查找使用阿拉丁产品的科研文献

Green synthesis and antimicrobial study on the catechin-functionalized Fe3O4-Ag magnetic nanocomposites

Shengkai Liu,Cheng Chang,Boyu Chen,Han Song,Jiashen Fan,Yujie Fu,Zhiguo Liu

In this study, catechin-functionalized Fe3O4-Ag nanocomposites were synthesized by a hydrothermal method. The motivation for this study was to develop a novel antibacterial agent with enhanced stability and biocompatibility. The objective was to create a nanocomposite combining the antimicrobial properties of silver with the antioxidant and bioactive characteristics of catechin. We hypothesized that the synergistic effect of catechin and Fe3O4-Ag would yield a highly effective antibacterial material against common pathogens. The obtained nanocomposites were characterized by TEM, SEM, AFM, XPS, XRD, FTIR and physical property measurement system (PPMS). TEM images indicated that catechin-functionalized Fe3O4-Ag nanocomposites have a spherical morphology with an average size of 25.7 nm. The SEM and AFM imaging revealed that the nanocomposites appear as a number of large particles with average diameter of 581 nm. XPS and XRD and FTIR measurement confirmed the presence of catechin components, Fe3O4 and Ag in the nanocomposites. Taken together, we conclude that the catechin-Fe3O4-Ag nanocomposites in this study have a jujube cake structure in which the Fe3O4-Ag alloy nanoparticles serve as the jujube and the condensed catechin form into the cake substrate. The antimicrobial test indicated the catechin-functionalized Fe3O4-Ag nanocomposites have obvious inhibitory effects on E.coli, S.aureus, and C.albicans.

In situ construction of CuBi2O4/Bi4O5Br2 Z-scheme heterojunction with enhanced photocatalytic degradation performance for polyphenolic contaminant in wastewater

Yuqing Shi,Yuhang Li,Yumeng Xue

Photocatalytic technique is one of the clean and promising routes for wastewater purification. In this work, a different CuBi 2 O 4 /Bi 4 O 5 Br 2 Z-scheme heterojunction were successfully prepared via an in-situ mechanical agitation method. The 10 % CuBi 2 O 4 /Bi 4 O 5 Br 2 (10 % CBO/BOB) heterojunction showed the highest photocatalytic degradation activity for catechin, and ∼99.8 % catechin was degrade within 40 min visible light stimulation, which is (0.0757/min) about 6.2-folds and 8.8-folds to that of Bi 4 O 5 Br 2 (0.0122/min) and CuBi 2 O 4 (0.0086/min), The pH = 7 is the optimal reaction condition for catechin degradation. Besides, The photocatalytic degradation capacity of the 10 % CBO/BOB heterojunction displayed the positive and negative relationship to the dosage of catalyst and initial concentration of catechin, respectively. The enhanced photocatalytic activity of CuBi 2 O 4 /Bi 4 O 5 Br 2 Z-scheme heterojunction can be ascribed to the improvement of the charge separation and light utilization rate. The results of ESR and trapping experiments revealed that the ·O 2 − , h + and ·OH are the primarily reactive substances for catechin degradation. Additionally, the transfer pathway of the photogenerated charges in the CuBi 2 O 4 /Bi 4 O 5 Br 2 Z-scheme heterojunction as revealed by the ESR, Mott-Schottky curve and UV–Vis diffuse reflectance absorption spectroscopy. This work provide a new idea for designing and preparing the novel Bi 4 O 5 Br 2 -based photocatalyst for TCM wastewater purification.

Effect of air drying temperature on the phenolics and antioxidant activity of Xuan-Mugua fruit

CHEN Jian-Peng,WANG Yue,ZHANG Xu-Yang,SUN Ping,WU Zheng-Fang,SHANG Ya-Fang,YANG Shao-Hua,MA Yi-Long,WEI Zhao-Jun

Xuan-Mugua is a Chinese traditional fruit and is mainly preserved by air drying. To explore the effect of temperature on the drying property and quality of the fruits, they were sliced and dried at 60-90 °C. The results indicated that the drying time shortened from 150 to 80 min with the increasing temperature and the minimal time was found at 90 °C. The total phenolic content and antioxidant activity generally decreased by 5.09-18.27% at higher temperature (90 °C) and their maximums respectively appeared at 60 and 80 °C. Compared with the medium temperatures (60 and 70°C), the phenolic profiles changed obviously at higher temperatures (80 and 90 °C), and a transformation of chlorogenic acid was detected; besides, with the increasing temperature, the main phenolics including catechin and chlorogenic acid respectively decreased by 29.3% and 18.4%. Taking the above findings together, 70 °C should be the proper temperature to dry Xuan-Mugua fruits.

