Formation, physicochemical properties, and biological activities of theabrownins.

Theabrownins (TBs) are heterogeneous mixtures of water-soluble brown tea pigments, and important constituents to evaluate the quality of dark tea. TBs have numerous hydroxyl and carboxyl groups and are formed by the oxidative polymerization of tea polyphenols. Many biological activities attributed to TBs, including antioxidant, anti-obesity, and lipid-regulating, have been demonstrated. This review summarizes the research progress made on the formation mechanism and physicochemical properties of TBs. It also discusses their protective effects against various diseases and associated potential molecular mechanisms. Additionally, it examines the signaling pathways mediating the bioactivities of TBs and highlights the difficulties and challenges of TBs research as well as their research prospects and applications.

Antidiabetic drug administration prevents bone mineral density loss: Evidence from a two-sample Mendelian randomization study.

The aim of this study was to investigate the effect of common antidiabetic drugs on BMD by two-sample Mendelian randomization (MR). The single nucleotide polymorphisms that were strongly associated with insulin, metformin, rosiglitazone and gliclazide were extracted as instrumental variables (IVs) for MR analysis. The inverse variance weighted (IVW) method was used as the primary MR method to assess the causal effect of antidiabetic drugs on BMD, and other MR methods, including Weighted median, MR Egger and Weighted mode, were used for complementary analysis. Reliability and stability were assessed by the leave-one-out test. In the present work, IVW estimation of the causal effect of insulin on heel BMD demonstrated that there was a null effect of insulin on heel BMD (ß = 0.765; se = 0.971; P = 0.430), while metformin treatment had a positive effect on heel BMD (ß = 1.414; se = 0.460; P = 2.118*10-3). The causal relationship between rosiglitazone and heel BMD analysed by IVW suggested that there was a null effect of rosiglitazone on heel BMD (ß = -0.526; se = 1.744; P = 0.763), but the causal effect of gliclazide on heel BMD evaluated by IVW demonstrated that there was a positive effect of gliclazide on heel BMD (ß = 2.671; se = 1.340; P = 0.046). In summary, the present work showed that metformin and gliclazide have a role in reducing BMD loss in patients with diabetes and are recommended for BMD loss prevention in diabetes.

Effects of storm runoff on the spatial-temporal variation and stratified water quality in Biliuhe Reservoir, a drinking water reservoir.

Stormflow runoff is an important non-point source of pollution in drinking water reservoirs. Storm runoff is usually very turbid and contains a high concentration of organic matter, therefore affecting water quality when it enters reservoirs. In order to investigate the impact of storm runoff on spatial-temporal variation and stratification of water quality during this rainstorm event, the inflow process of the storm runoff was studied through a combination of field investigation and simulation using the Delft3D-Flow model. Water samples were collected from Biliuhe Reservoir at four different periods: before storm runoff, storm runoff flood peak period, 1 week after storm runoff, and 5 weeks after storm runoff. The results showed that the input of storm runoff resulted in a significant increase in the nitrogen (N) and phosphorus (P) in the reservoir water, especially in the reservoir entrance. The concentrations of total nitrogen (TN) and total phosphorus (TP) gradually decreased after the flood peak period; however, the average concentrations of TN and TP in the entire reservoir remained higher than those before the storm runoff levels for an extended duration. The storm runoff will greatly contribute to the contamination of water quality in a reservoir, and the water quality cannot be quickly restored by self-purification in the short term. During the flood peak period, under the influence of density current, the electrical conductivity (EC) and turbidity increased significantly in the water depth of 10-15 m, so that the reservoir water had obvious stratification between 10 and 15 m. The form of pollutants in storm runoff was mostly in particle phosphorus. Total particulate phosphorus (TPP) concentration was 0.015 ± 0.011 mg/L, accounting for 44.12% of total phosphorus (TP) concentration in storm runoff flood peak period. The process of a rainstorm caused runoff, which carried high levels of turbidity, particulate phosphorus, and organic matter. The storm runoff disrupts the stratification of the reservoir water. In terms of vertical distribution, the turbidity in the reservoir area increased to 73.75 NTU. Therefore, the occurrence of significant turbidity density flow in the reservoir is frequently accompanied by intense rainfall events. Gaining insights into the impact of storm runoff on the vertical distribution of reservoir turbidity can help managers in selecting an appropriate inlet height to mitigate high turbidity outflow.

