Biological effects of essential oils - A review

The median-effect equation derived from the mass-action law principle at equilibrium-steady state via mathematical induction and deduction for different reaction sequences and mechanisms and different types of inhibition has been shown to be the unified theory for the Michaelis-Menten equation, Hill equation, Henderson-Hasselbalch equation, and Scatchard equation. It is shown that dose and effect are interchangeable via defined parameters. This general equation for the single drug effect has been extended to the multiple drug effect equation for n drugs. These equations provide the theoretical basis for the combination index (CI)-isobologram equation that allows quantitative determination of drug interactions, where CI 1 indicate synergism, additive effect, and antagonism, respectively. Based on these algorithms, computer software has been developed to allow automated simulation of synergism and antagonism at all dose or effect levels. It displays the dose-effect curve, median-effect plot, combination index plot, isobologram, dose-reduction index plot, and polygonogram for in vitro or in vivo studies. This theoretical development, experimental design, and computerized data analysis have facilitated dose-effect analysis for single drug evaluation or carcinogen and radiation risk assessment, as well as for drug or other entity combinations in a vast field of disciplines of biomedical sciences. In this review, selected examples of applications are given, and step-by-step examples of experimental designs and real data analysis are also illustrated. The merging of the mass-action law principle with mathematical induction-deduction has been proven to be a unique and effective scientific method for general theory development. The median-effect principle and its mass-action law based computer software are gaining increased applications in biomedical sciences, from how to effectively evaluate a single compound or entity to how to beneficially use multiple drugs or modalities in combination therapies.

http://www.protocol-online.org/forums/uploads/monthly_09_2010/post-8165-008503000%201284677034.ipb

Theoretical Basis, Experimental Design, and Computerized Simulation of Synergism and Antagonism in Drug Combination Studies

Antiseptics and disinfectants are extensively used in hospitals and other health care settings for a variety of topical and hard-surface applications A wide variety of active chemical agents (biocides) are found in these products, many of which have been used for hundreds of years, including alcohols, phenols, iodine, and chlorine Most of these active agents demonstrate broad-spectrum antimicrobial activity; however, little is known about the mode of action of these agents in comparison to antibiotics This review considers what is known about the mode of action and spectrum of activity of antiseptics and disinfectants The widespread use of these products has prompted some speculation on the development of microbial resistance, in particular whether antibiotic resistance is induced by antiseptics or disinfectants Known mechanisms of microbial resistance (both intrinsic and acquired) to biocides are reviewed, with emphasis on the clinical implications of these reports

/pdf/antiseptics-and-disinfectants-activity-action-and-resistance-4s72yz0ujj.pdf

Antiseptics and Disinfectants: Activity, Action, and Resistance

The glutathione S-transferases (GST) represent a major group of detoxification enzymes. All eukaryotic species possess multiple cytosolic and membrane-bound GST isoenzymes, each of which displays distinct catalytic as well as noncatalytic binding properties: the cytosolic enzymes are encoded by at least five distantly related gene families (designated class alpha, mu, pi, sigma, and theta GST), whereas the membrane-bound enzymes, microsomal GST and leukotriene C, synthetase, are encoded by single genes and both have arisen separately from the soluble GST. Evidence suggests that the level of expression of GST is a crucial factor in determining the sensitivity of cells to a broad spectrum of toxic chemicals. In this article the biochemical functions of GST are described to show how individual isoenzymes contribute to resistance to carcinogens, antitumor drugs, environmental pollutants, and products of oxidative stress.A description of the mechanisms of transcriptional and posttranscriptional regulat...

The glutathione S-transferase supergene family: regulation of GST and the contribution of the isoenzymes to cancer chemoprotection and drug resistance.

Theories of human behavior differ in their conceptions of human nature and what they regard as the basic determinants and mechanisms governing self-development, adaptation, and change. Social cognitive theory is rooted in an agentic perspective ( Bandura 1986, 2006a). To be an agent is to influence one's own functioning and events that affect one's life. In this view people are contributors to their life circumstances, not just products of them.


