Biologically active chemical

Kozubek, A., Tyman, J. Resorcinolic lipids, the natural non-isoprenoid phenolic amphiphiles and their biological activity. Chemical Reviews, Vol.99, No.l. Qanuary 1999), pp. 1-31, ISSN 0009-2665... 

Drug Any biologically active chemical that does not occur naturally in the human body. Drugs can be used to prevent and treat disease, alter mood and cognition or otherwise change behaviour. Drugs are classified into families according to their... 

For the alternant PAH that have been studied extensively, bay-region diol epoxides are important metabolically activated forms. Studies of the chemical and biological activity of a variety of diol epoxides have provided insight into the factors related to reactivity and biological activity. Chemical reactivity, as measured by spontaneous hydrolysis, correlated well with calculated quantum chemical parameters that estimate ir-electron stabilization upon conversion of the epoxide to a benzylic carbocation, provided... 

Environmental Quality. The abstracts come from journals or digests published by CSA on important issues including environmental pollution, toxicological studies of industrial chemicals, ecological impacts of biologically active chemicals, as well as health, safety, and risk management in occupational situations. The POLTOX CD-ROM contains over 200,000 records from these sources since 1981. 

Chemists can make, or synthesize, many biologically active chemical compounds in the laboratory. (Chemical, chemical compound, and compound are interchangeable terms.) One starts with readily available simple molecules and proceeds to build more complex structures, one step at a time, through chemical reactions. 

The optical activity of biologically-active chemicals is important to their activity and toxicology. Pure enantiomers, or optical isomers, of pharmaceuticals and agrochemicals can in many cases be made by enantiospecific synthesis. An alternative method is to use a less complicated synthesis followed by chromatographic resolution of the racemic mixture into its enantiomers. 

An expert system has been written which helps the agricultural chemist develop formulations for new biologically active chemicals. The decision making process is segmented into two parts. The first is which type of formulation to use. The second is how to make a formulation of that tyrpe with the chemical of interest. The knowledge base currently contains rules to determine which formulation type to try and how to make an emulsifiable concentrate. The next phase will add rules on how to make other types of formulations. The program also interfaces to several FORTRAN programs which perform calculations such as solubilities. 

Finally, researchers may use an ethnohotamcal approach, that is, one that focuses on medicinal plants that have traditionally heen used in various cultures. The assumption underlying this approach is that plants on which people have relied for medicines in the past may very well contain biologically active chemicals that can be either isolated, purihed, and used as drugs or used as models from which biologically active analogs can he produced. 

Key Words Biological activity chemical features chemical space cluster analysis compound databases dimension reduction molecular descriptors molecule classification partitioning algorithms partitioning in low-dimensional spaces principal component analysis visualization. 

Key Words Biological activity chemical descriptors chemical spaces classification methods compound databases decision trees diversity selection partitioning algorithms space transformation statistics statistical medians. 

This herbal product has the most data available to support its usefulness as an antidepressant. Nevertheless, only minimal information is available about its pharmacology and its relative risk-benefit ratio. At least seven different biologically active chemicals have been isolated from crude extracts of hypericum. Several are ubiquitous in the plant kingdom. The exceptions are hypericin and pseudohypericin, which have been assumed to be responsible for any antidepressant activity of this product. Nevertheless, there is the potential for one or more of these seven compounds and their metabolites to mediate desired or undesired effects, particularly when used in combination with other medications (i.e., herb-drug interactions). 

QSAR modeling has been traditionally viewed as an evaluative approach, i.e., with the focus on developing retrospective and explanatory models of existing data. Model extrapolation has been considered only in hypothetical sense in terms of potential modifications of known biologically active chemicals that could improve compounds activity. Nevertheless recent studies suggest that current QSAR methodologies may afford robust and validated models capable of accurate prediction of compound properties for molecules not included in the training sets. 

As is the case with all biologically active chemicals (i.e., enzymes and substrates), activity (i.e., turnover number and Km) is the relationship between a defined response and the concentration that causes it. Table G.0.1 shows some flavor activities and their definitions. 

The term alkaloids can be considered as more pharmaceutical and medical than chemical, since alkaloids come from a variety of otherwise-unrelated organic compounds. Alkaloids can be classified in terms of their biological activity, chemical structure (nucleus containing nitrogen), or biosynthetic pathway (the way they are produced in the plant). 

Active ingredient is the amount of biologically active chemical (e.g., the triazine) in the pesticide formulation. Adverse effect is functional impairment or pathological lesion that affects the performance of the organism or reduces its ability to respond to additional challenge. Adverse effects are intended to be effects that have an adverse health consequence, as opposed to just any effect. 

A chemist who devotes himself to the development of new biologically active chemicals is swiftly taught modesty. Success In this area Is always the product of Interdisciplinary cooperation. Please allow me to emphasize that I also accept this great honor In the name of all my colleagues, not only for the ones In Chemistry, but also in Biology, the Agrosciences, Medicine, and Toxicology. This honor and my thanks are also due to them. 

Through the years since 1945, more and more biologically active chemicals have been developed, first for agriculture and subsequently many adopted in forestry. By now, some 25 to 30 different chemicals are used as herbicides in forestry (11). 

Coating, enteric Encapsulating a biologically active chemical in a layer such as wax or biodegradable plastic that delays and regulates the rate of release of a drug into tissues. 

A simple example, which illustrates this approach in the chemical industry, was the one adopted a few years ago by the nuclear fuel company, BNFL (British Nuclear Fuels) in the UK in the early 1990s. This company had as one of its core technologies from within nuclear power context, the ability to handle fluorine on the bulk scale. It used this expertise to diversify into the manufacture of flu-orochemicals. One use for these organic chemicals was as intermediates in the production of biologically active chemicals and related materials. This fine chemicals business was a very different one to that of nuclear fuel. 

Ryszard Tadeusiewicz, Janusz Borysiewicz, and Jan Trabka, System for the Computer Evaluation of Biologically Active Chemical Compounds, Akad. Med. im M. Kopemika, Krakow, Poland, 1978. 

We are concerned here with the action of enzymes acting on substrates to liberate chemical messengers that trigger the de novo synthesis of new and more biologically active chemicals. Such a train of biochemical events inherently has a longer inductive and biosynthetic time-frame than does, say, the near instantaneous liberation of HCN following damage. 

Tanimoto index > 0.9 but may be very different in terms of activity (chemically similar, biologically diverse), while completely different strucmres are known to have the same biological activity (chemically diverse, biologically similar). This intrinsic drawback to the computational screening of virtual libraries should always be considered when interpreting screening results of a computationally designed library, and real data should be used to refine any virtual SAR information based on chemical similarity or dissimilarity. 

Active ingredient (a.i.) The chemical component of a pesticide formulation or end-use product that is intended to act as a pest deterrent also known as the biologically active chemical agent in a pesticide product (USEPA, 1997c). 

The Hansch Structure-Activity Approach As an Aid in Designing New Biologically Active Chemicals... 

---