Phosphoprotein Phosphatases ; Kinetics ; Protein Phosphatase 2/metabolism*

Gut bacterial nitroreductases play an important role in reduction of various nitroaromatic compounds to the corresponding N-nitroso compounds, hydroxylamines or aromatic amines, most of which are carcinogenic and mutagenic agents. Inhibition of gut nitroreductases has been recognized as an attractive approach for reducing mutagen metabolites in the colon, so as to prevent colon diseases. In this study, the inhibitory effects of 55 herbal medicines against Escherichia coli(E. coli) nitroreductase (EcNfsA) were examined. Compared with other herbal extracts, Syzygium aromaticum extract showed superior inhibitory potency toward EcNfsA mediated nitrofurazone reduction. Then, the inhibitory effects of 22 major constituents in Syzygium aromaticum against EcNfsA were evaluted. Compared with other tested natural compounds, ellagic acid, corilagin, betulinic acid, oleanic acid, ursolic acid, urolithin M5 and isorhamnetin were found with strong to moderate inhibitory effect against EcNfsA, with IC₅₀ values ranging from 0.67 to 28.98 mol·L^-1. Furthermore, the inhibition kinetic analysis and docking simulation demonstrated that ellagic acid and betulinic acid potently inhibited EcNfsA (K_i < 2 μmol·L ^-1) in a competitively inhibitory manner, which created strong interactions with the catalytic triad of EcNfsA. In summary, our findings provide new scientific basis for explaining the anti-mutagenic activity of Syzygium aromaticum, where some newly identified EcNfsA inhibitors can be used for developing novel agents to reduce the toxicity induced by bacterial nitroreductase.
Ellagic Acid/pharmacology* ; Escherichia coli ; Kinetics ; Nitroreductases/pharmacology* ; Plant Extracts/pharmacology* ; Syzygium

The present study explored the kinetics and variation of volatile components of Atractylodis Macrocephalae Rhizoma during the hot-air drying process to obtain the optimal process parameters under multiple goals such as drying efficiency and drying quality. The dry basis moisture content and drying rate curves along with the change of drying time of Atractylodis Macrocephalae Rhizoma were investigated at five levels of drying air temperatures(30, 40, 50, 60, and 70 ℃). The relationship between moisture ratio and time in the drying process of Atractylodis Macrocephalae Rhizoma was fitted and verified by Midilli model, Page model, Overhults model, Modified Page model, Logaritmic model, Two terms Exponential model, and Newton model. Meanwhile, the effective diffusion coefficient of moisture(D_(eff)) and activation energy(E_a) in Atractylodis Macrocephalae Rhizoma were calculated under different drying air temperatures. GC-MS was used to determine the volatile components and content changes of the fresh Atractylodis Macrocephalae Rhizoma and dried products at different temperatures. The dry basis moisture content and drying rate of Atractylodis Macrocephalae Rhizoma were closely related to the temperature of the drying medium, and the moisture of the Atractylodis Macrocephalae Rhizoma decreased with the prolonged drying time. As revealed by the drying rate curve, the drying rate increased with the increase in hot air temperature, and the migration of moisture was accelerated. The comparison of the correlation coefficient(R~2), chi-square(χ~2), and root mean standard error(RMSE) of each model indicated that the parameter average of the Midilli model had the highest degree of fit, with R~2=0.999 2, χ~2=8.78×10~(-5), and RMSE=8.20×10~(-3). Besides, the D_(eff) at 30-70 ℃ was in the range of 1.04×10~(-9)-6.28×10~(-9) m~2·s~(-1), and E_a was 37.47 kJ·mol~(-1). The volatile components of fresh Atractylodis Macrocephalae Rhizoma and dried products at different temperatures were determined by GC-MS, and 18, 18, 18, 17, 17, and 18 compounds were identified respectively, which accounted for more than 84.76% of the volatile components. In conclusion, the hot-air drying of Atractylodis Macrocephalae Rhizoma can be model-fitted and verified and the variation law of the moisture and volatile components of Atractylodis Macrocephalae Rhizoma with temperature is obtained. This study is expected to provide new ideas for exploring the drying characteristics and quality of aromatic Chinese medicine.
Atractylodes ; Drugs, Chinese Herbal ; Hot Temperature ; Kinetics ; Rhizome

