Utilization of albumin fraction from defatted rice bran to stabilize and deliver (-)-epigallocatechin gallate

Self-assembled nanostructures from rice protein and its fractions: Molecular approaches, physicochemical principles, and functional applications

This review investigates the structural composition and physicochemical properties of rice protein (RP) and their functional applications, unraveling the molecular self-assembly approaches of rice protein isolates (RPI), rice protein hydrolysates (RPH), and their different fractions. RPI complexes with polysaccharides through both non-covalent (electrostatic, hydrogen bonding, hydrophobic and π-interactions) and covalent interactions (Schiff base and enzymatic reactions), whereas with polyphenols, it forms colloidal structures mainly through non-covalent forces. After enzymatic hydrolysis and chain segment reorganization, RPH exhibits enhanced interfacial activity and self-assembles into stable nanostructures, with applications in encapsulation and delivery of bioactive compounds. Owing to variations in conformation and amino acid composition, different fractions of RP can assemble into multilevel structures, including nanofibrils, branching clusters, and spherical nanoparticles, under specific environmental conditions. An in-depth exploration of these self-assembly principles can greatly enhance the physicochemical and structural properties of RP, thereby paving the way for a wide range of functional applications.

Epigallocatechin-Gallate: Unraveling Its Protective Mechanisms and Therapeutic Potential

Epigallocatechin-gallate (EGCG), the predominant catechin in green tea, is a key constituent of tea polyphenols. Due to the EGCG's diverse biological activities of anti-inflammatory, antioxidant, and so forth, green tea is believed to exert a positive influence on a variety of diseases. And extensive research had uncovered a range of protective effects attributed to EGCG, indicating its potential to mitigate various pathological conditions. The precise mechanisms through which EGCG operates remain a subject of ongoing discussion among researchers. Reactive oxygen species (ROS), a primary culprit in oxidative stress, have been demonstrated to be reduced by EGCG. Furthermore, nuclear factor kappa-B (NF-κB), a pivotal signal molecular of inflammation progress, has been observed to be suppressed by EGCG. Sirtuins1 (Sirt1) is a histone deacetylase, the obligate substrate of which is NAD+. Evidence suggests that EGCG can enhance the activities of Sirt1 to induce autophagy to protect inflammation injury and oxidative stress in tissues and organs. Despite the promising protective effects of EGCG, its clinical use is constrained by its limited bioavailability. This review aims to consolidate the existing evidence and elucidate the mechanisms that support EGCG's protective role, as well as to explore the challenges and potential strategies for its clinical application.

Preparation of a chitosan/polyvinyl alcohol-based dual-network hydrogel for use as a potential wound-healing material for the sustainable release of drugs

Treating chronic wounds poses significant challenges in clinical medicine due to bacterial infection, reactive oxygen species (ROS) accumulation, and excessive inflammation. This study aimed to address these issues by developing a wound dressing with antibacterial, antioxidant, and anti-inflammatory properties. Chitosan was functionally modified with acrolein to covalently bind to epigallocatechin gallate (EGCG), enabling a high EGCG load. Subsequently, polyvinyl alcohol (PVA) and EGCG-modified chitosan were crosslinked to prepare a new double-network hydrogel with added cysteine (CSAEC/P50). CSAEC/P50 demonstrated optimal mechanical properties (low swelling rate, high water retention, and optimal flexibility), low hemolysis, high coagulation properties, and antibacterial and antioxidant activities. Cell scratch tests indicated that CSAEC/P50 can promote NIH3T3 cell migration. Immunofluorescence results showed that CSAEC/P50 promoted the transformation of proinflammatory M1 macrophages to anti-inflammatory M2 macrophages. These findings suggest that CSAEC/P50 has significant potential for use in wound dressing applications.

Ti3C2 (MXene), an advanced carrier system: role in photothermal, photoacoustic, enhanced drugs delivery and biological activity in cancer therapy

In the realm of healthcare and the advancing field of medical sciences, the development of efficient drug delivery systems become an immense promise to cure several diseases. Despite considerable advancements in drug delivery systems, numerous challenges persist, necessitating further enhancements to optimize patient outcomes. Smart nano-carriers, for instance, 2D sheets nano-carriers are the recently emerging nanosheets that may garner attention for targeted delivery of bioactive compounds, drugs, and genes to kill cancer cells. Within these advancements, Ti3C2TX-MXene, characterized as a two-dimensional transition metal carbide, has surfaced as a prominent intelligent nanocarrier within nanomedicine. Its noteworthy characteristics facilitated it as an ideal nanocarrier for cancer therapy. In recent advancements in drug delivery research, Ti3C2TX-MXene 2D nanocarriers have been designed to release drugs in response to specific stimuli, guided by distinct physicochemical  parameters. This review emphasized the multifaceted role of Ti3C2TX-MXene as a potential carrier for delivering poorly hydrophilic drugs to cancer cells, facilitated by various polymer coatings. Furthermore, beyond drug delivery, this smart nanocarrier demonstrates utility in photoacoustic imaging and photothermal therapy, further highlighting its significant role in cellular mechanisms.

