The organic chemicals in plants (phytochemicals) promote the health of humans.
Regular consumption of phytochemicals improves immunity; helps us to fight chronic diseases like:
- Hypertension and Cardiovascular diseases
This section deals with how consumption of plant-based-products could help fight against cancers.
Autophagy is the innate ability of cells to degrade and remove (or recycle) damaged organelles and damaged proteins (toxic materials) from cells.
Autophagy (self-digestion) is also known as cellular house-cleaning.
It is the ability of cells to remove damaged organelles and damaged proteins (for recycling) that keeps these cells healthy and enables cells to reproduce healthy daughter-cells.
A breakdown in autophagy results in the accumulation of damaged organelles and proteins within the affected cells (which are often toxic to these cells).
The accumulation of damaged organelles and abnormal proteins leads to chronic inflammation, chronic diseases, and cancer-cells formation.
Cells with irreparably damaged-DNA, commit suicide and drop outThe process is known as Apoptosis or cell-shedding
GENE-MUTATIONS AND CANCER CELL FORMATON
MUTATIONS: changes in DNA base-sequence which lead to the formation of unusual-genes.
Cells that inherit unusual-genes are frequently, transformed into cancer cells.
This is because gene mutations could help the cancer cells to escape detection and destruction by the immune system.
Gene-mutations that lead to the formation of cancer cells are known as Oncogenes.
Tumor suppressor genes are genes that normally, prevent healthy cells from being transformed into cancer cells.
Mutations in tumor suppressor genes, or inadequate production of tumor suppressor proteins provide cancer cells with selective growth advantage in comparison to normal cells; they lead to proliferation of cancer cells.
TUMOR SUPPRESSOR GENES.
Tumor suppressor genes are genes that block the transformation of healthy cells into cancer cells.
Tumor suppressor genes like the P53-gene, encodes for the production of the P53-protein.
P53-proteins repair damaged DNAs in cells.
If the damaged DNAs are beyond repair, the P53-protein sanctions the apoptosis of the affected cells.
Mutations in the P53-gene leads to either the absence of the p-53 proteins, or the presence of a non-functional p53-protein.
Most cancer cells develop as a result of mutations in the P53-gene.
Oncogenes are genes that promote the transformation of healthy cells into cancer cells.
The oncogenes help cells with damaged DNA to escape apoptosis.
Here are a few examples of oncogenes
1The murine double minute 2 genes (MDM2 genes).
MDM2-genes produce MDM2-proteins that attack and remove the P53 (tumor-suppressor) proteins form cells.
MDM2 genes are therefore, negative regulators of the P53 (tumor-suppressor) proteins
MDM2-proteins keep the levels of P53-proteins in check and thus, prevent cells with damaged DNA from undergoing apoptosis.
Most tumor cells contain high levels of MDM2 proteins
The RAS-gene acts in several ways to promote cancer cells development.
Ras-proteins augment the production of MDM2-proteins to neutralize P53-proteins and thus, prevent abnormal cells from undergoing apoptosis.
In addition, RAS-gene produces the enzyme collagenase that breaks down collagen-barriers to facilitate the spread of cancer cells throughout the body.
Other oncogenes like HER-2 genes promote the proliferation of breast cancer cells; BCL-2 genes prevent cancer cells from undergoing apoptosis.
Phytochemicals mediate cancer-cells-death through Autophagy and Apoptosis.
Cancers may be prevented if we could change our dietary habits.
For example, it has been known that the incidence of breast and prostate cancers in Asians who, consume diet high in soy products is relatively low when compared with their cousins living in the Western countries, who consume mainly, western diets.
Most of the research on how dietary consumption of fruits, vegetable, and other plant-products affect cancer-development, have been conducted in animal-studies.
Daily consumption of these plant products lowers the risk of developing cancers.
Let us discuss some of the well-studied phytochemicals, and their effects on cancer cells.
SILIBININ [C25 H22 O10]
Silibinin are plant phenolic compounds that have antioxidant and anti-neoplastic properties
Among the cancer cells that are destroyed by silibinin in laboratory studies are:
Prostate adenocarcinoma cells
Estrogen-dependent breast cancer cells
Cervical cancer cells
Colon cancer cells
Both small, and non-small lung cancer cells.
PLANT SOURCES OF SIBININ:
Milk thistle Silybum marianum (All plant partsMost especially, milk thistle seeds)
Grapes, and Peanuts contain trace amounts of silibinin.
