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In order to enhance the efficient utilization of polymeric proanthocyanidins from litchi pericarp, a process for transforming litchis’ polymeric proanthocyanidins (LPPCs) by using Lactobacilli has been established for products with highly antioxidative properties. Lactobacillus plantarum was selected to enhance the transformation effect. The transformation rate of LPPCs reached 78.36%. The content of litchis’ oligomeric proanthocyanidins (LOPCs) in the products achieved 302.84 μg grape seed proanthocyanidins (GPS)/mg DW, while that of total phenols was 1077.93 gallic acid equivalents (GAE) μg/mg DW. Seven kinds of substances have been identified in the products by using the HPLC-QTOF-MS/MS method, among which 4-hydroxycinnamic acid, 3,4-dihydroxy-cinnamic acid, and proanthocyanidin A2 were major components. The in vitro antioxidative activity of the products after transformation was significantly (p < 0.05) higher than those of LOPCs and LPPCs. The scavenging activity of the transformed products for DPPH free radicals was 1.71 times that of LOPCs. The rate of inhibiting conjugated diene hydroperoxides (CD-POV) was 2.0 times that of LPPCs. The scavenging activity of the products for ABTS free radicals was 11.5 times that of LPPCs. The ORAC value of the products was 4.13 times that of LPPCs. In general, this study realizes the transformation of polymeric proanthocyanidins into high-activity small-molecule substances.

Background: Ankylosing spondylitis (AS) is a chronic inflammatory disease that mainly affects the axial skeleton. Meanwhile, copper is a mineral nutrient involved in cell proliferation and death pathways and has been observed in various diseases. Methods: The purpose of this study was to identify potential new biomarkers of ankylosing spondylitis through biomarker analysis and explore its immune cell infiltration analysis. Gene expression profiles of GSE73754, GSE25101 and GSE18781 datasets were retrieved from the GEO database. Three machine learning algorithms, i.e., minimum absolute shrinkage and selection operator ( LASSO ), random forest ( RF ) and support vector machine recursive feature elimination ( SVM-RFE ), were used to screen cuprotosis-related genes ( CRGs ) of ankylosing spondylitis. Besides, ankylosing spondylitis specimens were classified using the consensus clustering method. The three machine learning results were intersected with the CRGs obtained by difference analysis and the differential CRGs obtained by clustering to obtain key genes. Additionally, the infiltration of immune cells was detected by ssGSEA, and the cuprotosis-related genes related to immune cells and immune function were detected by spearman correlation analysis. The nomogram model was established, and the accuracy of cuprotosis-related genes in predicting the development of AS disease was verified by external data sets. Result: The two AS libraries in the GEO database were merged after removing the batch effect. Through the difference analysis, 6 CRGs were obtained, 9 CRGs were obtained by LASSO algorithm, 4 CRGs were obtained by SVM-RFE, and 13 CRGs were obtained by RF. It was also found by clustering the consistency of AS samples that they could be divided into 2 subtypes, and 5 CRGs were obtained as well. Finally, two key genes of SLC31A1 and PDHB were obtained by VENN intersection. The immune infiltration and GSEA analysis showed that PDHB had the strongest positive correlation with T cells CD8, followed by T cells CD4 memory resting, and had the strongest negative correlation with Neutrophils. Besides, SLC31A1 had the strongest positive correlation with NK cells resting and the strongest negative correlation with T cells CD8. By establishing a nomogram model, it was found that the two genes could better predict the development of AS, and the verification of the external data set GSE18781 indicated the stronger predictive ability of PDHB. Conclusion: In summary, the present study revealed several newly discovered cuprotosis-related genes that interfered with the progression of ankylosing spondylitis through immune infiltration, and found the large research space of PDHB.

Polyglycerol fatty acid esters (PGFEs), a type of nonionic surfactants, have been widely used in food industry. However, the effects of the aliphatic chain lengths in PGFEs and the concentrations of PGFEs on digestive profiles in emulsion-based systems are poorly understood. The present study has investigated the physicochemical stability, lipolysis dynamics and curcumin bioaccessibility in the nanoemulsions stabilized by synthesized PGFEs with different aliphatic chains (CThe online version contains supplementary material available at 10.1007/s11483-021-09681-z.

