2. Inflammation and infection

Pathogens like bacteria are responsible for the infection or inflammation in animals. These infections may be mild inflammation which is hardly noticeable or which appeared to human being in history as a big threat. According to one estimation, based on growing bacterial resistance, up to 2050, the death rate due to bacterial infection may increase to 390,000 in Europe and similarly all over the world as shown in Figure 1. Inflammation is a nonspecific immunological response by the organism's body to any trauma, neoplasm, autoimmune attack, or invading of the microbes. At the site of inflammation, several processes can be noticed such as blood supply increase and leakage of cellular fluid and small molecules, and protein penetration may take place. In the case of acute injury, body defense mechanism, i.e., leucocyte and plasma protein migration to the site of infection become activated. Neutrophils invade bacteria when seeking entrance in the body and prevent the body from further infection. The process of infection starts within a second or minute and prolongs to hours or days to heal. It causes the sequential symptoms, like inflammation, redness, warmth, and pain, which consequently affect the functions of the tissue or organ. Inflammation may be a nonspecific process, but infection consists of stepwise progress in inflammation which might be chronic if it could not be addressed timely.

Figure 1.

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

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

Pathogens like bacteria are responsible for the infection or inflammation in animals. These infections may be mild inflammation which is hardly noticeable or which appeared to human being in history as a big threat. According to one estimation, based on growing bacterial resistance, up to 2050, the death rate due to bacterial infection may increase to 390,000 in Europe and similarly all over the world as shown in Figure 1. Inflammation is a nonspecific immunological response by the organism's body to any trauma, neoplasm, autoimmune attack, or invading of the microbes. At the site of inflammation, several processes can be noticed such as blood supply increase and leakage of cellular fluid and small molecules, and protein penetration may take place. In the case of acute injury, body defense mechanism, i.e., leucocyte and plasma protein migration to the site of infection become activated. Neutrophils invade bacteria when seeking entrance in the body and prevent the body from further infection. The process of infection starts within a second or minute and prolongs to hours or days to heal. It causes the sequential symptoms, like inflammation, redness, warmth, and pain, which consequently affect the functions of the tissue or organ. Inflammation may be a nonspecific process, but infection consists of stepwise progress in inflammation which might be

history of human being [4].

Antioxidants

2. Inflammation and infection

chronic if it could not be addressed timely.

bodies.

352

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