Keywords:

Information Processing and Cognitions;
Psychology

https://www.uky.edu/~eushe2/Bandura/Bandura1989ACD.pdf

Social cognitive theory

The mechanisms of action of inhibitors of mutagenesis and carcinogenesis are reviewed in the light of our present knowledge. The identified mechanisms are classified into several categories and sub-categories, depending on the stage of intervention in the mutagenesis and carcinogenesis processes, and on the patterns of modulation of the host defense devices. Although a number of the known mechanisms fit into the proposed scheme, the available information on these problems is still fragmentary, and often inhibitors act through multiple mechanisms or can interact with other inhibitors. Moreover, due to the double-edged nature of many protective factors of the organism, and to the wide array of biological properties displayed by several inhibitors, the beneficial effects are in many instances counter-balanced by adverse reactions. Nevertheless, the present data-base on mechanisms of inhibitors, which is expected to grow rapidly in the near future, provides an extremely useful scientific premise for the primary prevention of mutation-related diseases. In this prospect, the elucidation of the underlying mechanisms complements the results emerging from the monitoring of protective end-points in mutagenicity and carcinogenicity test systems.

Mechanisms of inhibitors of mutagenesis and carcinogenesis. Classification and overview.

The mutagenic effect of 1,2-dichloroethane on Salmonella typhimurium I. Activation through conjugation with glutathion in vitro

To evaluate the usefulness of the micronucleus test as a short-term assay for the detection of carcinogens, the correlation between micronucleus test data for 143 chemicals and corresponding cancer data, has been analyzed. For comparison, analogous data from Ames's test have also been collected for the same chemicals. In a comparison of the micronucleus test and Ames's test it was found that they had about the same specificity (around 80%) and predictive value (around 90%), while there was a significant difference in sensitivity in favor of Ames's test. The difference in sensitivity could be partly explained by differences in metabolizing capacities of these two test systems. It is concluded that a more elaborate test procedure for the micronucleus test would increase the sensitivity of this test. The principal value of the micronucleus test lies in the fact that it is an in vivo method, which may pick up effects at the chromosomal level not covered by bacterial assays. This is emphasized by the finding that the combination of Ames's test and the micronucleus test did increase the sensitivity of the screening procedure for the prediction of carcinogenic effects.

The micronucleus test as part of a short-term mutagenicity test program for the prediction of carcinogenicity evaluated by 143 agents tested.

From a study of the effect of X irradiation on meiosis of the grasshopper Stethophyma grossum spermatocytes, it was deduced that the so-called “subchromatid aberrations” and the other effects which are generally referred to as physiological effects (i.e., stickiness, clumping and erosion of chromosomes) are in reality chromatid aberrations. The appearance of these aberrations results from the induction of breaks and exchanges in chromosomes during the prophase contraction, in which the chromatin fibers are held together in a three-dimensional organisation and cannot unfold. The origin of these kinds of aberrations can be explained on the basis of the folded fiber model of the chromosome. During meiosis in many organisms, a diffuse stage resembling the interphase nucleus (between pachytene and diplotene) is known to exist. If the diffuse stage is irradiated 48 hours or more before fixation with 500 R of X-rays, the diplotene folding is only partially realized and meiosis is blocked after the formation of an irregular network of chromatin fibers. The results indicate that although the diffuse stage looks like a regression to an interphase stage, the chromosome organisation is likely to be different. Irradiation with the same dose at a later stage (26 hours or less before fixation) does not prevent the course of meiosis.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1601-5223.1976.tb01581.x

Claes Ramel

Papers

Mechanisms of inhibitors of mutagenesis and carcinogenesis. Classification and overview.

The mutagenic effect of 1,2-dichloroethane on Salmonella typhimurium I. Activation through conjugation with glutathion in vitro

The micronucleus test as part of a short-term mutagenicity test program for the prediction of carcinogenicity evaluated by 143 agents tested.

An interpretation of the origin of subchromatid aberrations and chromosome stickiness as a category of chromatid aberrations

Geetic effects of organic mercury compounds. I. Cytological investigations on Allium roots.