Tzong-Huei Lee

Antioxidant Activity of Some Plant Extracts Towards Xanthine Oxidase, Lipoxygenase and Tyrosinase

Natural products have the potential to be developed into new drugs for the treatment of various diseases. The aim of the present study was to screen the antioxidant activities of some common edible fruits, garden plants and medicinal plants indigenous to Taiwan. This was performed by assessing the activities of lipoxygenase, xanthine oxidase and tyrosinase following incubation with extracts from these plants. A further aim was to use HPLC-DAD and tyrosinase to chromatographically identify the antioxidative constituents obtained from an extract exhibiting strong antioxidative properties. The acetone extracts of 27 cultivated plant species from Taiwan were tested for antioxidant activities towards xanthine oxidase, tyrosinase and lipoxygenase using spectrophotometric assays. Koelreuteria henryi, Prunus campanulata, and Rhodiola rosea showed the highest xanthine oxidase inhibitory activities. Camellia sinensis, Rhodiola rosea, and Koelreuteria henryi exhibited good tyrosinase inhibitory activities and potent anti-lipoxygenase activities. As Koelreuteria henryi had notable significant inhibitory activities towards xanthine oxidase, tyrosinase, and lipoxygenase, it was further tested with tyrosinase and HPLC-DAD. The results from this part of the study revealed that the more powerful the antioxidant capability of the extracted component, the greater the decrease in peak height obtained after reacting with tyrosinase. Additional studies are warranted to further characterize the compounds responsible for the antioxidant properties of the examined extracts.

New Constituents with iNOS Inhibitory Activity from mycelium of Antrodia camphorata.

In continuing our investigation on the bioactive constituents of mycelium of Antrodia camphorata, antroquinonol B (1), 4-acetyl-antroquinonol B (2), 2,3-(methylenedioxy)-6-methylbenzene-1,4-diol (3) and 2,4-dimethoxy-6-methylbenzene-1,3-diol (4) along with antrodin D (5) were isolated by the guidance of an inducible nitric oxide synthase (iNOS) inhibitory assay and identified on the basis of their spectroscopic analysis. The effect of these compounds on the inhibition of NO production in lipopolysaccharide (LPS)-activated murine macrophages was further evaluated. Compounds 4 and 5 significantly inhibited NO production without any cytotoxicity, the IC(50) values being 32.2 +/- 0.1 and 26.3 +/- 1.6 microg/mL, respectively. Compounds 1 and 2 possessed greater effects on NO inhibition, with IC(50) values of 16.2 +/- 0.8 and 14.7 +/- 2.8 microg/mL, respectively, but displayed cytotoxicity at considerably higher concentrations. Compound 3 showed the lowest percent cell viability of 45.5 +/- 1.8 % as observed in treated cells at a concentration of 16.8 microg/mL.

Arctigenin from Arctium lappa inhibits interleukin-2 and interferon gene expression in primary human T lymphocytes

BackgroundArctium lappa (Niubang), a Chinese herbal medicine, is used to treat tissue inflammation. This study investigates the effects of arctigenin (AC), isolated from A. lappa, on anti-CD3/CD28 Ab-stimulated cell proliferation and cytokine gene expression in primary human T lymphocytes.MethodsCell proliferation was determined with enzyme immunoassays and the tritiated thymidine uptake method. Cytokine production and gene expression were analyzed with reverse transcription-polymerase chain reaction.ResultsAC inhibited primary human T lymphocytes proliferation activated by anti-CD3/CD28 Ab. Cell viability test indicated that the inhibitory effects of AC on primary human T lymphocyte proliferation were not due to direct cytotoxicity. AC suppressed interleukin-2 (IL-2) and interferon-γ (IFN-γ) production in a concentration-dependent manner. Furthermore, AC decreased the IL-2 and IFN-γ gene expression in primary human T lymphocytes induced by anti-CD3/CD28 Ab. Reporter gene analyses revealed that AC decreased NF-AT-mediated reporter gene expression.ConclusionAC inhibited T lymphocyte proliferation and decreased the gene expression of IL-2, IFN-γ and NF-AT.

