compounds for their potential use in the healing process of infectious diseases. The plants also contain several types of secondary metabolites with diversity in their molecular structure and functional prop­erties. Many of the plant’s secondary metabolites are effective in treating several metabolic diseases as well as infectious diseases. An experimental basis of the study of these secondary metabolites of the plants and their efficacy on the human disease treatment process has been performed. Several scientific studies have revealed the promising use of phytochemicals for the treatment of viral infections (Inoue & Craker, 2014; Satpathy, 2020; Kaur & Ahmed, 2021; Satpathy, 2021). The development of antiviral drug molecules is an important task to combat the life-threatening disease caused by the deadliest virus (Figure 31.1). Also, many of the viruses do not have established anti-viral treatment methods. Hence, due to the urgency is concern, suitable phytochemicals are to be explored scientifically as effective and inexpensive anti-viral inhibitor molecules (Ghorbanpour et al., 2017). To date, several viral diseases have been reported and the mutant form of the deadly viruses are also occurring frequently. Among the emerging viral diseases, most of them are caused by pathogenic viruses like Human Immunodeficiency Virus (HIV), Influenza, Herpes simplex virus (HSV), Dengue, Chikungunya, Zika, Hepatitis B (HSB), Hepatitis C (HCV), Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and so on. Viral infections are associated with great health risks to human health. Also, the infection is difficult to control as the origin of new mutant forms of the viral strains. In the past, deadly viruses caused pandemics in the world thereby increasing the risk of spreading viral diseases between continents.

Several targets in the viruses are available to which the specific phytochemicals are targeted and block the metabolism of the virus (Kumar & Pandey, 2013; Ahmad et al., 2015; Lipson et al., 2017; Subudhi et al., 2018).

Research has been confirmed about the mangrove plants as an important source for the search for novel drug molecules due to their ecological adaptation leads to the synthesis of large numbers of phy­tochemicals. Among these phytochemicals, many show significant pharmacological properties and are used as active antiviral, antibacterial and antifungal compounds (Bandaranayake, 1998; Abeysinghe, 2010; Aljahdali et al., 2021). The biochemical investigations on several mangrove species have shown that the plants are a rich source of a variety of bio-active compounds such as alkaloids, flavonoids,

triterpenoids, polyphenolic compounds, xanthones, coumarins, tannins, and so on (Vadlapudi & Naidu 2009; Abeysinghe et al., 2006). Hence, these bioactive compounds of mangrove plants are frequently used as drugs against various critical human diseases (Kokpol et al., 1990; Reddy & Grace 2016; Ad-

hikari et al., 2017). Many species of mangroves are frequently used in the traditional medicine systems to treat several human health disorders. The therapeutic properties of the mangrove plant product are based on its phytochemical composition and the mangroves are known to possess different categories of secondary metabolites used to treat several human diseases (Premanathan et al., 1994; Mitter & Jadhav 2011; Piyusha et al., 2012). The common steps that are adapted for the extraction and characterization of potential phytochemicals from the mangroves have been shown in Figure 31.3. Specifically, several antimicrobial metabolites extracted from the mangrove plants have shown their antibiotic reactions on many pathogenic microbial genera like Shigella, Staphylococcus, Escherichia, and Penicillium (Kokpal et al., 1990).

docking and molecular dynamics simulation have been frequently used to establish phytochemicals as anti-viral compounds. Many of the phytochemicals from the mangrove sources have been identified to