Insight into the taste profiles of green tea made with fresh tea leaves plucked in summer

Xiangyang Guo,Shuangfeng Jiang,Lulu Wang,Keting Jin,Jingke Ma,Qiying Zhou

Purpose This study aims to investigate the suitability of summer-plucked fresh tea leaves (FTL-GT) for green tea production, challenging the common experience-based claim of their unsuitability. It seeks scientific evidence to support or refute this claim. Design/methodology/approach The study comprehensively analyzes the taste properties of green tea (GT) made from FTL-GT, including non-volatiles like polyphenols, caffeine, free amino acids, total sugar and L-theanine. Various indices during processing, such as dose-over-threshold (Dot) factors, catechin quality index (CQI), phenol/amino ratio (PAR) and non-esterified/esterified catechins ratio (NER). Additionally, sensory evaluation is conducted. Findings FTL-GT exhibits high CQI (256.38) and NER (0.58) and low PAR (5.37), indicating its suitability for producing high-quality GT. Green tea made from FTL-GT contains high catechin content and exhibits strong, mellow and umami-like tastes. EGCG, caffeine and L-theanine with high Dot factors of 680.47, 250.89 and 16.69, respectively, are identified as key contributors to the astringent, bitter and umami-like tastes in GT. Cysteine, with a Dot factor of 6.55, is the primary compound responsible for the sweet taste. Research limitations/implications This study primarily focuses on the taste properties of green tea made from summer-plucked fresh tea leaves but does not explore potential variations in other quality attributes such as aroma or appearance. Additionally, the study was conducted using a specific set of tea leaves and processing methods, limiting the generalizability of the findings. Implications for the tea industry include the potential to expand production seasons and improve the quality of green tea by utilizing summer-plucked leaves. Practical implications The study suggests that tea producers can consider using summer-plucked fresh tea leaves for green tea production, potentially expanding their production seasons and increasing yield. This could lead to more sustainable tea farming practices and higher quality green tea products. Additionally, the identified taste-active compounds and indices can guide tea processors in optimizing production methods to enhance the taste profiles of green tea. Social implications By demonstrating the suitability of summer-plucked fresh tea leaves for green tea production, this study could contribute to the economic development of tea-growing regions by providing farmers with an additional source of income. Furthermore, the promotion of high-quality green tea made from these leaves could enhance cultural appreciation and consumption of tea, fostering a deeper connection to traditional tea practices and encouraging healthy lifestyles among consumers. Originality/value The originality of this study lies in its comprehensive analysis of the taste properties of green tea made with summer-plucked fresh tea leaves, which challenges the commonly held belief based on experience that these leaves are not suitable for green tea production. The study provides scientific evidence to support the suitability of FTL-GT for green tea production and reveals the taste profiles of summer green tea. This information serves as a valuable reference for the tea industry and researchers interested in optimizing green tea production and quality.

Effects of pulsed electric field treatment on (+)-catechin–acetaldehyde condensation

Dan Zhao,Xin-An Zeng,Da-Wen Sun,Dan Liu

Condensation of (+)-catechin contributes significantly to wine taste during its aging process. In order to simulate and explore a feasible method to enhance conversion of proanthocyanidins (PAs), the effect of pulsed electric field (PEF) treatment on the condensation efficiency between (+)-catechin and acetaldehyde in a wine model solution was investigated in this paper. The PEF intensity used ranged from 0 to 50   kV/cm. The content of (+)-catechin was monitored by HPLC–PAD. Results showed that the condensation reaction between (+)-catechin and acetaldehyde was enhanced by PEF treatment. The (+)-catechin decrease rate had an obvious increase with increasing PEF intensity. Furthermore, it increased with reaction temperature, as well as with decreasing pH values under PEF treatment (40   kV/cm). It was observed that the content of (+)-catechin after reaction for 31.12   ms under 40   kV/cm was approximately equivalent to that after reaction for 62.23   ms without PEF treatment. In addition, it was demonstrated that activation energy ( E a ) of the condensation reaction was reduced remarkably by PEF treatment (from 41.59   kJ/mol to 28.98   kJ/mol under 40   kV/cm). Moreover, mass spectrometry analysis showed that both the reactions with and without PEF treatment fit the same pathway, indicating no change in reaction products. Future work will focus on the studies of changes of pH in the treatment chamber to verify the reaction mechanism. Industrial Relevance This study showed that pulsed electric field treatment (PEF) could be a novel and promising technology for the wine industry to accelerate the condensation between (+)-catechins, thus improving the quality of wine in a short time.

