Rootwork

Black Walnut

Juglans nigra

JuglandaceaeEastern North America from Ontario and New England south to Florida and west to Nebraska and Texas

Description

overall appearance

A large deciduous tree reaching 18–30 m tall with a straight trunk up to 1 m diameter and a broad, rounded crown. Produces distinctive large compound leaves, a rough, dark-furrowed bark, and large round fruits with an intensely staining green husk concealing the hard, furrowed nutshell.

roots

Deep taproot with extensive lateral roots; produces juglone (allelopathic chemical) that inhibits growth of many other plants in the root zone; roots spread 2–3x the crown radius

stem

Single trunk with thick, dark gray to black, deeply furrowed bark forming a diamond-shaped ridged pattern; inner bark is brownish; wood is heavy, strong, and highly valued

leaves

Alternate, pinnately compound, 30–60 cm long; 15–23 leaflets, ovate-lanceolate, 5–10 cm long; terminal leaflet often small or absent; finely serrate margins; dark yellow-green; strongly aromatic when crushed

flowers

Monoecious; male catkins 4–15 cm long, drooping; female flowers in small clusters of 1–5; blooms April–May with leaf emergence; wind-pollinated

fruits/seeds

Large, round to slightly obovoid green drupe 4–6 cm diameter; outer husk (hull) is thick, fibrous, intensely staining brown-black; inner nut is hard, deeply furrowed, brown-black; kernel is edible, oily, rich

Active Compounds

Juglone (5-hydroxy-1,4-naphthoquinone; primary active compound, particularly in hull and leaves)Tannins (gallotannins, ellagitannins; 5–15% in hull)Plumbagin (naphthoquinone derivative)Juglandic acidFlavonoids (quercetin, myricetin, kaempferol)Omega-3 fatty acids (linolenic acid in nut)Ellagic acidBeta-sitosterol and essential oils

Traditional Uses

  • Eastern Woodland Native American peoples (Cherokee, Iroquois, Ojibwe) used hull and bark for skin parasites (ringworm, scabies), worms, and as a laxative
  • Iroquois tradition used bark tea as a cathartic and anthelmintic; hull poultice for wounds and fungal infections
  • 19th-century Eclectic physicians prescribed black walnut hull for intestinal parasites, syphilis sores, and skin conditions
  • Appalachian folk medicine used black walnut hull tincture as one of the primary anthelmintic (antiparasitic) preparations
  • Traditional use as topical antifungal for athlete's foot, ringworm, and nail fungal infections
  • Bark tea used in folk medicine as a mild laxative and to induce menstruation
  • Hull juice used traditionally to darken hair and as a fabric dye
  • American folk medicine used as a treatment for herpes sores and chronic skin conditions

Modern Applications

  • Antiparasitic: juglone has demonstrated activity against intestinal parasites including giardia, Ascaris, and Candida in vitro; basis for widespread traditional use and modern herbal antiparasitic protocols
  • Antifungal: juglone and tannins show potent inhibition of Candida, dermatophytes, and other fungi; evidence supports topical and internal use
  • Antimicrobial: juglone active against MRSA, E. coli, Staphylococcus, and Helicobacter pylori in vitro
  • Anti-tumor: juglone induces apoptosis in multiple cancer cell lines (breast, colon, prostate) in preclinical studies; mechanism via JNK pathway activation
  • Antioxidant: ellagitannins and ellagic acid are potent antioxidants; ellagic acid shows anti-mutagenic activity
  • Laxative: tannins and hull constituents stimulate intestinal motility in traditional use; mechanism partially supported
  • Antiviral: juglone inhibits herpes simplex virus and other enveloped viruses in cell-based studies
  • Cardiovascular: nut consumption rich in omega-3s and ellagic acid associated with improved lipid profiles in epidemiological studies

⚠️ Safety Information

Contraindications

  • Pregnancy: juglone and tannins are potentially toxic to fetus; strongly contraindicated
  • Liver disease: juglone is hepatotoxic at high doses; avoid therapeutic use with impaired liver function
  • Nut allergy: significant allergenicity; anaphylaxis possible in tree-nut-allergic individuals
  • Long-term internal use: juglone is cytotoxic; therapeutic use should be limited to short courses (2–4 weeks) under professional supervision
  • Children under 12: insufficient safety data for therapeutic doses

Side Effects

  • Severe skin staining: juglone/hull juice causes intense dark brown staining of skin and clothing, resistant to washing
  • Gastrointestinal upset: nausea, cramping, and diarrhea at high doses from tannin and juglone content
  • Hepatotoxicity: juglone is cytotoxic at high doses; liver enzyme elevation possible with excessive use
  • Skin irritation and contact dermatitis from fresh hull handling
  • Potential genotoxicity: juglone has mutagenic activity in bacterial assays; avoid long-term high-dose use

Drug Interactions

  • Anticoagulants (warfarin): ellagic acid and flavonoids may alter clotting; monitor INR
  • Hepatotoxic drugs (acetaminophen, statins): additive liver stress risk
  • Immunosuppressants: ellagic acid modulates immune function; may interfere with transplant rejection drugs
  • Iron supplements: high tannin content significantly inhibits iron absorption; separate by 2+ hours

Parts Used

  • Outer hull (green husk, primary medicinal use)
  • Leaves
  • Inner bark (traditional)
  • Nut (food and oil)

Preparation Methods

Hull tincture (1:5 in 60% ethanol; fresh green hull): 2–4 ml three times daily for antiparasitic protocol; dark brown-black liquid

Standardized hull extract capsules: 500–1500 mg/day standardized to juglone content (0.5–1%)

Topical juglone solution (0.5–2% in carrier oil or cream): applied twice daily to fungal skin infections

Hull tea (dried hull decoction): 2–4 g dried hull in 250 ml water, simmer 15 minutes; 1–2 cups/day; bitter and astringent

Antiparasitic formula: black walnut hull + wormwood (Artemisia) + cloves; traditional Hulda Clark protocol (not FDA-evaluated)

Leaf poultice: bruised fresh leaves applied to skin for ringworm and minor wounds

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Acai

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Caboclo and ribeirinho peoples of the Amazon have consumed acai as a primary dietary staple for generations; a bowl of thick acai pulp ('vinho de açaí') may constitute 40% of daily caloric intakeTraditional use in the Amazon as a source of energy for workers, fishermen, and farmers performing heavy laborIndigenous Amazonian use of root bark tea as a febrifuge and to treat liver disease and jaundice
Disclaimer: For educational purposes only. This is not medical advice. Always consult a qualified healthcare provider.