Blueberry anthocyanin induces apoptosis in HepG-2 cells and the mechanism of the process

Endoplasmic Reticulum as a Therapeutic Target in Cancer: Is there a Role for Flavonoids?

Flavonoids are classified into subclasses of polyphenols, a multipurpose category of natural compounds which comprises secondary metabolites extracted from vascular plants and are plentiful in the human diet. Although the details of flavonoid mechanisms are still not realized correctly, they are generally regarded as antimicrobial, anti-fungal, anti-inflammatory, anti-oxidative; anti-mutagenic; anti-neoplastic; anti-aging; anti-diabetic, cardio-protective, etc. The anti-cancer properties of flavonoids are evident in functions such as prevention of proliferation, metastasis, invasion, inflammation and activation of cell death. Tumors growth and enlargement expose cells to acidosis, hypoxia, and lack of nutrients which result in endoplasmic reticulum (ER) stress; it triggers the unfolded protein response (UPR), which reclaims homeostasis or activates autophagy. Steady stimulation of ER stress can switch autophagy to apoptosis. The connection between ER stress and cancer, in association with UPR, has been explained. The signals provided by UPR can activate or inhibit anti-apoptotic or apoptotic pathways depending on the period and grade of ER stress. In this review, we will peruse the link between flavonoids and their impact on the endoplasmic reticulum in association with cancer therapy.

Ultrasound-Assisted Extraction of Anthocyanins from Malus ‘Royalty’ Fruits: Optimization, Separation, and Antitumor Activity

Red Malus ‘Royalty’ fruits are rich in anthocyanins. This study aimed to obtain the optimal parameters for the extraction and separation of anthocyanins from Malus ‘Royalty’ fruits and to evaluate the inhibitory effect of the enriched anthocyanin fraction on gastric cancer cells. Ultrasonic-assisted extraction was used for the extraction of the anthocyanins of Malus ‘Royalty’ fruit, and the extraction results showed that the optimum parameters were an extraction temperature of 20 °C, a solid–liquid ratio of 1:6 (g/mL), ethanol and formic acid contents of 70% and 0.4%, respectively, an extraction time of 40 min, and an ultrasonic power of 300 W. The optimum extraction parameters to achieve the highest anthocyanin yield by a single-factor experiment coupled with response surface methodology were identified. The separation results showed that the AB-8 macroporous resin was a better purifying material, with 60% ethanol as an adsorbent, and the adsorption–desorption equilibrium times were 6 h and 1 h, respectively. Cyanidin-3-galactoside was the main body composition separation of anthocyanins by a high-performance liquid chromatography-diode array detector. The antitumor activity results showed that the anthocyanins of Malus ‘Royalty’ fruits have a significant inhibitory effect on the gastric cancer cell line BGC-803. The in vitro cell viability test of CCK-8 showed that the inhibitory effect on tumor cells was more significant with the increased anthocyanin concentration, with a half maximal inhibitory concentration (IC₅₀) value of 105.5 μg/mL. The cell morphology was observed by an inverted microscope, and it was found that the backbone of BGC-803 treated with a high concentration of anthocyanins was disintegrated and the nucleoplasm was concentrated. The mechanism of apoptosis was analyzed by Western blotting, and the results showed that with increasing anthocyanin concentration in the medium, the expression levels of the proapoptotic proteins Bax and Bak increased, and the expression levels of the antiapoptotic proteins Bcl-2 and Bcl-xL decreased, which coordinated the regulation of cell apoptosis. This research suggests that the enriched anthocyanin fraction from Malus ‘Royalty’ fruits have potential antitumor and adjuvant therapeutic effects on gastric cancer.

Protective effects of non-extractable phenolics from strawberry against inflammation and colon cancer in vitro

Strawberry is a rich source of phenolics. However, most studies focused on extractable phenolics (EP) while neglecting non-extractable phenolics (NEP). The aim of this study was to characterize EP and NEP from strawberry (Fragaria × ananassa) and determine their anti-inflammatory and anti-colon cancer potentials in cell culture models. NEP contained flavonols, flavanols and phenolic acids that were released through alkaline hydrolysis. NEP dose-dependently inhibited lipopolysaccharides -induced NO production in RAW 264.7 macrophage. Western blotting showed that NEP reduced the expression levels of pro-inflammatory proteins such as iNOS and c-FOS, but increased the expression level of antioxidative protein, such as HO-1. Moreover, NEP markedly suppressed proliferation of human colon cancer HCT116 cells via inducing G2/M phase cell cycle arrest and apoptosis. Collectively, these findings illustrated preventive effects of strawberry NEP against inflammation and colon cancer, shedding light on potential contribution of NEP from strawberry as a health-promoting agent.

Study of injectable Blueberry anthocyanins-loaded hydrogel for promoting full-thickness wound healing

Injectable hydrogels with high anti-inflammatory and wound-healing properties are highly desirable for clinical application. In the present study, injectable hydrogels were prepared based on carboxymethyl chitosan and oxidized hyaluronic acid. Blueberry anthocyanins (BA), which are known for their antioxidant and antiinflammatory properties, were successfully loaded into the hydrogels. The gelation kinetics and mechanical properties of the hydrogels were investigated. Oxidized hyaluronic acid with an oxidation degree of 38.1% conferred a suitable gelation time (~70 s) and mechanical properties (76.0 kPa compression stress at strain of 80%) of the hydrogel. The injectable BA-loaded hydrogel significantly accelerated the wound healing process in a full-thickness skin wound model in rats, promoted epithelial and tissue regeneration, exerted antiinflammatory effects, and promoted collagen deposition and angiogenesis. Besides, the hydrogel could upregulate the expression of VEGF and IL-10 proteins, downregulate the NF-κB level, and promote macrophage transformation from M1 phenotype to M2. The promotion of the BA-loaded hydrogel on wound healing were mainly realized by its biological effects, including antioxidant and anti-inflammatory effects, and regulation of various wound healing related factors. The results suggested that BA and the hydrogels exert synergistic effects in promoting wound healing. Injectable BA-loaded hydrogels appear to be promising candidates for wound healing application.

Blueberry Malvidin-3-galactoside Suppresses Hepatocellular Carcinoma by Regulating Apoptosis, Proliferation, and Metastasis Pathways In Vivo and In Vitro

Anthocyanin, a natural antioxidant, is reported to have cytotoxicity against cancer cells; however, the mechanism remains unclear. The aim of the present study was to investigate the mechanism by which malvidin-3-galactoside (M3G), the prominent anthocyanin in blueberry, suppresses the development of hepatocellular carcinoma. In vitro, M3G suppressed the proliferation, polarization, migration, and invasion activities of HepG2 cells by regulating the protein expression of cyclin D1, cyclin B, cyclin E, caspase-3, cleaved caspase-3, Bax, p-JNK, and p-p38, activating phosphatase and tensin homologue deleted on chromosome 10 (PTEN), accompanied by a decrease in the p-AKT level, and lowering the protein expression levels of MMP-2 and MMP-9. In vivo, M3G promoted the apoptosis of liver tumor cells, as determined by immunohistochemistry (cleaved caspase-3, Ki-67, PTEN, and p-AKT), a terminal deoxynucleotidyl transferase dUTP nick end labeling assay, and hematoxylin-eosin staining. Overall, these results suggest that M3G, as an adjuvant ingredient or nutritional supplement, may be beneficial for liver cancer prevention and the modulatory mechanism seems to be associated with inhibition of proliferation, apoptosis, migration, and invasion-related pathways.