**1. Introduction**

Infectious diseases are diseases caused by the entry of one of four types of microbes, namely viruses, bacteria, protozoa or fungi that are harmful (pathogens). Of the millions of types of microbes that exist, only about 1,400 are pathogenic in humans, but critically only 150 have the ability to transmit from human to human and have the potential to cause epidemics [1].

Sepsis is a severe infection, and when the body is exposed to infection it will affect all organs of the body and many organs can affect it. Infection can come from the respiratory cavity, digestive tract, and wounds. When the human immune system drops, the body cannot overcome the infection and the infection will circulate throughout the body so that our body will respond to inflammation to fight the bacteria cause death [2].

By definition, sepsis is divided into several conditions, namely bacteremia or fungimia, infection, sepsis, severe sepsis and septic shock [3]. Sepsis is divided into several stages based on the body's response to infection, ranging from fever and leukocytosis to hypotension and impaired function of several organs [4]. Although almost any microorganism can be associated with sepsis and septic shock, the most common pathogenic etiologies are gram-positive bacteria (40%): *Staphylococcus aureus*, *Streptococcus pneumoniae*, Staphylococcus coagulase negative, and Enterococcus. Meanwhile, gram-negative bacteria (38%): *Escherichia coli* and *Pseudomonas aeruginosa* were the most frequently isolated bacteria in sepsis [3].

The biggest cause of sepsis is gram-negative bacteria (−) with a percentage of 60–70% of cases being the main cause of death in intensive care units, although antibiotics are new, mortality due to gram-negative sepsis remains high. This is because gram-negative bacteria tend to be more resistant to antimicrobial agents than gram-positive bacteria, due to the additional protection provided by the outer membrane [5]. This is why antibiotic resistance is now a public health problem worldwide involving a broad spectrum of microorganisms and different classes of antibiotics, including multidrug-resistant bacteria [6]. Therefore, it is very important to find new drugs to overcome this problem.

Sepsis infection produces various products that can stimulate immune cells. These cells will be stimulated to release inflammatory mediators. The product that plays an important role in sepsis is lipopolysaccharide (LPS). LPS or endotosin glycoprotein complex is the main component of the outer membrane of gram-negative bacteria. Lipopolysaccharides stimulate tissue inflammation, fever and shock in infected patients [7].

Sepsis is also defined as an irregular host response caused by infection and associated with severe microvascular, hemodynamic, metabolic, endocrine, and immune disorders, causing life-threatening organ dysfunction, characterized by a severe inflammatory response to systemic infection caused by pathogenic microorganisms. In severe cases, sepsis can lead to death with multiple organ failure as the main cause [7]. The catabolic response during acute sepsis severely depletes the body's nutritional resources, generates large amounts of cellular waste products and is in dire need of adequate nutrition [8].

Sepsis is characterized by early massive catabolism, loss of lean body mass and increased hypermetabolism that lasts for months to years. Insufficient nutrition and immune dysfunction did not have a synergistic effect on mortality in critically ill septic patients but it is expected that well-fed patients with normal immune function have the best chance of survival. Immunocompetent patients who are undernourished have the worst prognosis. Early nutrition should seek to correct micronutrient/vitamin deficiencies, provide adequate protein and moderate non-protein calories and well-nourished patients produce endogenous energy [9].

From a pathophysiological perspective, sepsis is often regarded as a syndrome that progresses from an initial inflammatory and hypermetabolic state to a more protracted state, characterized by lymphocyte exhaustion, apoptosis, and reduced capacity of monocytes and macrophages to release pro-inflammatory cytokines and trigger secondary infection [10] and cellular metabolic processes undergo fundamental changes without returning to normal homeostasis [11]. The degree of inflammation and immune suppression varies between individuals and is determined by host-(genetic heterogeneity, age, and comorbidities), pathogen-(burden, type, and virulence), and therapy-related factors (time, adequacy) [12].

*Potential Natural Product from Tropical Fruits: A Mixture Young Coconut Fruit and Kaffir… DOI: http://dx.doi.org/10.5772/intechopen.99005*

Since ancient times, humans have used plants to treat common infectious diseases and some of these traditional medicines are still included as part of the habit of treating various diseases. Chemicals from natural products facilitate a large number of several bioactive secondary metabolites that have been found to fight infectious diseases [1].

Natural products are secondary metabolites or chemical compounds produced by living organisms and which have bio-activity, can be useful against microbes originating from microorganisms that make secondary metabolites can be produced into drugs. The superiority of plants as a resource for the discovery of anti-infective drugs, and the latest technology allows a wider line of investigation. Natural plant products represent a promising and largely untapped source of new chemical entities from which new anti-infectives can be discovered [13].