Stored white tea ameliorates DSS-induced ulcerative colitis in mice by modulating the composition of the gut microbiota and intestinal metabolites

Changes in the chemical composition of white tea during storage have been studied extensively; however, whether such chemical changes impact the efficacy of white tea in ameliorating colitis remains unclear. In this study, we compared the effects of new (2021 WP) and 10-year-old (2011 WP) white tea on 3% dextrose sodium sulfate (DSS)-induced ulcerative colitis in mice by gavaging mice with the extracts at 200 mg kg-1 day-1. Chemical composition analysis showed that the levels of 50 compounds, such as flavanols, dimeric catechins, and amino acids, were significantly lower in the 2011 WP extract than in the 2021 WP extract, whereas the contents of 21 compounds, such as N-ethyl-2-pyrrolidinone-substituted flavan-3-ols, theobromine, and (-)-epigallocatechin-3-(3''-O-methyl) gallate, were significantly higher. Results of the animal experiments showed that 2011 WP ameliorated the pathological symptoms of colitis, which was superior to the activity of 2021 WP, and this effect was likely enhanced based on the decreasing of the relative abundance of the g_bacteroides and g_Escherichia-Shigella flora in mice with colitis and promoting the conversion of primary bile acids to secondary bile acids in the colon. These results will facilitate the development of novel functional products from white tea.

CsMYB67 participates in the flavonoid biosynthesis of summer tea leaves

Flavonoids are important compounds in tea leaves imparting bitter and astringent taste, which also play key roles in tea plants responding to environmental stress. Our previous study showed that the expression level of CsMYB67 was positively correlated with the accumulation of flavonoids in tea leaves as exposed to sunlight. Here, we newly reported the function of CsMYB67 in regulating flavonoid biosynthesis in tea leaves. CsMYB67 was localized in the nucleus and responded to temperature. The results of transient expression assays showed the co-transformation of CsMYB67 and CsTTG1 promoted the transcription of CsANS promoter in the tobacco system. CsTTG1 was bound to the promoter of CsANS based on the results of yeast one-hybrid (Y1H) and transient expression assays, while CsMYB67 enhanced the transcription of CsANS through protein interaction with CsTTG1 according to the results of yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC). Thus, CsMYB67-CsTTG1 module enhanced the anthocyanin biosynthesis through up-regulating the transcription of CsANS. Besides, CsMYB67 also enhanced the transcription of CsFLS and CsUFGT through forming transcription factor complexes. The function of CsMYB67 on flavonoid biosynthesis in tea leaves was validated by gene suppression assay. As CsMYB67 was suppressed, the transcriptional level of CsFLS was greatly reduced, leading to a significant increase in the contents of total catechins and total anthocyanidins. Hence, CsMYB67 plays an important role in regulating the downstream pathway of flavonoid biosynthesis in summer tea leaves.

Macrophage metabolism reprogramming EGCG-Cu coordination capsules delivered in polyzwitterionic hydrogel for burn wound healing and regeneration

Excessive reactive oxygen species (ROS) at severe burn injury sites may promote metabolic reprogramming of macrophages to induce a deteriorative and uncontrolled inflammation cycle, leading to delayed wound healing and regeneration. Here, a novel bioactive, anti-fouling, flexible polyzwitterionic hydrogel encapsulated with epigallocatechin gallate (EGCG)-copper (Cu) capsules (termed as EGCG-Cu@CBgel) is engineered for burn wound management, which is dedicated to synergistically exerting ROS-scavenging, immune metabolic regulation and pro-angiogenic effects. EGCG-Cu@CBgel can scavenge ROS to normalize intracellular redox homeostasis, effectively relieving oxidative damages and blocking proinflammatory signal transduction. Importantly, EGCG-Cu can inhibit the activity of hexokinase and phosphofructokinase, alleviate accumulation of pyruvate and convert it to acetyl coenzyme A (CoA), whereby inhibits glycolysis and normalizes tricarboxylic acid (TCA) cycle. Additionally, metabolic reprogramming of macrophages by EGCG-Cu downregulates M1-type polarization and the expression of proinflammatory cytokines both in vitro and in vivo. Meanwhile, copper ions (Cu2+) released from the hydrogel facilitate angiogenesis. EGCG-Cu@CBgel significantly accelerates the healing of severe burn wound via promoting wound closure, weakening tissue-damaging inflammatory responses and enhancing the remodeling of pathological structure. Overall, this study demonstrates the great potential of bioactive hydrogel dressing in treating burn wounds without unnecessary secondary damage to newly formed skin, and highlights the importance of immunometabolism modulation in tissue repair and regeneration.

