The functional genomic studies of curcumin

Curcumin Suppresses the Colon Cancer Proliferation by Inhibiting Wnt/β-Catenin Pathways via miR-130a

Curcumin exhibits anti-tumor effects in several cancers, including colorectal carcinoma (CRC), but the detailed mechanisms are still unclear. Here we studied the mechanisms underlying the anti-tumor effect of curcumin in colon cancer cells. SW480 cells were injected into mice to establish the xenograft tumor model, followed by evaluation of survival rate with the treatment of curcumin. The expression levels of β-catenin, Axin and TCF4 were measured in the SW480 cells in the absence or presence of curcumin. Moreover, miRNAs related to the curcumin treatment were also detected in vitro. Curcumin could suppress the growth of colon cancer cells in the mouse model. This anti-tumor activity of curcumin was exerted by inhibiting cell proliferation rather than promoting cell apoptosis. Further study suggested that curcumin inhibited cell proliferation by suppressing the Wnt/β-catenin pathway. MiR-130a was down-regulated by curcumin treatment, and overexpressing miR-130a could abolish the anti-tumor activity of curcumin. Our study confirms that curcumin is able to inhibit colon cancer by suppressing the Wnt/β-catenin pathways via miR-130a. MiR-130a may serve as a new target of curcumin for CRC treatment.

Curcumin affects gene expression and reactive oxygen species via a PKA dependent mechanism in Dictyostelium discoideum

Botanicals are widely used as dietary supplements and for the prevention and treatment of disease. Despite a long history of use, there is generally little evidence supporting the efficacy and safety of these preparations. Curcumin has been used to treat a myriad of human diseases and is widely advertised and marketed for its ability to improve health, but there is no clear understanding how curcumin interacts with cells and affects cell physiology. D. discoideum is a simple eukaryotic lead system that allows both tractable genetic and biochemical studies. The studies reported here show novel effects of curcumin on cell proliferation and physiology, and a pleiotropic effect on gene transcription. Transcriptome analysis showed that the effect is two-phased with an early transient effect on the transcription of approximately 5% of the genome, and demonstrates that cells respond to curcumin through a variety of previously unknown molecular pathways. This is followed by later unique transcriptional changes and a protein kinase A dependent decrease in catalase A and three superoxide dismutase enzymes. Although this results in an increase in reactive oxygen species (ROS; superoxide and H2O2), the effects of curcumin on transcription do not appear to be the direct result of oxidation. This study opens the door to future explorations of the effect of curcumin on cell physiology.

A Comparative Pharmacokinetic Assessment of a Novel Highly Bioavailable Curcumin Formulation with 95% Curcumin: A Randomized, Double-Blind, Crossover Study

OBJECTIVE

Curcumin exhibits many beneficial health-promoting characteristics. However, its poor oral absorption precludes its general use. This study assessed the bioavailability of a novel curcumin formulation compared to 95% curcumin and published results for various other curcumin formulations.

METHODS

A randomized, crossover, double-blind, comparator-controlled pharmacokinetic study was performed in 12 healthy adult subjects to determine the appearance of free curcumin and its metabolites curcumin sulfate and curcumin glucuronide in plasma after a single dose of a novel proprietary curcumin liquid droplet micromicellar formulation (CLDM) and unformulated 95% curcumin powder in capsule form. An equivalent 400-mg dose of each product was administered. The 95% curcumin contained 323 mg curcumin, and the CLDM contained 64.6 mg curcumin. Blood samples were drawn and plasma was analyzed for curcumin and its 2 conjugates without enzymatic hydrolysis by liquid chromatography-tandem mass spectroscopy.

RESULTS

Plasma levels of curcumin sulfate and curcumin glucuronide after 1.5 hours from CLDM were approximately 20 and 300 ng/mL, respectively, whereas the levels for 95% curcumin were near baseline. Free curcumin reached a maximum level of 2 ng/mL for CLDM and 0.3 ng/mL for 95% curcumin at 1.5 hours. For the CLDM, a small secondary free curcumin peak occurred at 12 hours and a tertiary 1.5-ng/mL peak occurred at 24 hours. The total curcumin absorbed as represented by the area under the curve (AUC)/mg administered curcumin for CLDM was 522 times greater than for the 95% curcumin.

CONCLUSIONS

The novel CLDM formulation facilitates absorption and produces exceedingly high plasma levels of both conjugated and total curcumin compared to 95% curcumin. A comparison of the C_max/mg curcumin and AUC/mg of administered curcumin for CLDM with data from pharmacokinetic studies of various enhanced absorption formulations indicate that the greatest absorption and bioavailability are produced with the novel CLDM formulation.