Stability and degradation mechanism of (-)-epicatechin in thermal processing

(-)-Epicatechin (EC) is a commonly dietary phytochemical that presents multi-physiological activities on human health. Thermal processing is a common method to extract EC, albeit likely to degrade EC considering its thermal instability. In this study, an 85-min non-durable bathing incubation assay was designed to simulate the state of EC in boiling water while cooking. Monitoring of degradation products was performed using ultra-performance liquid chromatography combined with electrospray ionization quadrupole tandem mass spectrometric detection (UPLC-ESI-TSQ-MS/MS). The results revealed that ca. 65.2 % loss of EC was detected in the first 10 min, and over 99.5 % of EC was degraded within 30 min. A total of 22 degradation products were identified based on retention time, full and tandem MS data were the first to be comprehensively reported. Isomerization, oxidation, hydroxylation, dimerization, and ring cleavage were the main chemical reactions that occurred for EC in boiling aqueous solution.

Recent advances in dietary androgen receptor inhibitors

As a nuclear transcription factor, the androgen receptor (AR) plays a crucial role not only in normal male sexual differentiation and growth of the prostate, but also in benign prostatic hyperplasia, prostatitis, and prostate cancer. Multiple population-based epidemiological studies demonstrated that prostate cancer risk was inversely associated with increased dietary intakes of green tea, soy products, tomato, and so forth. Therefore, this review aimed to summarize the structure and function of AR, and further illustrate the structural basis for antagonistic mechanisms of the currently clinically available antiandrogens. Due to the limitations of these antiandrogens, a series of natural AR inhibitors have been identified from edible plants such as fruits and vegetables, as well as folk medicines, health foods, and nutritional supplements. Hence, this review mainly focused on recent experimental, epidemiological, and clinical studies about natural AR inhibitors, particularly the association between dietary intake of natural antiandrogens and reduced risk of prostatic diseases. Since natural products offer multiple advantages over synthetic antiandrogens, this review may provide a comprehensive and updated overview of dietary-derived AR inhibitors, as well as their potential for the nutritional intervention against prostatic disorders.

Exploring the molecular mechanism of Artemisia rupestris L. for the treatment of hepatocellular carcinoma via PI3K/AKT pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Hepatocellular carcinoma (HCC) is a common gastrointestinal malignancy in China. Most tumors develop from chronic inflammation. Artemisia rupestris L. (ARL) has been found to have a significant effect on viral influenza and hepatitis, but the mechanism of action of ARL against liver cancer is unclear.

AIM OF THE STUDY

The study objective was to explore the mechanism of action of ARL for the treatment of hepatocellular carcinoma (HCC) by ethanol extract and in vitro experimental design.

MATERIALS AND METHODS

Interactions between ARL and cellular target proteins against HCC were analyzed through network pharmacology and network topology with the utilization of the DAVID database. The rate of HepG2 cells' growth inhibition was assessed using the MTT assay in vitro cellular assay; hoechst33342 detects apoptosis of cells; the ability of HepG2 cells to migrate and invade was assessed using the transwell assay and the cell scratch experiment; and the levels of protein expression in HepG2 cells were assessed using the western blot assay.

RESULTS

Network pharmacology prediction results demonstrated that 22 active ingredients were tested, 176 possible action targets were discovered, and the PI3K/Akt signaling pathway was found to be the most pertinent action pathway for the treatment of hepatocellular carcinoma. In vitro results showed that it can effectively restrict HepG2 cell proliferation, apoptosis, migration, and invasion as well as the regulation of protein expressions.

CONCLUSION

Conclusively, Quercetin, Linarin, and Kaempferol were found most essential active ingredients from ARL that regulate the antitumor effects against HCC through the PI3K/Akt signaling pathway. The study provides a fundamental basis for further comprehensive evaluation of ARL to treat tumor diseases in general and its therapeutic potential against hepatocellular carcinoma in particular.

Quercetin improves epithelial regeneration from airway basal cells of COPD patients

BACKGROUND

Airway basal cells (BC) from patients with chronic obstructive pulmonary disease (COPD) regenerate abnormal airway epithelium and this was associated with reduced expression of several genes involved in epithelial repair. Quercetin reduces airway epithelial remodeling and inflammation in COPD models, therefore we examined whether quercetin promotes normal epithelial regeneration from COPD BC by altering gene expression.

