Walnut is an extremely versatile tree. It's best known for its dark, and decorative wood, often used as flooring, furniture, and for the stocks of guns and knives.
The green seed husks are boiled to make a yellow dye, and the nut makes a delicious and highly nutritious meal. The oil from this nut is useful as a polish for wood and as a mixer for paint. It's also been used as lamp oil and for cooking purposes.
The medicinal content of the wood is strong, offering powerful astringent activity, and purgative action. The strongest medicinal uses of this tree, however, are in its seed husks, especially while green and unripe.
The chemicals contained in these unripe husks, particularly the chemical juglone, is a powerful destroyer of worms and other parasites. When applied as a salve or balm it is useful for reducing sweating of the hands and feet, and can be used to treat fungal and parasitic infections on the skin such as athletes foot or ringworm.
The anti parasitic action works if employed in the garden as a strong infusion of the husks or leaves as well to destroy worms or other insects and won't injure the grass. In the wild, it's been found that no insects will touch the leaves or bark of this plant.
Leaves, bark, or fruit husk
Liquid Extract (1:1)
Herbal Actions (Nut/Husk):
- Stimulating hepatic
- Digestive tonic
- Antifungal 
- Hypoglycemic 
- Anti-cancer [1, 4]
- Anticholesterol [1, 3, 10]
Herbal Actions (Bark and Leaves):
- Alterative 
- Laxative 
- Astringent [1, 10]
- Detergent 
- Purgative (Bark)
- Anthelmintic 
- Stimulant 
- Digestive tonic [1, 10]
- Insecticidal 
- Hepatoprotective [12-17]
- Anticancer 
- Antihypertensive (leaves) 
- Antioxidant [1, 10, 17]
- Anticholesterol [1, 3, 10]
- Mouth and throat infections
- Chronic constipation
- Diarrhea and dysentery
- Haemorrhoids and portal congestion
- Pinworms or threadworms in children
- Skin eruptions (Whole plant)
- Respiratory infections
- Fungal infections
- Athletes foot
- Itchy scalp
- Eyelid inflammation
- Excessive perspiration on the hands and feet
- Venous insufficiency (Leaves) .
- Haemorrhoids (leaves) 
- As a gargle to clean teeth and gums 
Culpepper suggests its bark is a great astringent, stating that it "doth bind and dry very much". He also states that the older, more bitter leaves are useful for killing broad-worms in the stomach. The nuts, and leaves are suggested for poison, snakebites, or dog bites. .
He also suggests the green husks, boiled with honey is a great remedy for sore throats and inflammations of The mouth and stomach. .
In Iran, walnut is often used as an extract and its hydrosol to control blood sugar [2, 3].
In southern Morocco, the leaves are used in the treatment of hypertension and diabetes .
The walnut tree is an enormous deciduous tree, reaching heights of 40-60 feet, and have very large, spreading tops. The trunk is very thick, and can reach over 20 feet in circumference. .
The genus Juglans, contains 3 species: Juglans nigra (Black walnut), Juglans regia (English walnut), Juglans cinerea (White walnut). .
Habitat Ecology, and Distribution:
Juglans species are found primarily in temperate areas and are cultivated commercially throughout southern Europe, Northern Africa, eastern Asia, the United States, and western South America . It is in fact the most widespread tree nut in the world .
In the Himalaya, the walnut inhibits mountain slopes at elevations of 1200 - 2100 m (4000 to 7000 feet) .
Harvesting Collection, and Preparation:
Still compiling research.
- Juglone (5-hydroxy-1, 4-naphthoquinone) (highest in green or unripe husks)
- Tannins (10%)
- Organic acids
- Volatile oils
- Volatile oils:
- β-pinene 
- β-caryophyllene 
- α-pinene 
- Germacrene-D 
- Limonene 
- Homoveratrole 
- Piperitone 
- Thymol 
- Carvacrol 
- Eugenol 
- γ-eudesmol 
- Nonadecane 
Pharmacology and Medical Research:
Juglans regia (English walnut) extracts were shown in an experimental study to significantly reduce blood glucose, glycosylated hemoglobin, LDL, triglycerides, and total cholesterol, as well as significantly increase insulin and HDL levels [1, 3]. The mechanism of action is suggested to be through either a stimulation of the beta-cells of the pancreas to release insulin, increase in the sensitivity of the cells to insulin, or interference with dietary carbohydrate absorption [1, 8, 9]. If the first suggestion is true (stimulates the beta-cells of pancreas to secrete insulin), then this action will not work on those with type 1 diabetes, as this conditions means that most of the insulin secreting beta-cells are absent. Since the majority of study of this herb in this area are conducted on type 2 diabetic models it is hard to understand how this will affect those lacking beta cells.
Other studies have found similar results .
Still Compiling research.
The leaves of the walnut tree contains a high amount of cancer fighting polyphenols. These chemicals are well known to possess antioxidant, and anti-inflammatory actions, both of which have a direct benefit in treating, or preventing cancer cell lines .
