Chemical reaction mechanism of decoction of traditional Chinese medicines: a review / 中国中药杂志

Complicated chemical reactions occur in the decoction of traditional Chinese medicines(TCMs) which features complex components, influencing the safety, efficacy, and quality controllability of TCMs. Therefore, it is particularly important to clarify the chemical reaction mechanism of TCMs in the decoction. This study summarized eight typical chemical reactions in the decoction of TCMs, such as substitution reaction, redox reaction, isomerization/stereoselective reaction, complexation, and supramolecular reaction. With the "toxicity attenuation and efficiency enhancement" of aconitines and other examples, this study reviewed the reactions in decoction of TCMs, which was expected to clarify the variation mechanisms of key chemical components in this process and to help guide medicine preparation and safe and rational use of medicine in clinical settings. The current main research methods for chemical reaction mechanisms of decoction of TCMs were also summed up and compared. The novel real-time analysis device of decoction system for TCMs was found to be efficient and simple without the pre-treatment of samples. This device provides a promising solution, which has great potential in quantity evaluation and control of TCMs. Moreover, it is expected to become a foundational and exemplary research tool, which can advance the research in this field.

Research progress of microparticles in traditional Chinese medicine decoction / 药学学报

Decoction is a classical dosage form of traditional Chinese medicines. In the process of decocting, various complex components produce physical interactions and chemical reactions, among which physical interactions include van der Waals force, hydrogen bond, electrostatic interaction, π-π stacking, etc., and chemical reactions include Maillard reaction, oxidation reaction, hydrolysis reaction, degradation reaction, polymerization reaction, etc. New substances and original ingredients from chemical reactions can be further activated. These effects form the basis of particle formation in the broth. The sizes of the particles in decoctions range from nanoscale to micron scale, mostly composed of polysaccharide, protein matrix, wrapped in water insoluble molecules, can increase the dispersion of insoluble components and the stability of unstable components, as well as reduce the volatile components and toxic components of volatile components, and ultimately achieve the purpose of efficient absorption and toxicity reduction. From the angle of physical change and chemical reaction in the process of decoction, this paper expounds the formation mechanism of particles in decoction, expounds the research method of particles, analyzes the components in particles and the interaction between components, and then explains the pharmacodynamic characteristics of traditional Chinese medicine decoction, which provides the foundation for the modernization of Chinese decoction.

Biological homochirality and stoichiometric network analysis: Variations on Frank's model / Homoquiralidad biológica y el análisis de redes estequiométricas: el modelo de Frank y sus variantes / Homoquiralidade biológica e análise de redes estequiométricas: O modelo de Frank e as suas variantes

Abstract Biological homochirality is modelled using chemical reaction mechanisms that include autocatalytic and inhibition reactions as well as input and output flows. From the mathematical point of view, the differential equations associated with those mechanisms have to exhibit bistability. The search for those bifurcations can be carried out using stoichiometric network analysis. This algorithm simplifies the mathematical analysis and can be implemented in a computer programme, which can help us to analyse chemical networks. However, regardless of the reduction to linear polynomials, which is made possible by this algorithm, in some cases, the complexity and length of the polynomials involved make the analysis unfeasible. This problem has been partially solved by extending the stoichiometric matrix with rows that code the duality relations between the different reactions occurring in the network given as input. All these facts allow us to analyse 28 different network models, highlighting the basic requirements needed by a chemical mechanism to have spontaneous mirror symmetry breaking.

Resumen El origen de la homoquiralidad biológica se ha modelado usando mecanismos de reacción con pasos autocatalíticos, de inhibición y flujos de entrada y salida. Desde el punto de vista de las matemáticas, las ecuaciones diferenciales asociadas a tales mecanismos deben exhibir biestabilidad. La búsqueda de tales bifurcaciones se puede hacer usando el análisis de redes estequiométricas. Tal algoritmo facilita el trabajo matemático y se puede implementar en un programa de computadora, con lo que se simplifica el análisis y ayuda a entender y mejorar los mecanismos de reacción. No obstante, y a pesar de la reducción en la complejidad que es alcanzada usando el análisis de redes estequiométricas, la dificultad y la longitud de los polinomios involucrados hacen que, en los casos más difíciles y de mayor envergadura, la solución de estos no sea posible. En este trabajo se ha superado parcialmente el problema, adicionando a la matriz estequiométrica un conjunto de filas que codifican la relación de dualidad entre las diferentes reacciones presentes en la red química dada como entrada al programa. Así, hemos logrado analizar 28 modelos diferentes de homoquiralidad biológica, extrayendo de ellos el conjunto de requisitos necesarios para tener un modelo cinética y termodinámicamente consistente.

