1. Introduction

Microbes are known to human civilization due to their beneficial and lethal effects. When the symbiotic relation of microorganisms goes beyond the limit, they may cause pathogenic infections and diseases, causing damage to the body and sometimes leading to death: this is a major concerning issue especially in developing countries. The determination of exact site of infection in the body is very critical for curing the pathogenesis caused by bacteria at their early stage. Antimicrobial agents especially antibiotics, which are either obtained from natural sources or through total synthetic procedures, are practiced against pathogens. Antibiotic may be obtained naturally from living organism (e.g., fungi, actinomycete, and bacillus species), prepared synthetically and semisynthetically in the laboratory. Its mechanism of action is divided into two spectrums (narrow and broad-range spectra).

Broad-spectrum antibiotics act against both Gram-positive and Gram-negative bacteria [1]. A good antibiotic should have the following characteristics: long shelf life, nontoxic to human body, soluble in the body fluid, low cost, show long-lasting antibacterial effect, and low possibility of bacterial resistance to the agent. However, all these standard parameters for an ideal antibiotic are difficult to meet, while developing synthetic antibacterial agents that is the reason a big threat is being felt from pathogenic bacterial resistance which is the main public health-related issue, all over the globe [2]. This appeared during the last decade in a more prominent way which mainly originated either due to wrong identification of bacterial strain and prescription of antibiotic or due to imbalance use of antibacterial agents. The transmission of bacterial resistance among the individuals and across the geological border is one way of antimicrobial resistance [3]. Further, on the other way, to handle the bacterial resistance threat, the pipeline of the development of new synthetic antibacterial agents is gradually drying up. And it might be possible, on the bases of continuously increasing level of bacterial resistance; at some stage pathogenic bacteria halt antibiotic therapy—that stage will be not good in the history of human being [4].

Antioxidants such as polyphenols, vitamins, and carotenoids are the organic compounds mainly extracted from natural sources and dominantly involved in living defense system. Due to continuously increasing resistance to synthetic antibiotics, there is an urgent need to shift our focus toward natural antioxidantbased antibacterial products due to their vast chemical diversity which provide potent therapeutic effect and make the microbes unable to copy them for creating resistance. Out of many natural products and antioxidants which are showing great healthy impact on human beings, polyphenols have been reported as natural agents that fight as antioxidants, antibacterial, anticancer, anti-inflammation, and antiviral agents. We, in this chapter, tried to review the role of antioxidants as natural antibiotics. In the following section, we will discuss the inflammation and infectious process and how antioxidants play their role in fixing them. Then we will also discuss antibacterial mechanism of natural antioxidants as antibiotics in animal bodies.

3. Types of infection

Antioxidants: Natural Antibiotics

DOI: http://dx.doi.org/10.5772/intechopen.84864

An estimation of deaths caused by bacterial infection worldwide [5].

of action.

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Figure 1.

4. Antibiotics

Infections can be categorized as viral, bacterial, fungal, protozoan, prion, and parasitic. Some viral infections are influenza, rotavirus, chicken pox, HIV, and herpes. Pneumonia, tetanus, cellulites, chlamydia, gonorrhea, etc. are the common bacterial infections. Fungal infections are ringworm, candidiasis, and athlete's foot. Malaria and African sleeping sickness are common protozoan infections transmitted through plasmodium and tsetse fly, respectively. Prion is the poisonous entities or protein infection particles which cause fatal neurodegenerative disease. Amebiasis, dysentery, and coccidiosis infections are caused by parasites. Antibiotics are the

major agents to cope and fix these infections. There are mainly two types of antibacterial agents, i.e., synthetic antibiotics and natural antibiotics. In the following section, we will discuss antibiotics, natural antibiotics, and their mode

till now, which have been discovered and are in clinical practice.

In the ancient times, it is believed that antibiotics were the chemicals released by microorganisms, causing prompt deleterious effect on humans. However, later this notion was reversed, i.e., these compounds were used against microbes instead of isolating from them. Antibiotics are generally of two types, bactericidal which kill the bacterial cell and bacteriostatic which inhibit the bacterial growth and may kill the bacteria. The first antibiotic was discovered by Alexander Fleming in 1928 from Penicillium notatum, a soil-inhabiting fungus, and the clinical trials on humans are conducted in 1940. There are five generations of different classes of antibiotics, up
