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Journal of Thermal Analysis and Calorimetry
Authors:
Yumei Han
,
Dan Yan
,
Yanling Zhao
,
Cheng Peng
, and
Xiaohe Xiao

Abstract

Rhizoma Coptidis consists mainly of protoberberine alkaloids (PAs), and has been used for many years as a traditional medicine. Recent research revealed the toxicity of Rhizoma Coptidis, but studies focusing on the relationships between the structures of PAs and their toxicities are lacking. The toxic effects of four PAs from Rhizoma Coptidis on the growth of Tetrahymena thermophila BF5 were investigated by microcalorimetry. The power-time curves of T. thermophila BF5 with and without PAs were obtained; the extent and duration of toxic effects on the metabolism of this organism were evaluated by studying thermokinetic parameters and the half-inhibitory ratio (IC 50). All the thermokinetic parameters showed regular variations with alteration of PA concentrations. The magnitude of the toxic effects of PAs was ascertained from IC 50 values: palmatine > jateorhizine > berberine ≈ coptisine. The structure–function relationship of PAs indicated that the C2 and C3 positions contributed more to the toxic effect of PAs. That is, when substituted with methoxyl groups, the toxic effect would be increased.

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Abstract  

In this study, the microcalorimetric method was applied to investigate the activity of berberine on Shigella dysenteriae (S. dysenteriae). Heat flow power (HFP)–time curves of the growth metabolism of S. dysenteriae affected by berberine were determined using the thermal activity monitor (TAM) air isothermal microcalorimeter, ampoule mode, at 37 °C. By analyzing these curves and some quantitative parameters using multivariate analytical methods, similarity analysis (SA) and principal component analysis (PCA), the antibacterial activity of berberine on S. dysenteriae could be accurately evaluated from the change of the two main parameters, the maximum heat flow power P m 2 and total heat output Q t: berberine at low concentration (25 μg mL−1) began to inhibit the growth of S. dysenteriae, high concentrations (50–200 μg mL−1) of berberine had strong antibacterial activity on S. dysenteriae, when the concentration of berberine was higher (250–300 μg mL−1), this antibacterial activity was stronger. All these illustrated that the antibacterial activity of berberine on S. dysenteriae was enhanced with the increase of the concentration of this compound. Berberine can be used as potential novel antibacterial agent for treating multidrug-resistant Shigella. This work provided a useful idea of the combination of microcalorimetry and multivariate analysis for studying the activity of other compounds or drugs on organisms.

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Abstract  

Using a LKB-2277 bioactivity monitor, stop-flow mode, the power–time curves of Candida albicans growth at 37 °C affected by berberine were measured. The check experiments were studied based on agar cup method to observe the inhibitory diameter and serial dilution method to determine the minimal inhibitory concentration (MIC) of berberine on C. albicans growth. By analyzing the quantitative thermogenic parameters taken from the power–time curves using correspondence analysis (CA), we could find that berberine at a low concentration (5.0 μg mL−1) began to inhibit the growth of C. albicans and at a high concentration (75.0 μg mL−1) completely inhibited C. albicans growth. The anti-fungal activity of berberine could also be expressed as half-inhibitory concentration IC50, i.e., 50% effective in this inhibition. The value of IC50 of berberine on C. albicans was 34.52 μg mL−1. The inhibitory diameters all exceeded 10 mm in test range and the MIC was 500 μg mL−1. Berberine had strong anti-fungal effect on C. albicans growth. This work provided an important idea of the combination of microcalorimetry and CA for the study on anti-fungal effect of berberine and other compounds. Compared with the agar cup method and serial dilution method, microcalorimetry not only offered a useful way for evaluating the bioactivity of drugs, but also provides more information about the microbial growth and all this information was significant for the synthesis and searching of antibiotics.

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Abstract

The power–time curves of mice splenic lymphocytes growth at 37 °C affected by ginsenoside Rh2 were determined by microcalorimetry using a 3114/3236 TAM air bioactivity monitor with ampoule mode. Then, the minimal inhibitory concentration (MIC) of Rh2 on splenic lymphocytes growth was determined by serial dilution method. From factor analysis (FA) on six quantitative thermokinetic parameters from the power–time curves, the activity of Rh2 on splenic lymphocytes could be quickly evaluated by analyzing the changes in the two main parameters: growth rate constant k, and maximum heat-output power, P m. The results showed that Rh2 had strong inhibitory activity on splenic lymphocytes growth, and this inhibitory activity was strengthened with increasing concentration of Rh2 in the concentration range of 1.0–32.0 μg mL−1. This strong inhibitory also could be confirmed from the MIC of 50.0 μg mL−1 of Rh2 on splenic lymphocytes growth in RPMI-1640 culture medium. This study illustrated that microcalorimetry could not only offer a useful method for evaluating the activity of drugs, but also serve as a quantitative, sensitive, and simple analytic tool for the evaluation of drugs on cell growth.