Physicochemical Characterization of Inclusion Complex of Catechin and Glucosyl-β-Cyclodextrin

Bin Li,Wenbo Zhang,Hanjun Ma

Mesoporous catechin hydrogel for enhanced astaxanthin-based inflammatory bowel disease therapy

Guo Ningli,Shi Jiayi,Zhang Xinyu,Xu Hui,Ji Tongyao,Qiu Fengkai,Li Kai,Wu Zhenyi,Ma Ji,Weng Qiaoyou,Qiu Rongfang,Shu Gaofeng,Chen Zhang,Chen Jingfeng,Wang Xiaojing

Inflammatory bowel disease (IBD) is a persistent intestinal inflammation driven by epithelial barrier dysfunction, immunological imbalance, and microbial dysbiosis. The restoration of gut homeostasis through biomaterial-based strategies offers a potential avenue for alleviating inflammation in IBD. Herein, an alginate-based hydrogel incorporating astaxanthin-loaded mesoporous catechin nanoparticles (AST@MCN-Gel) was designed to relieve inflammation and rebalance gut homeostasis. The mesoporous framework of MCN enabled effective encapsulation of the hydrophobic AST, thereby increasing its water solubility and bioavailability. In lipopolysaccharide-induced macrophages, AST@MCN exhibited superior ROS-scavenging capacity and anti-inflammatory activity relative to either AST or MCN. Mechanistically, AST@MCN modulated macrophage phenotype from pro-inflammatory (M1) to anti-inflammatory (M2) state through regulation of the MAPK/NF-κB pathway. On the other hand, the alginate-based hydrogel effectively enhanced the intestinal retention of AST@MCN, resulting in a marked improvement in oral therapeutic efficacy. In a DSS-induced IBD mouse model, oral administration of AST@MCN-Gel significantly alleviated the clinical symptoms and restored intestinal barrier integrity. Analysis of the gut microbiome further indicated that AST@MCN-Gel ameliorated gut dysbiosis by restoring microbial diversity and suppressing the proliferation of pathogenic species. Collectively, these underscore the potential of AST@MCN-Gel as an effective biomaterial-based therapeutic approach for restoring intestinal homeostasis and improving IBD therapy.

Catechin promotes the germination of Pistacia chinensis seeds via GA biosynthesis

Guo Huanhuan,Li Shiqin,Liu Yong,Yang Qinsong

Background and AimsChinese pistachio (Pistacia chinensis Bunge), an important horticultural plant species, holds great ornamental value with beautiful leaves and fruits. Seedling propagation of this tree species is restricted by its erratic seed germination, however, the germination mechanism is ambiguous yet. The aim of this study was to figure out the germination mechanism from the novel perspective based on the multi-omics data.MethodsThe multi-omics technique combined with hormone content measurement was first applied in seed germination of Chinese pistachio.Key ResultsDue to the great accumulation during seed germination, catechin stood out from the identified metabolites by broadly targeted metabolomic analysis. Exogenous catechin of 10 mg/L significantly improved the germination of Chinese pistachio seeds. An interesting result of hormone analysis showed that the improving effect of catechin could be attributed to increase of the gibberellic acid 3 (GA3) content rather than decrease of the abscisic acid (ABA) content before germination. The paclobutrazol (PAC, a GA biosynthesis inhibitor) and PAC + catechin treatments also showed that the promoting effect of catechin on seed germination depends on GA biosynthesis. Transcriptome analysis and qRT‒PCR further revealed that catechin induced the expression of PcGA20ox5 to activate GA biosynthesis. Several transcription factors were induced by catechin and GA treatments, such as TCP, bZIP and C3H, which may play an important regulatory role in GA biosynthesis in a catechin-mediated way.ConclusionsCatechin promotes seed germination via GA biosynthesis in Chinese pistachios. This study proposes a novel mechanism by which catechin promotes seed germination via the GA pathway, which provides new insight into a comprehensive understanding of seed dormancy and germination.

