(Borago officinalis L.)
The large, deep green, leaves of common borage are covered with white, stiff, prickly hairs, and occasionally the leaves of borage may be confused with the large, fussy, deep green leaves of foxglove. Misidentification of foxglove for borage resulted in digitoxin poisoning after the patient ingested a brewed tea from the misidentified foxglove leaves.1
Common Name: Common Borage, Bee Plant, Bee Bread, Ox's Tongue
Scientific Name: Borago officinalis L.
Botanical Family: Boraginaceae (borage, bourraches)
Physical Description: This hairy, annual herb grows up to 2–3 ft (∼60–90 cm) in height. The leaves are alternate, wrinkled, oval, and pointed with dimensions of about 1.5 by 3 in (∼4 cm by 8 cm). Bright blue to pink, star-shaped flowers appear in loose racemes during the summer. Borage has a salty flavor with an aroma of cucumbers.
Distribution and Ecology: This plant inhabits wide areas of the west coast and the northern and northeastern states of the United States, as well as southern Europe. Although this plant is native to Syria, common borage has naturalized in the warmer parts of central, eastern, and western Europe. The common name, bee plant, is derived from the use of this plant as an attractant for honeybees.
The leaves of borage are used raw in salads, steamed as a tea, or cooked in vinegar as a vegetable. Common borage is widely cultivated as an ornamental plant and as a pot herb
Borage oil (starflower oil) is an alternative to evening primrose as a source of γ-linolenic acid. Traditional herbal uses for borage include the treatment of arthritis, chest congestion with or without cough, inflammation, sore throat, depression, seborrheic dermatitis, and menopausal symptoms. Borage oil is a supplement increasing used by older patients for the treatment of premenstrual syndrome, diabetes, skin disorders, and rheumatoid arthritis.2 Borage oil is a traditional treatment for a hangover.3
The decreased production of anti-inflammatory dihomo-γ-linolenic acid metabolites (e.g., prostaglandin E1, 15-hydroxyeicosatrienoic acid) in patients with atopic dermatitis suggests a role for γ-linolenic acid in the treatment of this disorder. The amount of γ-linolenic is substantially higher in borage oil than in evening primrose oil (i.e., about 23–25% vs. 8–10%, respectively). Studies on atopic dermatitis following the use of evening primrose yield conflicting results.4 One hundred sixty patients with stable, moderate disease activity of atopic dermatitis were randomized to a treatment group (500mg borage oil capsules) and to placebo (bland lipid miglyol) over 24 weeks.5 Although several clinical symptoms (erythema, vesiculation, excoriation, lichenification, insomnia) improved in the treatment group compared with placebo, the overall response to borage oil did not reach statistical significance as measured by the amount of topical corticosteroid used and clinical symptoms (Costa score). However, there was some improvement in the subgroup of the treatment group that included patients with documented compliance and increased erythrocyte dihomo-γ-linolenic acid. A similar borage oil-induced reduction is postulated for the elevation of tumor necrosis factor-α associated with rheumatoid arthritis,6,7 but there are inadequate clinical data to support the routine use of borage oil supplements for the treatment of rheumatoid arthritis. A randomized, double-blind, placebo-controlled, 24-week trial of 37 patients with rheumatoid arthritis and active synovitis suggested that daily treatment with 1.4 g γ-linolenic acid in borage seed oil improved the symptoms and signs of rheumatoid arthritis.8
Borage oil is a dietary supplement in the United States. The German Commission E does not approve the use of borage oil because of concerns about potential hepatic and carcinogenic effects of the pyrrolizidine alkaloids in borage oil.
Constituents of borage oil (CAS RN: 225234-12-8) include acids (acetic, lactic, malic silicic), alkaloids, fatty acids (γ-linolenic acid, linoleic acid, oleic acid, saturated fatty acids), mucilages, tannins, and saponins. Linoleic, linolenic, and oleic acids comprise about 75% of the total fatty acids in borage oil.9 γ-Linolenic acid is an essential ω-6 polyunsaturated fatty acid that also occurs in evening primrose (Oenothera biennis L.) and black currant seed (Ribes nigrum L.). This compound is one of at least 79 triacylglycerols present in borage oil as measured by silver-ion high-performance liquid chromatography (HPLC)/atmospheric pressure chemical ionization/mass spectrometry.10 In addition, borage oil contains small amounts (<10 ppm dry weight leaves) of pyrrolizidine alkaloids (e.g., amabiline, intermedine, lycopsamine, supinine), which are potentially hepatotoxic. As a result of the presence of pyrrolizidine alkaloids, the German Federal Health Agency limits the consumption of unsaturated pyrrolizidine alkaloids to ≤1 µg daily. Borage oils products are certified as being free of unsaturated pyrrolizidine alkaloids when the unsaturated pyrrolizidine alkaloid content is ≤0.5–1 µg/g.
