PDR for Herbal Medicines

HERBAL MONOGRAPHS

results in a somewhat darker elemi. Plasters are prepared

using 25% drug in ointment.

Storage: Store in well-sealed tins protected from light.

LITERATURE

•• Blaschek W, Hansel R, Keller K, Reichling J, Rimpler G,

Schneider G (Eds), Hagers Handbuch der Pharmazeutischen

Praxis. Folgebande 1 und 2. Drogen A-Z. Springer. Berlin,

Heidelberg 1998.

Chinese Rhubarb

(Da-Huang)

Rheum palmatum

DESCRIPTION

Medicinal Parts: The medicinal parts are the dried under-

ground parts, and most of the root bark in the dried form.

Flower and Fruit: The inflorescence is an erect panicle
foliated to the tip. The flowers have narrow, red, pink or
whitish yellow tepals. The tepals are curved and located far
^•back in the mature flowers to facilitate wind pollination. The
fruit is red-brown to brown, and oval. The fruit is angular,
about 10.2 mm to 7.8 mm wide and usually has scarious
wings. The nutlet is 6 to 10 mm long and 7 mm in diameter.
Leaves, Stem and Root: The plant is a large, sturdy
herbaceous perennial. The stem grows to over 1.5 m high.
The leaves are orbicular-cordate, palmate lobed, somewhat
rough on the upper surface and 3 to 5 ribbed. The lobes are
oblong-ovate to lanceolate, dentate or pinnatisect. The root
system consists of a tuber, which after a number of years
measures 10 to 15 cm in diameter and has arm-thick lateral
roots.
Habitat: The plant is indigenous to the western and north-
western provinces of China and is cultivated in many regions
around the world. The main producers are China and Russia.
Production: Chinese Rhubarb consists of the dried under-
ground parts of Rheum palmatum, Rheum officinale or of
both species. Stem parts, roots and most -of the bark are
removed from the rhizomes.
Not to be Confused With: Other Rheum species such as
Rheum rhaponticum or Rheum rhabarbarum. Garden Rhu-
barb is Rheum ponticum.
Other Names: Rhubarb
ACTIONS AND PHARMACOLOGY
COMPOUNDS
Anthracene derivatives (3-12%): chief components 1- or 8-
O-fJ-glucosides of the aglycones rheumemodin, aloe-emodin,

CHINESE RHUBARB (DA-HUANG) / 185

rhein, chrysophanol, physcion (together 60-80%), 8,8'-diglu-

cosides of dianthrones (10-25%), including among others,

sennosides A and B

Tannins: gallo tannins, including among others galloyl

glucose, galloyl saccharose, lindleyine, isolindleyine

Flavonoids (2-3%)

Naphthohydroquinone glycosides

EFrECTS

Main active principles: hydroxyanthracene derivatives, tan-

nins and a small proportion of flavonoids

The laxative effect is due to the hydrogogic and anti-

absorptive properties of the anthranoids. This effect causes

an increase in the volume of the intestinal contents resulting

in pressure and stimulation of intestinal peristalsis.

INDICATIONS AND USAGE

Approved by Commission E:

• Constipation

Unproven Uses: Rhubarb is used as an appetite stimulant and

for digestion problems, gastrointestinal catarrh and painful

teething (children). External uses include burn treatment and

skin conditions.

Chinese Medicine: In China, Rhubarb is used for delirium,

tenesmus, edema, amenorrhea and abdominal pain. Efficacy

for digestion problems is plausible because of the tannin

content but not without risk because of the anthranoids

(toxicity); efficacy for the other indications has not been

proven.

Homeopathic Uses: Homeopathic uses include diarrhea and

teething.

CONTRAINDICATIONS

Chinese Rhubarb is contraindicated in cases of intestinal

obstruction, acute inflammatory intestinal disease, appendici-

tis and abdominal pain of unknown origin.

PRECAUTIONS AND ADVERSE REACTIONS

General: Spasmodic gastrointestinal complaints can occur as

a side effect to the drug's purgative effect. Long-term use

leads to losses of electrolytes, in particular potassium ions.

The loss of electrolytes may lead to hyperaldosteronism,

inhibition of intestinal motility and enhancement of the

effect of cardioactive steroids. Long term use may lead to

heart arrhythmias, nephropathies, edema and accelerated

bone deterioration.

The increased incidence of carcinoma of the colon following

long-term administration of anthracene drugs has not yet

been fully clarified. Recent studies show no association