In this study, low-field nuclear magnetic resonance(LF-NMR) and magnetic resonance imaging(MRI) were employed to analyze the water distribution, status, and migration in the moistening process of Arecae Semen. Peleg model was adopted to study the water absorption kinetics of Arecae Semen moistened at different water temperatures(10, 30, and 50 ℃). The Arecae Semen samples soaked at different water temperatures all contained four water states: binding water T_(21), non-flowing water T_(22), free water T_(23), and unbound water T_(24). Non-flowing water had the largest increase in peak area during the moistening process, followed by free water. The peak areas of non-flowing water, free water, and total water were correlated with the water content(P<0.01). Therefore, LF-NMR can quickly and non-destructively predict the water content of Arecae Semen during moistening. The peak area of non-flowing water and the content of free water were correlated with the content of arecoline in the soaking solution(P<0.01), which indicated that the faster flow of non-flowing water and more free water corresponded to more arecoline dissolved. The MRI images showed that the water migration pathway varied at different soaking temperatures, and the moistening degree obtained by this means was consistent with that obtained based on traditional experience. The rate constant K_1 fitted by Peleg model decreased with the increase in water temperature, while the capacity constant K_2 showed an opposite trend. The Arrhenius equation fitting of K_1 with temperature showed that the activation energy of Arecae Semen in the moistening process was 32.98 kJ·mol~(-1). LF-NMR/MRI can be used to analyze the water status and content and determine the end moisturing point of Arecae Semen. Peleg model can accurately describe the water absorption properties of Arecae Semen in the moistening process. The findings of this study can guide the moistening optimization and mechanism research of other seed Chinese medicinal materials.
Areca ; Arecoline/analysis* ; Drugs, Chinese Herbal/analysis* ; Kinetics ; Seeds/chemistry* ; Water/analysis*

OBJECTIVE: To analyze the kinetic characteristics of lymphocyte subsets and myeloid-derived suppressor cell (MDSC) in patients who newly diagnosed intermediate- to high-risk aGVHD and treated with steroids-ruxolitinib as the first line therapy from a single-arm, open clinical trial (NCT04061876). METHODS: We prospectively observed the efficacy of 23 patients having intermediate- to high-risk aGVHD and treated with steroids-ruxolitinib as the first line therapy. The kinetic characteristics of lymphocyte subsets and MDSC were monitored, and then we compared them in steroids-ruxolitinib group (n=23), free-aGVHD group (n=20) and steroids group (n=23). RESULTS: Of the 23 patients, the CR rate was 78.26% (18/23) on day 28 after first-line treatment with steroids-ruxolitinib. On day 28 after treatment, patients had lower level of CD4⁺CD29⁺ T cells (P=0.08) than that of pre-treatment, whereas levels of other lymphocyte subsets in this study were higher than that of pre-treatment; CD4⁺CD29⁺ T cells in CR patients decreased, compared with refractory aGVHD patients. On day 28 of treatment, CD8⁺CD28^- T cells (P=0.03) significantly increased in patients with aGVHD than that in patients without aGVHD, so did CD8⁺CD28^- T / CD8⁺CD28⁺ T cell ratio (P=0.03). Compared with patients without aGVHD, patients with aGVHD had lower level of G-MDSC, especially on day 14 after allo-HSCT (P=0.04). Compared with pre-treatment, M-MDSC was higher in CR patients on day 3 and 7 post-treatment (P₃=0.01, P₇=0.03), e-MDSC was higher on day 28 post-treatment (P=0.01). Moreover, compared with CR patients, M-MDSC was lower in refractory aGVHD patients on day 3 post-treatment (P=0.01) and e-MDSC was lower on day 28 post-treatment (P=0.01). Compared with steroids group, MDSC in steroids-ruxolitinib group was higher, with the most significant difference in M-MDSC (P₃=0.0351; P₇=0.0142; P₁₄=0.0369). CONCLUSION We found that patients newly diagnosed intermediate- to high-risk aGVHD receiving first-line therapy with steroids-ruxolitinib achieved high response rate. Moreover, the novel first-line therapy has a small impact on the immune reconstitution of patients after allo-HSCT. Elevated MDSC might predict a better response in aGVHD patients receiving this novel first-line therapy. M-MDSC responded earlier to steroids-ruxolitinib than e-MDSC, G-MDSC.
Graft vs Host Disease ; Hematopoietic Stem Cell Transplantation ; Humans ; Kinetics ; Myeloid-Derived Suppressor Cells ; Nitriles ; Pyrazoles ; Pyrimidines ; Retrospective Studies ; Steroids

