Black Walnut Tree
Botanical Description & Habitat
Juglans nigra
Family
Juglandaceae
Common Names
American walnut
Circassian walnut
Caucasian walnut
Eastern black walnut
English walnut
Persian walnut
Walnut
Habitat
Eastern United States; black walnut is an indigenous forest tree which grows in rich woods and limestone soils.
Description
The black walnut is a tall forest tree, which can reach up to 120 feet in height. Its almost-black bark is divided into rough ridges by deep furrows; its large trunk divides into numerous, nearly horizontal branches. Black walnut leaves are pinnately compound, finely-toothed, and 3 to 3-1/2 inches long; there are 20-23 alternate leaves per stem. Its male and female flowers grow in separate catkins, distinct upon the same tree. The fruit is a deeply-grooved, edible nut, occurring singly or in clusters of 2-3 along the branch. The black walnut is 1-1/2 to 2 inches in diameter, with a thick, aromatic husk.
Medicinal Parts
Bark, leaves, and rind (shell) of fruit.
Historical Properties & Uses
Black walnut, including the kernel and the green hull, has been, and still is, used as a vermifuge by the Asians and some American Indians. The Chinese use it to kill tapeworm, with relative success. The herb's high tannic acid content is probably responsible for its anthelmintic property, although other constituents, such as juglandin, juglone, and juglandic acid, may also be involved.
Traditionally, black walnut has been used to fight cancer, and this use has received some experimental support. The herb also has alterative, laxative, astringent, detergent, and hepatic properties. Its astringent uses, as a douche for leukorrhea and a mouthwash for sores and inflammation, can be attributed to tannic acid. External applications can kill ringworm.
Walnut leaf (Juglandis folium) is approved by the German Commisssion E for external use in skin inflammation or excessive perspiration of the hands and feet.
Walnut hull, however, has not achieved approval status by the German Commission E. Either there was insufficient evidence in favor, or a contraindication.
References:
Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.
Method of Action
Black walnut components are antibiotic
Juglone from black walnut has antimicrobial properties against Trichophyton mentagrophtes, Bacillus anthracoides, B. cereus, B. anthracis, B. subtilis.
Black walnut has also shown some antitubercular activity.
Pharmacology of ellagic acid
Pharmacological studies on ellagic acid, an important constituent of this herb, have found intra-peritoneal injections in mice produce significant sedation, ataxia, potentiation of sodium pentobarbital sleeping time, and protection from death following a normally lethal electroconvulsive shock. Intravenous injections decreased blood pressure and produced elevated T waves. Heart and respiration rates initially increased and then decreased.
Further study found ellagic acid had an antagonistic effect on histamine liberators such as dextran and polymyxin B sulphate.
Black walnut may have anti-tumor properties
Compounds isolated from black walnut, including ellagic acid, juglone, and strong acid fractions, significantly depressed tumor growth rate in mice, when administered for 9-12 days, by intra-peritoneal injections.
Drug Interactions & Precautions
Possible Interactions
The topical application of the astringent black walnut, in conjunction with the acne product tretinoin (retinoic acid, vitamin A acid), may adversely affect the skin.
By sequestering black walnut, mineral oil may reduce the herb's anthelmintic effect. The same may be true, to a lesser extent, of antacids.
Safety Factors & Toxicity
No known toxicity exists. Caution is advised because black walnut is high in astringent tannins.
The German Commission E notes the possibility for mutagenic effects from juglone.
Walnut leaf has approval status by the German Commission E.
Walnut hull (Juglandis fructus cortex) is unapproved. Daily use is associated with an increased incidence of cancer of the tongue and leukoplakia of the lips.
References:
Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.
Preparation & Administration
Dried inner bark of the root
0.5-1 grams three times a day
This herb has approval status by the German Commission E.
Recommended daily dosages of walnut leaf in Germany are as follows:
2 - 3 g of the herb per 100 ml of water for compresses and partial baths.
References:
Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.
Note: This Herbal Preparation information is a summary of data from books and articles by various authors. It is not intended to replace the advice or attention of health care professionals.
References
Am Hospital Formulary Service. Am Soc of Hosp Pharm. Wash, D.C.
Bhargava, U.C., B. Wesfall & D. Siehr. Preliminary pharmacology of ellagic acid from juglans nigra (black walnut). Journal Of Pharmaceutical Sciences, 57(10), 1728-1732, 1968.
Bhargava, U.C. & B. Westfall. Antagonistic effect of ellagic acid on histamine liberators. Proceedings Of The Society For Experimental Biology And Medicine, 131(4), 1342-1345, 1969.
Bhargava, U.C. & B. Westfall. Mechanism of blood pressure depression by ellagic acid. Proceedings Of The Society Of Experimental Biology And Medicine, 132(2), 754-756, 1969.
Bhargava, U.C. & B. Westfall. Antitumor activity of juglans nigra (black walnut) extractives. J Of Pharm Sci, 57(10), 1674-1677, 1968.
Barnes, R.A. & N. Gerber. J Of The Am Chem Soc, 77, 3259, 1955.
Bressler, R., M.D. Bogdonoff & G.J. Subak-Sharpe. 1981. The Physicians Drug Manual. Doubleday & Co, Inc. Garden City, NY. 1213 pp.
Felter, H.W. & J. Lloyd. King's Am Dispensatory, 18th Ed. 1898, reprinted by Eclectic Medical Publications: Portland, Or, 1983.
Fitzpatrick, F.K. Plant substances active against mycobacterium tuberculosis. Antibiotics And Chemotherapy, 4(5), 528-536, 1954.
Goodman, L.S. & A. Gilman. 1975. Pharm Basis of Thera. Macmillan, NY.
Hansten, P.D. 1979. Drug Interactions, 4th ed. Lea & Febiger, Phila.
Kastrup, E.K., ed. 1981. Drug Facts and Comparisons, 1982 edition. Facts and Comparisions Division, J.P. Lippincott Co, Phila(St. Louis).
List, P. & L. Hoerhammer. 1969-1976. Hagers Hanbuch der Pharmazeutischen Praxis, vols. 2-5. Springer-Verlag, Berlin.
Martin, E.W. 1978. Drug Interactions Index, 1978/79. J.B. Lippincott Company, Philadelphia.
Mowrey, Daniel B., Ph.D. Exper. Psych., Brigham Young University. Director of Nebo Institute of Herbal Sciences. Director of Behavior Change Agent Training Institute. Director of Research, Nova Corp.
Scientific Committee, British Herbal Pharmocopaeia, British Herbal Medicine Assoc, Lane House, Cowling, Na Keighley, West Yorks, Bd Bd220lx, l983.
Stuart, D.M. 1968. Drug metabolism Part 2. Drug interactions. PharmIndex, 10(10). pp. 4-16.
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