Walnut hull extracts have been found to contain a chemical called ellagitannins, which possess anticancer benefits, as well as anti-inflammatory actions [1, 4].
As a bi-product of the walnut oil industry, a large amount of protein is left behind. Part of this protein, has been found to possess significant apoptotic actions on cancer cells (MCF-7 cells). The whole protein itself was not responsible for this action, but rather the hydrosylates released via enzymatic processes. Such enzymes that can release these hydrosylates from the chain include pepsin, papain, trypsin, neutral protease and alkaline protease. Papain-derived hydrosylates were noted to have the most pronounced effect in this regard. The mechanism of action was found to be through an induction of apoptosis and autophagy of the cancer cells, and was suggested to offer other immunomodulatory action as well. .
It is currently unclear wether this hydrosylate will be produced in the stomach and upper intestines from the pepsin contained within these tissues, or if this will need to be hydrosylated in a lab with commercial enzymes. More research is needed.
Other extracts containing triterpene components taken from the green husk of Juglans manshurica were also found to possess anticancer activity on hepatic cancer cell lines in vitro (Hep-G2 Cancer cells) .
A Juglans regia bark extract was shown to possess significant antibacterial actions against E. coli and methicillin resistant S. aureus bacteria, but had little to no effect on gram-negative bacteria . This suggests a powerful bactericidal activity of the bark extract of Juglans regia on gram-positive bacterium, regardless of drug resistance to other antimicrobials, and particularly on Staphylococcus strains.
Fibrogenesis of the liver is characterized as an increase in extracellular matrix proteins such as collagen, which are mainly produced in the hepatic stelate cells. This buildup of proteins will lead to a degredation of the hepatic function, and can ultimatly lead to death. This reversible condition is an early stage of the more serious and generally non-reversible cirrhosis . Therefore, reducing the activation of these hepatic stellate cells, can result in a reduction or prevention of these damaging extracellular matrix protein buildup.
Hepatic stellate cell activation can occur from viral causes such as with HCV, or from drug or other toxic substances that will increase reactive oxygen species in the liver, or cause injury to the parenchymal hepatocytes .
The leaves and twigs of Juglans sinensis is known to contain the chemicals oleanene, and ursane triterpines and flavonoids which have been found to possess therapeutic benefits towards this hepatic fibrosis in both in vitro and in vivo models [12-16]. Based off of this knowledge, a study was done investigating the specific effects of an ethanolic extract of the leaves and twigs of Juglans sinensis, on liver injury in vivo. This study found that the extract was able to significantly reverse the pathological parameters associated with this type of liver injury. .
Other studies have found that the flavonoids contained within Juglans sinensis suppress reactive oxygen species generation by inhibiting some of the enzymatic activity involved with this free radicle production .
Part of the protein portion of the walnut fruit has been found to inhibit the activity of angiotensin I-converting enzyme (ACE) which has a significant activity on the cardiovascular system, namely blood pressure .
The perfect ratio of n-6 to n-3 polyunsaturated fatty acids are well known to exert positive effects on the cardiovascular function including blood pressure regulation as well .
The fruit of the walnut tree (AKA a walnut) provides high nutritional value. The nut contains a perfect balance of n-6 and n-3 polyunsaturated fatty acids, which has been determined to be a 4:1 ratio respectively .
The toxicity of Juglans regia is fairly high, suggested to be 100 times higher than the dose needed to produce antimicrobial actions .
Juglone, contained in the fresh or unripe walnuts and husks, is toxic. It is not found in nearly as high quantities in the dried leaves however .
Traditional Chinese medicine:
Pinyin: Hu Tao Ren
Taste: Sweet 
Energy: Warm 
Channels: Kidney, lung, large intestines 
Actions: Tonifies kidneys, warms the lungs, moistens the intestines 
Indications: Coughs and asthma due to deficiency-cold, constipation due to dry intestines 
Cautions: Do not use with excess fire due to yin deficiency, coughs due to phlegm heat and with loose stools 
- For gripping mix with ginger
- For skin eruptions mix with Taraxacum officinalis root
- May have synergy with wormwood for its similar actions against parasitic infections
Other Botanical Medicines
The Sunlight Experiment
Updated: July 2017
Recent Blog Posts
- Moravej, H., Salehi, A., Razavi, Z., Moein, M. R., Etemadfard, H., Karami, F., & Ghahremani, F. (2016). Chemical Composition and the Effect of Walnut Hydrosol in Glycemic Control of Type 1 Diabetic Patients. Int J Endocrinol Metab, 14(1). doi:10.5812/ijem.34726
- Mohammadi J, Delaviz H, Malekzadeh JM, Roozbehi A. (2012). The effect of hydro alcoholic extract of Juglans regia leaves in streptozotocin-nicotinamide induced diabetic rats. Pak J Pharm Sci. 2(25):407–11.
