Biological activity definition

Cheeseright, T., Mackey, M., Rose, S., and Vinter, A. (2006) Molecular field extrema as descriptors of biological activity definition and validation. Journal of Chemical Information and Modeling, 46 (2), 665-676. 

In addition to effects on biochemical reactions, the inhibitors may influence the permeability of the various cellular membranes and through physical and chemical effects may alter the structure of other subcellular structures such as proteins, nucleic acid, and spindle fibers. Unfortunately, few definite examples can be listed. The action of colchicine and podophyllin in interfering with cell division is well known. The effect of various lactones (coumarin, parasorbic acid, and protoanemonin) on mitotic activity was discussed above. Disturbances to cytoplasmic and vacuolar structure, and the morphology of mitochondria imposed by protoanemonin, were also mentioned. Interference with protein configuration and loss of biological activity was attributed to incorporation of azetidine-2-carboxylic acid into mung bean protein in place of proline. 

These pharmacophore techniques are different in format from the traditional pharmacophore definitions. They can not be easily visualized and mapped to the molecular structures rather, they are encoded as keys or topological/topographical descriptors. Nonetheless, they capture the same idea as the classic pharmacophore concept. Furthermore, this formalism is quite useful in building quantitative predictive models that can be used to classify and predict biological activities. 

The term bioavailability has various definitions. Previously, the authors of this chapter have defined bioavailability as the proportion of a nutrient (or other food component) that is digested, absorbed and utilised in normal metabolism - with the practical measurement of bioavailability usually relying upon estimates of amounts absorbed (Southon and Faulks, 2001). Biological activity, or bioactivity , has been viewed and described as a separate stage which follows on from bioavailability in the journey of a compound from food to function. However, here we present a new definition of bioavailability that recognises the functional consequences of absorption. 

Thiosemicarbazone (RNH-CS-NH-N=CR/R//, tsc) complexes of cobalt(III) have been extensively studied since the early 1980s and continue to attract attention, gaining particularly from an interest in their biological activity and potential cytotoxicity. A truly extensive range of tsc compounds has now been reported, although structural definition of their complexes widely relied on basic analytical and spectroscopic techniques up to the late 1980s, when X-ray crystal structural studies of tsc compounds became more common. A review of thiosemicarbazone and S-alkyldithiocarbazate complexes has appeared.1053... 

Glycan array allows for the definition of fine differences in specificity among related lectins giving clues about the basis for differences in their biological activities. For example comparison of a set of human galectins demonstrated that Gal-1, Gal-2, and Gal-3 all bind /V-acetyllactosamine but... 

The quantitation of a protein that has a specific biological function, a hormone, for instance, may not give a true indication of its biological activity owing to the inactivation of some of the protein. For proteins that have definite biological functions the choice is between chemical quantitation and bioassays. For this reason the catalytic activity of an enzyme is more frequently measured than is its protein concentration. 

General Comment. The foregoing examples clearly show that poly(vinyl alcohol) can be modified readily and that some of these derivatives have potential (and/or actual) biological activity. This survey is definitely not encyclopedic in scope but rather illustrative. No doubt many more examples of potentially biologically active poly(vinyl alcohol) derivatives will be developed in the future and it is entirely possible that some of these may become of value in chemotherapy and other areas where biologically active polymers are now being studied. 

Lignans are secondary plant metabolites possessing a variety of biological activities [1,2]. They are dimers of phenylpropenes, which are by definition connected between C(8) and C(8 ) [3]. Lignans are of great structural variety due to numerous potential oxidation states at the C(7)/C(7 ) and C(9)/C(9 ) positions, and to the possibility of aryl-aryl bond formation [1-3]. 

Note 2 Usually, degradation results in the loss of, or deterioration in useful properties of the material. However, in the case of biodegradation (degradation by biological activity), polymers may change into environmentally acceptable substances with desirable properties (see Definition 3.1... 

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