Charles O. Esimone1, Damian C. Odimegwu2,3 and Kenneth G. Ngwoke4
1
Faculty of Pharmaceutical Sciences, Nnamdi Azikiwe University, Awka Nigeria
2
Department of Molecular and Medical Virology, Ruhr University Bochum Germany
3
Faculty of Pharmaceutical Sciences, University of Nigeria Nsukka Nigeria
Queen’s University Belfast, United Kingdom
4
The efficiency of antibiotics in combating microbial infections was very promising shortly after
their introduction. It was even thought that the microbial war was as good as over as was
declared by the Surgeon General of the United States. However, resistance to these agents
developed rapidly afterward and the problem of antibiotic resistance has remained a menace
threatening the benefits of antibacterial agents. As a result, a solution to the issue of
antimicrobial resistance is a matter of urgent importance. Natural products are viewed as a
privileged group of structures which have evolved to interact with a wide variety of protein
targets for specific purposes. Also the same protein structure with little or no variation serves
different purposes in different organisms. As a result, it is anticipated that the search for
antimicrobial leads from natural sources will yield better results than from combinatorial
chemistry and other synthetic procedures. This explains why over 90% of antibiotics in clinical
use are from natural origin. The same reasons however have been given to explain the ease
with which microorganisms adapt to and resist new antibacterial agents. Believing that
pathogens will not easily resist small synthetic compounds which are alien to nature,
combinatorial chemistry and other synthetic methods were deployed but the results has been
dismal. Since compounds from bacteria and fungi are easily resisted and synthetic chemistry
are not yielding the desired result due to lack of ‘privileged structures’ in synthetic compounds, a
compound from natural origin which is not derived from bacteria or fungi but has the desired
‘privileged structure’ will prove to be the ideal antimicrobial agent. Phytochemicals suit this
description and have proven to be potent antimicrobial agents as will be discussed later in this
chapter.
Keywords: Antimicrobial agents, natural products, antibiotic resistance, synthetic chemistry,
microoorganisms