A critical review of Fuzhuan brick tea: processing, chemical constituents, health benefits and potential risk.

Fuzhuan brick tea (FBT) is a traditional popular beverage in the border regions of China. Nowadays, FBT has been attracted great attention due to its uniquely flavor and various health-promoting functions. An increasing number of efforts have been devoted to the studies on health benefits and chemistry of FBT over the last decades. However, FBT was still received much less attention than green tea, oolong tea and black tea. Therefore, it is necessary to review the current encouraging findings about processing, microorganisms, chemical constituents, health benefits and potential risk of FBT. The fungus fermentation is the key stage for processing of FBT, which is involved in a complex and unique microbial fermentation process. The fungal community in FBT is mainly dominated by "golden flower" fungi, which is identified as Aspergillus cristatus. A great diversity of novel compounds is formed and identified after a series of biochemical reactions during the fermentation process of FBT. FBT shows various biological activities, such as antioxidant, anti-inflammatory, anti-obesity, anti-bacterial, and anti-tumor activities. Furthermore, the potential risk of FBT was also discussed. It is expected that this review could be useful for stimulating further research of FBT.

Antioxidant properties of polyphenols from snow chrysanthemum (Coreopsis tinctoria) and the modulation on intestinal microflora in vitro.

CONTEXT: Coreopsis tinctoria Nutt (Asteraceae), named snow chrysanthemum, is known to have a high level of polyphenols. However, the potential prebiotic effect on modulating intestinal microflora is still unclear. OBJECTIVE: The chemical composition, antioxidant properties of snow chrysanthemum polyphenols (SCPs) and their effects on human intestinal microbiota were investigated. MATERIALS AND METHODS: SCPs were extracted using ultrasonic-assisted extraction, and further determined using UPLC-QE Orbitrap/MS. Five assays were used to investigate the antioxidant activities of SCPs. Subsequently, the effects of SCPs on intestinal microbiota in vitro were determined by high throughput sequencing and bioinformatics analysis. RESULTS: Marein, isookanin and cymaroside were the major phenolic compounds, which accounted for 42.17%, 19.53% and 12.25%, respectively. Marein exhibited higher scavenging capacities in DPPH (EC50 = 8.84 µg/mL) and super anion radical assay (EC50 = 282.1 µg/mL) compared to cymaroside and isookanin. The antioxidant capacity of cymaroside was weakest among the three phenolic compounds due to the highest EC50 values, especially for superoxide anion radical assay, EC50 > 800 µg/mL. The result of in vitro fermentation showed that the three phenolic compounds increased the relative abundances of Escherichia/Shigella, Enterococcus, Klebsiella, etc., and isookanin notably increased the relative abundance of Bifidobacterium and Lactobacillus. DISCUSSION AND CONCLUSIONS: SCPs exhibited antioxidant properties and potential prebiotic effects on modulating the gut microbiota composition. The findings indicated that SCPs consumption could exert prebiotic activity that is beneficial for human health.

Fuzhuan brick tea polysaccharides serve as a promising candidate for remodeling the gut microbiota from colitis subjects in vitro: Fermentation characteristic and anti-inflammatory activity.

The purified fraction 3 of polysaccharides from Fuzhuan brick tea (FBTPS-3) could attenuate the colitis and modulate the gut microbiota. However, the relationship between anti-inflammatory effect of FBTPS-3 and the gut microbiota is still unknown. Thus, the anaerobic fermentation in vitro was used to investigate the potential mechanism. FBTPS-3 could be utilized and degraded by gut microbiota from inflammatory bowel disease (IBD) subjects. Furthermore, FBTPS-3 could modulate the composition and structure of IBD gut microbiota toward to that of healthy group. FBTPS-3 showed a superior modulated effect on IBD gut microbiota by increasing Bacteroides and decreasing Escherichia/Shigella. Furthermore, the fermentation solution rather than FBTPS-3 itself showed anti-inflammatory effects on lipopolysaccharide-treated RAW264.7 macrophages, which might be due to the metabolites such as short-chain fatty acids (SCFAs). Thus, FBTPS-3 can be expected as novel prebiotics for treatment of IBD via modulating gut microbiota, and promoting the production of SCFAs.

Effects of Tai-Chi and Running Exercises on Cardiorespiratory Fitness and Biomarkers in Sedentary Middle-Aged Males: A 24-Week Supervised Training Study.

