Autophagy is an evolutionarily conserved pathway in which cytoplasmic contents are degraded and recycled. This study found that submicromolar concentrations of urolithin A, a major polyphenol metabolite, induced autophagy in SW620 colorectal cancer (CRC) cells. Exposure to urolithin A also dose‐dependently decreased cell proliferation, delayed cell migration, and decreased matrix metalloproteinas‐9 (MMP‐9) activity. In addition, inhibition of autophagy by Atg5‐siRNA, caspases by Z‐VAD‐FMK suppressed urolithin A‐stimulated cell death and anti‐metastatic effects. Micromolar urolithin A concentrations induced both autophagy and apoptosis. Urolithin A suppressed cell cycle progression and inhibited DNA synthesis. These results suggest that dietary consumption of urolithin A could induce autophagy and inhibit human CRC cell metastasis. Urolithins may thus contribute to CRC treatment and offer an alternative or adjunct chemotherapeutic agent to combat this disease.

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Rhein, an active ingredient extensively found in plants such as Aloe, Cassitora L., rhubarb and so on, has been used for a long time in China. Pharmacological tests revealed that rhein not only had a strong antibacterial action, but also may be useful in cancer chemotherapy as a biochemical modulator. Its therapeutic action and toxicity is still the subject of considerable research. With microsome incubation assays in vitro and HPLC methods, the inhibition of rat liver CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A enzymes by rhein were studied kinetically. The results showed the most inhibition of CYP2E1 by rhein (K(i) = 10 microm, mixed); CYP3A and CYP2C9 were also inhibited by rhein, K(i) = 30 microm (mixed) and K(i) = 38 microm (mixed), respectively; rhein revealed some inhibition of CYP1A2 (K(i) = 62 microm, uncompetitive) and CYP2D6 (K(i) = 74 microm, mixed). Drug-drug interactions, especially cytochrome P450 (CYP)-mediated interactions, cause an enhancement or attenuation in the efficacy of co-administered drugs. Inhibition of the five major CYP enzymes observed for rhein suggested that changes in pharmacokinetics of co-administered drugs were likely to occur. Therefore, caution should be paid to the possible drug interaction of medicinal plants containing rhein and CYP substrates.

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Cobalt phthalocyanine supported palladium nanoparticle composite materials have been used to modify a glassy carbon electrode to fabricate a sensitive and selective electrochemical nitrite sensor.