Diarylheptanoids with free radical scavenging and hepatoprotective activity in vitro from Curcuma longa.

Assay-guided fractionation of the EtOAc soluble fraction of the rhizomes of Curcuma longa furnished three DPPH free radical scavenging diarylheptanoids, curcumin (1), demethoxycurcumin (2), and bisdemethoxycurcumin (3). Compounds 1-3 showed the DPPH radical scavenging effects with IC(50) values of 2.8, 39.2, 308.7 microM, respectively. L-Ascorbic acid and resveratrol as positive controls exhibited IC(50) values of 22.5 and 25.0 microM, respectively. Compounds 1-3 showed significant hepatoprotective effects on tacrine-induced cytotoxicity in human liver-derived Hep G2 cells. The EC(50) values of 1-3 are 86.9, 70.7, and 50.2 microM, respectively. Silybin (EC(50) = 69.0 microM) and silychristin (EC(50) = 82.7 microM) were used as positive controls.

Roles of extracellular signal-regulated kinase and p38 mitogen-activated protein kinase in apoptosis of human monoblastic leukemia U937 cells by lectin-II isolated from Korean mistletoe.

The mitogen-activated protein kinase (MAPK) family members have been implicated in cell survival. We have previously demonstrated that cytotoxic lectin-II isolated from Korean mistletoe induces apoptotic cell death in the human monoblastic leukemia cell line, U937, via the activation of the stress-activated protein kinases/c-Jun N-terminal kinase (SAPK/JNK). In the present study, the roles of extracellular signal-regulated kinases (ERK1/2) and p38 MAPK in lectin-II-induced apoptosis have been investigated. Treatment of U937 cells with lectin-II resulted in apoptotic DNA fragmentation, which was preceded by the activation of ERK1/2, p38 MAPK and SAPK/JNK. This lectin-II-induced DNA fragmentation was significantly enhanced when ERK1/2 activation was selectively inhibited by PD098059. 12-O-tetradecanoylphorbol-13-acetate, which stimulates ERK activity in U937 cells, markedly reduced lectin-II-induced DNA fragmentation. Inhibition of p38 MAPK activity with p38-specific inhibitor, SB203580, partially inhibited lectin-II-induced DNA fragmentation. These results suggest that ERK1/2 and p38 MAPK may have opposite effects on cell survival in response to cytotoxic mistletoe lectin-II, which may contribute to the modulation of lectin-II-mediated cytotoxic activity.

Effect of an extract of the root of Scutellaria baicalensis and its flavonoids on aflatoxin B1 oxidizing cytochrome P450 enzymes.

The inhibition of aflatoxin B1 (AFB1) metabolism by a water extract of the root of Scutellaria baicalensis and its flavonoids was examined in liver microsomes. AFB1 is known to be metabolized to aflatoxin M1 (AFM1), aflatoxin Q1 (AFQ1), and AFB1-8,9-epoxide (AFBO). The water extract potently inhibited the production of AFM1 by cytochrome P450 (CYP)1A1/2 and slightly reduced AFBO formation by CYP1A1/2, CYP2B1, CYP2C11 and CYP3A1/2 in TCDD-treated rat liver microsomes. IC50 values for AFM1 and AFBO formation were 6.8 and 122.4 microg/ml, respectively. Wogonin showed the highest inhibitory activity towards AFM1 formation among the flavonoids isolated from the extract. On the other hand, the extract had no effects on the formation of AFBO and AFQ1 in human liver microsomes, and on the activities of CYP2B1, CYP2C11 and CYP3A1/2 which were detected by hydroxylation patterns of testosterone. These results demonstrated that the extract of the root of Scutellaria baicalensis has a specific inhibitory effect on CYP1A1/2 among CYP enzymes involved in AFB1 metabolism by rat and human microsomes.

Inhibitory effects of methanol extract of Cyperus rotundus rhizomes on nitric oxide and superoxide productions by murine macrophage cell line, RAW 264.7 cells.

The rhizomes of Cyperus rotundus (C. rotundus) have been used in oriental traditional medicines for the treatment of stomach and bowel disorders, and inflammatory diseases. Nitric oxide (NO) and superoxide (O2-) are important mediators in the pathogenesis of inflammatory diseases. This study was undertaken to address whether the metanol (MeOH) extract of rhizomes of C. rotundus could modulate NO and O2- productions by murine macrophage cell line, RAW 264.7 cells. The MeOH extract of rhizomes of C. rotundus showed the inhibition of NO production in a dose-dependent manner by RAW 264.7 cells stimulated with interferon-gamma plus lipopolysaccharide. The inhibition of NO production by the extract was due to the suppression of iNOS protein, as well as iNOS mRNA expression, determined by Western and Northern blotting analyses, respectively. In addition, the MeOH extract suppressed the production of O2- by phorbol ester-stimulated RAW 264.7 cells in dose- and time-dependent manners. Collectively, these results suggest that the MeOH extract of rhizomes of C. rotundus could be developed as anti-inflammatory candidate for the treatment of inflammatory diseases mediated by overproduction of NO and O2-.

