Antimicrobial activity of natural products

Natural products have been the most productive source of leads for the development of drugs. Natural products provide an unlimited opportunity for new drug leads because of the unparalleled chemical diversity. Many pharmaceutical agents have been discovered by screening natural products from plants, animals, marine organisms and microorganisms. These biologically derived antibacterial compounds could have reasonable value in controlling antibiotic resistant pathogens also. The prevalence of antibacterial natural products drugs may be due to the evolution of secondary metabolites as biologically active chemicals that conferred selective advantages to the producing organisms. This chapter provides an overview of natural products, their sources, their role in increasing antibiotic susceptibility of drug resistant bacteria and the synergism between natural products and antibiotics.