This study examined the effectiveness of Tai-Chi and running exercises on cardiorespiratory fitness and biomarkers in sedentary middle-aged adults under 24 weeks of supervised training. Methods Thirty-six healthy middle-aged adults (55.6 ± 5.3 yr) were randomly assigned into Tai-Chi, running and control groups. During a 24-week training period, the Tai-Chi and running groups were asked to perform exercises for 60 min/day and 5 days/week, which were supervised by Tai-Chi and running instructors throughout. Resting heart rate, lean mass, blood pressure and blood lipids were measured, and cardiorespiratory fitness (VO2max, Vmax and Peak heart rate) was assessed at the baseline and the 12- and 24-week interventions. Results Compared to the no-exercise control group, both the Tai-Chi and running groups significantly decreased resting heart rate, diastolic blood pressure and cardiorespiratory fitness and increased lean mass across the training session (p < 0.05). Compared to the Tai-Chi group, the running group showed greater improvement in VO2max and Vmax (p < 0.05) and reduced triglyceride and low-density lipoprotein cholesterol (p < 0.05). Conclusion Both Tai-Chi and running exercise showed beneficial effects on cardiorespiratory fitness and enhanced health-related outcomes in middle-aged adults. Although Tai-Chi exercises were less effective in VO2max than running, Tai-Chi may be considered as a plausible alternative to running exercises that can be achieved in the indoor-based setting.

Selenium in cereals: Insight into species of the element from total amount.

Selenium (Se) is a trace mineral micronutrient essential for human health. The diet is the main source of Se intake. Se-deficiency is associated with many diseases, and up to 1 billion people suffer from Se-deficiency worldwide. Cereals are considered a good choice for Se intake due to their daily consumption as staple foods. Much attention has been paid to the contents of Se in cereals and other foods. Se-enriched cereals are produced by biofortification. Notably, the gap between the nutritional and toxic levels of Se is fairly narrow. The chemical structures of Se compounds, rather than their total contents, contribute to the bioavailability, bioactivity, and toxicity of Se. Organic Se species show better bioavailability, higher nutritional value, and less toxicity than inorganic species. In this paper, we reviewed the total content of Se in cereals, Se speciation methods, and the biological effects of Se species on human health. Selenomethionine (SeMet) is generally the most prevalent and important Se species in cereal grains. In conclusion, Se species should be considered in addition to the total Se content when evaluating the nutritional and toxic values of foods such as cereals.

Phenolics and Carbohydrates in Buckwheat Honey Regulate the Human Intestinal Microbiota.

Intestinal microbiota plays an important role in human health. The aim of this paper is to determine the impact of the phenolics and carbohydrate in buckwheat honey on human intestinal microbiota. We investigated the phenolics and carbohydrate compositions of eight buckwheat honey samples using high-performance liquid chromatography and ion chromatography. The human intestinal microbes were cultured in a medium supplemented with eight buckwheat honey samples or the same concentration of fructooligosaccharides. The bacterial 16S rDNA V4 region sequence of DNA extraction was determined by the Illumina MiSeq platform. 12 phenolics and 4 oligosaccharides were identified in almost all buckwheat honey samples, namely, protocatechuic acid, 4-hydroxy benzoic acid, vanillin, gallic acid, p-coumaric acid, benzoic acid, isoferulic acid, methyl syringate, trans,trans-abscisic acid, cis,trans-abscisic acid, ferulic acid, 4-hydroxybenzaldehyde, kestose, isomaltose, isomaltotriose, and panose. Most notably, this is the first study to reveal the presence of 4-hydroxybenzaldehyde in buckwheat honey. 4-Hydroxybenzaldehyde seems to be a land marker of buckwheat honey. Our results indicate that buckwheat honey can provide health benefits to the human gut by selectively supporting the growth of indigenous Bifidobacteria and restraining the pathogenic bacterium in the gut tract. We infer that buckwheat honey may be a type of natural intestinal-health products.

Modulation of gut microbiota by Ilex kudingcha improves dextran sulfate sodium-induced colitis.

