innovative chemical compounds that are capable of treating diseases caused by bacteria that are resistant to several drugs. It is extremely necessary to find novel compounds in nature to produce new antibacterial compounds. In recent years, there has been a change in secondary metabolites that are employed in antimicrobial medications. Actinobac­teria has become the dominant source of these compounds. Marine bioactive chemicals including polyphenols, proteins, and essential fatty acids possess different biological effects such as antioxidant, antithrombotic, anticoagulant, anti-inflammatory, antipro­liferative, hypotensive, diabetic, and cardioprotective properties (Table 13.1). The food industry may also profit from the advantageous rheological qualities that they possess (Ameen et al., 2021).

In the later stages of the development of cancer, antioxidants are very necessary. Even though the particular mechanisms underlying this are still being investigated, there is a growing body of evidence that oxidative processes have a role in the development of cancer. Antioxidants have the potential to stop the spread of precancerous lesions and their

might be advantageous in dealing and anticipation of oral leukoplakia, which is a disorder that has the potential to progress into mouth cancer. It is well recognized that natural foods are high in β-carotene, α-tocopherol, and vitamins C and E. This indicates that plant extracts and isolated components of plant origin may be examined for their potential antioxidative and anticancer activities, which might lead to the creation of new anticancer medicines (Vishwakarma and Piddini, 2020).

The human body is equipped with a variety of defense mechanisms that it uses to combat free radicals and reactive oxygen species (ROS). Because different defenses act on various classes of oxidants or in various compartments of the cell, they are mutually supportive of one another. In most circumstances, the presence of high amounts of superoxide dismutase (SOD) maintains levels of superoxide that are not sufficient to prevent the formation of Peroxynitrite. Although glutathione (GSH) is not a food, it exists in all the aerobic tissues because it can be synthesized from sulfhydryl group containing amino acids. It has a very significant role in the metabolic process of antioxidant intermediates. Consuming nutritious foods on a regular basis is critical for the proper functioning of enzymes that shield the body from damaging effects of free radicals (Carreira-Casais et al., 2021). A few instances of essential components required for the structure or catalytic functions of such enzymes are selenium, copper, manganese, and zinc. Vitamin E, on the other hand, is not associated with the activity of any single-enzyme system. Vitamin E functions as an antioxidant by eliminating free radicals and preserves the structural integrity of phospholipid and lipid membranes. V itamin E has a significant impact on other antioxidants already present in the body , for instance, GSH and vitamin C. Evidence is mounting that vitamin E can influence cellular processes like gene expression and inflammatory response. Vitamin C is also a potent antioxidant since it may donate an electron of hydrogen in exchange for the formation of the comparatively stable ascorbyl free radical or L-ascorbate anion. It has been shown that ascorbate is an effective reactive oxygen species scavenger against singlet oxygen, hydrogen peroxide, hydroxyl radical, and superoxide radical anion. In addition, dangerous nitrogen oxide species are also eliminated by vitamin C. To prevent the target molecules from getting nitrosated, it works in this way. Ascorbyl has the potential to undergo further oxidation, which would result in the formation of dehydroascorbate. Alternatively, it might acquire an additional hydrogen atom and transform into reduced ascorbate. Ascorbate is more water-soluble than dehydroascorbate, and erythrocytes absorb dehydroascorbate 10–20 times more quickly than ascorbate. The hexose monophosphate shunt then converts it back into ascorbate, either via GSH or Nicotinamide adenine dinucleotide phosphate (NADPH). Therefore, there is no limit to the mechanisms in which vitamin C can be used. Tissue metabolism generates free radicals, but the cell’s antioxidant capacity and its repair

The intricate process of apoptosis causes a variety of alterations in the dying cells and utilizes several signaling channels. A change in the ratio of anti- and pro-apoptotic proteins activates apoptotic machinery. Apoptosis may be reduced by upregulating antiapoptotic proteins, downregulating proapoptotic proteins, and downregulating caspase expression. It is known that evading apoptosis speeds up the growth of cancer by preventing differentiation. In conditions when there is inadequate apoptosis, which results in cancer, dysregulation of apoptotic signaling may be very important. Caspase 8 is a mitochondrial initiator caspase that promotes cytochrome C release and links death receptor with mitochondrial pathways of apoptosis. Caspase 3 is a cell-killing effector caspase that is required for cell survival. Apoptosis induction is a promising strategy for inhibiting cancer cell proliferation (Matulja et al., 2022). Cancer has been treated with radiation and chemicals such as tamoxifen, which may induce apoptosis. Several chemo-preventive substances cause apoptosis to have an anticarcinogenic effect. Plant extracts’ ability to induce apoptosis of malignant cells may be linked to upregulated immune surveillance, an increase in macrophages, and activation of signal complexes that cause death. Malignant cells have been shown to undergo apoptosis in vitro when exposed to natural food components such as curcumin and resveratrol. The macrophages may be stimulated and made to undergo apoptosis by the marine phytochemicals (Yao et al., 2022). Fucoidan, an immunomodulator that directly affects macrophage and T lymphocyte, is derived from the Laminaria japonica plant and may restore the immunological capabilities of immunosuppressed mice. In rats exposed to radiation, it may also encourage the restoration of immune function. The mechanism is connected to the fucoidans ability to stop lymphocyte apoptosis. Dendritic cells that are potent antigen-presenting cells are affected by fucoidan from Focus vesiculosus in an immunostimulant and growing method via a nuclear factor-B route (NF-κB) (Yarley et al., 2021).

Marine plants are expected to meet the need for food and nutrients for handling human ailments. The majority of cancer-preventive diets focus on including foods that come from plants as their primary source of nutrition. A higher frequency of consumption of a wide variety of plant foods is recommended for cancer prevention. “Plant-based” diets place more emphasis on nutrient-dense, fiber-rich (and thus, nonstarch polysaccharide-rich), and calorie­poor foods. Consuming a diet rich in fruits and vegetables that are low in starch may reduce the risk of developing some cancers. Seaweeds are often ingested by people and have been used medicinally for a very long time. Seaweeds possess many unique biological features against tuberculosis, arthritis, colds, influenza, cancer, and so on (Yusefi

et al., 2020).

been a number of investigations into the antioxidant, anticancer, and immunomodulatory properties of seaweeds. It has been shown that certain types of edible seaweed such as Palmaria palmate are rich in antioxidants that inhibit the development of cancer cells. Red algae Acanthophora spicifera has tumorcidal activity on mice that have developed Ehrlich’ s