METHODS

COPD BC treated with DMSO or 1 µM quercetin for three days were cultured at air/liquid interface (ALI) for up to 4 weeks. BC from healthy donors cultured at ALI were used as controls. Polarization of cells was determined at 8 days of ALI. The cell types and IL-8 expression in differentiated cell cultures were quantified by flow cytometry and ELISA respectively. Microarray analysis was conducted on DMSO or 1 µM quercetin-treated COPD BC for 3 days to identify differentially regulated genes (DEG). Bronchial brushings obtained from COPD patients with similar age and disease status treated with either placebo (4 subjects) or 2000 mg/day quercetin (7 subjects) for 6 months were used to confirm the effects of quercetin on gene expression.

RESULTS

Compared to placebo-, quercetin-treated COPD BC showed significantly increased transepithelial resistance, more ciliated cells, fewer goblet cells, and lower IL-8. Quercetin upregulated genes associated with tissue and epithelial development and differentiation in COPD BC. COPD patients treated with quercetin, but not placebo showed increased expression of two developmental genes HOXB2 and ELF3, which were also increased in quercetin-treated COPD BC with FDR < 0.001. Active smokers showed increased mRNA expression of TGF-β (0.067) and IL-8 (22.0), which was reduced by 3.6 and 4.14 fold respectively after quercetin treatment.

CONCLUSIONS

These results indicate that quercetin may improve airway epithelial regeneration by increasing the expression of genes involved in epithelial development/differentiation in COPD.

TRIAL REGISTRATION

This study was registered at ClinicalTrials.gov on 6-18-2019. The study number is NCT03989271.

Poly(ε-caprolactone)-poly(ethylene glycol) Tri-Block Copolymer as Quercetin Delivery System for Human Colorectal Carcinoma Cells: Synthesis, Characterization and In Vitro Study

Quercetin is a hydrophobic molecule with short blood circulation times and instability. The development of a nano-delivery system formulation of quercetin may increase its bioavailability, resulting in greater tumor suppressing effects. Triblock ABA type polycaprolactone-polyethylenglycol- polycaprolactone (PCL-PEG-PCL) copolymers have been synthetized using ring-opening polymerization of caprolactone from PEG diol. The copolymers were characterized by nuclear magnetic resonance (NMR), diffusion-ordered NMR spectroscopy (DOSY), and gel permeation chromatography (GPC). The triblock copolymers self-assembled in water forming micelles consisting of a core of biodegradable polycaprolactone (PCL) and a corona of polyethylenglycol (PEG). The core-shell PCL-PEG-PCL nanoparticles were able to incorporate quercetin into the core. They were characterized by dynamic light scattering (DLS) and NMR. The cellular uptake efficiency of human colorectal carcinoma cells was quantitatively determined by flow cytometry using nanoparticles loaded with Nile Red as hydrophobic model drug. The cytotoxic effect of quercetin-loaded nanoparticles was evaluated on HCT 116 cells, showing promising results.

Targeting microbiota-host interactions with resveratrol on cancer: Effects and potential mechanisms of action

Resveratrol (RSV) is a natural polyphenolic compound detected in grapes, berries, and red wine. The anticancer activities of RSV have been observed in vivo and in vitro studies. However, the pharmacology mechanism of RSV is confusing due to its low bioavailability. According to studies of the metabolic characteristics of RSV, the gut intestine is a crucial site of its health benefits. Dietary RSV exhibits a profound effect on the gut microbiota structure and metabolic function. In addition, emerging evidence demonstrates a protective effect of RSV metabolites against carcinogenesis. Therefore, to better understand the anticancer mechanisms of dietary RSV, it is vital to evaluate the role of RSV-microbiota-host interactions in cancer therapy. In this review, we summarized significant findings on the anticancer activities of RSV based on epidemiological, experimental and clinical studies involved in investigating the metabolic characteristics and the traditional anticancer mechanisms of RSV. Special attention is given to the putative mechanisms involving microbiota-host interactions, such as the modulation of gut microecology and the anticancer effects of RSV metabolites. The changes in microbiota-host interactions after RSV supplementation play vital roles in cancer prevention and thus offering a new perspective on nutritional interventions to treat cancer.