Assessment of the response characteristics of pollution load in Huntai Basin under climate change.

This study establishes a calibrated SWAT (Soil and Water Assessment Tool) model for the Huntai Basin, driven by SSP126, SSP245, SSP585, and multi-model ensemble (MME) models in CMIP6 (Coupled Model Intercomparison Project-6), to investigate the effects of climate change on hydrological processes and pollution load in the Huntai Basin. The results show that the annual mean temperature and the annual precipitation will gradually increase. The nitrogen and phosphorus pollution loads in the basin exhibit a trend of decreasing-increasing-decreasing. The correlation between the nitrogen-phosphorus pollution load and the hydrological process strengthens with increasing radiative forcing. In the four scenarios, CO2 is a primary driving factor that contributes greatly to nitrogen and phosphorus pollution. The main differences are in the total driving factors, and SSP126 and SSP245 are less than those of other models. The total phosphorus and total nitrogen pollution in different climate models were higher than the average level during the benchmark period, except for ammonia nitrogen pollution, which was lower. The nitrogen and phosphorus pollution in SSP126 and SSP245 modes will reach the maximum in 2040s, and the pollution in other periods will be lower than that in SSP585 and MME scenarios. In the long run, the development state between SSP126 and SSP245 may be better appropriate for the Huntai Basin's future sustainable development. This paper analyzes the occurrence and influencing factors of nitrogen and phosphorus pollution under climate change to provide reference to the protection of water environment under changing environments.

Green tea polysaccharide conjugates and bovine serum albumin have a synergistic effect in improving the emulsification ability.

Our previous study revealed that green tea polysaccharide conjugate (gTPC) has emulsion effect, but its emulsifying ability is weak. In order to improve the emulsification ability of gTPC, gTPC and bovine serum albumin (BSA) were combined to form five different mass proportions of the TPC/BSA (TB) complex: TPC/BSA: 5:1, 5:2, 5:3, 5:4, and 5:5 w/w. We observed that the 5:5 w/w TB emulsion was more hydrophobic and surface-active. Furthermore, the emulsions prepared using 50.00 wt% medium-chain triglycerides exhibited the best stability. In addition, the TB emulsion exhibited stability in adverse environments of pH, salt, and heat; in particular, under salt conditions, no significant changes were observed in zeta potential. Subsequently, in vitro simulated digestion experiments were performed to investigate the use of TB emulsions for ß-carotene encapsulation. We observed that the encapsulation efficiency for ß-carotene was approximately 90.0 %; it was subsequently released in the intestine.

Highly Efficient Photosensitizers with Molecular Vibrational Torsion for Cancer Photodynamic Therapy.

The development of highly effective photosensitizers (PSs) for photodynamic therapy remains a great challenge at present. Most PSs rely on the heavy-atom effect or the spin-orbit charge-transfer intersystem crossing (SOCT-ISC) effect to promote ISC, which brings about additional cytotoxicity, and the latter is susceptible to the interference of solvent environment. Herein, an immanent universal property named photoinduced molecular vibrational torsion (PVT)-enhanced spin-orbit coupling (PVT-SOC) in PSs has been first revealed. PVT is verified to be a widespread intrinsic property of quinoid cyanine (QCy) dyes that occurs on an extremely short time scale (10-10 s) and can be captured by transient spectra. The PVT property can provide reinforced SOC as the occurrence of ISC predicted by the El Sayed rules (1ππ*-3nπ*), which ensures efficient photosensitization ability for QCy dyes. Hence, QTCy7-Ac exhibited the highest singlet oxygen yield (13-fold higher than that of TCy7) and lossless fluorescence quantum yield (ΦF) under near-infrared (NIR) irradiation. The preeminent photochemical properties accompanied by high biosecurity enable it to effectively perform photoablation in solid tumors. The revelation of this property supplies a new route for constructing high-performance PSs for achieving enhanced cancer phototherapy.

Effect of hydrophobic property on antibacterial activities of green tea polysaccharide conjugates against Escherichia coli.

