Antiulcerative properties

Antischistosomal activity, of 5-nitro-2-aminothiazoles, 72 Antispasmodic activity, 150, 439 Antitrichomonal activity, 138 of 5-nitro-2-aminothiazoles, 72 Antitubercular activity, 139, 140,441,442 Antitumor activity, 149, 152 Antitussive, 144, 148 Antiulcer properties, 148 Antiviral, 138, 139, 140, 144,438 Appetite depressant, 147 Aprotic solvent, see Solvent effect Aromatic aldehydes, with aminothiazoles, 40... 

The spectrum of biological activity displayed by tetramic acid-containing natural products is remarkable in its diversity it includes potent antibiotic, antiviral and antiulcerative properties, cytotoxicity and mycotoxicity, the inhibition of tumors (in mice and humans) as well as fungicidal action." Other members of this class are responsible for the pigmentation of certain molds and sponges. 

Perimidines substituted in the 1- and 2-position have been found to possess antiulcer properties, to be CNS active, and to be active as carcinostatic and antimicrobial agents. 

These antiulcer properties have also been related to flavonic extracts of different species, in which phytochemical study has demonstrated that these polyphenols are the prevailing compounds (Fig. 2). 

Chitosan has been widely used for many biomedical applications because of its favorable characteristics such as biodegradability (Struszczyk et al. 1991), biocompatibility (Chandy and Sharma 1990, Hirano et al. 1990), inexpensiveness, and nontoxicity. However, the level of toxicity of the chitosan depends on the molecular weight and the degree of deacetylation. Hirano and Knapezk et al. has reported that chitosan has low oral toxicity with an LDjq in rats of 16g/kg, which is close to that of salt or sugar (Hirano et al. 1990, Knapezk et al. 1984). Chitosan is also bioactivite and bioadhesive compared with other natural polymers commonly used in drug delivery. It has antacid and antiulcer properties that prevent or weaken drug irritation in the stomach (Kumar 2000). 

Thermodynamic properties such as heats of reaction and heats of formation can be computed mote rehably by ab initio theory than by semiempirical MO methods (55). However, the Hterature of the method appropriate to the study should be carefully checked before a technique is selected. Finally, the role of computer graphics in evaluating quantum mechanical properties should not be overlooked. As seen in Figures 2—6, significant information can be conveyed with stick models or various surfaces with charge properties mapped onto them. Additionally, information about orbitals, such as the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), which ate important sites of reactivity in electrophilic and nucleophilic reactions, can be plotted readily. Figure 7 shows representations of the HOMO and LUMO, respectively, for the antiulcer dmg Zantac. 

Studies have focused on the many pharmacological effects of glycyrrhizin, including its antiulcer, anti-inflammatory, antiviral, and antispasmodic properties. It is also reported to have cor-ticoid activity (2,9,97). It should be used in moderate amounts as a sweetener because of its phar-... 

Additionally there is an increasing interest in carotenoids because of their potentially beneficial health effects, such as provitamin A, anticarcinogenic, antiulcer, antiaging, and antioxidant properties and increased immune responses (27,28). Because the vitamin A potential of cis isomers is less than those of their all-trans counterparts, it is important to distinguish and quantify the various forms (29). According to reports and clinical studies carotenes may be important in the prevention of some forms of cancer (30). Since the National Cancer Institute has recommended an increased intake of food high in carotenoids (31), more detailed information about the carotenoid composition of foodstuffs is desirable. 

Tannins are used in medicine primarily because of their astringent properties, which are due to the fact that they react with the proteins of the layers of tissue with which they come into contact. Tannins are known to tan the outermost layer of the mucosa and to render it less permeable and more resistant to chemical and mechanical injury or irritation however, the correlation between the molecular structures of tannins and the astringent/antiulcer activity is not known. 

On occasions, the useful biological activity may only be a minor property or a side-effect of a compound. The aim then would be to enhance the side-effect and eliminate the major biological activity. The story of the antiulcer agent cimetidine (Fig. 7.29) is a case in point. The desired biological property was selective antagonism of histamine receptors in the stomach. The lead compound was a histamine agonist with a very weak antagonism for the receptors of interest. 

Documented scientific evidence justifies some of the antirheumatic, antiseptic and astringent properties, but no clinical data are available. An antiulcer activity has been found in aqueous extracts, with the greatest activity in flowers. Some bacteriostatic activity is also found. 

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