Cancer, an umbrella term encompassing over a hundred different disorders, represents an uncontrolled proliferation of abnormal cells capable of infiltrating and metastasizing to various parts of the body (Singla et al., 2022c; Chavda et al., 2023).
It ranks as the second leading cause of death worldwide, accounting for 7.6 million deaths in 2005 (Abbas and Rehman, 2018). Shockingly, the global burden of cancer has been on a relentless rise, with an estimated 11 million new cases diagnosed and projected to reach 16 million by 2020 (Sarfati et al., 2016).
However, amidst these grim statistics, there is hope. Research suggests that one-third of all new cancer cases can be cured with early and effective diagnosis and treatment (Wang et al., 2013; Ricks, 2015).
One of the cornerstones of cancer treatment is chemotherapy. It exploits the fundamental difference between cancer cells and normal cells: the former’s lack of many regulatory processes that govern the latter. This enables chemotherapeutic agents to selectively target and eliminate cancer cells (Zugazagoitia et al., 2016; Prager et al., 2018). Over decades of research and development, a substantial arsenal of chemotherapeutic drugs has been amassed. However, these drugs are not without their drawbacks, often causing a plethora of side effects.
For instance, 5-fluorouracil, a commonly used chemotherapeutic agent, is known to induce myelotoxicity and cardiotoxicity, with rare occurrences of vasospastic reactions (Klein et al., 2022; Labianca et al., 1982; Rastogi et al., 1993).
Doxorubicin, another frequently employed chemotherapy drug, has been associated with cardiac toxicity, renal toxicity, and myelotoxicity (Avilés et al., 1993; Desai et al., 2008; Damiani et al., 2016). The toxicities associated with chemotherapy are a significant concern in the treatment of cancer through conventional medicine (allopathy) (Zugazagoitia et al., 2016; Gezici and Şekeroğlu, 2019).
The Role of Natural Products in Cancer Prevention
In the quest for alternative approaches to combat cancer and mitigate the side effects of chemotherapy, natural products have gained prominence (Rani et al., 2022). Among these, plants have emerged as a valuable source of anticancer compounds. Plants are rich in phytochemicals, compounds responsible for their anticancer properties.
The diversity of natural plant chemicals is vast, with many being aromatic compounds, primarily phenols or their oxygen-substituted counterparts. Focusing on active phytochemicals for herbal therapy offers the potential to reduce adverse effects and the development of pathogenic resistance to antibiotics (Kooti et al., 2017).
The significance of plants and their secondary metabolites in combating diseases, directly or indirectly, has been long recognized (Greenwell and Rahman, 2015; Sharma et al., 2022). Despite the availability of synthetic antitumor drugs, researchers continue to seek potent naturally occurring anticarcinogens capable of preventing, delaying, or reversing cancer progression (Singla et al., 2022b). In fact, plant-derived chemicals constitute more than half of all anticancer drugs (Omara et al., 2020).
Opuntia ficus-indica: A Natural Cancer Fighter
Opuntia ficus-indica (L.) Mill, commonly known as cactus pear, offers a fascinating prospect in the realm of cancer prevention and treatment. This plant, belonging to the Cactaceae family, has multiple species that evolved in Central America, particularly Mexico. For generations, Opuntia fruits and young stems have been employed in folk medicine to treat a range of conditions, including hypertension, diabetes, allergies, asthma, burns, swelling, and nausea (Abou-Elella and Ali, 2014).
The most noteworthy bioactive compounds found in cactus pear are betaxanthin, betacyanin, and phenolic compounds, all renowned for their potent antioxidant properties (Gentile, 2004; Kuti, 2004). Phenolic compounds, characterized by an aromatic ring bearing one or more hydroxyl groups, are highly diverse in their chemical structure and concentration, influenced by factors such as plant tissue type, variety, and ripening stage (Kuti, 2000).
Cactus pear, owing to its phenolic compounds’ antioxidant qualities, plays a pivotal role in protecting human health against degenerative diseases like cancer, diabetes, hyperglycemia, hypercholesterolemia, arteriosclerosis, and gastric ailments (Galati et al., 2003).
