Rhubarb deserves more than one line.

Iodine rich and anti-cancer, anti-fibrotic in our bodies, and good in Blueberry-Rhubarb Jam on toast.

Oct 03, 2022

Rhubarb has been used medicinally in Traditional Chinese Medicine for “antibacterial, anti-inflammatory, anti-fibrotic and anticancer medicines” since 270 BC - that is an evidence trail. Preparation methods and difference in growing conditions or varieties effect quality and reduce efficacy. (Xiang, et al, 2020) Blueberry-rhubarb jam is a preparation method I have tried, and included in the second half of this post.

"Rhubarb (also named Rhei or Dahuang), one of the most ancient and important herbs in traditional Chinese medicine (TCM), belongs to the Rheum L. genus from the Polygonaceae family, and its application can be traced back to 270 BC in “Shen Nong Ben Cao Jing”. Rhubarb has long been used as an antibacterial, anti-inflammatory, anti-fibrotic and anticancer medicine in China. However, for a variety of reasons, such as origin, variety and processing methods, there are differences in the effective components of rhubarb, which eventually lead to decreased quality and poor efficacy." (Xiang, et al, 2020)

Rhubarb is a good source of iodine, as the plant can uptake iodine from the soil better than other plants and then contain a higher concentration of iodine than the soil. Low iodine soil might lead to a less beneficial phytonutrient content.

Three major rhubarb anthraquinones: emodin, aloe-emodin and rhein.

"The most abundant anthraquinone of rhubarb, emodin, was capable of inhibiting cellular proliferation, induction of apoptosis, and prevention of metastasis. These capabilities are reported to act through tyrosine kinases, phosphoinositol 3-kinase (PI3K), protein kinase C (PKC), NF-kappa B (NF-kappaB), and mitogen-activated protein kinase (MAPK) signaling cascades.
Aloe-emodin is another major component in rhubarb found to have anti-tumor properties. Its anti-proliferative property has been demonstrated to be through the p53 and its downstream p21 pathway. Our recent proteomic study also suggests that the molecular targets of these two anthraquinones are different. However, both components were found to be able to potentiate the anti-proliferation of various chemotherapeutic agents.
Rhein is the other major rhubarb anthraquinone, although less well studied. This compound could effectively inhibit the uptake of glucose in tumor cells, caused changes in membrane-associated functions and led to cell death. Interestingly, all three major rhubarb anthraquinones were reported to have in vitro phototoxic." (Huang, et al, 2007)

“in vitro phototoxic” - phototoxicity refers to topical application of a chemical that causes skin irritation in the presence of light. “in vitro” means it was tested in lab conditions. Emodin and aloe-emodin are also found in aloe vera gel and is beneficial for skin health, but maybe sun-sensitivity too?

What is phototoxicity potential? Phototoxicity potential is evaluated by the relative reduction in viability of cells exposed to the test chemical in the presence as compared to the absence of simulated sunlight. Chemicals identified as positive in this test may be phototoxic in vivo following topical application to the skin, eyes, and other external light-exposed epithelia. (oecd.org)

Rhubarb also has a phytonutrient, parietin, that has been shown to be effective against cancer cells. A concentrated amount of the parietin was used however: (express.co.uk) Parietin is an orange pigment found in the rhubarb and in many types of lichen. I don't happen to have an image of rhubarb handy but here's some pretty lichen on a rock in a desert area:

Colorful lichen on a rock in the desert during early winter, with colored pieces of glass, found nearby.

The chemical left healthy cells unharmed which is unlike typical chemotherapy treatments. The parietin may be stopping cancer cell growth by blocking anaerobic metabolism - the burning of energy without oxygen. (express.co.uk) Our bodies preferentially use metabolic pathways that use oxygen (and cause oxidative stress as a byproduct) and produce ATP more efficiently - more usable energy per molecule of sugar and less oxidative stress chemicals for the body to clean up.

This article contains a list of many other beneficial phytonutrients and vitamins found in whole rhubarb. It contains antioxidants and a variety of beneficial things in addition to iodine. New study: Substance in rhubarb cuts cancer cell growth in half. (naturalhealth365.com)

Ginger Rhubarb sauce or frozen dessert.

A simpler recipe than the jam recipe that follows is a sauce that I made to use up a lot of rhubarb all at once. Rhubarb Ginger Sauce turned into a sorbet-like frozen treat after I froze the bulk instead of canning it. The texture frozen was so good I ate it as a sorbet. I also used some thawed in baked goods as a substitution for part of the liquid in a recipe similar to substituting applesauce.