Zearalenone (ZEA), a nonsteroidal estrogenic mycotoxin produced by multiple Fusarium species, contaminates cereals and threatens the health of both humans and animals by inducing hepatotoxicity, immunotoxicity, and genotoxicity. A new alkali tolerant enzyme named Ase, capable of degrading ZEA without H2O2, was derived from Acinetobacter sp. SM04 in this study. The Ase gene shares 97% sequence identity with hypothetical proteins from Acinetobacter pittii strain WCHAP 100004 and YMC 2010/8/T346 and Acinetobacter calcoaceticus PHEA-2, respectively. Based on the Acinetobacter genus database, the gene encoding Ase was cloned and extracellularly expressed in Escherichia coli BL21. After degrading 88.4% of ZEA (20 µg/mL), it was confirmed through MCF-7 cell proliferation assays that Ase can transform ZEA into a nonestrogenic toxic metabolite. Recombinant Ase (molecular weight: 28 kDa), produced by E. coli BL21/pET32a(+)-His-Ase, was identified as an oxygen-utilizing and cytochrome-related enzyme with optimal activity at 60 °C and pH 9.0.

PurposeWeber's hypothesis about China is the hypothesis forwarded by Weber that why capitalist production did not appear in eastern countries such as China in the first place. Weber considered that the reason may be Chinese Confucianism and Taoism lack protestant ethic like Western countries.Design/methodology/approachThe clarification has aroused wide discussion, meanwhile, East Asian capitalism belonging to the Chinese cultural circle has successfully refuted Weber's proposition. Chinese scholars have a broad debate around this topic while no agreement has been reached. This paper tries to explain Weber's hypothesis by Marx's theory of capital origin, which can be explained that the landlord economy caused by China's federal society under centralism leads to the result that the commodity of labor cannot exist in that environment.FindingsThe answer from Marxist economics has not only solved an enormous theoretical problem, but also it has vital practical significance. It easily clarifies the fact that the commodity of labor in full sense still cannot emerge in China nowadays, which is an important reason causing China to enter the New Normal and New Era.Originality/valueTherefore, it leaves China the only way of the socialist road with Chinese characteristics and revitalizing China's rural economy, which means China can only promote rural industrialization and urbanization under the principle of adhering to rural collective ownership, while implementing various forms of integrated agricultural and industrial business models based on local conditions.

Background: Coronavirus disease 2019 (COVID-19) is an acute respiratory infectious disease that makes breathing difficult and is often accompanied by abdominal pain and distension. Moxibustion, a special external treatment of traditional Chinese medicine, has shown beneficial effects in the treatment of abdominal pain. Currently, there is a lack of systematic reviews on moxibustion for the treatment of abdominal pain. We conduct this study to evaluate the efficacy and safety of moxibustion in the treatment of abdominal pain. This study is designed to evaluate the effectiveness and safety of moxibustion for abdominal pain in COVID-19. Methods: Randomized controlled trials from December 2019 to December 2021 will be included, without restrictions on language or publication date. PubMed, EMBASE, Cochrane Library, Web of Science, Chinese Biomedical Databases, China National Knowledge Infrastructure, Wanfang Database, and VIP Database were searched. Two researchers will independently select studies, extract data, and evaluate study quality. The Cochrane risk of bias tool for randomized trials will be used to assess the risk of bias in the included studies. Statistical analyses will be conducted using the RevMan 5.3 software. Results: This study aimed to prove the efficacy and safety of moxibustion for abdominal pain in patients with COVID-19. Our study provides a more accurate treatment method for abdominal pain during COVID-19. We will publish our results in a peer-reviewed journal. Conclusion: This study will provide more convincing evidence for clinicians to treat these conditions and help them make appropriate decisions. Ethics and dissemination: This study did not include personal information. Ethical approval was not required for this study. INPLASY registration number: INPLASY2021120104.