Increasing evidence shows that the gut microbiota contributes to the occurrence and development of colitis. Kudingcha (KDC), made from the leaves of Ilex kudingcha, could mitigate inflammation, however, little is known about the relationship between modulatory effect on gut microbiota by KDC and improvement of colitis. In this study, the attenuating effects of KDC extract (KDCE) on dextran sulfate sodium (DSS)-induced colitis and gut microbiota in C57BL/6 mice were investigated. It was found that the supplementation of KDCE could alleviate typical symptoms of IBD including weight loss, colon shortening, intestinal barrier damage, and decreases in the colitis disease activity index and pro-inflammatory cytokines. Moreover, KDCE supplementation could reverse the alteration of gut microbiota in the colitic mice by increasing the abundances of potential beneficial bacteria, e.g. Odoribacter, Prevotella and Helicobacter, and decreasing the abundances of potential harmful bacteria, e.g. Parabacteroides, Bacteroides, Turicibacter, Parasutterella and Lachnospiraceae. The levels of short-chain fatty acids in feces, cecum contents and serum were also regulated by KDCE. Furthermore, the correlation analysis suggested that KDCE could attenuate DSS-induced colitis which might be related to the alteration of gut microbiota. Therefore, the modulation of gut microbiota by KDCE might be a potential strategy for improving inflammation-driven diseases.

Anti-inflammatory effects of dicaffeoylquinic acids from Ilex kudingcha on lipopolysaccharide-treated RAW264.7 macrophages and potential mechanisms.

Increasing evidence has shown that dicaffeoylquinic acids (DiCQAs) have anti-inflammatory activity. However, the underlying molecular mechanisms of the anti-inflammatory effects of DiCQAs are still unclear. In the present study, the anti-inflammatory effects of DiCQAs from the leaves of Ilex kudingcha and the potential molecular mechanisms on LPS-induced inflammatory responses in RAW264.7 macrophage cells were investigated. The results showed that pretreatment with DiCQAs could suppress the production of NO, PGE2 and also pro-inflammatory cytokines TNF-α, IL-1ß and IL-6, and the mRNA expression of two major inflammatory mediators of COX-2 and iNOS. The phosphorylated IκBα, ERK, JNK and p38 proteins in LPS-treated cells were significantly increased, which could be reversed by pretreatment with DiCQAs in a concentration-dependent manner. Taken together, the results suggest that DiCQAs from I. kudingcha have potent anti-inflammatory effects on LPS-induced inflammatory responses by inhibiting the NF-κB and MAPKs pathways and may be a prophylactic for inflammation.

Effects of Dicaffeoylquinic Acids from Ilex kudingcha on Lipid Metabolism and Intestinal Microbiota in High-Fat-Diet-Fed Mice.

Kudingcha made from the leaves of Ilex kudingcha and chlorogenic acid have antiobesity and intestinal microbiota modulating effects. However, the effects of kudingcha dicaffeoylquinic acids (diCQAs) on obesity and intestinal microbiota are still poorly understood. In the present study, the effects of kudingcha diCQAs on adipose accumulation and intestinal microbiota were investigated in high-fat-diet-fed mice. As a result, kudingcha diCQAs decreased the liver and adipose tissue masses, concentrations of serum inflammatory factors, and hepatic expressions of lipid synthesis related genes and increased the expressions of genes involved in lipid degradation in the liver. Kudingcha diCQAs also exhibited considerable effects on intestinal microbiota. They increased the relative abundances of Bifidobacterium and Akkermansia and affected the function of the microbial community including bile acid biosynthesis. Kudingcha diCQAs had antiobesity potential, possibly acting through affecting intestinal microbiota. Furthermore, the effects of kudingcha diCQAs on fat accumulation and intestinal microbiota had a dose-dependent manner.

In vitro bioaccessibility and speciation changes of selenium in Pleurotus eryngii during the growing stage.

The production of Pleurotus eryngii by selenium (Se) biofortification is an effective way to improve the demand for Se in humans. In order to investigate the Se bioaccessibility and speciation of Se-enriched P. eryngii during the growing stage, the Se distribution in biochemical fractions, and the molecular weight and the Se species of Se-containing compounds derived from in vitro simulated gastrointestinal fluids were analyzed by size exclusion and anion exchange-high performance liquid chromatography and inductively coupled plasma mass spectrometry. The results showed that albumin had the highest Se content among biochemical fractions, approximately 34.40% of total Se, followed by glutelin, globulin and gliadins. Selenomethionine that was proved to be the major Se species would increase with P. eryngii growing from 45.85% to 59.32%, while selenocysteine would decrease from 40.68% to 15.17% of total Se. In conclusion, selenocysteine would gradually convert to selenomethionine, and thus the bioaccessibility of Se was greater in mature P. eryngii than in younger mushrooms.