Genistein and its monoglucoside derivatives play important roles in food and pharmaceuticals fields, whereas their applications are limited by the low water solubility. Glycosylation is regarded as one of the effective approaches to improve water solubility. In this paper, the glycosylation of sophoricoside (genistein monoglucoside) was investigated using a cyclodextrin glucosyltransferase from Penibacillus macerans (PmCGTase). Saturation mutagenesis of D182 from PmCGTase was carried out. Compared with the wild-type (WT), the variant D182C showed a 13.42% higher conversion ratio. Moreover, the main products sophoricoside monoglucoside, sophoricoside diglucoside, and sophoricoside triglucoside of the variant D182C increased by 39.35%, 56.05% and 64.81% compared with that of the WT, respectively. Enzymatic characterization showed that the enzyme activities (cyclization, hydrolysis, disproportionation) of the variant D182C were higher than that of the WT, and the optimal pH and temperature of the variant D182C were 6 and 40℃, respectively. Kinetics analysis showed the variant D182C has a lower K_m value and a higher k_cat/K_m value than that of the WT, indicating the variant D182C has enhanced affinity to substrate. Structure modeling and docking analysis demonstrated that the improved glycosylation efficiency of the variant D182C may be attributed to the increased interactions between residues and substrate.
Cyclodextrins ; Genistein ; Glucosyltransferases/metabolism* ; Glycosylation ; Kinetics

β-glucosidase has important applications in food, medicine, biomass conversion and other fields. Therefore, exploring β-glucosidase with strong stability and excellent properties is a research hotspot. In this study, a GH3 family β-glucosidase gene named Iubgl3 was successfully cloned from Infirmifilum uzonense. Sequence analysis showed that the full length of Iubgl3 was 2 106 bp, encoding 702 amino acids, with a theoretical molecular weight of 77.0 kDa. The gene was cloned and expressed in E. coli and the enzymatic properties of purified IuBgl3 were studied. The results showed that the optimal pH and temperature for pNPG hydrolysis were 5.0 and 85 ℃, respectively. The enzyme has good thermal stability, and more than 85% of enzyme activity can be retained after being treated at 80 ℃ for2 h. This enzyme has good pH stability and more than 85% of its activity can be retained after being treated at pH 4.0-11.0 for 1 h. It was found that the enzyme had high hydrolysis ability to p-nitrophenyl β-d-glucoside (pNPG) and p-nitrophenyl β-d-xylopyranoside (pNPX). When pNPG was used as the substrate, the kinetic parameters K_m and V_max were 0.38 mmol and 248.55 μmol/(mg·min), respectively, and the catalytic efficiency k_cat/K_m was 6 149.20 s^-1mmol^-1. Most metal ions had no significant effect on the enzyme activity of IuBgl3. SDS completely inactivated the enzyme, while EDTA increased the enzyme activity by 30%. This study expanded the β-glucosidase gene diversity of the thermophilic archaea GH3 family and obtained a thermostable acid bifunctional enzyme with good industrial application potential.
beta-Glucosidase/chemistry* ; Archaea/metabolism* ; Escherichia coli/metabolism* ; Hydrogen-Ion Concentration ; Temperature ; Glucosides ; Enzyme Stability ; Substrate Specificity ; Kinetics

