PDR for Herbal Medicines

HERBAL MONOGRAPHS POPLAR 607

Unproven Uses: Folk medicine uses have focused on

primary hypertension and arthritis. Various species of

Rhododendron have been used for rheumatic and gouty

conditions and for stones.

PRECAUTIONS AND ADVERSE REACTIONS

All medicinal administration of the drug is discouraged. The

observed effect (lowered blood pressure resulting from

bradycardia) is the first sign of a toxic reaction.

The plant is toxic because of its andromedan derivative

content. The grayanotoxins it contains prevent the closure of

the sodium channels and thus inhibit conduction.

OVERDOSAGE

Symptoms of poisoning in case of overdosage could include

salivation, cold sweats, paresthesia, vomiting, diarrhea,

severe stupor, coordination disorders, spasm, bradycardia,

cardiac arrhythmias, hypotension, and eventually death

through cardiac failure or apnea. While poisonings among

humans have not been documented, poisonings (including

fatal ones such as "goat death") occur frequently among

animals. The presumed explanation is that the leathery leaves

are not tempting to humans to eat, and because of the low

levels of andromendan derivatives present in medicinal

preparations.

Toxic and/or lethal dosage levels cannot be determined with

any precision because the plant's andromendan derivative

content can vary so wildly. The LD50 for mice amounts to

5.1 mg grayonotoxin I/kg body weight, p.o.

Following gastrointestinal emptying (inducement of vomit-

ing, gastric lavage with burgundy-colored potassium per-

manganate solution, sodium sulfate), installation of

medicinal charcoal and shock prophylaxis (quiet, warmth),

the therapy for poisonings consists of treating spasms with

diazepam (IV), bradycardia with atropine and electrolyte

substitution, and treating possible cases of acidosis with

sodium bicarbonate infusions. In case of shock, plasma

volume expanders should be infused. It is crucial that no

opiates are administered. Monitoring of kidney function is

essential. Intubation and oxygen respiration may also be

necessary.

DOSAGE

Mode of Administration: Whole drug. Folk medicine modes

also include administration as a tea or cigarette.

How Supplied: Forms of commercial pharmaceutical prepa-

rations include coated tablets and compound preparations.

Daily Dosage: There are no more exact details available.

LITERATURE
Hansel R, Keller K, Rimpler H, Schneider G (Ed), Hagers
Handbuch der Pharmazeutischen Praxis, 5. Aufl., Bde 4-6

(Drogen), Springer Verlag Berlin, Heidelberg, New York. 1992-

1994.

Keller S, von Kiirten S, Pachaly P, Zymalkowski F, Sterines

and triterpenes from Rhododendron ponticum. Pharmazie.

25:621-5, 1970 Oct.

Thieme H, Walewska E, Winkler HJ, Isolation of salidroside

from leaves of Rhododendron ponticum x catawbiense.

Pharmazie, 24:783, 1969 Dec 12.

Poplar

Populus species

DESCRIPTION

Medicinal Parts: The medicinal parts are the bark, leaves.

and leaf buds.

Flower and Fruit: The plant is dioecious. The carmine red

flowers are in large, cylindrical hanging, thick catkins with

carmine anthers. The male flowers have carmine red anthers:

the female flowers have carmine stigmas. The flowers appear

before the leaves. The seeds, which ripen in May/June, are

very small and have a white lanate tuft of hair.

Leaves, Stem and Root: The tree may grow up to 30 m. The

bark is initially yellow brown and later black-gray and

fissured. The leaf buds are viscid. The leaves are almost

circular with a dark green upper surface and a light grey-

green under surface. They are dentate or lobed with obtuse

teeth, initially silky-haired, later glabrous. The petioles are

long, thin and laterally compressed.

Habitat: There are both European and North American

species within the genus that have spread to other temperate

zones.

Other Names: White Poplar, Canadian Poplar, Black Poplar.

Trembling Poplar, European Aspen, Quaking Aspen

Production: Poplar bark consists of the fresh or dried bark of

salicin-rich Poplar species as well as their preparations.

Poplar leaves consist of the leaves of salicin-rich Poplar

species as well as their preparations. Poplar buds consist of

the dried, unopened leaf buds of Populus species, as well as

their preparations.

ACTIONS AND PHARMACOLOGY

COMPOUNDS: POPLAR BARK AND LEAVES

Glycosides and esters yielding salicylic acid:

In Populus alba (leaf 6%, bark 2%) chief components:

salicortin, tremulacin, salicin

In Populus nigra (leaf 2%, bark 1.5%) chief components:

salicortin, salicin