Clinical trials suggest that borage oil is a relatively safe dietary supplement in daily doses of 500–720mg. In these studies, daily doses of borage oil administered as 500-mg borage capsules5 or 720-mg γ-linoleic acid in gelatin capsules11 were well tolerated.
In vitro studies indicate that neutrophils rapidly elongate γ-linolenic acid by two carbons to dihomo-γ-linolenic acid (DGLA) following the use of borage oil as a dietary supplement.12 Subsequently, biotransformation of DGLA by 15-lipoxygenase results in the formation of 15-hydroxy-eicosa-trienoic acid.13
Theoretically, the ingestion of borage oil may lower the seizure threshold based on the development of seizures with evening primrose oil, which contains 8–10% γ-linolenic acid.14 However, there are no well-documented case reports associating the use of borage oil with seizures.
In a study of 80 patients treated with 500mg borage oil daily for 24 weeks, there were no definite herb-related adverse effects. One patient was withdrawn from the study for headache, diarrhea, and vomiting, but these effects could not be causally linked to borage oil. There are few data including case reports on the toxicity of borage or borage oil. A case report associated the development of atrial fibrillation, bradycardia, and gastrointestinal distress in a 72-year-old woman, who drank tea from leaves that she thought were borage.1 Subsequent laboratory analysis indicated that she confused borage leaves for foxglove, and thus she probably had digitoxin poisoning.
Methods for the detection of α- and γ-linolenic acid moieties include silver-ion HPLC followed by online atmospheric pressure chemical ionization/mass spectrometry (APCI/MS). HPLC/APCI/MS identified 79 triacylglycerols in borage oil derived from Borago officinalis seeds.15
Treatment is supportive. Decontamination measures are unnecessary.
- 1. [Bradycardiac atrial fibrillation after consuming herbal tea]. Dtsch Med Wochenschr 1997; 122: 930-932. [German]. , .
- 2. Increasing trends in elderly persons' use of nonvitamin, nonmineral dietary supplements and concurrent use of medications. J Am Dietetic Assoc 2005; 105: 54-63. , , , , , , et al.
- 3. Interventions for preventing or treating alcohol hangover: systematic review of randomised controlled trials. BMJ 2005; 331(7531):1515-1518. , , .
- 4. Meta-analysis of placebo-controlled studies of the efficacy of Epogam in the treatment of atopic eczema. Relationship between plasma essential fatty acid changes and clinical response. Br J Dermatol 1989; 121: 75-90. , , , , , , et al.
- 5. Double-blind, multicentre analysis of the efficacy of borage oil in patients with atopic eczema. Br J Dermatol 1999; 140: 685-688. , , , , , , et al.
- 6. Treatment of rheumatoid arthritis with gammalinolenic acid. Ann Intern Med 1993; 119: 867-873. , , .
- 7. Evening primrose oil and borage oil in rheumatologic conditions. Am J Clin Nutr 2000; 71(suppl):352S-356S. , .
- 8. Treatment of rheumatoid arthritis with gammalinolenic acid. Ann Intern Med 1993; 119: 867-873. , , .
- 9. Potential of evening primrose, borage, black currant, and fungal oils in human health. Ann Nutr Metab 2001; 45: 47-57. .
- 10. Analysis of triacylglycerols by silver-ion high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. Lipids 1996; 31: 1311-1322. , .
- 11. Effect of borage oil consumption on fatty acid metabolism, transepidermal water loss and skin parameters in elderly people. Arch Gerontol Geriatr 2000; 30: 139-150. , .
- 12. Metabolism of gammalinolenic acid in human neutrophils. J Immunol 1996; 156: 2941-2947. , , , , , .
- 13. Dietary supplementation with oils rich in (n-3) and (n-6) fatty acids influences in vivo levels of epidermal lipoxygenase products in guinea pigs. J Nutr 1990; 120: 36-44. , , , .
- 14. Herbal medicinals: Selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med 1998; 158: 2200-2211. .
- 15. Analysis of triacylglycerols by silver-ion high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. Lipids 1996; 31: 1311-1322. , .
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