**3. Types of bioactive compounds**

The biological elements found in a different classes of microalgae are beneficial for various diseases, and they acts as a treatment, which further helps in lowering the complexity of the ailment. Many therapeutic and pharmacological benefits can be availed [52]. The compounds act upon the tumors and could suppress their ability to metastasize. High-value chemicals (HVC) are isolated from variants of microalgae that could toxicant the cell at the cellular level, reduce the invasiveness of the tumor, and increase the possibility of apoptosis [17]. In **Table 2** different types of bioactive compounds effective against cancer cell lines are presented in **Table 2**. A detailed overview of the different bioactive from microalgae are summarized below:

## **3.1 Pigments**

*Fucoxanthin,* which is a carotenoid, can excite the *tumor suppressor genes* and cease the life cycle of the cell, but unfortunately, it cannot be effective for apoptosis. It is purified from microalgae, diatom, and brown seaweeds [67, 68]. When the agent *5-fluorouracil* was blended with *colorectal cancer*, it showed good results. It works by natural medication inhibition and cure of reactive oxygen species (ROS) [69]. The basis is the deoxyribonucleotide acid cleavage of the topoisomerases complex, which is Box-2 [70]. It is the intermediate stability in the working catalytic aspect of *topoisomerase* that stimulates apoptosis [62]. An example includes astaxanthin-KATO-III and SNU-1 cell lines for gastric cancer. There is an escalated expression of p27 in gastric cell lines because of the kinase regulated by the extracellular environment (ERK) [62]. To treat rats with induced colon carcinoma, astaxanthin was utilized, but it is very expensive [64]. The anti-inflammatory action of nuclear factor Kappa (Nf-kB) [55] is responsible for creating disruptions leading to cancer, and one of them is breast cancer [57, 58]. Acetylenic carotenoids like Fucoxanthin HL-60, which homosapiens leukemia cell line [58]. *C-Phycocyanin* is a product of *Spirulina platensis*, which labors for pathological amendment, the formation of fragments of the genetic material, and the *regression of Bcl-2 proteins,* accelerates and excites *caspase 2, 3,4,6,8,9,10 HeLa MCF-7 cell line [9]*.

*Exploring the Anti-cancer Potential of Microalgae DOI: http://dx.doi.org/10.5772/intechopen.104831*


#### **Table 2.** *Bioactive compounds effective against cancer lines.*

*Scytonemin* is a natural sunscreen, and it ceases proliferation and inflammation. It is purified from *Stigonema sp.* It is not in favor of human fibroblast and endothelial cells [65].

### **3.2 Polysaccharide and Polyunsaturated fatty acids (PUFAs)**

Polysaccharides are intracellular storage compounds. They also include an extracellular mucilaginous matrix or exopolysaccharides (EPS') and sulfated polysaccharides [63] They provide several health benefits, such as anti-cancer, anti-inflammatory, and immunostimulant [71]. Chrysolaminarin, a food storage polymer, inhibits the proliferation of tumoral colon cells [72]. For example, chrysolaminarin from *Chaetoceros muelleri* showed an immuno-stimulatory effect. Sulfated polysaccharides have radical scavenging activity that prevents oxidative stress, which otherwise cause l chronic degenerative diseases [73]. Fucoidan-sulphated, which has a high amount of fucose and is isolated from kelp, is effective against HeLa cells and human uterine cancer [74]. GA3P (D-galactose+ L-(+) Lactic acid) constrains the DNA topoisomerase I and II duties and is further obtained from the dinoflagellate Gyminidium [70]. The microalgae are rich in docosahexaenoic acid (DHA) which results in toxic accumulation in cells and highly controlled lipid peroxidation [9]. It stimulates programmed cell death of colonic malignant cell HT29 and aggregation of DHA in cardiolipin. In stomach cell lines, the compound DHA escalates in-cell cytochrome c, Bax, and p53 [57].

#### **3.3 Toxins and polyketide**

Algal species, *Protoceratium reticulatum*, *Yessotoxins* are isolated, which intensifies the apoptotic death in HeLa cells. It could upturn pathological group of cell alterations, segregation of genetic material, and changes in membrane potential of a powerhouse of the cell [53]. The neurotoxin *Cryptophycin1,* which is obtained from *Nostoc sp. GSV 224,* shows promising results against solid tumors and cell lines [56]. *Cryptophycin-8* is a semi-synthetic alternative of *Cryptophycin*, which exhibits action on proliferation in vivo [9] *Borophycin* is an acetate derivative of polyketide. It is mined from marine *Spongioform* [59]. It shows its activity in kB cell lines, which are supposed to contain *human papillomavirus18 sections*, and *LoVo lines*, which were first found in a *supraclavicular region* with the diagnosis of colon cancer. It works as a cytotoxic agent against *human epidermoid* and *colorectal tumors* [60]. Bio-product by *Lyngbya majuscule, Cucarin-A* is operative for breast and renal carcinoma [75]. It dominates the binding capacity of the process of making polymers of tubulin into the formation of a Colchicine pocket for binding [9].

## **3.4 Peptides**

As basic knowledge or key concept, which delivers the point that peptide, is obtained from enzymatic hydrolysis, which means the cleavage of bonds by water in which enzyme is involved [9, 76]. Dolastatin works for human ovarian and colon malignant tumors. The B16, colon 26 adenocarcinoma, and M50 76 sarcoma and HT29 [77]. The medicine is extracted from *Lyngbya* sp. *and Sympleca sp*. The *Chlorella vulgaris* isolated peptide stops AGS gastric cancer after the stage of the G1 step of the life of a cell. Algal sulfolipids, which are subjected to Nostoc ellipsosporum, are operational against HIV [78]. It can also be extracted from E.coli, which could even deactivate HIV. The glycolipids are effective against HT29 in colorectal cell lines which also use 5-fluorouracil and oxaliplatin for the cure [79].

*Exploring the Anti-cancer Potential of Microalgae DOI: http://dx.doi.org/10.5772/intechopen.104831*