Evaluation of chemical property, cytotoxicity and antioxidant activity in vitro and in vivo of polysaccharides from Fuzhuan brick teas.

Fuzhuan brick tea (FBT) possesses various health-promoting functions. However, the available information regarding biological activity of polysaccharides from FBT (FBTPS) is still limited. In this work, the chemical property, cytotoxicity and antioxidant activity in vitro and in vivo of FBTPS were evaluated. It was found that FBTPSs were typical acidic heteropolysaccharides mainly composed of Man, Rha, GalA, Glc, Gal and Ara with little molar content of Rib and GlcA. FBTPS showed little toxicity to human hepatic epithelial (L-02) cell. FBTPS exhibited antioxidant activities, including limited scavenging activity on DPPH free radicals (ranged from 54.3 ±â€¯1.9 to 67.8 ±â€¯2.5%), noticeable scavenging activity on superoxide radicals (over 85%), superior scavenging activity on ABTS radicals (near 100%), and protective effect on H2O2-induced oxidative injury in rat pheochromocytoma line 12 (PC12) cell. Moreover, FBTPS showed significant amelioration of high-fat diet-induced oxidative injury in mice. The results suggest that FBTPS, as natural safe antioxidants, may have potential application in functional foods.

Fuzhuan Brick Tea Polysaccharides Attenuate Metabolic Syndrome in High-Fat Diet Induced Mice in Association with Modulation in the Gut Microbiota.

An increasing amount of evidence suggests that the gut microbiota composition and structure contribute to the pathophysiology of metabolic syndrome (MS), which has been put forward as a new target in the treatment of diet-induced MS. In this work, we aimed to investigate effects of Fuzhuan brick tea polysaccharides (FBTPS) on MS and gut microbiota dysbiosis in high-fat diet (HFD) fed mice and to further investigate whether its attenuation of MS is related to the modulation of gut microbiota. The results showed that FBTPS intervention could significantly attenuate metabolic syndrome in HFD-induced mice. Based on results of sequencing, FBTPS treatment could increase the phylogenetic diversity of HFD-induced microbiota. FBTPS intervention could significantly restore the HFD-induced increases in relative abundances of Erysipelotrichaceae, Coriobacteriaceae, and Streptococcaceae. Spearman's correlation analysis showed that 44 key OTUs were negatively or positively associated with MS. Our results suggested that FBTPS could serve as a novel candidate for prevention of MS in association with the modulation of gut microbiota.

Kudingcha and Fuzhuan Brick Tea Prevent Obesity and Modulate Gut Microbiota in High-Fat Diet Fed Mice.

SCOPE: Kudingcha (KDC) from Ilex kudingcha and Fuzhuan brick tea (FBT) are popular beverages in China, and their preventive and therapeutic roles in metabolic disorders have been reported. However, the relationship between the gut microbiota modulatory effects of KDC and FBT and prevention of obesity is still not clearly understood. METHODS AND RESULTS: KDC and FBT are tested individually for their capacities to prevent obesity and modulate the gut microbiota in high-fat diet (HFD) fed C57BL/6J mice. The results show that both KDC and FBT supplementation could modulate oxidative injury, inflammation, lipid metabolism, and reduce HFD induced obesity significantly. Both KDC and FBT could enhance the diversity of gut microbiota. KDC could reduce the relative abundance of Erysipelotrichaceae, while FBT could reduce the ratio of Firmicutes to Bacteroidetes and enhance the relative abundance of Bifidobacteriaceae. CONCLUSION: These findings suggest that KDC and FBT could attenuate features of the metabolic syndrome in HFD-fed mice, which might be due to the modulation of gut microbiota by KDC and FBT.

Digestion under saliva, simulated gastric and small intestinal conditions and fermentation in vitro by human intestinal microbiota of polysaccharides from Fuzhuan brick tea.