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Application of microcalorimetry and principal component analysis

Antibacterial evaluation of Benzoinum and Styrax on Staphylococcus aureus growth

Journal of Thermal Analysis and Calorimetry
Authors:
Jian Wang
,
Danhong Cheng
,
Nan Zeng
,
Houlin Xia
,
Yong Fu
,
Dan Yan
,
Yanling Zhao
, and
Xiaohe Xiao

Abstract  

A useful microcalorimetric technique based on the bacterial heat production was applied to evaluate the antibacterial effects of Benzoinum and Styrax on the growth of Staphylococcus aureus (S. aureus). The thermogenic power-time curves of S. aureus growth in the presence of the two drugs were determined by a thermal activity monitor (TAM) air isothermal microcalorimeter, ampoule mode, at 310 K. Some quantitative metabolic parameters, such as growth rate constant k, the heat-flow power P, the appearance time for the heat power t, and the heat production Q were obtained from these curves. By analyzing these curves and some quantitative parameters using principal component analysis (PCA), the antibacterial effects of Benzoinum and Styrax on S. aureus growth were accurately evaluated from the change of the two main parameters, the heat-flow power for the second peaks P 2nd and total heat production Q t: the antibacterial effects of the two drugs at concentrations of 0–125 mg mL−1 were both enhanced with increasing the concentration, and Benzoinum with IC50 of 132.2 mg mL−1 had stronger antibacterial effect than Styrax with IC50 of 179.8 mg mL−1. This study provides some useful references for the application of Benzoinum and Styra as potential antibacterial agents. Microcalorimetry is a powerful analytical tool for the characterization of the microbial growth progress and the evaluation of the drugs’ efficiency.

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Journal of Thermal Analysis and Calorimetry
Authors:
Xingfeng Li
,
Cheng Jin
,
Wei Liu
,
Jian Zhou
,
Weijun Kong
,
Bing Dai
,
Jiabo Wang
,
Dan Yan
,
Yanling Zhao
,
Yun Luo
, and
Xiaohe Xiao

Abstract

Using microcalorimetry, the characteristic metabolic heat flow power-time curves of S. aureus growth affected by Ursodesoxycholic acid and Hyodeoxycholic acid were measured at 37 °C. The thermal-kinetic parameters such as, growth rate constant k, the maximum power output (P m), the time corresponding to the maximum power output (t p), total heat-production Q t , half inhibitory concentration of the drugs (IC 50) were calculated from the growth curves. For both HDCA and UDCA, with the increasing of concentration, k, P m, and Q t decreased, meanwhile, kc fit a linear equation, t p was prolonged correspondingly. Principle component analysis, the results indicated t p might be the main parameter in evaluating the antibacterial activity of HDCA and UDCA in microcalorimetric method. Combining with t p and IC 50, the results revealed that the differences and trends of antibacterial activity of these bile acid derivatives were: HDCA > UDCA. Structure-activity relationship (SAR) analysis showed that the α-OH at C-3 and C-6 position at equal pace on the steroid nucleus enhanced the hydrophilicity of HDCA, which led to a stronger antibacterial effect than UDCA. In this study, a useful tool was provided to accurately evaluate the antibacterial effects of bile acid derivatives. The thermolysis curve recorded by microcalorimetry could provide a lot of kinetic and thermodynamic information for the study of growth process of living microbial, which could be helpful in the screening of high efficacy antibacterial agents.

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Application of microcalorimetry and chemometric analysis

Effects evaluation of angle and nail animal drugs on Bacillus subtilis growth

Journal of Thermal Analysis and Calorimetry
Authors:
Xiaoyan Xing
,
Yanling Zhao
,
Weijun Kong
,
Yanwei Zhong
,
Dan Yan
,
Ping Zhang
,
Yumei Han
,
Lei Jia
,
Cheng Jin
, and
Xiaohe Xiao