We previously found that green tea polysaccharide conjugates (gTPCs) have antibacterial activity against Escherichia coli. In this study, the effect of hydrophobic property on the antibacterial activities of gTPCs was evaluated to elucidate their property-activity relationship. Three gTPCs (gTPCs-5 h, gTPCs-12 h and gTPCs-24 h) were extracted from green tea with the ethanol precipitation time of 5 h, 12 h and 24 h, respectively. These three gTPCs did not differ significantly in terms of molecular weight distribution, amino acids composition and zeta potentials. Fourier transform infrared spectroscopy results revealed that gTPCs-5 h and gTPCs-12 h processed more hydrogen bonds than gTPCs-24 h. The surface hydrophobicity and contact angle of gTPCs-5 h were larger than that of gTPCs-12 h and gTPCs-24 h. The antibacterial activity of gTPCs against E. coli decreased in the order of gTPCs-5 h > gTPCs-12 h > gTPCs-24 h. There wasn't significant difference among the zeta potentials of E. coli treated by gTPCs-5 h, gTPCs-12 h and gTPCs-24 h, but the bacterial contact angles of E. coli treated by gTPCs-5 h were higher compared with those of the other two gTPCs. Furthermore, gTPCs-5 h exhibited higher activity to decrease bacterial membrane proteins, and increase bacterial membrane permeability than the other two gTPCs. In conclusion, gTPCs with higher hydrophobicity property exhibited stronger antibacterial activity against E. coli.

Regulating effects of phytosterol esters-loaded emulsions stabilized with green tea polysaccharide conjugates and Tween on lipids in KKAy mice.

Phytosterol esters (PSE) have been shown to have cholesterol-lowering effects, but their insolubility in water limits their applications. Green tea polysaccharide conjugates (gTPC) have hypoglycemic and emulsifying effects. To address lipid dysregulation in diabetic patients, we developed PSE-loaded emulsions stabilized with gTPC and Tween-20 (gTPC-PSE emulsions) and evaluated their physicochemical properties. We subsequently investigated the lipid-regulating potential of these emulsions to in KKAy mice. The KKAy mice were randomly assigned to eight groups: the model group, the Lipitor (10 mg·kg-1)-acarbose (30 mg·kg-1) combination group, two gTPC groups, two PSE groups, and two gTPC-PSE groups with a 1:2 mass ratio of gTPC to PSE. The administered doses were 90 and 270 mg kg-1, respectively. Administration of a 270 mg·kg-1 dose of gTPC-PSE emulsions led to the most significant effects including increased levels of liver and serum high-density lipoprotein cholesterol (HDL-CH), reduced serum leptin and insulin, and improved liver superoxide dismutase (SOD) and reduced malondialdehyde (MDA). In general, gTPC and PSE demonstrated a synergistic effect on lipid regulation in mice. Our results indicate that gTPC-PSE emulsions hold potential as a nutritional intervention for diabetes by modulating lipid levels.

Deep eutectic solvent combined with ultrasound technology: A promising integrated extraction strategy for anthocyanins and polyphenols from blueberry pomace.

To avoid wasting blueberry pomace resources, deep eutectic solvents (DESs) were combined with ultrasound technology to establish an efficient green method for the recovery of anthocyanins and polyphenols from plant-derived by-products. Choline chloride:1,4-butanediol (molar ratio of 1:3) was chosen as the optimal solvent based on the screening of eight solvents and single-factor experiments. Response surface methodology was applied to optimize the extraction parameters: water content, 29%; extraction temperature, 63 °C; liquid-solid ratio, 36:1 (v/w). The yields of total anthocyanins and total polyphenols from the optimized extraction were 11.40 ± 0.14 mg cyanidin-3-glucoside equiv./g and 41.56 ± 0.17 mg gallic acid equiv./g, respectively, which were both significantly better than the yields achieved with 70% ethanol. The purified anthocyanins showed excellent inhibition of α-glucosidase (IC50 = 16.57 µg/mL). The physicochemical parameters of DES suggest that it can be used for the extraction of bioactive substances.

Recent progress of TP/NIR fluorescent probes for metal ions.

