Hypoglycemic bioactivity of anthocyanins: A review on proposed targets and potential signaling pathways.

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease with complicated interrelationships responsible for initiating its pathogenesis. Novel strategies for the treatment of this devastating disease have attracted increasing attention worldwide. Anthocyanins are bioactive compounds that are widely distributed in the plant kingdom, and multiple studies have elucidated their beneficial role in preventing and managing T2DM. This review summarizes and comments on the hypoglycemic actions of anthocyanins from the perspective of molecular mechanisms and different target-related signaling pathways in vitro, in vivo, and clinical trials. Anthocyanins can ameliorate T2DM by functioning as carbohydrate digestive enzyme inhibitors, facilitating glucose transporter 4 (GLUT4) translocation, suppressing the effectiveness of dipeptidyl peptidase IV (DPP-IV), promoting glucagon-like peptide-1 (GLP-1) secretion, inhibiting protein tyrosine phosphatase 1B (PTP1B) overexpression, and interacting with sodium-glucose co-transporter (SGLT) to delay glucose absorption in various organs and tissues. In summary, anthocyanin is a promising and practical small molecule that can hyperglycemic symptoms and accompanying complications suffered by patients with diabetes. However, rational and potent doses for daily intake and clinical studies are required in the future.

Colon-targeted delivery of polyphenols: construction principles, targeting mechanisms and evaluation methods.

Polyphenols have received considerable attention for their promotive effects on colonic health. However, polyphenols are mostly sensitive to harsh gastrointestinal environments, thus, must be protected. It is necessary to design and develop a colon-targeted delivery system to improve the stability, colon-targeting and bioavailability of polyphenols. This paper mainly introduces research on colon-targeted controlled release of polyphenols. The physiological features affecting the dissolution, release and absorption of polyphenol-loaded delivery systems in the colon are first discussed. Simultaneously, the types of colon-targeted carriers with different release mechanisms are described, and colon-targeting assessment models that have been studied so far and their advantages and limitations are summarized. Based on the current research on polyphenols colon-targeting, outlook and reflections are proposed, with the goal of inspiring strategic development of new colon-targeted therapeutics to ensure that the polyphenols reach the colon with complete bioactivity.

The comparison between zein-anthocyanins complex and nanoparticle systems: Stability enhancement, interaction mechanism, and in silico approaches.

This research aimed to compare and characterize the physicochemical properties and interaction mechanism of zein and anthocyanins (ACNs) from experimental and theoretical perspectives. Zein-ACNs complex (ZACP) was prepared by mixing ACNs with different concentrations of zein, and zein-ACNs nanoparticles (ZANPs) were formed using ultrasound-assisted antisolvent precipitation method. The hydrated particle sizes of the two systems were 590.83 nm and 99.86 nm, respectively, and observed to be spherical under transmission electron microscopy (TEM). The multi-spectroscopy approaches confirmed hydrogen bonding and hydrophobic forces were the dominant forces for stabilizing ACNs. The retention of ACNs, color stability and antioxidant activities were also improved in both systems. Furthermore, molecular simulation results were consistent with the multi-spectroscopy findings, which clarified the contribution of van der Waals forces to the binding of zein and ACNs. This study provided a practical approach for stabilizing ACNs and expanding the utilization of plant proteins as stabilization systems.

Flavonoids mitigation of typical food thermal processing contaminants: Potential mechanisms and analytical strategies.

Due to unique chemical structure, flavonoids are secondary metabolites with numerous biological activities. Thermal processing of food usually produces some chemical contaminants, which cause an adverse effect on food quality and nutrition. Therefore, it is vital to reduce these contaminants in food processing. In this study, current researches around the inhibitory effect of flavonoids on acrylamide, furans, α-dicarbonyl compounds and heterocyclic amines (HAs) were summarized. It has been shown that flavonoids inhibited the formation of these contaminants to varying degrees in chemical or food models. The mechanism was mainly associated with natural chemical structure and partly with antioxidant activity of flavonoids. Additionally, methods and tools of analyzing interactions between flavonoids and contaminants were discussed. In summary, this review demonstrated potential mechanisms and analytical strategies of flavonoids in food thermal processing, providing new insight of flavonoids applying on the food engineering.

The isolation of anthocyanin monomers from blueberry pomace and their radical-scavenging mechanisms in DFT study.

This study explored the isolation of anthocyanin monomers using a medium- and high-pressure separation technique as a means to increase the added value of a by-product of the blueberry juice industry. Six anthocyanin monomers were isolated with a purity of 95% and identified as mono-galactoside, glucoside, and isomers of delphinidin, malvidin, and even malvidin-3-O-arabinoside, malvidin-3-(6″-acetyl)-O-glucoside by LC-MS and 1H NMR. Following the conformation search, the computer calculation manifested the active sites of six anthocyanins (C4'-OH) and their stabilities based on the structural and energy parameters. The DPPH tests demonstrated that delphinidin glycoside's free radical scavenging ability (89.93 ± 2.03 % and 86.50 ± 3.16 %) was significantly higher than that of malvidin (80.39 ± 1.30 % and 81.02 ± 0.45 %), and that malvidin's capacity was improved by conjugation arabinoside (87.48 ± 2.39 %) and acetylated glucoside (88.39 ± 1.37 %), which was compatible with the computer calculation.

Mechanism of sugar degradation product 5-hydroxymethylfurfural reducing the stability of anthocyanins.

The coexistence of anthocyanin with the sugar degradation product 5-hydroxymethylfurfural (5-HMF) is inevitable during the processing and storage of anthocyanin-rich juices. It was determined from our study that lower concentrations of 5-HMF have little effect on the stability of Cyanidin-3-O-glucoside (C3G), and even cause a slight increase for a short period of time. As the concentration of 5-HMF increased, the retention of C3G decreased and the color of the solution changed from orange-red to purple-red. The reaction sites of 5-HMF and C3G in its hemiketal form were predicted by quantum chemical calculations in order to investigate the pathways of action of the two. The degradation mechanism of 5-HMF on anthocyanin was verified by Ultraviolet and Visible spectrophotometer and Ultra performance liquid chromatography-mass spectrometry. Therefore, this article provides further theoretical support for the study of the effect of furfural compounds, which are sugar degradation products, on the stability of anthocyanins.

Effects of sucrose degradation product furfural on cyanidin-3-O-glucoside: Mechanism of action, stability, and identification of products in sugar solutions.

Anthocyanins are often affected by the sweetener sucrose during processing, which is closely related to its typical degradation product, furfural (Ff). However, the specific mechanism is unclear. In this study, Ff and cyanidin-3-O-glucoside (C3G) were used to explain the mechanism of the effect. The results showed that Ff destabilized anthocyanins by chemically reacting with C3G to generate three new adducts. Meanwhile, the color of the C3G solution changed from bright red to dark purple, and the value of the color difference (ΔE) increased significantly by 2.69. Furthermore, the new adducts were less stable than C3G and continued to promote the degradation of C3G when they coexisted with it. The above adducts were also detected in sugar solutions supplemented with C3G, and these adducts were more likely to accumulate under light storage conditions. These results provide a theoretical basis for reducing anthocyanin loss in food processing.