The natural cucurbitacins constitute a group of triterpenoid substances which are well-known for their bitterness and toxicity. Structurally, they are characterized by the tetracyclic cucurbitane nucleus skeleton, namely, 19-(10-->9beta)-abeo-10alpha-lanost-5-ene (also known as 9beta-methyl-19-norlanosta-5-ene), with a variety of oxygen substitutions at different positions. According to the characteristics of their structures, cucurbitacins are divided into twelve categories. The biological effects of the cucurbitacins are also covered.

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Bioactive components from dietary supplements such as curcumin may represent attractive agents for cancer prevention or treatment. DNA methylation plays a critical role in acute myeloid leukemia (AML) development, and presents an excellent target for treatment of this disease. However, it remains largely unknown how curcumin, a component of the popular Indian spice turmeric, plays a role in DNA hypomethylation to reactivate silenced tumor suppressor genes and to present a potential treatment option for AML. Here we show that curcumin down-regulates DNMT1 expression in AML cell lines, both in vitro and in vivo, and in primary AML cells ex vivo. Mechanistically, curcumin reduced the expression of positive regulators of DNMT1, p65 and Sp1, which correlated with a reduction in binding of these transcription factors to the DNMT1 promoter in AML cell lines. This curcumin-mediated down-regulation of DNMT1 expression was concomitant with p15INK4B tumor suppressor gene reactivation, hypomethylation of the p15INK4B promoter, G1 cell cycle arrest, and induction of tumor cell apoptosis in vitro. In mice implanted with the human AML MV4–11 cell line, administration of curcumin resulted in remarkable suppression of AML tumor growth. Collectively, our data indicate that curcumin shows promise as a potential treatment for AML, and our findings provide a basis for future studies to test the clinical efficacy of curcumin – whether used as a single agent or as an adjuvant – for AML treatment.

Purpose Curcumin has shown a variety of biological activity for various human diseases including cancer in preclinical setting. Its poor oral bioavailability poses significant pharmacological barriers to its clinical application. Here, we established a practical nano-emulsion curcumin (NEC) containing up to 20% curcumin (w/w) and conducted the pharmacokinetics of curcuminoids and curcumin metabolites in mice. Methods This high loading NEC was formulated based on the high solubility of curcumin in polyethylene glycols (PEGs) and the synergistic enhancement of curcumin absorption by PEGs and Cremophor EL. The pharmacokinetics of curcuminoids and curcumin metabolites was characterized in mice using a LC–MS/MS method, and the pharmacokinetic parameters were determined using WinNonlin computer software. Results A tenfold increase in the AUC0→24h and more than 40-fold increase in the Cmax in mice were observed after an oral dose of NEC compared with suspension curcumin in 1% methylcellulose. The plasma pharmacokinetics of its two natural congeners, demethoxycurcumin and bisdemethoxycurcumin, and three metabolites, tetrahydrocurcumin (THC), curcumin-O-glucuronide, and curcumin-O-sulfate, was characterized for the first time in mice after an oral dose of NEC. Conclusion This oral absorption enhanced NEC may provide a practical formulation to conduct the correlative study of the PK of curcuminoids and their pharmacodynamics, e.g., hypomethylation activity in vivo.