Metal ions are of significance in various pathological and physiological processes. As such, it is crucial to monitor their levels in organisms. Two-photon (TP) and near-infrared (NIR) fluorescence imaging has been utilized to monitor metal ions because of minimal background interference, deeper tissue depth penetration, lower tissue self-absorption, and reduced photodamage. In this review, we briefly summarize recent progress from 2020 to 2022 of TP/NIR organic fluorescent probes and inorganic sensors in the detection of metal ions. Additionally, we present an outlook for the development of TP/NIR probes for bio-imaging, diagnosis of diseases, imaging-guided therapy, and activatable phototherapy.

Interactions between tea polyphenols and nutrients in food.

Tea polyphenols (TPs) are important secondary metabolites in tea and are active in the food and drug industry because of their rich biological activities. In diet and food production, TPs are often in contact with other food nutrients, affecting their respective physicochemical properties and functional activity. Therefore, the interaction between TPs and food nutrients is a very important topic. In this review, we describe the interactions between TPs and food nutrients such as proteins, polysaccharides, and lipids, highlight the forms of their interactions, and discuss the changes in structure, function, and activity resulting from their interactions.

Effects of pile fermentation on the physicochemical, functional, and biological properties of tea polysaccharides.

This study investigated the influence of pile fermentation on the physicochemical, functional, and biological properties of tea polysaccharides (TPS). Results indicated that the extraction yield, uronic acid content, and polyphenol content of TPS greatly increased from 1.8, 13.1 and 6.3 % to 4.1, 27.9, and 7.8 %, respectively, but the molecular weight markedly decreased from 153.7 to 76.0 kDa after pile fermentation. Additionally, the interfacial, emulsion formation, and emulsion stabilization properties of TPS were significantly improved after pile fermentation. For instance, 1.0 wt% TPS isolated from dark tea (D-TPS) can fabricate 8.0 wt% MCT oil-in-water nanoemulsion (d32 ≈ 159 nm) with potent storage stability. Moreover, the antioxidant and α-glucosidase inhibitory activities of D-TPS was higher than that of TPS isolated from sun-dried raw tea (R-TPS). Overall, this study indicated that pile fermentation markedly affected the physicochemical and structural characteristics of TPS, thereby improving their functional and biological properties.

Optimization of the ultrasound-assisted aqueous enzymatic extraction of Pinus koraiensis nuts oil by response surface methodology.

Response surfaces methodology was established in order to optimize ultrasound-assisted aqueous alkaline protease extraction parameters of Pinus koraiensis nuts oil (PNO) in this short communication. On the oil yield, the impacts of single factors were studied. The solid-liquid ratio, enzyme concentration, enzyme hydrolysis temperature, and enzyme hydrolysis duration were chosen for further optimization of the extraction process utilizing a Box-Behnken design based on statistical significance analysis. Under ideal extraction conditions, a maximum oil recovery of 68.35% was achieved: solid-liquid ratio, enzyme concentration, enzyme hydrolysis temperature, and enzyme hydrolysis duration were 1:5 (g/mL), 3.23 mg/g, 44 °C, and 2.84 h, respectively. Furthermore, physicochemical properties testing revealed that the oil was of higher quality than other approaches. Meanwhile, the DPPH radical-scavenging activities increased with increased content compared to olive oil, with an IC50 value of 0.082 mg/mL. The method has a lot of potential when it comes to extracting oils from plants.

Physicochemical and Colon Cancer Cell Inhibitory Properties of Theabrownins Prepared by Weak Alkali Oxidation of Tea Polyphenols.

Existing studies on the biological activity of theabrownins are not based on their free state but on the complexes of theabrownins, polysaccharides, proteins, and flavonoids. In this study, theabrownins (TBs-C) were prepared by weak alkali oxidation of tea polyphenols. The ultraviolet-visible scanning spectrum of TBs-C showed two characteristic absorption peaks at 203 and 270 nm. The zeta potential of the TBs-C aqueous solution was negative, and the values varied from - 6.26 to -19.55 mV with a solution pH of 3-9. Storage conditions of pH 5.0-7.0 and around 25 °C were beneficial for the physical and chemical stability of the TBS-C solution. Cells were treated with series concentrations and examined by MTT, HE staining, PI immunofluorescence staining, flow cytometry, and real-time PCR to investigate the antiproliferative effect of TBs-C on human colon cancer HT-29 cells. The results showed that TBs-C, particularly at 500 µg/mL, inhibited cell growth. TBs-C induced HT-29 cell apoptosis, as confirmed by morphological changes, nucleus propidium iodide staining, and distributions of the cell cycle. The apoptotic mechanism may be due to the intracellular redox imbalance induced by TBs-C.