MECHANISM OF ACTION OF SILIBININ
Silibinin induce Apoptosis in the cancer cells by blocking the mTOR pathways.
In addition to its Anti-tumor properties, Silibinin has also Antiviral, Antioxidant properties.
Silibinin protect liver and brain neurons from cellular damage.
Fisetin is an mTOR-inhibitor that has anti-inflammatory properties
Plant sources of Fisetin:
- , Apples
MECHANISM OF ACTION OF FISETIN
Laboratory studies indicate that Fisetin possesses Anticancer properties that involve Apoptosis, inhibition of cell growth, and cutting-off blood supply to cancer cells.
The cancer cells that Fisetin has anticancer effect (from laboratory studies) are:
Prostate cancer cells
Bladder cancer cells
Cervical cancer cells
Studies indicate, the anti-inflammatory effects of Fisetin are similar to those of the corticosteroids.
Fisetin consumption helps alleviate symptoms of Allergic diseases as well.
Plant source: Chili pepper
MECHANISM OF ACTION
Capsaicin causes Apoptosis in several cancer cells in laboratory animalsThey include Pancreatic tumors and Bladder cancers.
High-dose capsaicin triggers Autophagy in high-grade Bladder tumors
Laboratory studies indicate capsaicin triggers cytotoxic-Autophagy in Melanoma cells.
Most herbal teas contain catechins
Green teas have several catechins: Catechins (C), Epicatechins (EC), Epigallocatechin (ECG), Epigallocatechin-3 gallate (EGCG)
MECHANISM OF ACTION
The anticancer properties of green teas reside in the EGCGs.
1Induces Apoptosis in cancer cells
2Attack the mTOR pathways
3Offer protection against oxidative stress.
EGCG have been found to inhibit tumor development in
Lycopene is the red pigment found in fruits and vegetables like:
It has been observed that higher intake of lycopene is associated with much lower incidence of prostate cancers.
MECHANISM OF ACTION ON CANCER CELLS
Lycopene stimulate Apoptosis and cell-cycle arrest in prostate cancer cells
Ingested lycopene accumulates naturally, in the prostate gland, (the prostate has the higher concentration of lycopene than all other tissues).
Daily consumption of lycopene reduces progression of benign prostate enlargement.
Dried Soy Beans
Phytoestrogens (plant estrogens) occur naturally in many plantsThey are structurally, similar to the synthetic estrogens, and are biologically, active in humans.
One group of phytoestrogens is the Isoflavonoids that include isoflavones.
Isoflavones occur naturally, in legumes: Soy Beans and Soy-products.
Small amount of Isoflavones occur in Lentil, Pea beans Chick peas, and other beans.
Much smaller amounts of Isoflavones are found in cereals, fruits and vegetables.
Epidemiological and clinical studies show that rich phytoestrogen-diets decrease the incidence of breast and endometrial cancers.
The isoflavones include: Genistein, (which is most important in cancer prevention) and Daidzein
MECHANISM OF ACTION
Isoflavones induce apoptosis in cancer cellsThey cut off new blood supply-lines to cancer cells, and prevent cancer cells from spreading.
Of note is that Asians who consume a traditional diet high in soy products do have low incidence of Breast and prostate cancers.
Take home point: consume soy beans, and soy-bean products every day.
Quercetin, a plant polyphenol is found in variable quantities in all plants.
Red onions and Tomatoes contain adequate quantities of quercetin, however, heat (cooking, boiling, frying) lowers the initial quantities of quercetin in these vegetablesSo, eating red onions raw, is a better way of preserving the amount of quercetin consumed.
Quercetin has been found to be cytotoxic to cancer cells.
Mechanism of cytotoxicity
- Apoptosis and cell cycle arrest
Among the cancers which quercetin has been found to prevent are:
- Gastric cancers
- Breast cancers
- Prostate cancers
- Colon cancer
- Lung cancers.
Resveratrol are polyphenols (2-phenyl rings with a methylene-group between them) found in great amount in:
- Cocoa beans
Resveratrol prevents cancer development in
- Prostate gland
- Liver, Stomach
- Skin and myeloma cancer cells.
Mechanism of cancer prevention includes
- Sirtuin-1 activation
- Decreases chronic inflammations
- Blocks the development of new blood vessels to cancer cells, and also,
- Prevents spread of cancer cells.