Background: The incidence of insomnia is very high and seriously affects the lives of its patients. Long-term insomnia can induce other diseases and even cause sudden death. Tian Meng oral liquid is a type of Chinese patent medicine that has been used in the clinical treatment of insomnia and has certain clinical effects. However, its wide application is limited by the lack of evidence-based medical evaluation. Methods: Using retrieval strategies, randomized controlled trials on Tian Meng oral liquid for insomnia were obtained from China National Knowledge Infrastructure, WanFang, Chinese Scientific Journals Database PubMed, Embase, and Cochrane Library, regardless of publication date or language. Studies were screened based on inclusion and exclusion criteria, and the Cochrane risk bias assessment tool was used to evaluate the quality of the studies. The meta-analysis was performed using RevMan 5.3 and STATA 14.2 software. Ultimately, the evidentiary grade for the results will be evaluated. Results: This study aims to evaluate the efficacy and safety of Tian Meng oral liquid in the treatment of insomnia and to provide a more reasonable option for clinical medication. Conclusion: Our findings will provide a strong basis for the effectiveness and safety of Tian Meng oral liquid in the treatment of insomnia.

s Triglycerol monolaurate (TGML) was widely used as an emulsifier in food, cosmetic and other products, and was generally accepted as safe. In the study, the inhibitory activity of TGML against common foodborne pathogens, Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Listeria monocytogenes, Candida albicans and Cryptococcus neoformans was investigated with comparison to sodium benzoate and potassium sorbate. The minimum inhibitory concentrations (MIC) of TGML against six pathogens were 0.16, 0.16, 0.08, 0.04, 0.64 and 1.25 mg/mL, the minimum bactericidal concentrations (MBC) were 0.64, 1.25, 0.32, 0.16, 5.0 and 5.0 mg/mL, respectively, both lower than that of sodium benzoate and potassium sorbate. The MIC remained stable when the pH values increased from 3 to 9. Besides, the growth of Staphylococcus aureus and Listeria monocytogenes was almost inhibited for 72 h, whereas the inhibition effect on the rest four strains degraded at 36–48 h and 4–5 days, respectively. The action mechanism of TGML was further studied by detecting plasma membrane permeability, membrane surface damage and the impact of cell cycle and intracellular biomacromolecules synthesis. Results revealed that TGML increased cell membrane permeability, destroyed cell membrane integrity and caused depressions and holes, caused cell cycle arrest and biomacromolecules synthesis inhibition. These results suggest that TGML can effectively exert good inhibitory effect on bacteria and yeast by cell membrane action and intracellular inhibition.

Background: Acute cerebral infarction (ACI) has a high incidence, recurrence rate, and mortality. Chinese herbal injections (CHIs) are widely used in the substitution therapy of ACI. Due to the lack of randomized trials comparing the efficacy of various injections directly, it is still difficult to judge the relative efficacy. Therefore, we intend to conduct a network meta-analysis to evaluate the benefit among these CHIs. Methods: According to the retrieval strategies, randomized controlled trials (RCTs) on CHI therapies for ACI will be obtained from China National Knowledge Infrastructure, WanFang, Chinese Scientific Journals Database, PubMed, Embase and Cochrane Library, regardless of publication date or language. Studies were screened based on inclusion and exclusion criteria, and the Cochrane risk bias assessment tool will be used to evaluate the quality of the literature. The network meta-analysis will be performed in Markov Chain Monte Carlo method and carried out with Stata 14 and WinBUGS 1.4.3 software. Ultimately, the evidentiary grade for the results will be evaluated. Results: This study will compare the efficacy and safety of CHIs in the treatment of ACI, and give a more reasonable choice. Conclusion: Our findings will provide references for future clinical decision and guidance developing. INPLASY registration number: INPLASY202060087.

Background: From the end of 2019 to the present, coronavirus disease 2019 (COVID-19) has put considerable pressure on the worlds medical system and caused significant mortality and economic losses around the world. In China, the Shufeng Jiedu capsule has been widely used in the treatment of COVID-19, but there is still a lack of evidence-based medical evaluation. Methods: According to the retrieval strategies, randomized controlled trials (RCTs) on the Shufeng Jiedu capsule for COVID-19 were obtained from CNKI, WanFang, VIP, PubMed, Embase and Cochrane Library, regardless of publication date, or language. Studies were screened based on inclusion and exclusion criteria, and the Cochrane risk bias assessment tool was used to evaluate the quality of the studies. The meta-analysis was performed using RevMan 5.3 and STATA 14.2 software. Ultimately, the evidentiary grade for the results will be evaluated. Results: This study will evaluate the efficacy and safety of the Shufeng Jiedu capsule in the treatment of COVID-19 and provide a more reasonable choice of medication in clinical practice. Conclusion: Our findings will provide references for future clinical decision and guidance development. Registration: INPLASY registration number: INPLASY202070024.

