Bioactive substances have been misunderstood at times as plant toxins. Today, it is becoming increasingly clear that they have healing and protective functions that we are only now beginning to realize. One example is their helpful effect against cancer stem cells.
Bioactive substances – also known as secondary plant substances – are biologically active compounds. They are found in plants and promote growth by spoiling the appetite of pests through their taste. They also attract birds and insects with colors, which then distribute the pollen and seeds. This ensures the survival of the plant.
Bioactive plant substances have long been ignored in the false assumption that they are all poisonous.
Bioactive Substances Promote Health
In contrast to primary plant substances, which include carbohydrates, fats, and proteins, they only occur in very small quantities in the plant. But their importance persists – after eating plants, their protection and health-promoting properties extend to humans. Research has initially ignored them because there are also highly toxic substances among them, which led to the fallacy that all secondary plant substances were toxic.
Available Everywhere!
According to the German Society for Nutrition (DGE), secondary plant substances in foods help to reduce the risk of certain cancers and cardiovascular diseases. According to DGE estimates, about 1.5 g of secondary plant substances should be taken daily with the mixed diet. This assumes that one eats according to the applicable nutritional recommendations, especially with regard to whole foods.
First Studies
Cancer or tumour stem cells are the targets of intensive research. They are believed to be responsible for the malignancy of a tumour in terms of growth rate and degree of malignancy. In the Journal of Nutritional Biochemistry, Prof. Young Kim and colleagues at the US National Cancer Research Institute in Maryland published a study on the growth-inhibiting effect of certain substances on cancer stem cells. The observed effects were not specific for certain tissues or organs. Therefore, it could be deduced that a type of primordial cancer cell is inhibited.
The researchers found cancer treatment effects for vitamins A & D, genistein, EGCG from green tea and curcumin, among others.
What Has Cancer-Inhibiting Effect?
A blocking effect on cancer stem cells could be observed for vitamins A and D, genistein (plant estrogen from the group of isoflavonoids found in soybeans and red clover), epigallocatechin gallate (EGCG, a carboxylic acid ester of gallic acid – the antioxidant accounts for about one third of the dry mass of green tea), Sulforaphane (an isothyocyanate, strong indirect antioxidant), curcumin (root ingredient of the curcuma plant), piperine (main alkaloid of black pepper and carrier of the pungent pepper flavour), theanine (amino acid contained in the leaves of green and black tea) and choline (component of lecithins).
Concrete Results
EGCG (green tea catechin) was already in concrete trials in breast cancer patients who took EGCG in addition to radiotherapy for 2 to 8 weeks (“green tea group”). A comparison group received only radiation therapy.
The green tea group found significantly lower serum levels of VEGF (Vaso Endothelial Growth Factor) – a signal molecule that promotes the formation of new blood vessels in tumour tissue. Also reduced was the activity of the so-called metalloproteinases-9 and -2, which are essential for the tumour invasion – i.e. the injection process into other tissues.
What Does This Mean for the Future?
On the one hand, green tea catechin is a promising way to improve the efficacy of radiotherapy in breast cancer patients. On the other hand, this combination could also reduce the radiation dose in cancer therapies with the same anticarcinogenic effect.