Resumo A origem da homoquiralidade biológica foi modelada usando mecanismos de reação com etapas autocatalíticas, de inibição e fluxos de entrada e saída. Do ponto de vista da matemática, as equações diferenciais associadas a tais mecanismos devem ser instáveis. A instabilidade pode ser estudada usando o algoritmo de análise de redes estequiométricas. Tal algoritmo facilita o trabalho matemático e pode ser implementado num programa de computador, o que simplifica a análise e ajuda a entender e melhorar os mecanismos de reação. No entanto, e apesar da redução na complexidade que é alcançada usando a análise de redes estequiométricas, a complexidade e comprimento dos polinômios envolvidos fazem que, nos casos mais complexos e de maior envergadura, a solução dos mesmos não seja possível. Neste trabalho, o problema foi superado, parcialmente, adicionando à matriz estequiométrica um conjunto de linhas que codificam a relação de dualidade entre as diferentes reações presentes na rede química dada como entrada ao programa. Desta forma foi possível analisar 28 modelos diferentes de homoquiralidade biológica, extraindo deles o conjunto de requisitos necessários para ter um modelo cinético e termodinamicamente consistente.

Studies on scutellarin and its degradation kinetics in Dengzhanhuasu Injection / 中草药

Objective: To investigate the stability of aqueous solution of scutellarin at different pH values, temperature, ionic strengths, and initial concentration under the condition of dynamic characteristics of the degradation reaction according to ICH guidelines. Methods: The content of scutellarin change with time in different conditions was studied using HPLC method. Based on the chemical reaction kinetics, the parameters of degradation kinetics were calculated under different conditions. The activation energy and half-time (t1/2) were evaluted. Results: The degradation of scutellarin in different conditions followed the first-order kinetics process. The most stable enviroment was in aqueous solutions of pH 7 at 25℃, the half-life period was 203.87 h and the reaction activation energy was 97.9 kJ/mol. But with the temperature increased, the degradation reaction rate greatly accelerated. Under any condition, the stability is higher than the monomer. The initial concentration and ionic strength of Na+ and Cl- had no influence for its degradation. Conclusion: The degradation of scutellarin in different conditions follows the first-order kinetics process and is greatly influenced by the environment of high temperature, strong acid, and weak alkaline. The injection with five kinds of commonly used infusion compatibility is unstable.

Como estudantes compreendem uma reação química? Concepções sobre um processo de combustão / How do students understand a chemical reaction? Conceptions of a combustion process

O presente trabalho tem por objetivo conhecer as concepções de estudantes ingressantes no ensino médio a respeito de conceitos fundamentais que caracterizam as transformações químicas. Trata-se de um estudo de caso, em que dezessete estudantes de uma instituição pública de ensino propuseram explicações para um problema sobre um processo de combustão. As respostas por eles elaboradas foram categorizadas por meio da análise de conteúdo. Foi evidenciado que os estudantes utilizam distintos modelos para interpretar o que acontece durante uma reação química e que, na maioria das situações, esses modelos constituem obstáculos para a aprendizagem dos conceitos que são objeto de estudo da química. Embora indiquem a não conservação das substâncias como critério para justificar a ocorrência de uma reação química, a não conservação da matéria e da massa estão presentes nas ideias de transmutação, desaparecimento, substituição, entre outras. Além disso, foram explicitadas confusões conceituais no emprego da linguagem científica e na representação da combustão (desenho), de modo que, ressalta-se a importância dos resultados evidenciados nesta investigação para a proposição de ações que busquem qualificar o ensino e da aprendizagem da química na educação básica

This paper aims understanding students' conceptions of fundamental concepts that characterize the chemical transformations. Thisis a case study in which seventeen students of the first year in a public high school proposed explanations for a problem about a combustion process. The answers given were categorized by means of content analysis. It was evident thatstudents use different models to interpret what happens during a chemical reaction and that, in most situations, these models constitute barriers that prevent students from learning the concepts that are the object of study of chemistry. Althoughthey mention the loss of substance as a criterion to justify the occurrence of a chemical reaction, the notion of mass and matter loss is present in the ideas of transmutation, disappearance and replacement, among others. Furthermore, conceptual misunderstandings were explicitin the use of scientific language and in the representation of combustion (drawings), so that the study emphasizes the relevance of the results found in this research to propose actions that seek to qualify the teaching and learning processes of chemistry in basic education

Chemical Reaction of VOCs in Indoor Air and Health Effects / 环境与健康杂志

Many kinds of volatile organic compounds(VOCs)exist in the indoor air,the chemical reaction will occur among the pollutants when O3 and NO2 exist simultaneously.This reaction can severely impact the indoor air quality and produce some adverse effects on human health.The main chemical reactions among the indoor air pollutants and the potential health effects associated with inhalation exposure to the products of the chemical reaction in the indoor air were discussed in the present paper.The study of the chemical reactions among indoor VOCs is very important for human health and is helpful for revising the Indoor Air Quality Standard and making the 'Ecologic Label' of building materials.