Rhubarb is a perennial herb that grows in temperate regions. Its roots have traditionally been used in Chinese medicine as a laxative and for other medicinal purposes. Rhubarb contains anthraquinone glycosides and tannins that are responsible for its pharmacological effects. While the roots are medicinal, the leaves contain toxic levels of oxalic acid and should not be consumed. Rhubarb is commonly used to treat constipation and digestive issues and has also shown anti-inflammatory properties.

1. 000
Rhubarb
Presented by :-
Department of pharmacy
UCMS
9/8/2019
1

2. Introduction
9/8/20192
 Rhubarb is a strange plant. Its roots have many
medicinal uses. Its stems makes tasty pie. And its
leaves are poisonous. Rhubarb plays a strong role in
the traditional Chinese therapy and is commonly
used as a laxative and a bitter stomachic.
Approximately 60 species of Rheum have been found
of which 40 are Chinese. Out of these, minimum 18
possess medicinal properties. As per the official
pharmacopoeia (both E.P. and B.P.) the drug is
required to contain not less than 2.2% of
hydroxyanthraquinone derivatives calculated as
rhein. Chrysophamol, emodin, aloe-amodin, rhein,
physcion were the free anthraquinones to be first

3. Cont..
9/8/20193
 It is often called a greenhouse plant because of outer
its outer curtain of translucent bracts which passes a
visible light , creating a greenhouse effect , while
blocking ultraviolet radiation . These are the important
defenses against the increase UV- B exposure and
extreme cold in its high altitude range . (Rheum
nobile)

4. Synonyms
9/8/20194
 Also known as redix rhei , rheum , ravandchini ,
rhaptonic , turkey rhuber, himalyan rhubarb.
 Nepali name : padamchal (पदमचाल)

5. Classification
9/8/20195
 Kingdom- Plantae
 Subkingdom- Tracheobionta
 Superdivision- Spermatophyta
 Division- Magnoliophyta
 Class- Magnoliopsida
 Subclass- Caryophyllidae
 Order- Polygonales
 Family- Polygonaceae
 Genus- Rheum
 Species- Rheum palmatum

6. Biological source
•Rhubarb consist of dried root and rhizomes of Rheum
emodi wall (indian rhubarb), Rheum palmatum linn
belonging to the family polygonaceae.
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7. Geographical source
(habit and habitat)
9/8/20197
 It is obtained both from wild and cultivated species
grown in regions ranging from south east to china to
tibet and korea.
 Rheum officinale or Rheum palmatum are grown in
China whereas the other species Rheum webbianum
, Rheum austrele , Rheum emodi are native to India,
Pakistan or Nepal.
 High altitude (more than 3000 m ) is prerequesite for
growth of rhubarb . It is a drought resistant plant.
 It is perennial herb . It grows on topical and
subtropical climate. It grows up to 2m .

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9. Collection and preparation
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 The drug is mostly obtained from wild plants.
 It is propagated by seeds or from rhizomes.
 The drug is obtained from 6-10 year old plant.
 The rhizome portion is dug up in spring or autumn .
Aerial portion dies in winter and rhizomes remaining in
ground regenerate in next spring.
 The collected rhizomes are cleaned , decorated and
dried. The larger rhizomes are cut transversly or
longitudinally.
 The pieces are threaded by piercing a hole in them
and such threaded pieces are dried under shade .

10. Cont…
• Some of the pieces are artificially dried.
• The drug is packed in wooden cases.
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11. Organoleptic properties
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 Colour : the surface is covered with a yellow power
smooth and pale brown to red in colour .
 Odour : sharp
 Taste : bitter astringent

12. Macroscopic character
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 The drug coming to market is called as either flats or
rounds . Round pieces are prepared from small
rhizomes which are cut only transversely and hence
they are barrel shaped , cylindrical or conical with 8-
10 cm length and 4 cm in thickness .

13. Cont…
9/8/201913
 Flat pieces are prepared from large rhizomes which
are cut longitudinally and hence they are plano
convex and tapering at both ends . Flats are 7-10 cm
in length and 3-6 cm in thickness towards middle
portion .

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15. Microscopic character
9/8/201915
• Parenchyma – abundant, present in all parts, contain
starch (simple 4-18 µ or compound 30 µ). Also contain
calcium oxalate crystals 20-200 µ.
• Medullary rays – it shows both, normal radiates of xylem
and phloem. In the star-spot, it contains a yellow masses
(insoluble in alcohol, but soluble in water – become
reddish pink in ammonia, and deep blood red by caustic
alkali). Xylem vessels are reticulated and remarkable
(their walls are cellulosic and not lignified)..
• ›Star-spots have collapsed phloem at the center,
surrounded sec. phloem developed by the cambium.
• Externally, the cambium forms the xylem with large
vessels ( the radiating arms of the star-spots are the
medullary rays.
• Older star-spots shows mucilage cavities in the phloem
just within the cambiform tissue. No sclerenchyma fibers.

