Poinsettia

Scientific Name(s):Varieties of Euphorbia pulcherrima Wild. ex Klotzsch Family: Euphorbiaceae (spurges)

Common Name(s): Poinsettia , Christmas flower , Easter flower , papagallo , Mexican flame leaf , lobster flower plant

Uses

Poinsettias are used as Christmas ornamentation; their latex for a dipilatory; and for other uses such as pain relief, antibacterial and emetic. Folk uses include remedies for skin, warts, and toothache.

Dosing

There is no recent clinical evidence to support specific dosage of poinsettia in a therapeutic context. Its reputed toxicity gives reason for caution.

Contraindications

Contraindications have not yet been identified.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

There is little published evidence to suggest that the plant poses a great toxicologic danger; however, the following side effects have occurred: Nausea, vomiting, local mucosa irritation, GI tract distress, skin irritation, eye inflammation, and temporary blindness.

Toxicology

Many published reports have warned of the toxicity of this plant; however, there appears to be little factual evidence for this claim. These reports seem to stem from one poorly documented case of a known fatality, but several authors have concluded that the report was based more on hearsay than fact.

Botany

The Euphorbiaceae (spurge family) is a large family of more than 1000 herbs, shrubs, and trees. Many members of this family are characterized by the presence of a milky latex emulsion found in lactiferous vessels. When damaged, the plants secrete this latex. The poinsettia is a perennial ornamental found throughout the warmer climates of the US, including Hawaii, and Mexico. The flowers are small and yellow; it is the showy red leaf (bract) that is prized for its decorative effect. This plant has also been referred to as E. poinsettia Buist and Poinsettia pulcherrima Grah.

History

The plant was introduced from Mexico into the US by J. R. Poinsett in the early 1800s. Many members of the genus Euphorbia have been used in folk medicine. E. pulcherrima sap has been used as a depilatory, and extracts of the plant have been used as an antipyretic and to stimulate the flow of breast milk. The plant may have once been used as an abortifacient. 1 Folk uses include remedies for skin, warts and toothache. 2

Chemistry

The stems and leaves may contain small amounts of alkaloids; however, there is conflicting data regarding the presence of these compounds. The latex contains from 7% to 15% caoutchouc. 3 Compounds found in the leaves and stems include germanicol, beta-amyrin, pseudotaraxasterol, pulcherrol, octaeicosanol, beta-sitosterol, rubber, caffeic acid and anthocyanin. 2 Epigermanicyl acetate, germanicyl acetate, germanicol, octacosanol and beta-sitosterol from poinsettia fruits have also been isolated. 4

Uses and Pharmacology

Because this plant has often been associated with potential toxicity, a number of investigations have tried to establish the pharmacology of its components. The plant's latex has been used as a depilatory. Other reported uses include pain relief, antibacterial, and emetic. The latex contains 5% to 15% caoutchouc and some resin. 2

Animal data

In rats fed 15 g/kg bracts or 5 g/kg leaf blades for 1 week, no change in behavior, body weight or adrenal weight was found. 5

An increase in thyroid weight was observed among rats fed 15 g/kg of leaf material. No other pharmacologic activity was observed. Extracts of the plant have no antibiotic activity. 1

Clinical data

Research reveals no clinical data regarding the use of poinsettia.

Dosage

There is no recent clinical evidence to support specific dosage of poinsettia in a therapeutic context. Its reputed toxicity gives reason for caution.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

The National Clearinghouse for Poison Control Centers reported 228 cases of human ingestion of poinsettia in 1973; of these, only 14 cases had symptoms, the most serious being nausea and vomiting. A case report describes symptoms of local mucosa irritation and GI tract distress in an 8-month-old female who had chewed a poinsettia leaf. 6

Some reports suggest that the milky latex of the poinsettia, like that of some other members of the Euphorbiaceae family (eg, pencil plant), may result in skin irritation in susceptible individuals, 7 or eye inflammation and temporary blindness. 2 , 8 However, animal studies and the lack of repeated documentation of topical irritation in humans indicates that this problem may not be widespread.

Suggested treatment of ingestion includes gastric lavage or emesis followed by symptomatic treatment, 9 in addition to demulcents, intestinal astringents and gastric sedatives. Give fluids to prevent dehydration. 8

Toxicology

Many published reports have warned of the toxicity of this plant; however, there appears to be little factual evidence for this claim. These reports seem to stem from a single case of death in a 2-year-old Hawaiian child after the ingestion of the leaves. 10 This poorly documented case remains the only known fatality and several authors have concluded that the report was based more on hearsay than fact. 1

The results of an acute and a 1-week feeding study in rats found no changes in most parameters evaluated. 5 No deaths were found among 160 rats fed up to 22.5 g/kg of poinsettia, suggesting that the plant lacks oral toxicity. 11 Winek et al published the results of perhaps the most comprehensive evaluation of the toxicity of poinsettia. No rats died during an attempt to establish the oral LD-50; therefore, the LD-50 was considered to be greater than 25 g/kg body weight. Assuming no interspecies variation in toxicity, a 50 lb child would have to ingest about 1.25 lbs (500 to 600 leaves) to surpass the experimental LD-50. Vomiting would most likely preclude the ingestion of this amount of plant. 1

Oral administration of poinsettia extracts in rats did not result in local toxicity (no erythema, edema, bleeding of the oral cavity) and instillation of the latex into the rabbit eye induced no corneal, iridal or conjunctival damage. No histologic abnormalities were found in rats fed high doses of the plant for 5 days. Repeated exposure to a water suspension of the plant induced mild skin irritation in albino rabbits, but this disappeared within 36 hours. Some photosensitivity was seen in albino rabbits. 7

In mice, the intraperitoneal injection of 3 g of leaf extract per 100 g body weight resulted in one death in six animals tested; extracts of flowers and bracts, however, caused no deaths indicating a general lack of acute systemic toxicity. No alkaloids or glycosides were found in the plant. 12

Bibliography

1. Winek CL, et al. Clin Toxicol . 1978;13:27.
2. Duke J. Euphorbia Pulcherrima Wild . CRC Handbook of Medicinal Herbs, Boca Raton, FL: CRC Press Inc. 1989;163-164.
3. Dominguez X, et al. J Pharm Sci . 1967;59:1184.
4. Gupta D, et al. J Nat Prod . 1983 Nov-Dec;46:937–938.
5. Runyon R. Clin Tox . 1980;16:167.
6. Edwards N. J Pediatr . 1983 Mar;120:404–405.
7. D'Arcy WG. Arch Derm . 1974;109:909.
8. DerMarderosian A. Common Poisonous Plants in Natural Product Medicine . Philadelphia, PA: George F. Stickley Co. 1988;153.
9. Hardin JW, et al. Human Poisoning from Native and Cultivated Plants , 2nd ed. Durham NC: Duke University Press, 1974.
10. Rock JF. Hawaiian Forest Agric . 1920;17:61.
11. Stone and Collins. Toxicon . 1971;9:301.
12. DerMarderosian A, et al. J Toxicol and Env Health . 1976;1:939.

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