First report of microcystins in Taiwan

This is the first report on microcystins from Microcystis aeruginosa Kützing in Taiwan. A total of nine strains of cyanobacteria have been isolated from eutrophic aquaculture ponds and water reservoirs. By mouse toxicity assay, six of the nine strains had LD100 in the range of 25-100 mg per kg mouse for dried bacterial mass. Microcystin-LR and -RR were found in all toxic strains and their contents ranged from 0.11-10.06 microg and 0.08 2.21 microg per mg of dried bacteria, respectively. Microcystin-RA, a minor component found only in M. TN-2 and M. CY-1 strains, was identified as a new microcystin. All three toxins were isolated by a serial separation on an LH-20 column, Si-flash column chromatography and reverse phase HPLC. Toxins were further identified by comparing their FABMS, 1H and 1H-1H COSY NMR spectra with the authentic microcystin-LR. Several other microcystin-like compounds were also found in the cultured strains and their structures are being determined.

Cephalochromin induces G0/G1 cell cycle arrest and apoptosis in A549 human non-small-cell lung cancer cells by inflicting mitochondrial disruption

The fungus-derived compound cephalochromin, isolated from the fermented broth of Cosmospora vilior YMJ89051501, shows growth-inhibitory and apoptotic activity against human lung cancer A549 cells in a concentration-dependent manner with an IC50 value of 2.8 μM at 48 h. Cephalochromin induced cell cycle arrest at the G0/G1 phase through down-regulation of cyclin D1, cyclin E, Cdk 2, and Cdk 4 expressions. Cephalochromin markedly increased the hypodiploid sub-G1 phase (apoptosis) of the cell cycle at 48 h as measured by flow cytometric analysis. Reactive oxygen species generation and loss of the mitochondrial membrane potential (MMP) were also markedly induced by cephalochromin. Moreover, the immunoblotting assays showed that cephalochromin reduced survivin and Bcl-xL expression and induced the activation of caspase-8, -9, and -3 and the cleavage of poly(ADP-ribose) polymerase, indicating the involvement of a caspase signaling cascade. The caspase inhibitor Z-VAD-fmk significantly suppressed cephalochromin-induced apoptosis. Cephalochromin also triggered LC3 II, autophagic marker, expression. Taken together, this is the first report that cephalochromin induced an antiproliferative effect on human lung cancer cells through mitochondrial disruption and down-regulation of survivin, leading to cell cycle arrest at the G0/G1 phase, loss of MMP, and subsequently apoptotic cell death.

Antroquinonol D, isolated from Antrodia camphorata, with DNA demethylation and anticancer potential

DNA methyltransferase 1 (DNMT1) catalyzes DNA methylation and is overexpressed in various human diseases, including cancer. A rational approach to preventing tumorigenesis involves the use of pharmacologic inhibitors of DNA methylation; these inhibitors should reactivate tumor suppressor genes (TSGs) in tumor cells and restore tumor suppressor pathways. Antroquinonol D (3-demethoxyl antroquinonol), a new DNMT1 inhibitor, was isolated from Antrodia camphorata and identified using nuclear magnetic resonance. Antroquinonol D inhibited the growth of MCF7, T47D, and MDA-MB-231 breast cancer cells without harming normal MCF10A and IMR-90 cells. The SRB assay showed that the 50% growth inhibition (GI50) in MCF7, T47D, and MDA-MB-231 breast cancer cells following treatment with antroquinonol D was 8.01, 3.57, and 25.08 μM, respectively. d-Antroquinonol also inhibited the migratory ability of MDA-MB-231 breast cancer cells in wound healing and Transwell assays. In addition, antroquinonol D inhibited DNMT1 activity, as assessed by the DNMT1 methyltransferase activity assay. As the cofactor SAM level increased, the inhibitory effects of d-antroquinonol on DNMT1 gradually decreased. An enzyme activity assay and molecular modeling revealed that antroquinonol D is bound to the catalytic domain of DNMT1 and competes for the same binding pocket in the DNMT1 enzyme as the cofactor SAM, but does not compete for the binding pocket in the DNMT3B enzyme. An Illumina Methylation 450 K array-based assay and real-time PCR assay revealed that antroquinonol D decreased the methylation status and reactivated the expression of multiple TSGs in MDA-MB-231 breast cancer cells. In conclusion, we showed that antroquinonol D induces DNA demethylation and the recovery of multiple tumor suppressor genes, while inhibiting breast cancer growth and migration potential.