As the outbreak of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly spread over the world, the World Health Organization has declared the outbreak of COVID-19 an international public health emergency. Besides typical respiratory symptoms and signs of COVID-19, digestive symptoms and liver injury have been frequently reported during the course of the disease. The purpose of this study was to evaluate the efficacy and safety of moxibustion in the treatment of anorexia in patients with COVID-19.According to the retrieval strategies, randomized controlled trials on moxibustion therapies for C19-A will be obtained from the China National Knowledge Infrastructure, WanFang Data, Chinese Scientific Journals Database, PubMed, Embase, and Cochrane Library, regardless of publication date or language. Studies will be screened based on inclusion and exclusion criteria, and the Cochrane risk bias assessment tool will be used to evaluate the quality of the literature. The network meta-analysis will be performed with the Markov chain Monte Carlo method and carried out with Stata 14.2 and WinBUGS 1.4.3 software. Ultimately, the quality of the evidence obtained from the results will be evaluated.This study will evaluate whether moxibustion therapy can effectively treat anorexia in patients with COVID-19.This study will provide evidence for whether moxibustion therapy is beneficial to the treatment of anorexia in patients with COVID-19.CRD42022302499.

Background: Percutaneous coronary intervention (PCI), as the most common treatment for coronary heart disease (CHD), has the advantages of simple operation, minimal invasion, rapid reconstruction, and vessels opening. The problem, however, is that many patients develop restenosis within 6 months after PCI. In traditional Chinese medicine (TCM), Huoxue Huayu decoction (HXHYD) is widely used to treat cardiovascular diseases, and its important role as a complementary and alternative therapy for the prevention and treatment of post-PCI restenosis in CHD patients has been extensively reported. However, controversy exists among different studies. Therefore, we collected relevant randomized controlled trials for a meta-analysis to assess the efficacy and safety of HXHYD in the prevention of post-PCI restenosis in patients with CHD. Methods: Randomized controlled trials of HXHYD in the prevention of post-PCI restenosis in patients with CHD will be retrieved from PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure, Wan Fang Database, Chinese Biomedical Literature Database, VIP Database for Chinese Technical Periodicals, and Clinical Trial Register. The 2 authors will independently conduct the literature search, literature screening, data extraction, and quality assessment. Data analysis will be performed using STATA 14.0. Results: The results of this meta-analysis will be submitted to a peer-reviewed journal for publication. Conclusion: This study will provide high-quality, evidence-based medical evidence for the efficacy and safety of HXHYD in the prevention of post-PCI restenosis in patients with CHD. Ethics and dissemination: Ethical approval is not required for this study. The systematic review will be published in a peer-reviewed journal, presented at conferences, and shared on social media platforms. This review would be disseminated in a peer-reviewed journal or conference presentations. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/PNZSM.

Zearalenone (ZEN), mainly produced by Fusarium species in many crops worldwide, is an estrogenic mycotoxin that causes reproductive disorders in livestock. In this study, we developed a different degradation mode by choosing specific microorganisms to catalyze directional reactions to produce less toxic or non-toxic target products. One promising strain, Candida parapsilosis ATCC 7330, with high reductase activity was evaluated for its ability to directly convert ZEN to less toxic β-Zearalenol (β-ZOL). Glucose was added to trigger ZEN glucosylation by yeast. Thin layer chromatography (TLC) combined with liquid chromatography-mass spectrometry (LC-MS) revealed that ZEN exposed to C. parapsilosis ATCC 7330 was transformed into β-ZOL and zearalenone glucosides ([M+H]+ at 643.2581), and it was proposed to be ZEN-14,16-diglucoside according to NMR analysis, which was stable under digestive conditions. Furthermore, kinetic analysis indicated that the ZEN level (20 μg/mL) decreased by 97% within 5 h, which relied on enzymes on the cell membrane. In addition, C.parapsilosis ATCC 7330 also exhibited glucosyltransferase activities toward β-ZOL, α-Zearalenol (α-ZOL) and Zearalanone (ZAN) with yields of 100%, 76%, and 100%, respectively. Considering the estrogenic toxicity of target metabolites after complex transformation without coenzyme addition, detoxification by specific biodegradable microorganisms may open new opportunities and innovations for mycotoxin detoxification.