Physicochemical characterization, emulsifying and antioxidant properties of the polysaccharide conjugates from Chin brick tea (Camellia sinensis).

Tea polysaccharide conjugate fractions (TPCs) with different molecular weights (TPC-40, TPC-60, and TPC-80, MW = 1355 to 204 kDa) were prepared from Chin brick tea using graded alcohol precipitation. The physiochemical and functional properties of TPCs were investigated. Results showed that TPC-80 (204 kDa) had the highest antioxidant activity attributed to its higher phenolic and theabrownin contents. Moreover, this fraction had the highest surface pressure (16.2 ± 0.9 mN/m), but the lowest interfacial dilatational modulus (30.3 ± 2.2 mN/m) than TPC-40 (1355 kDa) and TPC-60 (955 kDa). As a result, TPC-80 had the highest emulsifying activity but the lowest emulsion stabilizing properties due to its fastest adsorption kinetics but the relatively thin interfacial coating on the oil droplets. Overall, our results indicate that the chemical compositions and structural characteristics of TPCs significantly impact their functional attributes. TPCs have the potential to be a novel natural antioxidant emulsifier in food industry.

Rationally designed Ru(ii)-metallacycle chemo-phototheranostic that emits beyond 1000 nm.

Ruthenium complexes are emerging as potential complements to platinum drugs. They also show promise as photo-diagnostic and therapeutic agents. However, most ruthenium species studied to date as potential drugs are characterized by short excitation/emission wavelengths. This limits their applicability for deep-tissue fluorescence imaging and light-based therapeutic treatments. Here, we report a Ru(ii) metallacycle (Ru1100) that emits at ≥1000 nm. This system possesses excellent deep-tissue penetration capability (∼7 mm) and displays good chemo-phototherapeutic performance. In vitro studies revealed that Ru1100 benefits from good cellular uptake and produces a strong anticancer response against several cancer cell lines, including a cisplatin-resistant A549 cell line (IC50 = 1.6 µM vs. 51.4 µM for cisplatin). On the basis of in vitro studies, it is concluded that Ru1100 exerts its anticancer action by regulating cell cycle progression and triggering cancer cell apoptosis. In vivo studies involving the use of a nanoparticle formulation served to confirm that Ru1100 allows for high-performance NIR-II fluorescence imaging-guided precise chemo-phototherapy in the case of A549 tumour mouse xenografts with no obvious side effects. This work thus provides a paradigm for the development of long-wavelength emissive supramolecular theranostic agents based on ruthenium.

TiO2 nanoparticles negatively impact the bioavailability and antioxidant activity of tea polyphenols.

This study was to investigate the influence of TiO2 nanoparticles (NPs) on the stability, bioavailability, and antioxidant activity of co-ingested tea polyphenols extract using an in vitro digestion model. The tea polyphenol contents decreased significantly after addition of 0.5 % (w/w) TiO2 NPs. The gallocatechin gallate level decreased the most, changing from 101.9 to 27.2 µg/mL (about 73.3%). The TiO2 NPs also reduced the bioavailability of the tea polyphenols in a dose-dependent manner, which was ascribed to the formation of large polyphenol-TiO2 NP complex aggregates that could not pass through the pores in the dialysis tube used to simulate the gut wall. Additionally, the TiO2 NPs decreased the antioxidant activity of the tea polyphenols within the simulated gastrointestinal tract. In summary, our results show that high levels of TiO2 NPs (but within the current legal limits in many countries) may negatively impact the bioavailability and bioactivity of polyphenols in foods.

Flood impact on the transport, transition, and accumulation of phosphorus in a reservoir: A case study of the Biliuhe Reservoir of Northeast China.

