Recent Patents on Anti-Infective Drug Discovery - Volume 4, Issue 3, 2009

Pyrazolines are well known and important nitrogen containing 5-membered heterocyclic compounds and various methods have been worked out for their synthesis. Numerous pyrazoline derivatives have been found to possess considerable biological activities, which stimulated the research activity in this field. They have several prominent effects, such as antimicrobial, antimycobacterial, antifungal, antiamoebic, anti-inflammatory, analgesic, antidepressant and anticancer activities. They also possess some potent receptor selective biological activity like Nitric oxide synthase (NOS) inhibitor and Cannabinoid CB1 receptor antagonists activity. 4,5-dihydro-1H- pyrazolines seem to be the most frequently studied pyrazoline type compounds. As a result, a large number of such pyrazolines using different synthetic methods for their preparation have been described in the chemistry literature. The present review provides an insight view to pyrazolines synthesis and its biological activities along with the compilation of recent patents on pyrazolines.

Conventionally, the successful targets for the drug development in cancer range from the DNA damage, replication, signal transduction pathways, hormones, cytokines, anti-angiogenic agents, and radio/photo-sensitizers. They dominate the therapeutic arena after the initial debulking surgery. More recently, tubulin, the primary constituent of microtubules (MTs), has made a fairly successful debut in the therapeutic armamentarium. Tubulin binding drugs come in two classes: that depolymerize microtubules and that over-polymerize and bundle them. Microtubule (MT) binding drugs are in some ways superior in nature primarily because of their less debilitating side effects when compared to the generalized DNA metabolism targeting agents, and many new promising patents are being funneled into the drug development pipeline. Nevertheless, many of these relatively new agents still face challenges relating to their delivery methods, bioavailability, toxicities, and the inevitable resistance shared by all chemotherapeutics. Finally, we disclose a new genre of anti-MT drugs, noscapinoids that have just begun climbing the clinical trials ladder. The lead compound, noscapine, is a plant derived, orally available, minimally-toxic (if at all) agent that has shown phenomenal promise in the preclinical experimentation and Phase-I clinical trial. A rational approach based upon the precise molecular model of the tubulin-noscapine complex is bound to inspire novel and better therapeutic analogs in future.

Recombinant fusion proteins consisting of the extracellular domain of immunoregulatory proteins and the constant (Fc) domain of immunoglobulin (Ig) represent a growing class of human therapeutics. Immunoadhesins combine the binding region of a protein sequence, with a desired specificity, with the effector domain of an antibody. Immunoadhesins have two important properties that are significant to their potential as therapeutic agents: the target specificity, and the pharmacokinetic stability (half-life in vivo that is comparable to that of antibodies). Immunoadhesins can be used as antagonist to inhibit or block deleterious interactions or as agonist to mimic or enhance physiological responses. Here, we review the recent advances in the development of immunoadhesins as tools for immune therapy, particularly for the treatment of infectious diseases. The present article is a short review for the recent patents related to immunoadhesins for immune therapy.

In the fight against pathogenic and opportunistic bacteria, development and spreading of resistance to antibiotics is an increasing public health problem. The available antibacterial treatments are becoming less and less effective, making urgent the discovery of new active molecules. One strategy that has been explored to bypass the bacterial adaptation to drugs is to target the iron metabolism of bacteria, since iron is critical for all bacteria to grow. To date, three major ways have been assessed to exploit weaknesses in the bacterial iron metabolism: the “Trojan Horse strategy” which takes advantages of natural iron-uptake systems to deliver antimicrobial compounds inside the cells; the use of iron-antagonists and iron-chelators in order to reduce iron availability and the inhibition of enzymatic steps of iron metabolism via chemical compounds. This review discusses these antibacterial strategies interfering with several levels of the bacterial iron metabolism, with a special emphasis on recently published and/or patented discoveries.

Honey and other bee products were subjected to laboratory and clinical investigations during the past few decades and the most remarkable discovery was their antibacterial activity. Honey has been used since ancient times for the treatment of some diseases and for the healing of wounds but its use as an anti-infective agent was superseded by modern dressings and antibiotic therapy. However, the emergence of antibiotic resistant strains of bacteria has confounded the current use of antibiotic therapy leading to the re-examination of former remedies. Honey, propolis, royal jelly and bee venom have a strong antibacterial activity. Even antibiotic-resistant strains such as epidemic strains of methicillinresistant Staphylococcus aureus (MRSA) and Vancomycine resistant Enterococcus (VRE) have been found to be as sensitive to honey as the antibiotic-sensitive strains of the same species. Sensitivity of bacteria to bee products varies considerably within the product and the varieties of the same product. Botanical origin plays a major role in its antibacterial activity. Propolis has been found to have the strongest action against bacteria. This is probably due to its richness in flavonoids. The most challenging problems of using hive products for medical purposes are dosage and safety. Honey and royal jelly produced as a food often are not well filtered, and may contain various particles. Processed for use in wound care, they are passed through fine filters which remove most of the pollen and other impurities to prevent allergies. Also, although honey does not allow vegetative bacteria to survive, it does contain viable spores, including clostridia. With the increased availability of licensed medical stuffs containing bee products, clinical use is expected to increase and further evidence will become available. Their use in professional care centres should be limited to those which are safe and with certified antibacterial activities. The present article is a short review of recent patents on antibiotics of hives.

Tuberculosis is the most prevalent infectious disease in the world. It is also believed that in developing countries, as many as 40 to 80% of individuals with AIDS are at risk of developing tuberculosis. In recent years there has been a significant increase in the incidence of tuberculosis due to the emergence of multi-drug resistant strains of Mycobacterium tuberculosis and due to increased numbers of highly susceptible immuno-compromised individuals arising from the AIDS pandemic. Extreme drug resistant tuberculosis raises the possibility that the current tuberculosis epidemic of mostly drug-susceptible tuberculosis will be replaced with a form of tuberculosis with severely restricted treatment options. This phenomenon would jeopardize the progress made in recent years to control tuberculosis globally and would also put at risk the plans to progress towards universal access to HIV prevention and treatment. Patients with extreme drug-resistant tuberculosis would have to be managed in the same way as tuberculosis patients before the antibiotic era. No new anti-tuberculosis drugs have been brought into the clinic in the past 40 years. Immuno-adjunctive therapy appears to be promising in improving outcome of clinical control of refractory mycobacterial infections, including multi-drug resistant tuberculosis and Mycobacterium avium complex infection. The tripeptide, glutathione protects all cells against oxidizing agents, free radicals and reactive oxygen intermediates, either directly or through enzymatic action of glutathione peroxidases and glutathione-transferases. This review article is a compilation of our major research findings on the innate immune responses against Mycobacterium tuberculosis infection. We discuss in detail both the direct antimycobacterial effects as well as the immune enhancing effects of glutathione leading to the inhibition of growth of Mycobacterium tuberculosis. The article presents some new promising patents related to the control of Mycobacterium tuberculosis infection.

The patents annotated in this section have been selected from various patent databases. These recent patents are relevant to the articles published in this journal issue, categorized by therapeutic area/targets and therapeutic agents related to anti-infective drug discovery.