Breast cancer treatment with plant-derived anticancer compounds
Nature provides various medicinal plants for humans to combat different diseases and improve public health. Since ancient times, people have used plants and their bioactive substances as medicines. It is reported that numerous types of medicinal plants and their phytochemicals avoid the spread and development of cancer (39). There are over 250 000 plant species in the plant kingdom, but only about 10% of those have been studied for potential treatments of different diseases. Plant elements such as the flower, flower stigmas, pericarp, sprouts, fruits, seeds, roots, rhizomes, stem, leaf, embryo, and bark contain phytochemicals and their derived counterparts, which have a variety of therapeutic uses. Several primary and secondary metabolites play important roles in hindering cancer cell activating proteins, enzymes, and signaling systems or in activating DNA repair processes, promoting the formation of protective enzymes, and triggering antioxidant activity, resulting in potent anticancer effects, including Lignans, flavonoids, alkaloids, vitamins, terpenes, taxanes, saponins, mineral substances, oily substances, gums, glycosides, biological molecules (45, 46) . Table 2 provides detailed information on some medicinal plants on cell lines of breast cancer. Additionally, Figure 2 shows the generalized concept of carcinogenesis, immune responses, and the efficiency of natural phytochemicals against cancer.
Different strategies for the development of plant-derived anticancer substances
The potency of medicinal plants as therapeutic agents depends on the type and quantity of their active compounds, which vary from species to species depending on latitude, longitude, altitude, age, climate, and season. Different parts of the plant may have various pharmaceutical effects, which propose them as bioactive compounds in anticancer treatments. Several techniques are used to purify active compounds including combinatorial chemistry, isolation tests, and bioassay-guided fractionation. The purification of these compounds are carried out in several steps. Firstly, natural extracts (from dry or wet plant materials) with known biological activities are evaluated. Appropriate matrices, such as Superdex, Sephadex, and Silica, are then employed for the fractionation of natural extracts. The fractionated extracts are tested for bioactivity, and then the active fractions are separated using a variety of analytical techniques such as thin layer chromatography (TLC), high performance liquid chromatography (HPLC), fourier-transform infrared spectroscopy (FTIR), mass spectroscopy (MS), and nuclear magnetic resonance (NMR). Although these steps are flexible, it is important that the bioactive chemicals have the highest purity, quality, and quantity. This can be achieved by utilizing high-quality solvents and matrices as well as careful handling. The extracted compounds must be purified before evaluating in vitro or in vivo anticancer effects. Furthermore, it is necessary that more studies are performed on some characteristics of the extracted bioactive compounds such as pharmacokinetics, pharmacodynamics, immunogenicity, metabolic fate, biosafety and side effects, drug interactions, and dose concentration. Figure. 3 depicts a thorough planning for the synthesis, characterization, testing, and prospective use of a bioactive chemical as a cancer treatment agent.
Current challenges of plant-derived anticancer compounds
Although bioactive compounds have potent anticancer properties, they also have drawbacks that need to be resolved before their application in clinical trials and improved for the approved drugs. The main concerns in regard to the use of these compounds are their poor aqueous solubility, poor penetration into tumors, absorption by normal cells, limited therapeutic activities, and harmful side effects (47, 48). Today, the uses of colchicine, camptothecin, and derivatives of podophyllotoxin side are limited due to their adverse events. In addition, some anticancer compounds like vinca alkaloids have a limited impact and are usually employed in conjunction with other medications (49). Further challenges in the discovery and development of new anticancer agents are associated with their extraction, synthesis, optimization, and characterization. New developments in analytical technology and computational methodologies are anticipated to facilitate the identification of new compounds, improve their extraction, and/or decide on their chemical synthesis or modifications.