Chemistry and biology of roseophilin and the prodigiosin alkaloids: a survey of the last 2500 years

The pyrrole alkaloids of the prodigiosin family make up an unusual chapter in the chemistry of natural products. Owing to the characteristic red color of these secondary metabolites, colonies of the Gram-negative-producing bacteria may strikingly resemble droplets of blood. This phenomenon caused considerable confusion in the past and was likely responsible for many seemingly miraculous (prodigious) events. After the eventual transition from superstition to science, the prodigiosins started to attract considerable attention because of their promising physiological properties. Most interesting are the immunosuppressive activities at doses that are not cytotoxic, in particular since in vivo studies suggest that the prodigiosins act synergistically with cyclosporine A or FK 506, which are presently the dominant drugs in clinical immunosuppressive regimens. Furthermore, the chemistry of the closely related and structurally rather unique alkaloid roseophilin is summarized, a cytotoxic agent that recently became the focal point of many innovative total syntheses.

History of quinolones and their side effects

Fluoroquinolone development from 1985 to the present was reviewed. Severe drug adverse events were noted for enoxacin, pefloxacin and fleroxacin, which were phototoxic. Temafloxacin was associated with severe hemolytic-uremic syndrome, lomefloxacin caused phototoxicity and central nervous system (CNS) effects, and sparfloxacin was associated with phototoxicity and QTc prolongation. Tosufloxacin caused severe thrombocytopenia and nephritis, and hepatotoxicity was reported for trovafloxacin. Grepafloxacin was withdrawn due to cardiovascular effects, and clinafloxacin was associated with phototoxicity and hypoglycaemia. The structure of the quinolones directly relates to both their activity and side-effect profiles. The relationship among specific substituents attached to the quinolone nucleus are clarified. The incidence of specific adverse events associated with individual fluoroquinolones was reviewed in a five-year post-marketing surveillance (PMS) study in Japan, in which a total adverse drug reaction (ADR) rate of 1.3% was found for levofloxacin, compared to total ADR rates of 3.3% for pazufloxacin, 3.6% for tosufloxacin, 4.5% for gatifloxacin and 5.4% for balofloxacin. Gastrointestinal effects were the most common adverse events for all fluoroquinolones. Levofloxacin had the lowest rate of CNS effects and skin adverse events among the agents listed.

Historical perspective on the use of otic antimicrobial agents

Treatment of otorrhea has been described in the literature since 1500 BC. A multitude of therapeutic options have been described, including the use of astringents, antiseptics, alcohol, benzoin and various powders. Since the middle of the 20th century, antibiotic usage has been promoted as the most effective means of therapy. Until recently none of the agents that were used was found to be safe for middle ear use. Since 1990 there have been publications describing the safety and efficacy of fluoroquinolone drops for acute and chronic otorrhea. This article details the transition from treatment of otorrhea with nonspecific means to an era of antimicrobial therapy based on sound scientific evidence.

From chloroquine to antineoplastic drugs? the story of antibacterial quinolones

Chemotherapy has not only proved valuable in treating many diseases but the history of discovery of some drugs makes exciting reading. The aim of this article is to outline one such story.