Rhubarb Summary:

Rhubarb is often cultivated for its large foliage, tart flavoured stems, and medicinal rhizomes. Three species are used medicinally (Rheum palmatum, R. tanguticum, and R. officinale), with the main one being Chinese rhubarb (Rheum palmatum). 

Rhubarb is a strong laxative, and is useful in constipation. Its also highly astringent, which combines well with its laxative effects. together, these actions make rhubarb very useful in cleansing the gut. First it flushes it out with the laxative actions, and then seals, tones, and cleans the system with its astringing  and antimicrobial actions. 

The main ingredients responsible for the laxative effects is known as anthraquinones which can be found in a variety of different plants. These compounds are very useful for clearing out the digestive tract but can be dangerous in high amounts. It is important to stick within the dosage range with this herb. 


Botanical Name

Rheum palmatum

Rheum tanguticum

Rheum officinale

Family

Polygonaceae

Part Used

Rhizome

Herbal Actions:

  • Bitter
  • Laxitive [1]
  • Cholagogue
  • Antimicrobial
  • Antineoplastic
  • Hepatoprotective
  • Nephroprotective [10, 11]
  • Astringent (low dose)
  • Styptic
  • Stomachic (low dose)

Dosage

Tincture (1:5)

2-4 mL/day

A note on dosage:

Dosage with this herb varies depending on the desired actions. A lower dose will provide tonic, hepatic, and bitter actions. Larger doses are purgative and cathartic. 

Recommended Source

Indications:

  • Constipation (Higher dose)
  • Diarrhea (Low dose)
  • Liver complaints (As bitter in lower dose)
  • Dysentery
  • Functional dyspepsia

Common Names:

  • Chinese rhubarb
  • Rheum
  • Da Huang (Chinese)

Traditional Uses:

In China, Rheum palmatum was referred to as Da Huang where it was commonly employed as a laxative [1]. 

    + Western Herbal Medicine

    It has been used traditionally as a mild stimulating tonic to the alimentary mucous membrane, liver, and gall ducts, and removes mucous. In smaller doses it was considered a hepatic, while large doses were used as a cathartic. [16].

    + Traditional Chinese Medicine

    Pinyin: Dá Huáng

    Taste: Bitter [17, 18]

    Energy: Cold [17, 18]

    Channels: Spleen, stomach, large intestine, liver, heart [18]

    Actions: Purges heat and accumulations, loosens bowels, promotes blood circulation, removes stagnation, drains fire, removes blood stasis and invigorates blood [2-4, 17, 18].

    Indications: Constipation due to heat accumulation, accumulation in intestine, abdominal pain, damp-heat jaundice, blood heat haemorrhage, red eyes, sore throat, intestinal abscesses, swellings, sores, and ulcers [17].


    Botanical Description:

    Rhubarb is a perennial, herbaceous plant, with large triangular leaves with reddish petioles. Its root is short and thick. 


    Habitat Ecology, and Distribution:

    Although various species of rhubarb are cultivated all over the world, it is mainly found naturally in Northern China, and Tibet. 


    Harvesting Collection, and Preparation:

    Rhubarb grows extremely quickly, and can reach heights of up to 3m high, only to die back to the soil each winter. Rhubarb is an easy garden vegetable/medicine species, and is easy to cultivate in both shady, and sunny locations. 


    Constituents:

    [2, 6-8, 12, 16]

    • Anthraquinones
      • Aloe-emodin
      • Rhein
      • Emodin
      • Chrysophanol
      • Physcion
      • Sennosides A-E
    • Tannins
    • Volatile oil
    • Rutin
    • Fatty acids
    • Calcium oxylate
    • Polysaccharides
    • Stilbene derrivatives

    Constituents

    Chemical class Chemical Name % Dried Weight Solubility
    INSERT INSERT Unknown N/A
    INSERT INSERT Unknown N/A
    INSERT INSERT Unknown N/A
     

    Pharmacology and Medical Research:

     

    Hello, World!

    + Blood Brain Barrier Attenuation

    Rhubarb is reported to attenuate the BBB after hemmorhagic stroke in rats. The mechanism of action was suggested to be through increased zonula-occludens-1 expression [9]. This may prove a useful medicine for neuroprotection in intracerebral haemorrhages in the future, more research is needed.

    + Laxative

    The laxative actions of Rhubarb was investigated in a rat model. The study found that rhubarb (Rheum palmatum) influenced ion transport (Na+ and Cl-) across the rat ileum epithelia [1].

    Anthraquinone's, which are contained in rhubarb root in high amounts are well known to produce laxative effects within the body [13].

    [Suggested to be due to stimulation of intestinal musculature, probably via prostaglandin mediation - takes 8-14 hours after ingestion]

    + Kidney Protective

    Rhubarb has been shown to have a beneficial effect on chronic and acute renal failure in vivo [10, 11].

    Its been found to have the ability to reduce proteinurea, as well as generally improve renal function when used alone. Synergy has been suggested for this action when used with angiotensin-converting enzyme inhibitors [11].

    In a study investigating the protective effects of 4 rhubarb extracts on HgCl2-induced acute renal failure (ARF) found that the anthraquinone containing extract had significant protective actions on the kidneys using this model [14]. more research is needed to determine whether this effect is exclusive to rhubarb, or if other anthraquinone containing herbs can achieve the same action.

     

    Toxicity

    Avoid use if on heart medications [16]. 

     

    Cautions:

    • May increase the effect of cardiac glycosides and interact with anti arrhythmic drugs through promoting the loss of potassium [16]. 
    • May decrease the absorption of other drugs through a decrease in transit time. [16].
    • May discolour the urine with a red or yellow hue. [16].

    Traditional Chinese Medicine:

    Pinyin: Dá Huáng

    Taste: Bitter [17, 18]

    Energy: Cold [17, 18]

    Channels: Spleen, stomach, large intestine, liver, heart [18]

    Actions: Purges heat and accumulations, loosens bowels, promotes blood circulation, removes stagnation, drains fire, removes blood stasis and invigorates blood [2-4, 17, 18]. 

    Indications: Constipation due to heat accumulation, accumulation in intestine, abdominal pain, damp-heat jaundice, blood heat haemorrhage, red eyes, sore throat, intestinal abscesses, swellings, sores, and ulcers [17]. 


    Synergy:

    Synergy has been suggested for rhubarbs kidney protective actions when used with angiotensin-converting enzyme inhibitors [11]. This may include herbs such as Camellia sinensisHibiscus sabdariffaVaccinum mytrillus, or Cryptomeria japonica [15].


    Author:

    Justin Cooke

    The Sunlight Experiment

    Updated: July 2017


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    References:

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    2. Zhao, L., Liang, J., Li, W., Cheng, K., Xia, X., Deng, X., & Yang, G. (2011). The Use of Response Surface Methodology to Optimize the Ultrasound-Assisted Extraction of Five Anthraquinones from Rheum palmatum L. Molecules, 16(12), 5928-5937. doi:10.3390/molecules16075928
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    7. Zhou, X.; Song, B.; Jin, L.; Hu, D.; Diao, C.; Xu, G.; Zou, Z.; Yang, S. (2006). Isolation and inhibitory activity against ERK phosphorylation of hydroxyanthraquinones from rhubarb. Bioorg. Med. Chem. Lett. 16, 563-568.
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