Nitrogen bases, drugs from

The fact that N-arginyl-Met-enkephalin(/3-lipotropin 60-65) has an activity comparable with that of the parent by in vitro tests,<173) prompted the examination of benzomorphan derivatives in which the piperidino nitrogen was linked to a variety of amino acids (Gly, Met, Leu, Arg). The Arg derivative 20 was close in potency to Met-enkephalin in a binding assay against [3H]naloxone (as was the nor-base) and all others had very low activities.074 Peptidase action, liberating the active drug from Arg derivatives of both the enkephalin and benzomorphan, may explain these results, although there is contrary evidence in the case of peptide. 

Fig. 6.17 Structures of some quinolones, a broad family of synthetic chemotherapeutic antibacterials based on the 4-quinolone (a) and 1,8-naphthyiidine (b) structures. Norfloxacin and nalidixic acid, respectively, are examples of a drug from each of these groups. Qnoxacin is an example of a quinolone antibacterial based on cinnoUne, an aromatic heterocyclic with two attached six-mem-bered tings containing adjacent nitrogens at positions one and two (d). The basic fluoroquinolone pharmacophore is shown in (c). The addition of a fluorine atom at position six of the two-ring nucleus produced a 100-fold increase in the antibacterial minimum inhibitory concentration...

Quinghaosu is the latest fundamental discovery in this area and is a heterocyclic compound that does not have a nitrogen atom in its structure. It is taken from a Chinese folk medicine. It is isolated from the plmt Artemisia annua. It is amazing that this compound, which is completely different than the other drugs described in this chapter in terms of structure, exhibits the exact same therapeutic effect. The main interest in quinoghaosu is based on the fact that it is active against resistant forms of malaria caused by P falciparum, and even its cerebral forms. Synonyms of this drug are artemisine, artemisinin, and others. 

---