoptosis. NF-kappaB has also been shown to inhibit apoptosis in response to chemotherapeutic agents. As examined by the DNA-binding of NF-kappaB activation, we found that PTX-2 suppressed constitutive NF-kappaB activation and determined by p65 and p50 nuclear translocation, and IkappaBalpha degradation through dephosphorylation of Akt. Attenuation of constitutive NF-kappaB activity by pretreatment with pyrrolidine dithiocarbamate (PDTC), an NF-kappaB nuclear translocation inhibitor, induced significantly apoptosis in the presence of PTX-2. In addition, treatment of PTX-2 down-regulated NF-kappaB-dependent gene expression, Cox-2, IAP-1, IAP-2 and XIAP, at the transcriptional and translational level. Taken together, these results suggest that anti-cancer activities induced by PTX-2 may be mediated in part through suppression of constitutive NF-kappaB activity.

A new 2,3-dimethyl butenolide from the brittle star Ophiomastix mixta.

A new butenolide (1) was isolated, along with a known acyclic polyhalogenated monoterpene (2), from the brittle star Ophiomastix mixta. The structures were defined by analysis and comparision of the spectral data with those in the literature. The 2,3-dimethyl butenolide (1) is uncommon and first encountered in a marine organism. The compounds were tested for cytotoxicity against a panel of five human solid tumor cell lines and displayed mild to significant activity.

Ircinin-1 induces cell cycle arrest and apoptosis in SK-MEL-2 human melanoma cells.

We investigated the effects of ircinin-1, a lipid compound (a C25 sesterterpene tetronic acid) isolated from marine sponges (Sarcotragus sp.), on the modulation of cell cycle and induction of apoptosis in SK-MEL-2 human skin cancer cells (mutant p53). Ircinin-1 treatment on SK-MEL-2 cells resulted in a dose-dependent inhibition of cell growth and induced apoptotic cell death. Flow cytometric analysis revealed that ircinin-1 resulted in G1 arrest in cell cycle progression which was associated with a marked decrease in the protein expression of D-type cyclins and their activating partners Cdk 4 and 6 with concomitant inductions of p21WAF1/CIP1 and p27KIP1. The induction of p21WAF1/CIP1 appears to be transcriptionally upregulated and is p53-independent. In addition, ircinin-1 suppressed the phosphorylation of pRb protein and increased the co-association of pRb or proliferating cell nuclear antigen (PCNA) with p21WAF1/CIP1 in these cells. Ircinin-1 treatment also resulted in induction of apoptosis as determined by morphological changes, DNA fragmentation, alternated ratio of Bax/Bcl-2, cleavages of poly(ADP-ribose) polymerase and PLC-gamma1, and flow cytometric analysis. Ircinin-1 also induced cytochrome c release, cleavage activations of caspase-3 and -9, and upregulation of Fas and Fas-L. Even though the inhibitor of apoptosis protein (IAP) was expressed in ircinin-1-untreated or -treated SK-MEL-2 cells, only the level of cIAP-1, but not XIAP or cIAP-2, was decreased during ircinin-1-induced apoptosis at Western blot and RT-PCR studies. Taken together, these findings suggest that ircinin-1 has strong potential for development as an agent for prevention against skin cancer.

A new phlorotannin from the brown alga Ecklonia stolonifera.

A new phlorotannin, named eckstolonol (1), was isolated from the EtOAc soluble fraction of the methanolic extract of the brown alga, Ecklonia stolonifera OKAMURA, along with three known phlorotannins, eckol (2), phlorofucofuroeckol A (3), and dieckol (4). The structure of eckstolonol was identified as 5,8,13,14-tetraoxa-pentaphene-1,3,6,9,11-pentaol on the basis of spectroscopic evidence. The new compound was found to be a radical scavenger on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical.