The structure–activity relationship (SAR) is the relationship between the
chemical structure
A chemical structure of a molecule is a spatial arrangement of its atoms and their chemical bonds. Its determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target m ...
of a molecule and its
biological activity
In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or ...
. This idea was first presented by
Alexander Crum Brown
Alexander Crum Brown Fellow of the Royal Society of Edinburgh, FRSE Fellow of the Royal Society, FRS (26 March 1838 – 28 October 1922) was a Scottish Organic chemistry, organic chemist. Alexander Crum Brown Road in Edinburgh's King's Buildi ...
and
Thomas Richard Fraser at least as early as 1868.
The analysis of SAR enables the determination of the chemical group responsible for evoking a target biological effect in the organism. This allows modification of the effect or the
potency
Potency may refer to:
* Potency (pharmacology), a measure of the activity of a drug in a biological system
* Virility
* Cell potency, a measure of the differentiation potential of stem cells
* In homeopathic dilutions, potency is a measure of ho ...
of a
bioactive compound
A bioactive compound is a compound that has an effect on a living organism, tissue or cell, usually demonstrated by basic research in vitro or in vivo in the laboratory. While dietary nutrients are essential to life, bioactive compounds have not ...
(typically a drug) by changing its chemical structure.
Medicinal chemists use the techniques of
chemical synthesis
Chemical synthesis (chemical combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In modern laboratory uses ...
to insert new chemical groups into the biomedical compound and test the modifications for their biological effects.
This method was refined to build mathematical relationships between the chemical structure and the biological activity, known as
quantitative structure–activity relationship
Quantitative structure–activity relationship models (QSAR models) are regression or classification models used in the chemical and biological sciences and engineering. Like other regression models, QSAR regression models relate a set of "predi ...
s (QSAR). A related term is structure affinity relationship (SAFIR).
Structure-biodegradability relationship
The large number of synthetic organic chemicals currently in production presents a major challenge for timely collection of detailed environmental data on each compound. The concept of structure biodegradability relationships (SBR) has been applied to explain variability in persistence among organic chemicals in the environment. Early attempts generally consisted of examining the degradation of a homologous series of structurally related compounds under identical conditions with a complex "universal"
inoculum, typically derived from numerous sources. This approach revealed that the nature and positions of substituents affected the apparent
biodegradability of several chemical classes, with resulting general themes, such as halogens generally conferring persistence under aerobic conditions. Subsequently, more quantitative approaches have been developed using principles of QSAR and often accounting for the role of
sorption
Sorption is a physical and chemical process by which one substance becomes attached to another. Specific cases of sorption are treated in the following articles:
; Absorption: "the incorporation of a substance in one state into another of a d ...
(bioavailability) in chemical fate.
See also
*
Combinatorial chemistry
Combinatorial chemistry comprises chemical synthesis, chemical synthetic methods that make it possible to prepare a large number (tens to thousands or even millions) of compounds in a single process. These compound library, compound libraries can b ...
*
Congener
*
Conformation activity relationship
Conformation generally means structural arrangement and may refer to:
* Conformational isomerism, a form of stereoisomerism in chemistry
** Carbohydrate conformation
** Cyclohexane conformation
** Protein conformation
** Conformation activity rel ...
*
Quantitative structure–activity relationship
Quantitative structure–activity relationship models (QSAR models) are regression or classification models used in the chemical and biological sciences and engineering. Like other regression models, QSAR regression models relate a set of "predi ...
*
Pharmacophore
References
External links
Molecular Property ExplorerQSAR World
{{DEFAULTSORT:Structure-activity relationship
Medicinal chemistry