Potent inhibition of human carbonyl reductase 1 (CBR1) by the prenylated chalconoid xanthohumol and its related prenylflavonoids isoxanthohumol and 8-prenylnaringenin

Tissue distribution and pharmacokinetics of isoxanthohumol from hops in rodents

Vegetables and fruits contain prenylflavonoids with biological functions that might improve human health. The prenylflavonoid isoxanthohumol (IXA) and its derivative, 8-prenylnaringenin (8-PN), have beneficial activities, including anti-cancer effects and suppression of insulin resistance. However, their pharmacokinetic profile is unclear. Previous studies suggested flavonoids have low systemic availability and are excreted via the feces. Therefore, this study investigated the tissue distribution dynamics of high-purity IXA (>90%) from hops administered orally, either singly (50 mg/kg body weight [BW]) or daily for 14 days (30 mg/kg BW), to mice. High-pressure liquid chromatography demonstrated that IXA was absorbed rapidly after a single administration and reached plasma maximum concentration (C max) (3.95 ± 0.81 μmol/L) by 0.5 h. IXA was present at high levels in the liver compared with the kidney, pancreas, lung, skeletal muscle, spleen, thymus, and heart. The highest IXA level after 14 days of IXA ingestion was observed in the liver, followed by the kidney, thymus, spleen, lung, and brain. There was no significant difference in IXA accumulation in tissues between the single and multiple dose groups. Analyses of the livers of rats treated with different concentrations of IXA (112.5-1500 mg/kg BW) once a day for 28 days demonstrated that IXA accumulated dose-dependently with a correlation coefficient of .813. The accumulation of 8-PN was dependent on the intake period but not the intake amount of IXA (correlation coefficient -.255). In summary, IXA and 8-PN were detected in tissues and organs up to 24 h after ingestion, suggesting that orally ingested IXA might have health benefits as a nutraceutical.

The Potent Phytoestrogen 8-Prenylnaringenin: A Friend or a Foe?

8-prenylnaringenin (8-PN) is a prenylated flavonoid, occurring, in particular, in hop, but also in other plants. It has proven to be one of the most potent phytoestrogens in vitro known to date, and in the past 20 years, research has unveiled new effects triggered by it in biological systems. These findings have aroused the hopes, expectations, and enthusiasm of a “wonder-drug” for a host of human diseases. However, the majority of 8-PN effects require such high concentrations that they cannot be reached by normal dietary exposure, only pharmacologically; thus, adverse impacts may also emerge. Here, we provide a comprehensive and up-to-date review on this fascinating compound, with special reference to the range of beneficial and untoward health consequences that may ensue from exposure to it.

Amorphous solid dispersions in poly(ε-caprolactone)/xanthohumol bioactive blends: physicochemical and mechanical characterization

This paper reports the obtention of amorphous solid dispersions (ASDs) of xanthohumol (XH) in PCL containing up to 50 wt% of the bioactive compound in the amorphous form thanks to the advantageous specific interactions established in this system. The miscibility of the PCL/XH blends was investigated using DSC. Melting point depression analysis yielded a negative interaction parameter indicating the occurrence of favorable inter-association interactions. XRD analyses performed at room temperature agree with the crystallinity results obtained on the heating runs performed by DSC. FTIR spectroscopy reveals strong C[double bond, length as m-dash]OO-H specific interactions between the hydroxyl groups of XH and the carbonyl groups of PCL. The AFM analysis of the blends obtained by spin-coating shows the variation of crystalline morphology with composition. Finally, tensile tests reveal high toughness retention for the blends in which XH can be dispersed in the amorphous form (containing up to 50 wt% XH). In summary, PCL is a convenient matrix to disperse XH in the amorphous form, bringing the possibility of obtaining completely amorphous bioactive materials suitable for the development of non-stiff biomedical devices.

The epigallocatechin gallate derivative Y6 reduces the cardiotoxicity and enhances the efficacy of daunorubicin against human hepatocellular carcinoma by inhibiting carbonyl reductase 1 expression

ETHNOPHARMACOLOGICAL RELEVANCE

Green tea is the most ancient and popular beverage worldwide and its main constituent epigallocatechin-3-gallate (EGCG) has a potential role in the management of cancer through the modulation of cell signaling pathways. However, EGCG is frangible to oxidation and exhibits low lipid solubility and bioavailability, and we synthesized a derivative of EGCG in an attempt to overcome these limitations.

AIM OF THE STUDY

The anthracycline antibiotic daunorubicin (DNR) is a potent anticancer agent. However, its severe cardiotoxic limits its clinical efficacy. Human carbonyl reductase 1 (CBR1) is one of the most effective human reductases for producing hydroxyl metabolites and thus may be involved in increasing the cardiotoxicity and decreasing the antineoplastic effect of anthracycline antibiotics. Accordingly, in this study, we investigated the co-therapeutic effect of Y6, a novel and potent adjuvant obtained by optimization of the structure of EGCG.

