Overview of Antibacterial Products - Essay Example

?Antibacterials Search for compounds that has the potential of killing or retarding the growth of bacteria is an exciting area of chemical research. Such compounds known as antibacterial can be isolated from living organisms, obtained via chemical modification of natural compounds, or synthesized. The mechanism of action allowed classification of these compounds into two groups known as bactericidal antibacterials and bacteriostatic antibacterials. The former class kills and eliminates the bacteria while the later class retards the growth or reproduction of the bacteria. Their benefit in the medical field and personal hygiene notwithstanding, antimicrobial exhibit certain side effects. Introduction Antibacterial are host of compounds or substances that inhibit or retard the growth of bacteria. They belong to a larger family of compounds known as antimicrobials among which are antifungal and antiviral compounds. Chemically, antibacterial can be isolated from living organisms, obtained by chemical modification of natural compounds or synthesized (Von Nussbaum, 2006). Aminoglycosides, such as streptomycin, are classes of antibacterials that are isolated from living systems. Compounds, such as sulfonamides, that have antibacterial property are obtained solely by chemical synthesis. Semi-synthetic modification of natural compounds also yield antibacterial compounds such as penicillin. The biological activity of antibacterials differs. Some function by killing the target bacteria as in bactericidal agents, while others slow down the growth or reproduction of the bacteria as in bacteriostatic agents (Calderon and Sabundayo, 2007). Bactericidal agents are further grouped as bactericidal disinfectants, bactericidal antiseptic, and bactericidal antibiotics. Several factors, which include the host defense mechanism, the location of the infection, and the pharmacokinetic and pharmacodynamic properties of the antibacterial, affect the outcome of antibacterial therapy with antibacterial compound (Pankey and Sabeth, 2004). The concentration of the antibacterial also affects its biological activity of antibacterials, thus in vitro characterization of antibacterial activity commonly includes the determination of the minimum inhibitory concentration and minimum bactericidal concentration of the antibacterial agent being investigated. To ascertain the drug efficacy of an antibacterial, its antibacterial activity is usually combined with its pharmacokinetic profile, and results of other pharmacological parameters obtained during clinical studies. Mode of action of antibacterials The mode of action of antibacterial differs; indeed, this difference offers a criterion for classification of antibacterials as either bactericidal or bacteriostatic. Some bactericidal agents, such as penicillin, target the bacterial cell wall, while some, for example polymixins, disrupt cell membrane, and another group of bactericidal agents, for instance sulfonamides, interfere with essential bacterial enzymes (Calderon and Sabundayo, 2007). Antibacterial agents that are bacteriostatic in action, such as tetracyclines, target protein synthesis and eventually slow down the growth or reproduction of the bacteria (Calderon and Sabundayo, 2007). Bactericidal agents have found use as disinfectants, antiseptics and antibiotics. For instance, chloroxylenol, a phenolic, is the active antibacterial ingredient in Dettol (Acenzi, 1996), a household disinfectant and antiseptic. Figure 1. Chemical structure of chloroxylenol Chloroxylenol functions by disrupting the cell membrane potential of bacteria. Potassium permanganate, KmnO4, is a strong oxidizing agent that has find application as an antibacterial agent. It is used as antiseptic and disinfectant for treating aquariums and swimming pools. Mere exposure of KmnO4 to sunlight yields oxygen through its decomposition. 2 KMnO4(s) > K2MnO4(s) + MnO2(s) + O2(g) The oxygen oxidizes the cell membrane of the bacteria resulting in the loss of structure and ultimately, cell lysis and death of the bacteria. Bactericidal antibiotics also kill the bacteria. For instance, the beta-lactam antibacterial, penicillin inhibits cell wall synthesis (Kasten and Reski, 1997). Penicillin is effective in the treatment of bacterial infection caused by gram positive bacteria (Garrod, 1960). Penicillin Figure 2. Core structure of penicillin. R may variable organic group. function by inhibiting the formation of peptidoglycan cross-links in cell wall of bacteria (Kasten and Reski, 1997). The beta-lactam group of penicillin binds to the enzyme (DD-transpeptidase) that links the peptidoglycan molecules in bacteria (Kasten and Reski, 1997). This process eventually weakens the cell wall of the bacterium thereby leading to death through osmotic pressure. In addition, the build-up of peptidoglycan precursors triggers the activation of bacterial cell wall hydrolases and autolysins, which further digest the bacteria's existing peptidoglycan also result in the death of the bacteria (Kasten and Reski, 1997). Though many types of bacteria are becoming resistant to penicillin, it is still widely used as antibacterial antibiotic. Bacteriostatic antibiotics retard the growth of bacteria by interfering with bacterial protein production, DNA replication, or other aspects of bacterial cellular metabolism. Bacteriostatic antibiotics inhibit growth and reproduction of bacteria without eliminating them; elimination is done by bactericidal agents. An example of bacteriostatic agent is tetracyclines. Figure 3. Structure of tetracyline Tetracycline functions as a protein synthesis inhibitors, inhibiting the binding of aminoacyl-tRNA to the mRNA-ribosome complex (Viera et al., 2007). They do so mainly by binding to the 30S ribosomal subunit in the mRNA translation complex. Unfortunately, cells can become resistant to the action of tetracyline. Conclusion Search for natural substances, semi synthetic modification of natural compounds and synthesis of compounds that have antibacterial property is an exciting area of research in medicinal chemistry. Interest in antibacterial agents is worthwhile given the importance of these compounds in the field of medicine, and personal hygiene. Indeed, since the first discovery of penicillin, research in the field of antibacterial and other antimicrobials has exploded. This has led to a tremendous improvement in the global health care and disease treatment. Chemistry has played a tremendous role in this area and has also benefited from it. For instance, challenges in the search for and characterisation of these antibacterials have lead to important advancement in Chemistry. For instance, following the discovery of penicillin, X-ray diffraction was used to characterize the structure of this molecule. Since then, x-ray diffraction has grown to become a powerful technique for characterizing organic and inorganic molecules. Furthermore, millions of dollars has been allocated to research in this field of Chemistry, thereby providing job opportunities for chemists. Despite the beneficial use, antibacterial exhibit certain side effects. For instance, may lead to overgrowth of yeast species of the genus Candida in the vulvo-vaginal area. References Ascenzi, J. M. (1996). Chloroxylenol: an old-new antimicrobial. Handbook of disinfectants and antiseptics. New York: M. Dekker Calderon C. B & Sabundayo B. P. (2007). Antimicrobial Classifications: Drugs for Bugs. In Schwalbe R., Steele-Moore L., Goodwin A. C. (ed) Antimicrobial Susceptibility Testing Protocols. CRC Press. Taylor & Francis group Garrod, L. P. (1960). Relative Antibacterial Activity of Three Penicillins. British Medical Journal (5172): 527-29 Kasten, B. & Reski, R. (1997). "?-lactam antibiotics inhibit chloroplast division in a moss (Physcomitrella patens) but not in tomato (Lycopersicon esculentum)". Journal of Plant Physiology 150 (1-2): 137–140. Pankey G. A & Sabath L. D. (2004). Clinical relevance of bacteriostatic versus bactericidal mechanisms of action in the treatment of Gram-positive bacterial infections. Clin Infect Dis. 38 (6): 864–870 Viera, M. H, Perez, O. A, Berman, B. (2007). Incyclinide. Drugs of the Future 32 (3): 209–214 Von Nussbaum F. (2006). Medicinal Chemistry of Antibacterial Natural Products – Exodus or Revival?. Angew. Chem. Int. Ed. 45 (31): 5072–5129 Read More