16. Cont…
9/8/201916

17. Cont…
9/8/201917
1.
Reticulately thickened vessels associated withparenc
hyma and a medullary ray (m.r.) intangential
longitudinal section.
2. Starch granules.
3 . Fragments of reticulately thickened vessels.
4. Medullary ray (m.r.) in radial longitudinal section
underlying parenchymatous cells.
5. Cluster crystals of calcium oxalate,
6. Parenchyma of the ground tissue containing a
calcium oxalate crystal.
6a. Small-celled, rounded parenchyma of the ground
tissue.
6b. Parenchymatous cells of the ground tissueshowing

18. Chemical constituents
9/8/201918
 Rhubarb contains anthraquinone glycosides and astringent
principles . The anthraquinone glycosides ranging from 2 to
4.6 percent and are catogorized into four groups .
1. Anthraquinone with a carboxylic group like rhein and
glucorhein .
2. Antraquinones without a carboxylic group like aloe – emodin
, chrysophanol , physcion and also their glycosidal forms .
3. Anthrones and dianthrone of aloe – emodin , emodin ,
chrysophanol and physcion .
4. Heterodianthrones like palmidin A , palmidin B and palmidin C
. They are formed from two different anthrone molecules .
Palmidin A → aloe – emodin anthrone + emodin anthrone
palmidin B → aloe - emodin anthrone + chryosophanol
anthrone
palmidin C → emodin - anthrone + chrysophanol anthrone

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20. Cont…
9/8/201920
 The astringent part mainly consists of gallic acid as
glucogallin , along with tannin , catechin , and
epicatechin.

21. Chemical tests
9/8/201921
1. Rhubarb gives positive tests for modified
borntrager ̓s test.
2. Rhubarb shows red colour with addition of alkalies
due to presence of anthraquinone glycosides .

22. Standards
9/8/201922
1. Total ash : not more than 12 percent
2. Acid insoluble ash : not more than 1 percent
3. Foreign organic matter : not more than 1 percent
4. Dilute alcohol soluble extractive : not less than 30
percents .

23. Medicinal uses
9/8/201923
The root of the Chinese rhubarb is the most important
part of the plant extensively used for medicinal
purposes.
 The active constituents in the root may function as an
anti-inflammatory, laxative or as an antibacterial
during
toothaches, shingles, hypertension, burns, acute
appendicitis, acute infectious hepatitis, conjunctivitis,
swelling of gums, and sores of the mouth or tongue.
Moreover, the root of the plant has been used over
many centuries to cure stomach and intestinal
disorders, fevers and edema.
 The herbs can be crushed and dried sometimes to be
applied externally during fevers.

24. Pharmacological uses
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1.Blood Conditions​
 breaks up congealed blood​
 hyperlipidemia (in conjunction with other treatments)​
 invigorates blood​
2.Female Conditions​
 amenorrhea due to blood stasis​
3.Gastrointestinal Conditions​
 abdominal pain​

25. 9/8/201925
 atonic dyspepsia (in small doses)​
 bacillary dysentery​
 constipation​
 diarrhea caused by an irritating body in the intestines​
 dysentery​
 enteritis​
 gastrointestinal hemorrhage​
 increases the flow of saliva (when chewed)​
 stimulates appetite and digestion (cold extract in small
doses)​
 torpor and debility of the digestive organs (in small doses)​
4.Genitourinary System Conditions​
 early stages of chronic renal failure (in conjunction with
other age)

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5.Glandular conditions
 acute pancreatitis (in conjunction with other agents)​
6.Liver Conditions​
 acute hepatitis (in conjunction with other agents)​
 acute cholecystitis​
 jaundice due to damp heat​
7.Other Conditions​
 cancer

27. CULLINARY USES
9/8/201927
• The Chinese Rhubarb can be used in making pies
and jams, adding a wonderful flavor to them.
• It is also added to tonic wines.

28. Formulations
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28

29. Dosing
9/8/201929
 Dried rhubarb extract 20 to 50 mg/kg daily

30. Precaution
9/8/201930
• The root, if consume in high doses can be poisonous
as the oxalic acid crystals present in the leaves can
be risky for the health.
 It can be especially harmful for those who are
suffering from arthritis, kidney problems,
inflammatory bowel disease, or intestinal obstruction.
Also, pregnant women should also avoid taking this
as it may cause uterine stimulation.

31. Interactions
9/8/201931
 Interaction with cardiac glycosides (digoxin) and a
reduction in the absorption of orally administered
drugs have been noted when rhubarb is taken in large
quantities.

32. Toxicity
9/8/201932
 Young rhubarb flowers
 Rhubarb leaves contain poisonous substances,
including oxalic acid, which is
a nephrotoxic and corrosive acid that is present in many
plants.

33. Adulterants and substitutes
9/8/201933

Chinese rhapontic rhubarb:
 The centre may be hollow.
 ›Star spots are present as a ring.
 The odour is sweet and differs from the official
rhubarb.
 It contains mainly rhaponticin which is toxic.
Indian rhubarb:
 it occurs peeled or unpeeled, so cork cells are easily
detected in the powder.
 It contains anthraquinone derivatives and in ultraviolet
light shows a deep violet fluorescence.
 Its roots have anti-inflammatory activity.

34. Cont…
9/8/201934
English rhubarb:
1. › R. officinale:
 Similar to Chinese rhubarb but, star spots fewer and
more scattered and has the same active constituents.
2. › R. rhaponticum:
 It shows circles of isolated star spots and shows no
emodin, aloe-emodin or rhein. It contains mainly
rhaponticin.

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36. References
9/8/201936
 Kokate CK(2014). Pharmacognosy , Nirali
publication , 49th edition,9.20,9.21,9.22.
 “Rheum palmentum”. Natural resources
conservation service LANTS database . USDA
RETRIVED 1 february 2016.

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