Mini Reviews in Medicinal Chemistry - Volume 3, Issue 5, 2003

Insulin is a essential molecule for type I diabetes that is marketed by very few companies. It is the first molecule, which was made by recombinant technology; but the commercialization process is very difficult. Knowledge about biochemical structure of insulin and human insulin genome sequence map is pivotal to large scale manufacturing of recombinant DNA Insulin. This paper reviews human insulin genome sequence map, the amino acid sequence of porcine insulin, crystal structure of porcine insulin, insulin monomer, aggregation surfaces of insulin, conformational variation in the insulin monomer, insulin X-ray structures for recombinant DNA technology in the synthesis of human insulin in Escherichia coli.

Phytoestrogens constitute a promising alternative in the treatment of diseases associated with menopause. Nevertheless, the lack of data concerning their pharmacology and their toxicology requires use precautions. After reminding the pharmacology of estrogen receptors, this review outlines the estrogenicity and the therapeutic potentialities of phytoestrogens according to their structure.

Current anti-HIV drugs have extreme side effects and resistance to these drugs develops rapidly. The marine environment holds an unprecedented number of unusual chemical structural classes with activity against HIV. We review the literature on anti-HIV activity of marine natural products and discuss the efficacy of different structural classes.

The family Euphorbiaceae is widely distributed throughout both hemispheres and ranges in morphological form from large desert succulents to trees and even small herbaceous types. Many species contain a milky juice which is more or less toxic, especially for cold-blooded animals, and can produce a dermatitis similar to that from poison ivy. Separation procedures and characterization of the less polar fractions of the plant extracts have been widely described in the literature for their content in diterpene derivatives. In the continuing research on biologically active compounds from Euphorbiaceae, a series of studies on the isolation and structure elucidation of glyceroglycolipids (GGLs) and glycosphingolipids (GSLs) have been carried out in order to develop the novel medicinal resources from natural Euphorbiaceae products. Glyceroglycolipids are major constituents of the chloroplast membrane in the plant kingdom. Recently, glycolipids were found to possess antitumor-promoting activity while glyceroglycolipids isolated from Euphorbiaceae have shown an interesting anti-inflammatory activity in vivo. Glycosphingolipids are present at the outer layer of the lipid-bilayer in biological membranes and are thought to partecipate in antigen-antibody reactions and transmission of biologically informations. Sphingolipid breakdown products, sphingosine and lysosphingolipids, inhibit protein kinase C, a pivotal enzyme in cell regulation and signal transduction. Sphingolipids and lysosphingolipids affect significantly cellular responses and exhibit antitumor promoter activities in various mammalian cells. These molecules may function as endogenous modulators of cell function and possibly as second messengers.

Protein crystallography has the potential to accelerate drug discovery greatly. High-resolution structures of membrane proteins of pharmaceutical interest open new perspectives in drug design. Recent structural data obtained for cyclooxygenases, monoamine oxidase, squalene cyclase, rhodopsine, porins, aquaporins, and ABC transporters are presented and briefly discussed.

The use of microwave technology in solid-phase organic synthesis has attracted much attention in recent years. The combination of solid support, either as a medium for chemical synthesis or as a carrier for organic reagents, with microwave heating offers several advantages over conventional techniques. Rapid and elevated heating of reaction mixtures can induce the completion of chemical transformations in minutes while several hours or days may be required for the same chemistry under conventional conditions. With decreased time of exposure to high temperatures and lessened thermal degradation, microwave accelerated chemistries often deliver products of higher purity when compared to conventional heating techniques. Several chemical syntheses on solid-phase employing microwave irradiation have been reported in the literature. The reagents, solvents, and equipment selected for microwave-mediated synthesis are important contributors to the success of the chemical transformation. Owing to the timesavings in performing chemical synthesis under microwave irradiation, the technique has become an emerging partner in solid-phase organic synthesis.

The regular intake of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) has been associated with decreased incidence of certain types of cancer particularly those with an inflammatory component. The protective effects of these drugs in colorectal cancer are particularly marked, with a 40-50% reduction in risk. Research in this area has focussed on understanding and optimising these cytoprotective effects. NSAIDs are believed to operate by inhibiting COX-2, an enzyme that appears to be involved in a number of cancer promoting processes. This hypothesis is consistent with the observation that the COX-2 selective inhibitors dramatically decrease tumour formation in human and animal studies. Surprisingly aspirin, which is selective for COX-1 over COX-2, and sulindac, which is an equipotent inhibitor of the COX isoenzymes, appear to have a similar anticancer profile to the COX-2 selective NSAIDs. A number of mechanisms have been proposed to explain the anomalous effects of aspirin. The first of these relates to the unique mode of action of aspirin, which acetylates the COX-2 enzyme and generates the cancer-suppressing 15R-hydroxyeicosatetraenoic acid at the site of a potential tumour. The alternative rationale relates to the metabolism of aspirin to salicylic acid, which has a cyclooxygenase independent anti-inflammatory mechanism, preventing the inflammatory response at the gene transcription level. A new generation of drugs could evolve from approaches to improving the therapeutic index of aspirin or by modifications to known therapies such as sulindac and celecoxib.

The protein O6-alkylguanine-DNA alkyltransferase is the basis of an important process for repairing damage to cellular DNA, which renders cells resistant to drugs that alkylate at the O6-position of guanine residues. The development of various pseudosubstrates which inactivate this protein is reviewed, from a chemical standpoint. Study of the influence of pseudosubstrate molecular structure on their interaction with the active site cysteine has progressed together with direct investigation of protein structure. Combination therapy using a powerful inactivator with a suitable alkylating agent shows great clinical promise in the treatment of cancer, particularly when some degree of selectivity is possible.

This paper reviews and evaluates all the published QSAR treatments of LOX inhibitors. This reveals that in almost all cases, the clog P parameter plays an important part in the QSAR relationships. In some cases the steric factors (B1, B5 and L) as well as the overall molar refractivity (CMR) or the substitutents molar refractivity (MR) are important. Electronic effects except for the Hammet's constant , are comparatively unimportant. The study shows that log P as calculated from the Clog P program is suitable for this form of QSAR study. Log Po of 2.77-3.76 was found to be ideal, for the biological response.