MATERIAL AND METHODS

The cellular concentrations of DNR and its metabolite DNRol were measured by HPLC to determine the effects of EGCG and Y6 on the inhibition of DNRol formation. The cytotoxic effects of EGCG and Y6 were tested by MTT assay in order to identify non-toxic concentrations of them. To understand their antitumor and cardioprotective mechanisms, hypoxia-inducible factor-1α (HIF-1α) and CBR1 protein expression was measured via Western blotting and immunohistochemical staining while gene expression was analyzed using RT-PCR. Moreover, PI3K/AKT and MEK/ERK signaling pathways were analyzed via Western blotting. HepG2 xenograft model was used to detect the effects of EGCG and Y6 on the antitumor activity and cardiotoxicity of DNR in vivo. Finally, to obtain further insight into the interactions of Y6 and EGCG with HIF-1α and CBR1, we performed a molecular modeling.

RESULTS

Y6(10 μg/ml or 55 mg/kg) decreased the expression of HIF-1α and CBR1 at both the mRNA and protein levels during combined drug therapy in vitro as well as in vivo, thereby inhibiting formation of the metabolite DNRol from DNR, with the mechanisms being related to PI3K/AKT and MEK/ERK signaling inhibition. In a human carcinoma xenograft model established with subcutaneous HepG2 cells, Y6(55 mg/kg) enhanced the antitumor effect and reduced the cardiotoxicity of DNR more effectively than EGCG(40 mg/kg).

CONCLUSIONS

Y6 has the ability to inhibit CBR1 expression through the coordinate inhibition of PI3K/AKT and MEK/ERK signaling, then synergistically enhances the antitumor effect and reduces the cardiotoxicity of DNR.

Cinnamic acid derivatives as chemosensitising agents against DOX-treated lung cancer cells - Involvement of carbonyl reductase 1

Doxorubicin (DOX) therapy is limited by both cancer cells resistance and cardiotoxicity. DOX biotransformation to doxorubicinol (DOXol) by reductases enzymes (mainly by CBR1; carbonyl reductase 1) is a key process responsible for DOX adverse effects development. Thus, inhibition of CBR1 can increase the therapeutic effect of DOX. In the present study, we used a group of new synthetized cinnamic acid (CA) derivatives to improve the effectiveness and safety profile of DOX therapy against cancer cells in vitro. The possible mechanism of CBR1 inhibition was simulated by molecular modelling studies. The kinetics of DOX reduction in the presence of active CA derivatives were measured in cytosols. The chemosensitising activity of CA derivatives including proapoptotic, anti-invasiveness activity were investigated in A549 lung cancer cell line. In our research 7 from 16 tested CA derivatives binded to the active site of CBR1 enzyme and improved DOX stability by inhibition of DOXol formation. Co-treatment of A549 cells with active CA derivatives and DOX induced cells apoptosis by activation of caspase cascade. At the same time we observed decrease of invasive properties (cell migration and transmigration assays) and the rearangments of F-actin cytoskeleton in CA derivatves + DOX treated cells. Meanwhile, control, human lung fibroblasts stay realtivelly unvulnerable and viable. New synthetized CA derivatives may inhibit the activity of CBR1 leading to the stabilization of DOX therapeutic levels in cancer cells and to protect the myocardium against DOXol cytotoxic effect. Favourable physicochemical properties supported by a safety profile and multidirectional chemosensitising activity render CA derivatives a promising group for the development of agent useful in combined therapy.

The Modulation of Phase II Drug-Metabolizing Enzymes in Proliferating and Differentiated CaCo-2 Cells by Hop-Derived Prenylflavonoids

Prenylflavonoids in the human organism exhibit various health-beneficial activities, although they may interfere with drugs via the modulation of the expression and/or activity of drug-metabolizing enzymes. As intestinal cells are exposed to the highest concentrations of prenylflavonoids, we decided to study the cytotoxicity and modulatory effects of the four main hop-derived prenylflavonoids on the activities and mRNA expression of the main drug-conjugating enzymes in human CaCo-2 cells. Proliferating CaCo-2 cells were used for these purposes as a model of colorectal cancer cells, and differentiated CaCo-2 cells were used as an enterocyte-like model. All the tested prenylflavonoids inhibited the CaCo-2 cells proliferation, with xanthohumol proving the most effective (IC₅₀ 8.5 µM). The prenylflavonoids modulated the activities and expressions of the studied enzymes to a greater extent in the differentiated, as opposed to the proliferating, CaCo-2 cells. In the differentiated cells, all the prenylflavonoids caused a marked increase in glutathione S-transferase and catechol-O-methyltransferase activities, while the activity of sulfotransferase was significantly inhibited. Moreover, the prenylflavonoids upregulated the mRNA expression of uridine diphosphate (UDP)-glucuronosyl transferase 1A6 and downregulated that of glutathione S-transferase 1A1/2.