OBJECTIVES: To study the cooling reaction kinetic characteristics of the temperature difference between cadaver temperature and ambient temperature (hereinafter referred to as "cadaver temperature difference") according to the reaction kinetics method. METHODS: Thirty rabbits were randomly divided into 5 groups with 6 rabbits in each group. The rabbits were injected with 10% potassium chloride solution intravenously. After death, the rabbits were placed at 5 ℃, 10 ℃, 15 ℃, 20 ℃ and 25 ℃ environment condition, respectively, and the rectal temperature was measured every minute for 20 hours. The measured cadaver temperature was subtracted from ambient temperature, and the cadaver temperature difference data was calculated using the reaction kinetics formula. The linear regression equation was fitted for analysis, and the experimental results were applied to the temperature difference data of human body after death for verification. RESULTS: Under different environmental conditions, the linear coefficient determination of temperature difference -ln(C/C₀) in rabbits was 0.99, showing a good linear relationship with time t. The application of human body temperature data after death was consistent with the results of animal experiments. CONCLUSIONS Under stable conditions, the temperature difference cooling process after death in rabbits is a first-order kinetic response. The method can also be used to study the temperature difference in human body after death.
Animals ; Humans ; Rabbits ; Body Temperature ; Temperature ; Kinetics ; Cadaver

Content of multiple components (neochlorogenic acid,L-tryptophan,vicenin-2,isoquercitrin,and astragalin) in Moringa oleifera leaves was determined by high-performance liquid chromatography (HPLC),and the absolute content-time curves were plotted.Based on Fick's law of diffusion and Higbie's penetration theory,the parameters of the equations were calculated,and the measured results were substituted into the mathematical model to fit the equations.The n and a obtained from the equations on the decocting time factor and the solvent volume were close to each other.The dynamic models of the five components are as follows:■.The variation of the content of multiple components in M.oleifera leaves with time and solvent volume was explored.It was found that the content of the components was the highest when the leaves were decocted for 30 min with solvent volume 12 folds of the medicinal material.The dissolution and destruction of components and the diffusion movement of components are the main causes of the content change of M.oleifera leaves at different time and with different solvent volumes.The R~2of the linear equations on the content and the equations on the decocting process (5-30min and solvent volume 12-20 folds of the medicinal materials) was≥0.999 8 and≥0.9,respectively.Thus,the content determination and the decocting kinetic model had high accuracy,which can reflect the change law of the content of key components in M.oleifera leaves during the decoction.This study is expected to serve as a reference for optimizing the decocting technology.
Kinetics ; Moringa oleifera/chemistry* ; Plant Leaves/chemistry* ; Solvents ; Tryptophan/analysis*

This paper aims to study the difference in the intestinal absorption kinetics of main active components of Sini decoction and its separated recipes and explain the scientificity and rationality of the compatibility of Sini Decoction. A in situ intestinal perfusion rat model was established to evaluate the differences in the absorption of benzoylmesaconine, benzoylaconine, benzoylhypacoitine, mesaconitine, hypaconitine, glycyrrhizic acid, liquiritin and 6-gingerol from Sini Decoction and its separated recipes in the duodenum, jejunum and ileum by high performance liquid chromatography(HPLC). The results indicated that the Sini Decoction group was superior to the Aconiti Lateralis Radix Praeparata group in terms of absorption degree and rate for aconitum alkaloids. The absorption of benzoylmesaconine and hypaconitine in the duodenum, jejunum and ileum was faster and stronger in the Sini Decoction group(P<0.05). The absorption degree of glycyrrhizic acid in the duodenum was significantly higher in the Sini Decoction group than in the Glycyrrhizae Radix et Rhizoma group and the Glycyrrhizae Radix et Rhizoma-Zingiberis Rhizoma group(P<0.05). The absorption rate and degree of 6-gingerol in the ileum in the Sini Decoction group were significantly higher than those in the Zingiberis Rhizoma group(P<0.05). In short, Zingiberis Rhizoma and Glycyrrhizae Radix et Rhizoma can promote the absorption of aconitum alkaloids in different intestinal segments, which reflects the scientific composition of Sini Decoction.
Aconitine/analogs & derivatives* ; Aconitum ; Alkaloids ; Animals ; Catechols ; Drugs, Chinese Herbal ; Fatty Alcohols ; Glycyrrhizic Acid ; Intestinal Absorption ; Kinetics ; Rats