Active constituents definition

Larger studies are needed to definitively determine the efficacy of feverfew in the prevention of migraine and to identify the component or components responsible for its pharmacologic effects. Although parthenolide is considered the active constituent of feverfew, the pharmacokinetics of this constituent have not been characterized, and challenges remain in detecting this component analytically to allow evaluation of its metabolic fate. 

Owing to growing demand of herbals, the need of the hour is to intensify research in the field of medicinal herbs and to get authentical information on the subject. Herbal products are often questioned for quality control and assurance. Majority of the herbal products fails in the laboratory test for active constituents mentioned on the label. Extracts standardised to active constituents and marker compounds have definite advantage over the crude dmgs. 

The core material defined as the specific material to be coated can be liquid or solid in nature. The composition of the core material is varied, as the liquid core can include dispersed and/or dissolved material. The solid core can be a mixture of active constituents, stabilizers, diluents, recipients, and release-rate retardants or accelerators. The ability to vary the core material composition provides definite flexibility, and utilization of this characteristic often allows effectual design and development of the desired microcapsule properties. 

The activities of the various components 1,2,3. .. of an ideal solution are, according to the definition of an ideal solution, equal to their mole fractions Ni, N2,. . . . The activity, for present purposes, may be taken as the ratio of the partial pressure Pi of the constituent in the solution to the vapor pressure P of the pure constituent i in the liquid state at the same temperature. Although few solutions conform even approximately to ideal behavior at all concentrations, it may be shown that the activity of the solvent must converge to its mole fraction Ni as the concentration of the solute(s) is made sufficiently small. According to the most elementary considerations, at sufficiently high dilutions the activity 2 of the solute must become proportional to its mole fraction, provided merely that it does not dissociate in solution. In other words, the escaping tendency of the solute must be proportional to the number of solute particles present in the solution, if the solution is sufficiently dilute. This assertion is equally plausible for monomeric and polymeric solutes, although the... 

COPPER (In Biological Systems), The activity of copper in plant metabolism manifests itself in two forms 11) synthesis of chlorophyll, and 12) activity of enzymes. In leaves, most of the copper occurs in close association with chlorophyll, but little is known of ns rale in chlorophyll synthesis, other than the presence of cupper is required. Copper is a definite constituent of several enzymes catalyzing oxidation-reduction reactions (oxidases), in which the activity is believed to be due to the shuttling of copper between the +1 and +2 oxidalicm states,... 

Naturally, by this definition, activity at standard state of any constituent is unity. 

---