Cytotoxic steroidal saponins from Agave sisalana

Two new steroidal saponins, 8 and 10, along with 7 known steroidal sapogenins and saponins (1-7) and a furostanol saponin (9) were isolated from Agave sisalana Perrine ex Engelm. The structures of these two new compounds were identified and characterized by 1D and 2D NMR spectroscopy and mass spectrometry. In addition, acid hydrolysis and GC-FID were used to confirm the sugar moieties of 8 and 10. The cytotoxic effects of 1-10 on MCF-7, NCI-H460, and SF-268 cancer cells were evaluated, and among them, compound 10 proved to be the most cytotoxic with IC₅₀ values of 1.2, 3.8, and 1.5 µM, respectively.

Phthalides from Pittosporum illicioides var. illicioides with Inhibitory Activity on Superoxide Generation and Elastase Release by Neutrophils

Six new phthalides, (S)-3-ethyl-7-hydroxy-6-methoxyphthalide (1), (S)-3-ethyl-7-hydroxy-5,6-dimethoxyphthalide (2), (S)-3-ethyl-5,6,7-trimethoxyphthalide (3), (R)-3-ethyl-7-hydroxy-6-methoxyphthalide (4), (Z)-3-ethylidene-7-hydroxy-6-methoxyphthalide (5), and (Z)-3-ethylidene-6,7-dimethoxyphthalide (6), have been isolated from the root of Pittosporum illicioides var. illicioides, together with seven known compounds. The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1-4 exhibited inhibition (IC50<or=29.8 microM) of superoxide anion generation by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB). Compounds 5 and 6 inhibited fMLP/CB-induced elastase release with IC50 values of 38.6+/-4.3 and 33.9+/-3.9 microM, respectively.

Antroquinonol from Antrodia Camphorata suppresses breast tumor migration/invasion through inhibiting ERK-AP-1- and AKT-NF-κB-dependent MMP-9 and epithelial-mesenchymal transition expressions

Antroquinonol (ANQ) is an ubiquinon derivative isolated from the mycelium of Antrodia camphorata. However, the effect of ANQ on breast cancer treatment is unknown. We found that ANQ significantly suppressed the migration and invasion of breast cancer MDA-MB-231 cells, and inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced invasiveness by MCF7 cells. ANQ inhibiting MMP-9 gene expression and enzymatic activity occurred at transcriptional regulation. Mechanistically, activation of ERK and AKT is crucial for MMP-9 gene expression, and the addition of ANQ suppressed phosphorylation of ERK and AKT. The induction of the AP-1 and NF-κB pathway participated in MMP-9 gene expression. Suppression of ERK inhibited AP-1, whereas blocking AKT diminished NF-κB activity, and treatment with ANQ suppressed both AP-1 and NF-κB signaling. Moreover, ANQ suppressed EMT protein expression, and inhibited TPA-induced EMT through downregulating the ERK-AP-1 and AKT-NF-κB signaling cascades. Together, our data showed for the first time that ANQ inhibited breast cancer invasiveness by suppressing ERK-AP-1- and AKT-NF-κB-dependent MMP-9 and EMT expressions.

Trichodermin induces cell apoptosis through mitochondrial dysfunction and endoplasmic reticulum stress in human chondrosarcoma cells

Chondrosarcoma is the second most common primary bone tumor, and it responds poorly to both chemotherapy and radiation treatment. Nalanthamala psidii was described originally as Myxosporium in 1926. This is the first study to investigate the anti-tumor activity of trichodermin (trichothec-9-en-4-ol, 12,13-epoxy-, acetate), an endophytic fungal metabolite from N. psidii against human chondrosarcoma cells. We demonstrated that trichodermin induced cell apoptosis in human chondrosarcoma cell lines (JJ012 and SW1353 cells) instead of primary chondrocytes. In addition, trichodermin triggered endoplasmic reticulum (ER) stress protein levels of IRE1, p-PERK, GRP78, and GRP94, which were characterized by changes in cytosolic calcium levels. Furthermore, trichodermin induced the upregulation of Bax and Bid, the downregulation of Bcl-2, and the dysfunction of mitochondria, which released cytochrome c and activated caspase-3 in human chondrosarcoma. In addition, animal experiments illustrated reduced tumor volume, which led to an increased number of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells and an increased level of cleaved PARP protein following trichodermin treatment. Together, this study demonstrates that trichodermin is a novel anti-tumor agent against human chondrosarcoma cells both in vitro and in vivo via mitochondrial dysfunction and ER stress.