Interactions of legume phenols-rice protein concentrate towards improving vegan food quality: Development of a protein-phenols enriched fruit smoothie

Phenol-protein interaction is considered an effective tool to improve the functional properties of vegan proteins. The present work aimed to evaluate the covalent interaction between kidney bean polyphenols with rice protein concentrate and studied their characteristics for quality improvement in vegan-based foods. The impact of interaction on the techno-functional properties of protein was evaluated and the nutritional composition revealed that kidney bean was rich in carbohydrates. Furthermore, a noticeable antioxidant activity (58.11 ± 1.075 %) due to the presence of phenols (5.5 mg GAE/g) was observed for the kidney bean extract. Moreover, caffeic acid and p-Coumaric acid were confirmed using ultra-pressure liquid chromatography and the amount was 194.43 and 0.9272 mg/kg, respectively. A range of rice protein- phenols complexes (PPC0.025, PPC0.050, PPC0.075, PPC0.1, PPC0.2, PPC 0.5, PPC1) were examined and PPC0.2 and PPC0.5 showed significantly (p < 0.05) higher binding efficiency with proteins via covalent interaction. The conjugation reveals changes in physicochemical properties of rice protein, including, reduced size (178.4 nm) and imparted negative charges (-19.5 mV) of the native protein. The presence of amide Ⅰ, Ⅱ, Ⅲ, was confirmed in native protein and protein-phenol complex with vibration bands, particularly at 3784.92, 1631.07, and 1234 cm^-1, respectively. The X-ray diffraction pattern depicted a slight decrease in crystallinity after the complexation and scanning electron microscopy revealed the alteration in morphology from less to improved smoothness and continuous surface characteristics for the complex. Thermo gravimetric analysis revealed high thermal stability of the complex with a maximum weight loss at a temperature range of 400-500 °C. Protein-phenol complex added fruit-based smoothie was developed and it was found to be acceptable in terms of various sensory attributes including color & appearance, textural consistency, and mouthfeel as compared to the control smoothie. Overall, this study provided novel insights to understand the phenol-protein interactions and the possible use of the phenol-rice protein complex in the development of vegan-based food products.

Small-size Ti3C2Tx MXene nanosheets coated with metal-polyphenol nanodots for enhanced cancer photothermal therapy and anti-inflammation

As a controllable, simple method with few side effects, near-infrared (NIR) light-based photothermal therapy (PTT) has been proven an effective cancer therapeutic approach. However, PTT-induced inflammation is a potential negative factor. And the overexpressed heat shock proteins (HSPs) by cancer cells can protect them from hyperthermia during PTT. In this work, small-size Ti₃C₂T_x MXene nanosheets with high photothermal conversion efficiency in the region of NIR, high cargo loading capability and good free radical scavenging capability were chosen for cancer PTT and anti-inflammation. And (-)-epigallocatechin gallate (EGCG) was applied to form EGCG/Fe metal-polyphenol nanodots on the nanosheets. EGCG being released in acid cancer cells could reduce the expression of HSPs and could be used for anti-inflammation. As a result, the complex nanosheets named MXene@EGCG could achieve enhanced cancer PTT and be anti-inflammatory. Both in vitro and in vivo studies proved the good photothermal ability of MXene@EGCG and demonstrated that it could inhibit the expression of HSPs in tumor cells and relieve PTT-induced inflammation. Therefore, the nanosheets show good results in tumor ablation with a low level of inflammation, which provides another possibility for cancer therapy. STATEMENT OF SIGNIFICANCE: Photothermal therapy (PTT)-induced inflammation plays an essential role in some important stages of tumor development and is unfavorable for cancer treatment. And hyperthermia leads to the overexpression of heat shock proteins (HSPs) in cancer cells, which limits the therapeutic effect of PTT. Therefore, we coated small-size Ti₃C₂T_x MXene nanosheets with (-)-epigallocatechin gallate (EGCG)/Fe metal-polyphenol nanodots and named them as MXene@EGCG. This system shows a good photothermal conversion efficiency at 808 nm. And it can release EGCG in cancer cells to inhibit the expression of HSPs, thus achieving an enhanced cancer PTT. Both MXene and EGCG can also diminish the PTT-trigged inflammation. Both in vitro and in vivo studies prove the good anti-cancer PTT effect and anti-inflammation capability of MXene@EGCG.