The recipe was roughly 12 cups of washed and chopped rhubarb stalks, about 1/2 inch long sections, simmered with 3 cups of sugar and an inch or two section of ginger root, peeled and minced fine. Some might prefer less ginger or no ginger, that amount made a fairly zingy sauce. The stalks make their own sauce as they simmer and the chunks become soft and lose their form. Simmer for about 20 minutes.

Once frozen the sugary treat was ready and easy to eat like a fruit sorbet or old-fashioned Snow Cone rather than freezing into a more solid chunk of ice. The sugar content might be necessary for that effect, I think a sugar free sauce would freeze more solid.

Blueberry-Rhubarb Jam - reduced sugar.

Rhubarb is not traditionally a fruit used in jam or jelly but makes itself noticed in rhubarb and strawberry pie and would be good as a strawberry rhubarb jam too. The combination is tangy and the color of the strawberries and rhubarb blend together beautifully.

Blueberries are a low acid fruit that is also beneficial for health. They are typically used in jam, but extra lemon or lime juice is recommended with the low sugar, calcium set, pectin that I used. Rhubarb is acidic and tart. The more alkaline blueberries helped balance the tanginess of the rhubarb and it jelled nicely. The rhubarb helped balance the bulkiness of blueberry skins in a low sugar all blueberry jam.

The following was a double batch, based on the directions given with the pectin. A recipe using rhubarb was not included in the box of Pomona's Universal Pectin but their website has several variations that do call for some additional lemon juice. My version tastes good and jelled without additional lemon juice. *Less sugar or none could also be used with the Pomona's Universal Pectin method. Calcium dissolved in water is added to help the jelly set. The sugar concentration helps it gel compared to sugar free.

Pomona's Universal Pectin home page: [pomonapectin] Recipe pdf: [pomonapectin] The pectin is derived from citrus peel and its gelling power is activated by calcium rather than sugar. Sugar free jams and jellies or low sugar varieties can be made more easily with this type of pectin than with standard pectin. Traditional jelly recipes may use 7 cups of sugar per 4 cups of fruit.

Blueberry Rhubarb Jam (double batch)

4 cups blueberries
6 cups chopped rhubarb (this measurement was the raw product - 4 cups mashed/cooked was needed)
1 cup cane syrup *
2 cups powdered sugar *
(* cleaning out my cupboard - swap 2-3 cups regular sugar)
2 teaspoons calcium water mixture - follow jelly package directions.

Cook for about 10 minutes or until the rhubarb is softened.

1 cup white sugar - mixed with:
4 teaspoons Pomona's Pectin

Add the pectin/sugar mixture to the boiling fruit while stirring. Continue to stir for 1-2 minutes and then remove from the heat and ladle into sterilized jelly jars for canning.

Low sugar jams and jellies should not be preserved with the melted wax seal method. Sugar itself acts as a preservative when it is in greater concentration than other nutrients. The lower sugar jams and jellies should be sealed by pressure canning or stored in the refrigerator or freezer. Watch for mold on the surface.

USDA, Principles of Home Canning, pdf [nchfp.uga.edu]

Disclaimer: This information is provided for educational purposes within the guidelines of Fair Use. It is not intended to provide individual guidance. Please seek a health care provider for individualized health care guidance.

Reference List

(Huang, et al, 2007) Huang Q, Lu G, Shen HM, Chung MC, Ong CN. Anti-cancer properties of anthraquinones from rhubarb. Med Res Rev. 2007 Sep;27(5):609-30. doi: 10.1002/med.20094. PMID: 17022020. https://pubmed.ncbi.nlm.nih.gov/17022020/

(Xiang, et al, 2020) Xiang H, Zuo J, Guo F, Dong D. What we already know about rhubarb: a comprehensive review. Chin Med. 2020 Aug 26;15:88. doi: 10.1186/s13020-020-00370-6. PMID: 32863857; PMCID: PMC7448319. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7448319/

Test No. 498: In vitro Phototoxicity - Reconstructed Human Epidermis Phototoxicity test method | en | OECD, https://www.oecd.org/publications/test-no-498-in-vitro-phototoxicity-reconstructed-human-epidermis-phototoxicity-test-method-7b2f9ea0-en.htm
Giles Sheldrick, Rhubarb can save your life: Ingredient in plant kills half of cancer cells in 48 hours. Rhubarb contains an ingredient that speedily kills cancer, research has shown. Oct 21, 2015, express.co.uk, https://www.express.co.uk/life-style/health/613194/Cancer-killing-drug-rhubarb-ready-within-years
Dr. Veronique Desaulniers, New study: Substance in rhubarb cuts cancer cell growth in half, April 24, 2016, naturalhealth365.com, https://www.naturalhealth365.com/rhubarb-cancer-enzyme-1820.html