Abstract

In this study, microcalorimetry combined with chemometric analysis was used to investigate the effects of angle and nail animal valuable drugs on Bacillus subtilis (B. subtilis) growth. The power–time curves of the growth metabolism of B. subtilis affected by Cornu Cervi Pantotrichum, Cornu Cervi Elaphi, Cornu Saigae Tataricae, cornu caprae hircus, Cornu Bubali, Squama Manis, and Carapax Trionycis were determined using a thermal activity monitor (TAM) air isothermal microcalorimeter, ampoule mode, at 37 °C. By analyzing these curves and some quantitative parameters using principal component analysis, the effects of the seven animal drugs on B. subtilis could be quickly evaluated from the change of the two main parameters, the maximum heat-flow power P m 2 and total heat output Q t: Cornu Saigae Tataricae, cornu caprae hircus, Cornu Bubali, Squama Manis, and Carapax Trionycis inhibited the growth of B. subtilis, while Cornu Cervi Pantotrichum and Cornu Cervi Elaphi promoted the growth of B. subtilis. Further, the result of hierarchical clustering analysis showed that the drugs which promoted the growth of B. subtilis gathered in one cluster, the other drugs which inhibited the growth of B. subtilis gathered in the other cluster. All these illustrated that the internal characteristics of the seven animal drugs were different though they had similar resources and these drugs could be well clustered according the effects of them on B. subtilis growth with the help of chemometric methods. This study provided an useful idea of the combination of microcalorimetry and chemometric analysis for studying the effects of drugs on organisms.

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Abstract

The antibacterial effect of Curcumin on Staphylococcus aureus growth was evaluated by microcalorimetry. The heat flow power–time curves and nine quantitative parameters of the S. aureus growth were applied to investigate the inhibitory effect with Curcumin. By analyzing these curves and some quantitative parameters using multivariate analytical methods, similarity analysis and principal component analysis, the antibacterial activity of Curcumin on S. aureus could be accurately evaluated from the change of the two main parameters, the second exponential growth rate constant k 2 and the maximum heat flow power P m 2. The main two thermal parameters played more important role in the evaluation: at low concentration (0–10.5 μg mL−1), Curcumin hardly influence the growth of S. aureus, while at high concentration (10.5–43.4 μg mL−1) it could notably inhibit the growth. All these illustrated that the antibacterial activity of Curcumin on S. aureus was enhanced with the increase of the concentration of this compound. This study might provide an useful method and idea accurately evaluate the antibacterial effects of Curcumin, which provides some useful methods for evaluate the nature antibacterial agents.

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Abstract

Splenic lymphocytes play an important role in host acute or chronic diseases. The abnormality of these cells in the spleens of humans might lead to some riskful diseases for human. Hence, in this study, the effects of two ginsenosides Rg1 and Rb1 on splenic lymphocytes growth were studied by microcalorimetry. Some qualitative and quantitative information, such as the metabolic power-time curves, growth rate constant k, maximum heat-output power of the exponential phase P max, total heat output Q t of splenic lymphocytes were obtained to present the effects of Rg1 and Rb1 on these cells. The values of k, P max, and Q t from the thermogenic growth curves of splenic lymphocytes were found to increase in the presence of Rg1, while the change was adverse for Rb1, illustrating that Rg1 had promotion effect and Rb1 had inhibitory effect on splenic lymphocytes growth and these promotion or inhibitory effects were enhanced with increasing the concentration of the two compounds, respectively. The microcalorimetric results were confirmed by MTT assay for determining the MTT optical density (OD) value and [3H] Thymidine incorporation assay ([3H]-TdR) for determining the count per minute (cpm) value: Rg1 could increase the MTT OD value and the cpm value of [3H]-TdR incorporation into splenic lymphocytes, and these values were increased with increasing the concentration of this compound, while Rb1 had the adverse results. The structure–activity relationships showed that the glucopyranoside and hydroxyl groups at the dammarane-type mother nucleus skeleton might play a crucial role for the opposing effects of the two ginsenosides on splenic lymphocytes. Compared with the other two assay methods, the microcalorimetric method provided more useful and reliable information for quickly and objectively evaluating the effects of drugs or compounds on the living cells, which would be a highly promising analytical tool for the characterization of the biological process and the estimation of the drugs’ efficiency.

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Abstract

In this study, the activities of four ginsenosides Rc, Re, Rd, and Rf on splenic lymphocytes growth were studied by microcalorimetry. Some qualitative and quantitative information, such as the metabolic power–time curves, growth rate constant k, maximum heat-output power of the exponential phase P max and the corresponding appearance peak time t max, total heat output Q t, and promotion rate R p of splenic lymphocytes growth affected by the four ginsenosides were calculated. In accordance with thermo-kinetic model, the corresponding quantitative relationships of k, P max, t max, Q t, R p, and c were established. Also, the median effective concentration (EC50) was obtained by quantitative analysis. Based on both the quantitative quantity–activity relationships (QQAR) and EC50, the sequence of promotion activity was Rc > Re > Rd > Rf. The analysis of structure–activity relationships showed that the number, type, and position of sugar moieties on the gonane steroid nucleus had important influences on the promotion activity of Rc, Re, Rd, and Rf on splenic lymphocytes growth. Microcalorimetry can be used as a useful tool for determining the activity and studying the quantity–activity relationship of drugs on cell.

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