The internalization mechanisms and trafficking of the pea albumin in Caco-2 cells

Pea albumin (PA) can reach the intestine in the active form because it is highly resistant to gastric acid and proteolytic enzymes after their oral intake, which can supply various bioactivities. However, there is no detailed knowledge of the intestinal cell uptake about PA. The aim of this work was to study the internalization mechanism and intracellular trafficking route of PA. The uptake of PA-cyanine 5.5 NHS ester (Cy5.5) was a time-dependent and concentration-dependent process in Caco-2 cells. Endocytosis inhibitors or small interfering RNA (siRNA) techniques revealed that the internalization of PA-Cy5.5 was energy-dependent and mediated by caveolin-mediated endocytosis. Furthermore, we observed colocalization of PA-Cy5.5 and its subcellular localization in Caco-2 cells by using confocal laser scanning microscopy, which revealed that the intracellular trafficking process of PA-Cy5.5 was related to endoplasmic reticulum, Golgi, and lysosome. Interestingly, PA can alleviate lipopolysaccharide -induced ER stress, which may be the main reason why pea albumin is anti-inflammatory. Overall, our findings suggest caveolin may be critical for PA uptake in enterocytes and could contribute to explore the bioactivities mechanism of pea albumin in body.

Beneficial Effects of Green Tea EGCG on Skin Wound Healing: A Comprehensive Review

Epigallocatechin gallate (EGCG) is associated with various health benefits. In this review, we searched current work about the effects of EGCG and its wound dressings on skin for wound healing. Hydrogels, nanoparticles, micro/nanofiber networks and microneedles are the major types of EGCG-containing wound dressings. The beneficial effects of EGCG and its wound dressings at different stages of skin wound healing (hemostasis, inflammation, proliferation and tissue remodeling) were summarized based on the underlying mechanisms of antioxidant, anti-inflammatory, antimicrobial, angiogenesis and antifibrotic properties. This review expatiates on the rationale of using EGCG to promote skin wound healing and prevent scar formation, which provides a future clinical application direction of EGCG.

Simultaneous Preparation of Abundant Flavonol Triglycosides from Tea Leaves

Flavonol glycosides are important components of tea leaves, contributing to the bioactivities as well as bitterness and astringency of tea. However, the standards of many flavonol triglycosides are still not available, which restricts both sensory and bioactivity studies on flavonol glycosides. In the present study, we established a simultaneous preparation method of seven flavonol triglycoside individuals from tea leaves, which consisted of two steps: polyamide column enrichment and preparative HPLC isolation. The structures of seven flavonol triglycoside isolates were identified by mass and UV absorption spectra, four of which were further characterized by nuclear magnetic resonance spectra, namely, quercetin-3-O-glucosyl-rhamnosyl-glucoside, quercetin-3-O-rhamnosyl-rhamnosyl-glucoside, kaempferol-3-O-glucosyl-rhamnosyl-glucoside and kaempferol-O-rhamnosyl-rhamnosyl-glucoside. The purities of all isolated flavonol triglycosides were above 95% based on HPLC, and the production yield of total flavonol glycosides from dry tea was 0.487%. Our study provides a preparation method of flavonol triglycosides from tea leaves, with relatively low cost of time and solvent but high production yield.

Effect of washing, soaking and pH in combination with ultrasound on enzymatic rancidity, phytic acid, heavy metals and coliforms of rice bran

Simultaneous reduction in activity of fat destabilizing enzymes (lipase and lipoxygenase), contaminants heavy metals (As, Cd, Pb, and Hg), antinutrient phytic acid and hazardous coliforms in rice bran was investigated. Application of washing, soaking the washed sample at different pH values (2, 6 and 9) alone or in combination with ultrasonication were examined. While washing was beneficial, its low efficiency acquired further treatment, which was prevailed by application of acidic pH and ultrasound (28 kHz) treatments. Free fatty acids and peroxide value, as indicators of enzymes activity, implied the effectiveness of treatments with adverse impact of sonication on peroxide value. Remarkably, reduction of dominant heavy metals (As, Pb and Zn) and phytic acid were synergistically facilitated by sonication. Coliforms growth was inhibited at pH 2 even at the absence of ultrasonic treatment. Evidently, combination of acidic pH and ultrasound is a practical approach to improve rice bran stability and safety.