The aim of present study was to examine whether the digestivesystem (saliva, simulated gastric and small intestinal conditions) could break down and large intestinal microbiota could utilize the polysaccharides from Fuzhuan brick tea (FBTPS). The results showed that there was no change in molecular weight, monosaccharide content and content of reducing sugars before and after saliva, simulated gastric and small intestinal digestion, indicating that FBTPS could pass through the digestive system without being broken down and reach the large intestine safely. The content of carbohydrate was significantly decreased by fermentation in vitro of gut microbiota, suggesting that FBTPS could be broken down and utilized by gut microbiota. FBTPS could significantly modulate the composition and abundance of gut microbiota. Furthermore, the contents of short-chain fatty acids were significantly increased. Therefore, FBTPS is expected to be a functional food to improve human health and prevent disease through promoting the gut health.

Modulating Effects of Dicaffeoylquinic Acids from Ilex kudingcha on Intestinal Microecology in Vitro.

Dietary polyphenols have been considered as novel prebiotics, and polyphenols could exert their functions through modulating intestinal microbiota. The diverse bioactivities of kudingcha could derive from its phenolic compounds, but the effects of dicaffeoylquinic acids (diCQAs) from Ilex kudingcha on intestinal microbiota have not been investigated. In the present study, high-throughput sequencing and anaerobic fermentation in vitro were utilized to investigate the microecology-modulating function of I. kudingcha diCQAs. As a result, diCQAs raised the diversity and exhibited a more considerable impact than a carbon source on the microbial profile. DiCQAs increased the relative abundances of Alistipes, Bacteroides, Bifidobacterium, Butyricimonas, Clostridium sensu stricto, Escherichia/Shigella, Parasutterella, Romboutsia, Oscillibacter, Veillonella, Phascolarctobacterium, Lachnospiracea incertae sedis, Gemmiger, Streptococcus, and Haemophilus and decreased the relative abundances of Ruminococcus, Anaerostipes, Dialister, Megasphaera, Megamonas, and Prevotella. DiCQAs also affected the generation of short-chain fatty acids through microbiota. The contents of acetic and lactic acids were raised, while the production of propionic and butyric acids was reduced. Conclusively, diCQAs from I. kudingcha had significant modulating effects on intestinal microbiota in vitro, which might be the fundamental of diCQAs exerting their bioactivities.

Enhanced solubility and antioxidant activity of chlorogenic acid-chitosan conjugates due to the conjugation of chitosan with chlorogenic acid.

Chlorogenic acid-chitosan conjugate was synthesized by introducing of chlorogenic acid onto chitosan with the aid of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and hydroxybenzotriazole. The data of UV-vis, FT-IR and NMR for chlorogenic acid-chitosan conjugates demonstrated the successful conjugation of chlorogenic acid with chitosan. Compared to chitosan, chlorogenic acid-chitosan conjugates exhibited increased solubility in distilled water, 1% acetic acid solution (v/v) or 50% ethanol solution (v/v) containing 0.5% acetic acid. Moreover, chlorogenic acid-chitosan conjugates showed dramatic enhancements in metal ion chelating activity, total antioxidant capacity, scavenging activities on 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) and superoxide radicals, inhibitory effects on lipid peroxidation and ß-carotene-linoleic acid bleaching, and protective effect on H2O2-induced oxidative injury of PC12 cells. Particularly, chlorogenic acid-chitosan conjugate exhibited higher inhibitory effects on lipid peroxidation and ß-carotene-linoleic acid bleaching than chlorogenic acid. The results suggested that chlorogenic acid-chitosan conjugates could serve as food supplements to enhance the function of foods in future.

Effects of α-Galactooligosaccharides from Chickpeas on High-Fat-Diet-Induced Metabolic Syndrome in Mice.

The gut microbiota has the ability to modulate host energy homeostasis, which may regulate metabolic disorders. Functional oligosaccharide may positively regulate the intestinal microbiota. Therefore, effects of α-galactooligosaccharides (α-GOS) from chickpea on high-fat-diet (HFD)-induced metabolic syndrome and gut bacterial dysbiosis were investigated. After 6 weeks of intervention, HFD led to significant increases in levels of blood glucose, total cholesterol, triglyceride, glycated serum protein, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol of mice compared to normal-chow-fed mice. Meanwhile, all of the α-GOS-treated groups significantly decreased above parameters compared to the HFD group. HFD could significantly decrease the content of all bacteria, especially Bacteroides (9.82 ± 0.09 versus 10.3 ± 0.10; p < 0.05) and Lactobacillus (6.67 ± 0.18 versus 7.30 ± 0.24; p < 0.05), and a decrease in the production of short-chain fatty acids was also observed. Treatment with α-GOS significantly increased the number of Bifidobacterium (6.07 ± 0.23 of the low-dose treatment versus 5.65 ± 0.20 of the HFD group) and Lactobacillus (7.22 ± 0.16 of the low-dose treatment). It also significantly promoted the secretion of propionic and butyric acids. These results indicate that α-GOS from chickpeas may affect the metabolic disorders and gut bacterial ecosystem in a positive way.