The aqueous extract of Rhodiola sachalinensis root enhances the expression of inducible nitric oxide synthase gene in RAW264.7 macrophages.

In the present study, we examined the effects of the aqueous extract of Rhodiola sachalinensis root (RSE) on the expression of inducible nitric oxide (NO) synthase (iNOS) gene in RAW264.7 macrophages. RSE synergistically increased NO synthesis in interferon-gamma-primed macrophages. Reverse transcriptase polymerase chain reaction and Northern blotting analysis revealed that RSE may provide a second triggering signal for the synergistic induction of iNOS mRNA expression. Thus, iNOS-mediated NO synthesis in response to RSE may be one mechanism whereby this herbal medicine elicits its therapeutic effects.

Rhodiola sachalinesis induces the expression of inducible nitric oxide synthase gene by murine fetal hepatocytes (BNL CL.2).

We have examined the effect of the aqueous extract of Rhodiola sachalinensis root (RSE), a traditional herbal medicine, on nitric oxide (NO) synthesis in murine fetal hepatocytes (BNL CL.2) by measuring the stable end-product nitrite and the mRNA of inducible NO synthase (iNOS). Interferon-gamma (IFN-gamma) by itself failed to induce NO synthesis in BNL CL.2 cells. RSE also did not elicit NO synthesis at concentrations up to 1,000 microg/ml, but dose- and time-dependently induced NO synthesis in the presence of IFN-gamma in BNL CL.2 cells. Whereas RSE or IFN-gamma failed to induce detectable levels of iNOS mRNA, a combination of RSE and IFN-gamma markedly induced iNOS mRNA in BNL CL.2 cells. Thus, we found that RSE triggered IFN-gamma-primed BNL CL.2 cells to synthesize NO by inducing iNOS gene expression. The capability of RSE to induce NO synthesis might be related to the therapeutic efficacy of RSE on the liver diseases.

Polymethoxyflavonoids from Vitex rotundifolia inhibit proliferation by inducing apoptosis in human myeloid leukemia cells.

Three polymethoxyflavonoids from the fruit of Vitex rotundifolia, namely 2',3',5-trihydroxy-3,6,7-trimethoxyflavone (Vx-1), vitexicarpin (Vx-5) and artemetin (Vx-6), were tested for their antiproliferative activity in human myeloid leukemia HL-60 cells. They showed a dose-dependent decrease in the growth of HL-60 cells. The concentrations required for 50% inhibition of the growth (IC50) after 96 h were 4.03 microM, 0.12 microM and 30.98 microM for Vx-1, Vx-5 and Vx-6, respectively. Treatment of HL-60 cells with the flavonoids induced morphological changes that are characteristic of apoptosis. We judged the induction of apoptosis by the detection of DNA fragmentation in agarose gel electrophoresis and the degree of apoptosis was quantified by a double-antibody sandwich ELISA and by flow cytometric analysis. The C-3 hydroxyl and C-8 methoxyl groups were found not to be essential for the activity, but the C-3' methoxyl instead of hydroxyl group lowered the antiproliferative and apoptosis inducing activity. These results suggest that the polymethoxyflavonoids isolated from V. rotundifolia may be used as potential chemopreventive and chemotherapeutic agents.

Inhibitory effects of butanol fraction of the aqueous extract of Forsythia koreana on the nitric oxide production by murine macrophage-like RAW 264.7 cells.

The aim of this study was to investigate the effect of butanol fraction of the aqueous extract of Forsythia koreana fruits on the nitric oxide (NO) production and inducible nitric oxide synthesis (iNOS) gene expression in murine macrophage-like RAW 264.7 cells. Butanol fraction alone affected neither NO production nor iNOS gene expression in macrophage-like RAW 264.7 cells. However, the butanol fraction inhibited NO production and iNOS gene expression in RAW 264. 7 cells stimulated with interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS). These findings suggest that inhibition of NO production by this butanol fraction in RAW 264.7 cells stimulated with IFN-gamma plus LPS was due to the suppression of iNOS gene expression.

Diarylheptanoids with in vitro inducible nitric oxide synthesis inhibitory activity from Alnus hirsuta.

Four diarylheptanoids were isolated from the leaf of Alnus hirsuta (Betulaceae) and have been assessed for nitric oxide (NO) production inhibitory effects in vitro. Oregonin (1) and hirsutanonol (2) were found to be potent inducible nitric oxide synthase (iNOS) inhibitors. Compounds 1 and 2 showed inhibition of NO synthesis in dose-dependent manners by murine macrophage-like RAW 264.7 cells stimulated with interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS). Their 50% inhibitory concentrations (IC50) were 3.8 and 14.3 microM, respectively. The inhibitory effects of these compounds on NO synthesis were due to suppression of iNOS mRNA expression as determined by Northern blotting.

Lavandulylflavonoids: a new class of in vitro apoptogenic agents from Sophora flavescens.