- Hosseini S, Huseini HF, Larijani B, Mohammad K, Najmizadeh A, Nourijelyani K, et al. (2014). The hypoglycemic effect of Juglans regia leaves aqueous extract in diabetic patients: A first human trial. Daru. 22(1):19. doi: 10.1186/2008-2231-22-19.
- Amaral JS, Seabra RM, Andrade PB, Valentao P, Pereira JA, Ferreres F. (2004). Phenolic profile in the quality control of walnut (Juglans regia L.) leaves. Food Chem Toxicol. 88(3):373–9.
- Culpeper, N. (1995). Culpeper's complete herbal: A book of natural remedies for ancient ills. Ware, Denmark: Wordsworth Editions.
- A Modern Herbal. (1931). Walnut. Retrieved from http://www.botanical.com/botanical/mgmh/w/walnut06.html
- Farag MA. (2008). Headspace analysis of volatile compounds in leaves from the Juglandaceae (walnut) family. J Essent Oil Res. 20(4):323–7.
- Pitschmann A, Zehl M, Atanasov AG, Dirsch VM, Heiss E, Glasl S. (2014). Walnut leaf extract inhibits PTP1B and enhances glucose-uptake in vitro. J Ethnopharm. 152(3):599–602.
- Ezhumalai M, Radhiga T, Pugalendi KV. (2014). Antihyperglycemic effect of carvacrol in combination with rosiglitazone in high-fat diet-induced type 2 diabetic C57BL/6J mice. Mol Cell Biochem. (385):23–31.
- Almonte-Flores, D. C., Paniagua-Castro, N., Escalona-Cardoso, G., & Rosales-Castro, M. (2015). Pharmacological and Genotoxic Properties of Polyphenolic Extracts ofCedrela odorataL. andJuglans regiaL. Barks in Rodents. Evidence-Based Complementary and Alternative Medicine, 2015, 1-8. doi:10.1155/2015/187346
- A. Tahraoui, J. El-Hilaly, Z. H. Israili, and B. Lyoussi, (2007). “Ethnopharmacological survey of plants used in the traditional treatment of hypertension and diabetes in south-eastern Morocco (Errachidia province),” Journal of Ethnopharmacology, vol. 110, no. 1, pp. 105–117
- Kim, Y., Yang, H., & Sung, S. (2015). The ethanolic extract of Juglans sinensis leaves and twigs attenuates CCl 4 -induced hepatic oxidative stress in rats. Pharmacognosy Magazine,11(43), 533. doi:10.4103/0973-1296.160463
- Bai X, Qiu A, Guan J, Shi Z. (2007). Antioxidant and protective effect of an oleanolic acid-enriched extract of A. deliciosa root on carbon tetrachloride induced rat liver injury. Asia Pac J Clin Nutr. 16(Suppl 1):169–73.
- Lee MK, Ha NR, Yang H, Sung SH, Kim GH, Kim YC. (2008). Antiproliferative activity of triterpenoids from Eclipta prostrata on hepatic stellate cells. Phytomedicine. 15:775–80.
- Mandal AK, Das S, Basu MK, Chakrabarti RN, Das N. (2007). Hepatoprotective activity of liposomal flavonoid against arsenite-induced liver fibrosis. J Pharmacol Exp Ther. 320:994–1001.
- Shyu MH, Kao TC, Yen GC. (2008). Hsian-tsao (Mesona procumbens Heml.) prevents against rat liver fibrosis induced by CCl (4) via inhibition of hepatic stellate cells activation. Food Chem Toxicol. 46:3707–13.
- Cazarolli LH, Zanatta L, Alberton EH, Figueiredo MS, Folador P, Damazio RG, et al. (2008). Flavonoids: Prospective drug candidates. Mini Rev Med Chem. 8:1429–40.
- Ma, S., Huang, D., Zhai, M., Yang, L., Peng, S., Chen, C., Xu, M. (2015). Isolation of a novel bio-peptide from walnut residual protein inducing apoptosis and autophagy on cancer cells. BMC Complementary and Alternative Medicine, 15(1). doi:10.1186/s12906-015-0940-9
- Liu M, Du M, Zhang Y, Xu W, Wang C, Wang K, et al. (2013). Purification and identification of an ACE inhibitory peptide from walnut protein. J Agric Food Chem. 61(17):4097–100.
- Zhou, Y., Yang, B., Liu, Z., Jiang, Y., Liu, Y., Fu, L., … Kuang, H. (2015). Cytotoxicity of Triterpenes from Green Walnut Husks of Juglans mandshurica Maxim in HepG-2 Cancer Cells. Molecules, 20(10), 19252-19262. doi:10.3390/molecules201019252
- Farooqui, A., Khan, A., Borghetto, I., Kazmi, S. U., Rubino, S., & Paglietti, B. (2015). Synergistic Antimicrobial Activity of Camellia sinensis and Juglans regia against Multidrug-Resistant Bacteria. PLOS ONE, 10(2), e0118431. doi:10.1371/journal.pone.0118431
- Wu, J. N. (2005). An illustrated Chinese materia medica. New York: Oxford University Press. (Pg. 364-365).