curcumin and diallyl-trisulfide

Multidrug resistance is a principal mechanism by which tumors become resistant to structurally and functionally unrelated anticancer drugs. Resistance to chemotherapy has been correlated with overexpression of p-glycoprotein (p-gp), a member of the ATP-binding cassette (ABC) superfamily of membrane transporters. P-gp mediates resistance to a broad-spectrum of anticancer drugs including doxorubicin, taxol, and vinca alkaloids by actively expelling the drugs from cells. Use of specific inhibitors/blocker of p-gp in combination with clinically important anticancer drugs has emerged as a new paradigm for overcoming multidrug resistance. The aim of this paper is to review p-gp regulation by dietary nutraceuticals and to correlate this dietary nutraceutical induced-modulation of p-gp with activity of anticancer drugs.

Topics: Abietanes; Alkaloids; Allyl Compounds; Animals; Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B; Benzodioxoles; beta Carotene; Biflavonoids; Capsaicin; Catechin; Catechols; Curcumin; Dietary Supplements; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Drug Synergism; Fatty Alcohols; Furocoumarins; Humans; Indoles; Limonins; Neoplasms; Phytotherapy; Piperidines; Polyunsaturated Alkamides; Proanthocyanidins; Quercetin; Resveratrol; Stilbenes; Sulfides; Tea; Triterpenes; Xanthophylls

Various dietary phytochemicals seem to display antioxidant activity through the NF-E2-related factor 2 (Nrf2) pathway. However, few studies have demonstrated its antioxidant effect and Nrf2 dependency at the animal level. We constructed a zebrafish-based assay system to analyze the in vivo antioxidant activity of phytochemicals and examined the activity of 10 phytochemicals derived from spices, using this system as a pilot study. Hydrogen peroxide and arsenite were used as oxidative stressors, and Nrf2 dependency was genetically analyzed using an Nrf2-mutant zebrafish line. The activities of curcumin, diallyl trisulfide and quercetin were involved in the reduction of hydrogen peroxide toxicity, while those of cinnamaldehyde, isoeugenol and 6-(methylsulfinyl)hexyl isothiocyanate were involved in the reduction of arsenite toxicity. The antioxidant activities of these phytochemicals were all Nrf2 dependent, with the exception of cinnamaldehyde, which showed strong antioxidant effects even in Nrf2-mutant zebrafish. In summary, we succeeded in constructing an assay system to evaluate the in vivo antioxidant activity of various phytochemicals using zebrafish larvae. Using this system, we found that each spice-derived phytochemical has its own specific property and mechanism of antioxidant action.

Topics: Allyl Compounds; Animals; Antioxidants; Arsenites; Curcumin; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Hydrogen Peroxide; Larva; NF-E2-Related Factor 2; Quercetin; Spices; Sulfides; Zebrafish; Zebrafish Proteins

Fucoxanthin (Fx), one of the major xanthophylls in brown algae, is known to be effective for colorectal cancer (CRC) chemoprevention through inhibiting cell growth, cell cycle and caspase activation. Recently, we observed fucoxanthinol (FuOH), an anti-cancer active metabolite of Fx, treatment of human CRC cells resulted in plenty of living floating cells several hours after exposure, and induced apoptosis. In the present study, we investigated whether FuOH induced anchorage-dependent apoptosis, that is "anoikis", along with integrin signal suppression in human CRC cells. We found that cells exposed to 2.5 μM FuOH clearly showed anti-proliferative and apoptotic effects to DLD-1 cells, human CRC cells. FuOH treatment of DLD-1 cells led to an increase in anoikis-like changes represented by Calcein AM negative/ethidium homodimer-1 positive cell and living floating cells. Moreover, FuOH decreased FAK activation, and altered integrin β1 expression and distribution after 6 h treatment. After 24 h, the cells decreased PPARγ expression and Akt activation and increased integrin β1 expression. Our findings suggested that FuOH can induce anoikis in CRC cells through suppression of integrin signals in human CRC cells.

Topics: Allyl Compounds; Anoikis; Antineoplastic Agents, Phytogenic; beta Carotene; Cell Line, Tumor; Cell Proliferation; Colorectal Neoplasms; Curcumin; Dietary Supplements; Focal Adhesion Kinase 1; Gene Expression Regulation, Neoplastic; Humans; Integrin beta1; Isothiocyanates; Lipids; PPAR gamma; Sulfides; Sulfoxides