The root of Sophora flavescens has been reported to possess antitumor activity in Sarcoma 180, lymphoid leukemia 1210 and melanotic melanoma. We have isolated four cytotoxic flavonoids with a lavandulyl side-chain at C8 and tested for their effects on human myeloid leukemia HL-60 cells and human hepatocarcinoma HepG2 cells, in terms of inhibition of proliferation and induction of apoptosis. They showed potent antiproliferative effects with IC(50) values from 11.3 microM to 18.5 microM in HL60 cells and from 13.3 microM to 36. 2 microM in HepG2 cells. Treatment of HL-60 cells with the lavandulylflavonoids induced apoptosis in a dose-dependent manner. Apoptosis was judged by the detection of DNA fragmentation by agarose gel electrophoresis and the degree of apoptosis was quantified by a sandwich enzyme immunoassay. The hydration of C4"'C5"' double bond with or without C3 hydroxylation caused a complete loss of cytotoxicity. These results suggest that the lavandulyl side-chain is essential for the activity of the flavonoids isolated from S. flavescens which may be used as cancer chemotherapeutic and chemopreventive agents.

Sedative activity of two flavonol glycosides isolated from the flowers of Albizzia julibrissin Durazz.

The flowers of Albizzia julibrissin are used as a sedative in oriental traditional medicine. The phytochemical study of this plant allowed the isolation of two flavonol glycosides, quercitrin (1) and isoquercitrin (2). The sedative activity of these compounds was evaluated, and both compounds 1 and 2 increased pentobarbital-induced sleeping time in dose-dependent manner in mice. These results support the use of the flowers of this plant as a sedative agent.

Cytotoxic lavandulyl flavanones from Sophora flavescens.

Two new lavandulylated flavanones, (2S)-2'-methoxykurarinone (1) and (-)-kurarinone (2), were isolated from the root of Sophora flavescens, together with two known lavandulyl flavanones, sophoraflavanone G (3) and leachianone A (4), and two known isoflavonoids, formononetin and l-maakiain. The structures of 1 and 2 were determined on the basis of optical rotation and spectral evidence and by comparison with known compounds. Compounds 1-4 exhibited cytotoxic activity against human myeloid leukemia HL-60 cells.

Antiproliferative effects of alkaloids from Sedum sarmentosum on murine and human hepatoma cell lines.

The whole plant of Sedum sarmentosum (SS) has been traditionally used for the treatment of chronic viral hepatitis in China and South Korea. Certain hepatitis virus causes acute and chronic hepatitis and induces hepatocellular carcinoma (HC). In the present study, we examined whether the crude alkaloid fraction (CAF) of SS had any anticancer effects on hepatoma cell lines. Murine hepatoma (BNL CL. 2) and human hepatoma (HepG2) cell lines were cultured in the presence of CAF of SS at various doses (50-150 microg/ml) for 24 or 48 h. CAF caused a dose-dependent inhibition of cell proliferation without necrosis or apoptosis. Antiproliferative effects of CAF of SS were associated with an increase in the number of cells in the G1 phase of cell cycle. This study suggests that SS may improve survival of hepatoma patients via the inhibition of excessive growth of tumor cells.

Hyaluronidase inhibitory active 6H-dibenzo[b,d]pyran-6-ones from the feces of Trogopterus xanthipes.

Bioassay-guided fractionation of the MeOH extract of Pteropi faeces (the feces of Trogopterus xanthipes Milne-Edwards) furnished three hyaluronidase inhibitory active 6H-dibenzo[b,d]-pyran-6-ones (1-3), together with a new compound, 3,8,10-trihydroxy-6H-dibenzo[b,d]pyran-6-one (4). Their structures were established on the basis of the spectroscopic methods.

In vitro inducible nitric oxide synthesis inhibitory active constituents from Fraxinus rhynchophylla.

Bioassay-guided fractionation of an H2O extract of the barks of Fraxinus rhynchophylla has furnished two inducible nitric oxide synthase (iNOS) inhibitory compounds, ferulaldehyde (1) and scopoletin (3) together with a coumarin, fraxidin (2). Compounds 1 and 3 showed inhibition of nitric oxide (NO) synthesis in a dose-dependent manner by murine macrophage-like RAW 264.7 cells stimulated with interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS). The inhibition of NO synthesis of 1 was reflected in the decreased amount of iNOS protein, as determined by Western blotting.

A sesquiterpene, dehydrocostus lactone, inhibits the expression of inducible nitric oxide synthase and TNF-alpha in LPS-activated macrophages.

Nitric oxide (NO) and tumor necrosis factor alpha (TNF-alpha) are the major mediators produced in activated macrophages which contribute to the circulatory failure associated with septic shock. A sesquiterpene lactone compound (dehydrocostus lactone) isolated from the medicinal plant, Saussurea lappa, inhibited the production of NO in lipopolysaccharide (LPS)-activated RAW 264.7 cells by suppressing inducible nitric oxide synthase enzyme expression. This compound also decreased the TNF-alpha level in LPS-activated systems in vitro and in vivo. Thus, dehydrocostus lactone may be a possible candidate for the development of new drugs to treat endotoxemia accompanied by the overproduction of NO and TNF-alpha.