Part 4: Radioprotection with plant extracts
Ionizing radiations damage tissues and genetic material by generating free radicals that cause oxidation of membrane lipids, DNA, RNA, proteins and other cellular structure. This leads to chronic inflammation, organs dysfunction, mutations and disease in the body.
Certain natural compounds found in plant extracts provide remarkable protection against ionizing radiation injury and help curb inflammation. These bioactive substances have amazing antioxidant properties that slow down or prevent the damage caused by ionizing radiations. In addition, these bioactive compounds also help in the normal growth and development of cells.
Curcumin is the main bio-active ingredient in turmeric, a cooking spice that gives curries its yellow colour. While turmeric has a long history of use in Ayurvedic medicine to treat pain, swelling and inflammation, modern research also proves that curcumin is a heavy-duty antioxidant and anti-inflammatory. It lowers the biomarkers of inflammation in the body. Curcumin also:
- Boosts the immune system
- Detoxifies the body
- Has cancer protective properties
- Reduces side effects of radiation
Curcumin in radioprotection
Curcumin supplements reduce the oxidation of biological structures such as DNA and lipids – its primary mechanism is to limit the damage and provide protection against radiation exposure.
Studies suggest that curcumin appears to have a dual-mode of action. It not only protects normal, healthy cells and tissues from radiation injury but also triggers death in cancer cells, which makes it an important adjunct in radiation and chemo therapy to treat cancer. This 2007 study highlights the radioprotective and radiosensitizing effects of curcumin concluding that:
“the radioprotective effect might be mainly due to its ability to reduce oxidative stress and inhibit transcription of genes related to oxidative stress and inflammatory responses, whereas the radiosensitive activity might be due to the upregulation of genes responsible for cell death.” 
Another 2010 study shed some more light on curcumin’s role as a chemosensitizer and radiosensitizer for tumors and a protector for normal organs.  It reports that the protective effects of curcumin are due to its ability to:
- Activate NRF2 (a protein and stimulate the expression of antioxidant enzymes in the body)
- Increase glutathione levels
- Quench free radicals
Curcumin is a powerful anti-inflammatory and works by targeting many molecular pathways associated with promoting inflammation; for example, it:
- Reduces both the activity and synthesis of cyclooxygenase (COX-1 and COX-2) enzymes.
- Inhibits the NF-κB pathway (Nuclear factor-kappa B).
Resveratrol is a polyphenolic compound found in the skin of purple and red grapes. It is known to have tremendous anti-oxidant and anti-aging properties. Studies show that resveratrol:
- Scavenges free radicals and protects cells and tissues from oxidative damage
- Prevents the activity and production of pro-inflammatory chemicals
- Supports healthy replication in cells
- May prevent cancer
- Activates sirtuins – special enzymes associated with extending life span. Sirtuins work by regulating various biological pathways related to energy production and metabolism, inflammation, cellular protection against stress, mitochondrial functions and DNA repair mechanisms. 
Resveratrol in radioprotection
A 2010 study from China reported that resveratrol’s anti-oxidant properties help in safeguarding cells from hazardous radiations. 
Studies also suggest that resveratrol makes cancer cells more sensitive to radiation therapy.   And as a chemo-sensitizer, resveratrol enhances the body’s handling of chemotherapy drugs. Similar to curcumin, it also protects healthy tissues against radiation damage.
- Gingko Biloba Extract
Ginkgo biloba is one of the most potent natural radioprotectors. It protects cellular components and organs from radiation induced damage  and is effective even long after the exposure. It was effectively used to treat workers after Chernobyl nuclear reactor meltdown in 1986.
Gingko Biloba in radiation protection
Gingko Biloba extract provides a very high degree of radioprotection as it reduces the effects of clastogenic factors, such as plutonium and other radioactive nuclides.  These factors are found in the blood of persons irradiated either accidentally or those undergoing radiation therapy.
Clastogenic factors cleave DNA and cause chromosomal damage, leading to cell mutations and cancer. In fact, clastogenic factors continue to float in the bloodstream and keep causing DNA and chromosomal damage even years after the exposure. Clastogenic factors were detected in the blood samples of both Chernobyl and Japanese atomic bomb survivors even 30 years after radiation exposure.
- Jagetia GC. Radioprotection and radiosensitization by curcumin. Adv Exp Med Biol. 2007;595:301-20.
- Goel A, Aggarwal BB. Curcumin, the golden spice from Indian saffron, is a chemosensitizer and radiosensitizer for tumors and chemoprotector and radioprotector for normal organs. Nutr Cancer. 2010;62(7):919-30. doi: 10.1080/01635581.2010.509835.
- Hubbard et al. Evidence for a Common Mechanism of SIRT1 Regulation by Allosteric Activators. Science. 2013; 339 (6124): 1216.
- K. Ye et al. Resveratrol Attenuates Radiation Damage in Caenorhabditis elegans by Preventing Oxidative Stress. J Radiat Res 2010.
- Fang Y, Herrick EJ, Nicholl MB. A possible role for perforin and granzyme B in resveratrol-enhanced radiosensitivity of prostate cancer. J Androl. 2012
- Fang Y, DeMarco VG, Nicholl MB. Resveratrol enhances radiation sensitivity in prostate cancer by inhibiting cell proliferation and promoting cell senescence and apoptosis. Cancer Sci. 2012
- Shin et al. Protective effect of Gingko biloba against radiation-induced cellular damage in human peripheral lymphocytes and murine spleen cells. International Journal of Low Radiation, 2009.
- Emerit I, Arutyunyan Oganeasian N. et al. Radiation-induced clastogenic factors: anticlastogenic effect of Ginkgo Biloba extract. Free RAdic Biol Med, 1995 Jun: 18(6): 985-91