Elderberry is a shrub-like tree that produces clusters of purplish-black berries. The unripe berries are slightly toxic because they contain cyanide compounds, which diminish when the fruits are fully ripe or cooked. Ripe berries are used to make jam and both the flowers and fruit are used to make brandy and wine. In folk medicine, the flowers are brewed into tea to relieve congestion and fever and stimulate lactation in nursing mothers. Because elderberry might produce biological effects, drinking elderberry preparations while pregnant is not advisable unless supervised by a qualified health care practitioner.
Botanical Background
The botanical name for elderberry is Sambucus nigra, and it also is known as European elder, black elder, elder bush, boor tree, ellhorn and black-berried alder. This species is native to Europe, but Sambucus canadensis and Sambucus Mexicana, which are native to North America and Asia, are regarded as subspecies of S. nigra and used interchangeably in herbal medicine.
Chemical Constituents
Elderberry contains caffeic acid derivatives and volatile oils that contain up to 65 percent free fatty acids, such as palmitic acid. Several flavonoids are present, including rutin, hyperoside, quercitrin, astragalin and nicotoflorin. The bark, leaves, stems, unripe berries and roots of this plant contain a cyanogenic glycoside called sambunigrin, which can cause dizziness, vomiting, convulsions and irregular heart rhythm.
Pharmacological Actions
According to the “Physicians’ Desk Reference for Herbal Medicines,” elderberry compounds exert several biological effects, including antimicrobial, anti-inflammatory and antiviral properties. Michael Heinrich, co-author of “Fundamentals of Pharmacognosy and Phytotherapy,” says that tea made from elderberry flowers is diaphoretic, meaning it increases sweating. A study published in the "Journal of International Medical Research" in 2004 concludes that elderberry syrup is effective against influenza A and B viruses, safely resolving symptoms in people within five days. Further, in the February 2011 issue of "BMC Complementary and Alternative Medicine,” scientists reported for the first time that elderberry exerts antimicrobial activity against Streptococcus pyogenes and Branhamella catarrhalis, two pathogens that commonly infect humans.
Evidence of Safety
A 2011 review published in "Midwifery" reveals that out of more than 575 pregnant women surveyed, nearly 60 percent continued to use one or more herbal preparations. As the review authors note, however, there is very little clinical evidence to support the safety of the use of any herb during pregnancy, including elderberry. The reason for this is simple: No one wants to put mother or child at risk for injury. Besides potential toxicity, another good reason to consult your physician before drinking elderberry tea or syrup during pregnancy is that the tannin content in the herb might interfere with the absorption of iron.
References
- “Physicians’ Desk Reference for Herbal Medicines”; Thomas Brendler, et al.; 2007
- “Fundamentals of Pharmacognosy and Phytotherapy”; Michael Heinrich, Joanne Barnes, Simon Gibbons, Elizabeth M. Williamson; 2004
- "Journal of International Medical Research"; Randomized study of the efficacy and safety of oral elderberry extract in the treatment of influenza A and B virus infections; Z. Zakay-Rones, et al.; 2004
- "BMC Complementary and Alternative Medicine"; Inhibitory activity of a standardized elderberry liquid extract against clinically-relevant human respiratory bacterial fathogens and influenza A and B viruses; C. Krawitz, et al.; February 2011
- "Midwifery"; Safety and efficacy of herbal remedies in obstetrics-review and clinical implications; L. Holst, et al.; February 2011