### **2. Immunonutrition for infectius disease and sepsis**

The natural defenses of the human body depend on the integrity of the immune system which is responsible for curbing the course of pathogens and their complications. The immune system is divided into two types, innate and adaptive, each of which is responsible for responding to initial and repeated infections. Both types of immune systems rely on the use of mediators such as enzymes, pro-inflammatory cytokines, antibodies, and reactive oxygen and nitrogen species to combat many disease processes. The synthesis and functionality of these mediators depend on the individual immunonutrient components [14].

Immunonutrition is the term given to nutritional interventions that regulate immune and inflammatory responses. This is done by administering a formula containing a range of immunonutrients in greater amounts than is normally found in food. Some of the more commonly used immunonutrients include arginine, glutamine, branched-chain amino acids, omega-3, 6 and 9 fatty acids, trace metals (eg zinc, copper, iron), and nucleotides or antioxidants [15, 16]. The main targets of these immunonutrients involve mucosal barrier function, cellular defenses, and local or systemic inflammation [17].

Previous research has shown a close relationship between nutritional deficiencies and impaired immune function. The correlation between malnutrition and infection is particularly pronounced in less immunocompetent groups, such as young children and the elderly, who are prone to higher rates of respiratory and gastrointestinal diseases. One study determined that enteral glutamine administration reduced the incidence of moderate to severe sepsis and pneumonia in premature infants and critically ill patients. Other studies have shown that zinc supplementation at physiological levels for 1–2 months enhances immune response, decreases the incidence of infection, and ultimately improves survival [14].

In contrast, patients who have undergone surgery, trauma, or infection may experience the deleterious effects of a prolonged systemic inflammatory response because of the greater need for metabolic and essential nutrients. They may even experience compensatory immunosuppression as a result of chronic inflammation [4]. Many studies have shown that various combinations of immunonutrients can provide appropriate metabolic support for patients experiencing complications from malnutrition associated with illness, while effectively reducing infection rates and length of hospital stay. In addition, other immunonutrients such as proteins, vitamins, trace metals, and enzymes exhibit antioxidant properties that limit the extent of tissue damage and reduce the possibility of carcinogenesis [14, 18].

Nutritional therapy refers to the administration of nutrients with certain beneficial actions (eg for antioxidant effects) specifically aimed at immune defense mechanisms and to inhibit excessive proinflammatory responses during the catabolic phase of a disease [19, 20]. Future research on immunonutrition should be multidisciplinary and on a larger scale to further validate the great benefits of immunonutrition, while providing data on optimal mixes and doses for use in different groups of patients [17, 21, 22].

Immunonutrition therapy is an effort to reduce or eliminate potential pathogens and toxins, fulfill nutritional intake and act as antioxidants that can modulate natural and adaptive immune defense mechanisms in patients with critical illnesses such as sepsis. The concept of nutritional support in an effort to modulate immune function is known as immunonutrition (Immune-enhancing diets or Immuno-modulating diets) which is a therapeutic approach to pathological changes in adaptive and natural immunity, which arise secondary to inflammation and systemic infection through the administration of immunonutrients [23, 24]. The most relevant nutritional therapy in septic patients is the intake of the amino acids glutamine and arginine, fatty acids, selenium, and vitamin C [8].

Micronutrients are nutrients that the body needs to carry out body functions. The amount is less than 100% g per day and consists of vitamins and minerals. It cannot be synthesized in the body. Research in the United States states that the prevalence of sepsis tends to increase by 8.7% every year. In sepsis, nutrition is one of the important components that can promote the success of treatment. Micronutrients, especially fat-soluble vitamins, are toxic if the amount exceeds the body's ability to accept them. Although there are guidelines and mutual agreement on the use of sepsis, it is still necessary to pay attention to micronutrients that have the potential to have adverse effects. In the case of sepsis, micronutrients also determine the success of treatment because of the redistribution of vitamins and trace elements from circulation to tissues that play a role in protein formation and the immune system. Micronutrient supplementation is considered to reduce mortality. However, the toxicity of fat-soluble micronutrients still needs to be watched out for if the dose is excessive [25].

The role of micronutrients in metabolic processes is to maintain the function of body tissues. Hypermetabolism causes an increase in the production of Reactive Oxygen Species (ROS) as a result of an increase in oxidative metabolism that can damage cells, especially unsaturated fatty acids found in cell membranes and nucleus. Micronutrients also play a role in helping the body neutralize the negative effects of free radicals [26].