A heteropolysaccharide, named L2, from Lentinula edodes has been proved to possess immunostimulating and anti-ageing activities in previous studies, but its acting mechanism was not completely understood. In this study, 1H NMR spectroscopy approach was employed to investigate the metabolic profiles of the urine from adult mice after L2 intervention. Using principal component analysis (PCA) and partial least squares-discriminate analysis (PLS-DA), 22 potential biomarkers were found to be mainly involved in some metabolic pathways: amino acid metabolism, energy metabolism, lipid metabolism, tricarboxylic acid (TCA) cycle, urea cycle and gut microbiota metabolism. Among them, the significantly altered metabolites include: elevated glutamate (75%) and creatine (64%); decreased proline (65%), betaine (58%), fucose (63%) and dimethylamine (59%). In conclusion, the present data is helpful to understand the mechanisms related to previously confirmed immunomodulation and anti-aging effects of L2, and provide valuable information for mining new functions of L2.

Lentinula edodes-derived polysaccharides are well known for their immunomodulation and antitumor activities. However, the mechanisms of action have not been fully elucidated. This study presents proteomic analysis of the colon and small intestine from mice fed with an immunostimulating heteropolysaccharide L2 from the fruit body of L. edodes. Two-dimensional gel electrophoresis (2-DE) and MALDI-TOF-TOF MS/MS were employed to characterize the protein profiles. Twenty nine gel spots representing 20 proteins in colon tissues and 38 gel spots in small intestine tissues representing 23 proteins were identified as showing significant changes in abundance. These differential proteins in abundance are mainly involved in metabolism, binding, structural components, and response to stimulus. Protein-protein interaction network analysis demonstrated mapping of the 20 colon proteins to a 7-protein and a 3-protein sub-network, and mapping of the 23 small intestine proteins to a 9-protein and a 5-protein sub-network. All the 40 altered proteins were integrated into a unified network containing 25 proteins, suggesting the existence of a concerted mechanism, although acting on the colon and small intestine separately. These findings facilitate the understanding of the regulatory mechanism in response to L2 treatment.

Cronobacter sakazakii (C. sakazakii) is an opportunistic foodborne pathogen in infant formula. This study was designed to explore the inhibitory effect of TGML on C. sakazakii in reconstituted infant formula (RIF). Firstly, the growth curve of C. sakazakii in RIF treated by TGML and the effect of different temperatures (4, 10, 21, 30 and 37 °C), pH values (5, 6, 7, 8 and 9) and ionic strengths (25, 50, 100, 200, 400 and 800 mM) on its activity were assessed. The results showed that the inhibitory effect of TGML on C. sakazakii was dose-dependent, and 1, 2 and 5 μg/mL TGML delayed the visible growth of pathogen by 4, 12 and 24 h, respectively. Storage temperature above or below room temperature enhanced the bioactivity of TGML. And a decrease in pH also increased the antibacterial effect of TGML. However, the effect of ionic strength on its activity was not obvious. Subsequently, the antibacterial effect of TGML in physiological gastric acid and simulated gastric juice in vitro was further explored. We found that only 5 μg/mL TGML could inhibit the growth of pathogen below the infectious dose (10,000 CFU in total) in simulated gastric juice during the whole gastric emptying period (3.5–21 h), weaker than its antibacterial effect in physiological gastric acid and room temperature culture. Finally, the effect of TGML and the above environmental factors on the color and aroma of infant milk was evaluated by a 12-person panel. The results revealed that TGML did not affect the sensory flavor of milk, and the color and odor scores of infant milk under different environmental conditions did not show any significant differences. Therefore, it is concluded that TGML has a good inhibitory effect on C. sakazakii in RIF and a high sensory acceptability for consumers. Adjusting the temperature or lowering the pH enhances its bacteriostatic activity. However, the presence of infant gastric juice can impair the bioactivity of TGML. Overall, this study will provide some new ideas for controlling and eliminating the potential risk of C. sakazakii infection during infant feeding.