Hydrolysis of Dicaffeoylquinic Acids from Ilex kudingcha Happens in the Colon by Intestinal Microbiota.

Monocaffeoylquinic acids (mono-CQAs) can be hydrolyzed or metabolized by pancreatin, intestinal brush border esterase, and microbiota in the colon. Data about the conversion of dicaffeoylquinic acids (diCQAs) in digestion are scarce. The diCQA-rich fraction including 3,4-, 3,5-, and 4,5-diCQAs was prepared from Ilex kudingcha, and the conversion in simulated gastricintestine was investigated. Artificial saliva, gastric and pancreatic fluids, Caco-2 monolayer cells, and anaerobic fermentation model were utilized to mimic digestions of the oral cavity, stomach, small intestine, and colon in vitro. The results revealed that diCQAs remained intact in simulated saliva, gastric, and pancreatic fluids and within Caco-2 cells. In anaerobic fermentation with human fecal slurry, diCQAs were hydrolyzed to mono-CQAs and caffeic acid, which were further metabolized to caffeic acid and dihydrocaffeic acid, respectively. The hydrolysis of diCQAs depended on the chemical structures, carbohydrates in the culture medium, and microbial compositions. Our research demonstrated that hydrolysis of diCQAs happened in the colon by intestinal microbiota.

The effect of puerarin against IL-1ß-mediated leukostasis and apoptosis in retinal capillary endothelial cells (TR-iBRB2).

PURPOSE: Blood-retinal barrier (BRB) breakdown, the early hallmark of diabetic retinopathy (DR), is thought to depend on retinal inflammation and cell damage. The proinflammatory factor interleukin-1ß (IL-1ß) was demonstrated to cause inflammation as well as cell apoptosis during the process of BRB breakdown. This study extensively evaluated the protective effect of puerarin, a major active component extracted from the traditional herb Radix puerariae, against IL-1ß-induced cell dysfunction in TR-iBRB2 cells, a retinal capillary endothelial cell line. METHODS: TR-iBRB2 cells were pretreated with IL-1ß (10 ng/ml) for 24 h and then exposed to puerarin (0, 10, 25, and 50 µM) for another 24 h. Leukocyte endothelial adhesion was assessed through a cell-based assay using lymphoblastoid cells. Cell apoptosis was evaluated with flow cytometry, and the expression of adhesion molecules and apoptosis-related molecules was assessed with western blot analysis. RESULTS: Our data showed that puerarin attenuated IL-1ß-mediated leukostasis and cell apoptosis in TR-iBRB2 cells. Furthermore, puerarin strikingly prevented IL-1ß-induced molecular events of the upstream and downstream signaling pathways involved in this cellular process. CONCLUSIONS: These findings may significantly contribute to better understanding of the protective effect of puerarin, in particular for DR, as well as provide novel insights into the potential application of this compound in DR therapy.

A new method for the detection of adenosine based on time-resolved fluorescence sensor.

In this work, we report a thrombin binding aptamer complex based time-resolved fluorescence sensor for small molecule detection. The sensor employs two strands (DNA1 and DNA2) of oligonucleotides. This two strands of oligonucleotides contain two aptamer (α-aptamer and ß-aptamer) respectively. DNA1 and DNA2 were labeled with biotin and DIG at the 3'-end, respectively. Binding of the α-aptamer and ß-aptamer to the thrombin promotes the hybridization between the complementary stem sequences attached to the two oligonucleotide sequences. The hybridization then brings biotin to be hidden in the shield part on DNA1, shielding biotin from being approached by the streptavidin modified on the microplate due to the steric hindrance effect of the shield part of DNA1. Result in the thrombin-aptamer complex cannot be modified on the surface of microplate which further leads to no signal reported. The strategy integrates the distinguishing features of aptamer and fluorescent techniques. As a proof-of-principle, adenosine in serum was detected with a detection limit of 0.5 nM. A nice detection limit and linear relationship were obtained.