Stormflow runoff is the most important agent for phosphorus (P) input to reservoirs, as the particulates contained in runoff carry a substantial amount of P. The settling process of particulates affects the P content of water, and the distribution of particulates determines the P distribution in reservoir sediment. An understanding of flood impacts on the transport, transition, and accumulation of P in a reservoir is critical to reservoir management. In this study, water samples before and after flooding and sediment samples after flooding were collected from Biliuhe Reservoir in Northeast China. P content and load in the water and P-fractions and particle sizes of the sediments were analyzed. Results showed that total particulate P (TPP) increased sharply from 1.56 to 26.72 t after flooding, whereas dissolved organic P (DOP) decreased markedly from 3.24 to 1.17 t, which was largely caused by biological uptake directly or indirectly before flooding. Orthophosphate (PO43-) shared a similar trend with TPP, indicating that PO43- could be adsorbed onto settling particulates, helping to reduce the reactive P introduced by flooding. Reservoir sediment showed a fining trend downstream and the clay fraction exhibited an obvious correlation with P-fractions, demonstrating that the distribution of particulate matter determined P distribution in the sediment. This study also found that particulates from the largest tributary (Biliu River) were only minimally transported from its reservoir entrance to the dam because of a longer travel distance, while contrastingly, particulates from a smaller tributary (Bajia River) were maximally carried to the dam because of a shorter distance. Our fundings suggests that surface water in the reservoir should be released prior to flooding in order to mitigate control of P in the water, moreover, it is necessary to strengthen the effectiveness of pollutant control projects at the reservoir entrance of the Bajia River.

Quality Evaluation of Green and Dark Tea Grade Using Electronic Nose and Multivariate Statistical Analysis.

Aroma assessment remains difficult and uncertain in the present sensory assessment system. It is highly desirable to develop a new assessment method to discriminate the quality of various teas in the tea market. In the present work, based on linear discriminant analysis and principal component analysis, the aroma of dry and wet samples of different Xi-hu Longjing and Pu-erh teas were tested and differentiated by electronic noses (e-nose). The results confirm that e-nose can discriminate different priced Xi-hu Longjing tea samples in the range of 80-800 RMB/500 g and varying storage years of Pu-erh tea samples. Furthermore, for the detection of both dry and wet samples of Longjing and Pu-erh teas, the results reveal that all samples have specific aroma characteristics that e-nose can recognize. More importantly, contribution analysis in sensors indicates that nitrogen oxides, methane and alcohols are the characteristic components that contribute to the fragrances of different priced Xi-hu Longjing teas, while nitrogen oxides, aromatic benzene and amines make the fragrances of Pu-erh teas with different storage years disparate. PRACTICAL APPLICATION: This work demonstrates that e-nose can rapidly distinguish tea products with different price levels and varying storage years. With the advantages of ease of use, high portability and flexibility, e-nose will be widely expanded and applied in refined processing and the development of flavored foods.

Emulsifying Properties of Polysaccharide Conjugates Prepared from Chin-Brick Tea.

Chin-brick tea polysaccharide conjugates (TPC-C) were prepared to study their emulsion capabilities. Interfacial tension and the effects of some factors, such as storage time, metal ion concentrations (Na+, Ca2+), pH (2.0-8.0), and heat treatment (70-100 °C) on the emulsions stabilized by TPC-C were studied. The interfacial tension of TPC-C (10.88 mN/m) was lower than that of gum arabic (15.18 mN/m) at a concentration of 0.08%. As the TPC-C concentration increased from 0.1 to 3.0 wt %, the mean particle diameter (MPD) (d32) of emulsions stabilized by TPC-C decreased from 1.88 to 0.16 µm. Furthermore, at a concentration of 0.5 wt % or higher, the MPD (d32) of emulsions stabilized by TPC-C at 25 and 60 °C for 10 days was between 0.20 and 0.50 µm. In the tested pH conditions from 2.0 to 8.0, the MPD (d32) of emulsions stabilized by 2.0 wt % TPC-C was less than 0.20 µm. At Na+ concentration conditions between 0.10 and 0.50 mol/L, the MPD (d32) of emulsions was between 0.19 and 0.20 µm, and the zeta potential values varied from -34.10 to -32.60 mV. However, with an increasing Ca2+ concentration from 0.01 to 0.05 mol/L, the MPD (d32) of emulsions was between 0.20 and 21.65 µm, and the zeta potential raised sharply from -34.10 to -28.46 mV. The emulsions stabilized by TPC-C have a decent storage stability after a high-temperature heat treatment. Overall, tea polysaccharide conjugates strongly stabilized the emulsions, which support their new application as natural emulsifiers.