Background Acute bronchitis (AB) is a common cause of childhood morbidity. Tuina, a kind of Chinese massage, is frequently used for the treatment of AB in children by traditional Chinese medicine doctors. However, there is no relevant systematic review show its effectiveness and safety. The study aims to evaluate the effectiveness and safety of Tuina for children with AB. Methods The following electronic databases will be searched from the respective dates of database inception to January 1st, 2020: The Cochrane Library, Web of Science, the World Health Organization International Clinical Trials Registry Platform, Springer, EMBASE, MEDLINE, China National Knowledge Infrastructure, the Chinese Biomedical Literature Database, Wanfang database, the Chinese Scientific Journal Database, and other sources. All published randomized controlled trials and blinded researches that are relevant to the subject of interest only will be contained. Two independent researchers will operate article retrieval, duplication removing, screening, quality evaluation, and data analyses by Review Manager (V.5.3.5). Meta-analyses, subgroup analysis and/or descriptive analysis will be performed based on the included data conditions. Results High-quality synthesis and/or descriptive analysis of current evidence will be provided from the bronchitis severity score, symptom, and quality-of-life questionnaires, the questionnaire of clinical symptoms of cough and sputum, Patient Satisfaction Scale and adverse reactions. Conclusion This study will provide the evidence of whether Tuina is an effective and safe intervention for children with AB. Prospero registration number CRD42019140667.

Monoglyceride is an amphiphilic molecule with promising antimicrobial activity for bacteria; however, the key lethal effect in its antibacterial behavior was still unknown. In the study, monobutyrate (MB), monolaurate (ML), monomyristate (MM) were selected to represent the short, medium, and long chain monoglycerides to compare their inhibitory effect againstEscherichia coli, and a new dose-dependent inhibitory mechanism was proposed by the key lethal effect. The minimal inhibitory concentration and antibacterial curve showed a huge diversity existed in biology activity of MB, ML and MM. The results in scanning electron microscopy and flow cytometry assay indicated that the interference level of MB on cell membrane was obviously weaker than that of ML and MM, while the latter two had similar performance in increasing cell permeability at low doses. The results presented in UV-Vis spectroscopy, cell cycle and biomacromolecules synthesis inhibition assay showed that the cell cycle ofEscherichia coliwas obviously affected by three monoglycerides at doses near MIC, which was therefore regarded as the key lethal effect. The reason for the better biological activity of MM than ML was the stronger interference ability on bacterial cell cycle. In addition, an expanded antibacterial mode was raised that cell permeability increase at low doses was antimicrobial basis, cell cycle arrest at medium doses played the key lethal effect, and cell lysis at high doses was the result of combined action.

The intracellular antioxidant activities of diosmetin were evaluated by cellular antioxidant activity (CAA) assay, 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced erythrocyte hemolysis assay and cupric chloride (CuCl2)-induced plasma oxidation assay. The results showed that diosmetin exhibits strong cellular antioxidant activity (EC50 = 7.98 μmol, CAA value = 58 μmol QE/100 μmol). It was also found that diosmetin treatment could effectively attenuate AAPH-induced erythrocyte hemolysis (91.0% inhibition at 100 μg/mL) and CuCl2-induced plasma oxidation through inhibition of intracellular reactive oxygen species (ROS) generation. Diosmetin could significantly restore AAPH-induced increase of intracelluar antioxidant enzyme (SOD, GPx, and CAT) activities to normal levels, as well as inhibit intracellular malondialdehyde (MDA) formation. Thus, the intracellular antioxidant detoxifying mechanism of diosmetin is associated with both nonenzymatic and enzymatic defense systems.

Summary Interaction of flavonoids and enzyme may affect characteristics and physiological activities of both components. In this study, the effects of the interaction between four flavonoids (quercetin, luteolin, kaempferol and apigenin) and trypsin were examined. At the concentration of 2.7 mm, inhibition of trypsin (1.6 U mL−1) by quercetin, luteolin, kaempferol and apigenin was 46.4%, 32.6%, 26.8% and 17.7%, respectively. In the presence of trypsin, DPPH, ABTS and hydroxyl radical scavenging activities of flavonoids were obviously inhibited. Addition of flavonoids led to fluorescence quenching of trypsin. The decreasing order of binding force between flavonoids and trypsin was quercetin, luteolin, kaempferol and apigenin. It is concluded that the interaction between flavonoids and trypsin depends on the number and position of hydroxyl group of flavonoids.