Mechanisms of Action
The polyphenolic compounds in Opuntia ficus-indica have been shown to hyperpolarize the plasma membrane and increase intracellular calcium levels in human Jurkat T-cell lines, suggesting their potential in cancer therapy (Aires et al., 2004). These mechanisms may contribute to the inhibition of cancer cell proliferation and the induction of apoptosis, making Opuntia ficus-indica a promising candidate for further research in the fight against cancer.
Phytochemicals present in Opuntia ficus-indica and its Anticancer Attributes
Opuntia ficus-indica, commonly known as prickly pear or Indian fig, is a remarkable plant that contains a wide array of phytochemicals with potential anticancer properties. In this chapter, we delve into the various phytochemicals present in O. ficus-indica and their potential roles in combating cancer.
Polyphenolic compounds are a diverse group of secondary metabolites found in plants. They are characterized by at least one hydroxyl group and an aromatic ring. O. ficus-indica is rich in polyphenols, with more than 8000 phenolic chemicals identified, including over 4000 flavonoids.
In addition to phenolic compounds, O. ficus-indica contains organic acids such as malic, quinic, and aconitic acids. Quinic acid, in particular, has been studied for its antioxidant, anti-inflammatory, antibacterial, neuroprotective, and radioprotective properties. Cis-aconitic acid has shown promise in preventing carcinogenesis.
Phenolic acids have gained attention as potential anticancer agents due to their ability to induce apoptosis, inhibit proliferation, and target various cancer-related processes. O. ficus-indica contains several types of phenolic acids, including hydroxybenzoic and hydroxycinnamic acids. Notable hydroxycinnamic acids in O. ficus-indica include cinnamic, chlorogenic, coumaric, and ferulic acids. These compounds have demonstrated anticancer properties in various studies.
Betalains are nitrogen-containing pigments found in high quantities in the pulp and peel of O. ficus-indica. They are categorized into betacyanins and betaxanthins. Betanin, a betacyanin, has shown antiproliferative effects on various cancer cell lines, including ovarian and cervical cancer cells. Betalains are known for their strong antioxidant properties and have the potential to prevent cancer and cardiovascular diseases.
Carotenoids are abundant in O. ficus-indica, with the highest concentration found in the peel. These compounds, including lutein, carotene, and β-cryptoxanthin, have demonstrated anticancer potential by interfering with cell cycle regulation, inducing apoptosis, and inhibiting metastasis and angiogenesis. Various studies have suggested their effectiveness against cancers such as breast, lung, pancreatic, and gastric cancer.
O. ficus-indica contains essential fatty acids, including linoleic acid, which can make up a significant portion of the total fatty acid content. These fatty acids are associated with health benefits, including potential cancer prevention. Mono- and polyunsaturated fatty acids are known to influence cancer growth and development positively.
Phytosterols, such as sitosterol and campesterol, are abundant in O. ficus-indica. These compounds have been linked to a reduced risk of breast, colon, and prostate cancers. Phytosterols enhance cancer immune recognition, impact hormone-dependent cancer growth, and inhibit tumor growth and spread.
Taurine, an organic osmolyte and amino acid found in O. ficus-indica, has antioxidative properties and has been investigated for its potential anticancer effects. Taurine has been shown to inhibit cancer cell growth and induce apoptosis when used alone or in combination with other anticancer drugs.
Saponins are glycosides with triterpenoid or spirostane aglycones and have been associated with anti-mammalian disease pharmacological properties. Although more research is needed on saponins in O. ficus-indica, saponins in other plants have demonstrated anticancer effects through various mechanisms, including tumor angiogenesis suppression and apoptosis induction.
In the relentless battle against cancer, Opuntia ficus-indica (L.) Mill stands out as a natural ally. With its rich reservoir of bioactive compounds, notably phenolic compounds and antioxidants, this cactus pear offers hope for both cancer prevention and treatment.
Its potential to harness the power of nature in combating this deadly disease makes it a subject of great interest for further research and exploration. As we continue to search for effective and safe anticancer agents, the healing potential of Opuntia ficus-indica reminds us of the untapped resources within the natural world, waiting to be uncovered and harnessed for the benefit of humanity.
reference link : https://www.frontiersin.org/articles/10.3389/fpls.2023.1236123/full