**2. Microalgae: a potential anticancerous source**

Structurally, they are unicellular, photosynthetic microorganisms [13] and are seen as colorful plumes [21]. They have a simple cell structure [22], which is typically a marine or freshwater organism [23]. They transform sunlight, water, and carbon dioxide into algal biomass. Phosphorus, nitrogen, and carbon are the basic nutrients, which are required in high quantities for their growth and productivity [13]. They can form colonies and can also exist as filaments or spheres with the same kind of cells. The ability to carry out food making process, which is photosynthesis, is possible because of photosynthetic pigments [22]. The major chemical constituents are lipids, proteins, and carbohydrates [22]. Their ability to carry out the food making process, which is photosynthesis, is possible because of photosynthetic pigments [22]. *Exploring the Anti-cancer Potential of Microalgae DOI: http://dx.doi.org/10.5772/intechopen.104831*

The color is due to the pigments found in it, which are categorized as *Chlorophyta* (green), *Rhodophyta* (red), and *Phaeophyta* (brown) [13]. The different modes of nutrition are found in the variants whether it is autotrophs, heterotrophs, or mixotrophs [22]. They are capable of nitrogen fixation. The symbiotic relationship can also be found in fungi in lichens [22, 24]. Situations and nutrition when favorable can lead to algal bloom, which is red tide. The increased production of this releases a toxin that kills the fish. The species can absorb oxygen and hydrogen from water [6].

The microalgae have various aspects of being a potential source for medication [9]. It has several positive outlooks, which make it the best choice for people suffering from cancer [1]. The major priority basis is its production sources, bioactive substances, survival in extreme areas, adaptability, and cost efficiency [5]. The production of these species is very easy in the laboratory as well as in real-life areas. They are easily found, but their unique benefits can be reaped only when they are cultivated in different parts of the world [9]. The second aspect is the bioactive elements that are found in the variants [8]. They are proved to be very much fit to be applicable in the biotechnology sector. They are used in medications for various diseases and work as a drug delivery systems too [9]. It is a very good option for various processes, and in previous sections of this article, it is highlighted that it works effectively against malignancy with lesser or fewer side effects [25]. It is found in different areas, climates, and environmental conditions, so different varieties could be extracted and assessed to determine which element is suitable to fit in which sector and treatments [9]. It is cost-efficient because it is cheap and readily available, but everything which comes from nature expects humanity to pay the price for it [25].

The ethical issues need to be taken care of precisely. Nature should not be hampered, and it should not exceed the limit [9]. The medication for cancer and the different elements extracted from it work for different stages of the disease [26].


#### **Table 1.**

*Algae variants with mechanism of action and the cancer cell lines.*

The concentration of that medicine needs to be altered according to the patient's stage of cancer, his body and health condition, and the characteristics of the medicine that depend on which phase it is made to act. Some medicines and compounds are naturally designed to inhibit or completely cease malignancy [27]. Some could act in an intravasation state, and some could lead to dormancy. The dormancy can lead to secondary metastasis, which then could relapse after some years [28]. The concentration of elements specifically matters, which is different for different patient's according to the patient reports and conditions [27]. *Chemo-prevention:* the quality which either prevents or delays the onset of cancer [9]. *Microalgae are* adaptive, fast proliferation, renewable, and of interest for genetic process and modification for industrial purposes, and can be utilized as a whole [29]. It is autotrophic, which uses light for both positive and negative effects, like photo-inhibition. It requires secondary sources or metabolites for its various mechanisms, like protection, defense, etc. [9]. For instance, amino acids and peptides from *Chlorella vulgaris* protect the genetic evidence, hydroxyl radicals, scavenger effects, and gastrointestinal enzyme resistance, which comprises of 7.5 μm [30]. Algae variants with the mechanism of action and the cancer cell lines are presented in **Table 1**.