Antioxidant and Antimicrobial Effects of Catechin Liposomes on Chinese Dried Pork

Jieyu Wu,Rongfa Guan,Guozhou Cao,Zhenfeng Liu,Zhe Wang,Haitao Shen,Qile Xia

ABSTRACT In this study, catechin (CT), catechin liposome (CTL), and α-tocopherol (TP) were added to Chinese dried pork to achieve a healthy lipid composition. Their effectiveness in prevention of lipid oxidation was determined by measuring the values of thiobarbituric acid–reactive substances and peroxides. The total viable count in samples was used to identify the antimicrobial activities of CT, CTL, and TP, and the pH values of the samples were determined. Chinese dried pork with antioxidants added at 600 mg/kg was subjected to sensory evaluation. Thiobarbituric acid–reactive substance values, peroxide values, and total viable counts indicated that CTL significantly enhanced the antioxidant and antibacterial effects of CT on Chinese dried pork, especially after storage at room temperature for 25 days. Compared with the two other antioxidants, CTL could better maintain the pH stability of Chinese dried pork at room temperature. Sensory evaluation revealed that the scores of CTL were better than those of CT and TP in terms of preserving the color, flavor, tenderness, and overall acceptability of Chinese dried pork. Use of CTL in Chinese dried pork had good antioxidant and antibacterial effects and maintained color, flavor, and tenderness at a relatively stable level, suggesting that CTL could be used as an antioxidant in Chinese dried pork to enhance oxidative stability and prolong shelf life.

Gemini dodecyl O-glucoside-based vesicles as nanocarriers for catechin laurate

Jin Feng,Chunfang Lin,Hua Wang,Songbai Liu

In this work, gemini dodecyl O -glucoside-based vesicles were successfully developed employing (+)-catechin (C) and (−)-epigallocatechin (EGC) laurate as model compounds. Results revealed that vesicles displayed high loading capacity for both C and EGC laurate and the incorporation of C or EGC laurate were confirmed by dynamic light scattering, transmission electron microscope, Fourier-transform infrared spectra, and differential scanning calorimetry analyses. C and EGC laurate stiffened the vesicle bilayer at low concentrations but created a remarkable increase in the membrane fluidity afterward. Vesicles readily underwent aggregation under thermal treatment and osmotic stress. The thermal stability of C and EGC laurate were significantly improved by vesicle encapsulation. Compared with C and EGC, encapsulated C and EGC laurate exhibited lower 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical-scavenging activity due to the shielding effect of vesicles but higher lipid-oxidation inhibitory ability because they preferentially concentrated in the liposome membrane.

Improved oxidative stability of fish oil emulsion by grafted ovalbumin-catechin conjugates

Jin Feng,He Cai,Hua Wang,Chunyang Li,Songbai Liu

Conjugates of ovalbumin (OVA) with (+)-catechin (C), (−)-epigallocatechin (EGC) or (−)-epigallocatechin gallate (EGCG) were synthesized through a free-radical grafting approach. The covalent binding between OVA and catechins was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). OVA-catechin conjugates were further characterized by a combination of steady-state fluorescence spectroscopy, differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and circular dichroism (CD) analyses. Results suggested that the conjugates contained less α-helix but more β-sheet secondary structure than OVA. The catechin-grafting reaction led to improved surface hydrophobicity and decreased tertiary conformation stability of OVA. Compared with that emulsified by OVA, fish oil emulsion coated by conjugates demonstrated smaller droplet size, better storage stability and less viscosity. Besides, conjugates inhibited the lipid oxidation in fish oil emulsion more effectively than OVA because of their higher antioxidant activity and interfacial accumulation.

Catechin inhibits glycated phosphatidylethanolamine formation by trapping dicarbonyl compounds and forming quinone

Lipeng Han,Qingna Lin,Guoqin Liu,Dongxue Han,Li Niu,Dongxiao Su

It is important to inhibit food-derived potentially hazardous glycated lipids with natural products. A model reaction inhibition system was established, and products were identified with high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) to study the inhibitory effects of four types of catechins on the formation of glycated 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) products. The results show that the percentage inhibition of epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC) and epigallocatechin gallate (EGCG) on the formation of carboxymethyl 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (CM-DPPE) are 38.84%, 33.31%, 20.71% and 22.66%, respectively. The percentage inhibition of EC, ECG, EGC and EGCG on the formation of carboxyethyl 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (CE-DPPE) is 42.04%, 41.99%, 31.70% and 36.24%, respectively. In addition, catechin can capture glyoxal (GO) and methylglyoxal (MGO) to produce multiple products. O-Benzoquinone, the oxidation products of catechin, also captures DPPE to produce quinone–DPPE adducts. Therefore, there are two inhibitory mechanisms of tea-derived catechin for glycated DPPE: (1) catechin inhibits the formation of CM-DPPE and CE-DPPE by trapping reactive GO and MGO; and (2) catechin is oxidized to o-benzoquinone. O-Benzoquinone reacts with DPPE through nucleophilic substitution, which competes with the reaction between glucose and DPPE. This study will provide a theoretical basis for the use of natural products to inhibit the formation of food-derived glycated lipids.