Walnut (Juglans regia)
Walnut, the remedy for those who are affected by outside influences, is made by the boiling method.
Native to regions east of the Balkans, the common or Persian walnut is now found in Britain and is sometimes known as English walnut. In the UK, temperatures are not conducive to nut formation and this may have led to the tradition of pickling walnuts. This involves picking the whole fruit, or drupe, before the shell and kernel has formed inside. These are soaked in brine (salt and water), dried and bottled in a pickling vinegar containing spices, or boiled in a pickling syrup containing vinegar, sugar and spices. Pickled walnuts are traditionally eaten with cheese during the Christmas season.
The nuts contain large amounts of alpha-linoleic acid, an omega-3 fatty acid. This can reduce the chances of developing breast cancer and heart disease. Walnuts can also reduce inflammation and joint pain in rheumatoid arthritis and inhibit the growth and reduce the size of prostate tumours. Walnuts were rated the number one nut in a study comparing the anti-oxidant properties of nine types of nut. An added benefit is that they are usually eaten raw whereas other nuts may be roasted, reducing the quality of the antioxidants. These antioxidants were estimated to be between 2 and 15 times more potent than vitamin E. What’s more, eating only seven walnuts a day should provide all the health benefits of walnuts discovered so far.
Traditionally, the bark and leaves were primarily used to treat skin conditions such as herpes, eczema, ulcers and scrofulous diseases (i.e. resembling or due to tuberculosis of the lymph glands). Coachmen sometimes sponged down horses with a solution made by steeping walnut leaves. The husks and leaves were used to treat worms and the juice of the green husks was gargled with honey to treat sore mouths or throats. The skin coating the kernel was dried and powdered and used to treat colic. The seed oil was also used to treat colic as well as, externally, to treat skin conditions and wounds.
Followers of the Doctrine of Signatures, believing God marked plants to tell us how they could be used, advocated use of the kernels to treat the brain and the outer husk for wounds to the head. Husks or kernels were sometimes burned and used with oil and wine to stop hair falling out and to make it fair and a piece of green husk was put into a hollow tooth to relieve pain.
Limited trials of the leaf extract have shown beneficial effects for the treatment of type-II diabetes – the extract caused a reduction in cholesterol and triglyceride and HbA1c (haemoglobin bound glucose), with no adverse effects. The leaves were used in Austrian folk medicine to treat diabetes. Other proven effects of the leaf extracts include as anti-inflammatory and anti-tumour agents.
Walnut oil is sometimes used in salad dressings or for cooking. It is also used as a medium for pigments in oil paintings. It is said to yellow less than linseed oil, a popular alternative, but does tend to quickly become rancid. Renaissance painter Leonardo da Vinci used walnut oil paints and wrote about the detrimental effect of the husks on the quality of the paint – the colouring matter of the husk would rise up to the surface of the painting and cause it to change.
The compound juglone, or nucin, occurs almost throughout the tree, mainly in the bark and hulls but not in the kernels. It is an allelopathic compound, leached into the surrounding soil to deter other plants from growing – originally the effect of walnut trees on other plants was known as “walnut wilt”. It is also toxic to some insects, fish and microorganisms including bacteria and fungi. It is active against Heliobacter pylori, a bacterium affecting around 50% of the world’s population. It has also shown anti-tumour and anti-fungal properties and may be of use in the treatment of athlete’s foot and ringworm. Current medicinal use is limited to its sedative effect on animals and other potential uses are as a herbicide and biocide.
Juglone is related to lawsone (from henna) and plumbagin (found in Ceratostigma willmottianum (cerato) and other leadworts). It is an orange-brown colouring agent used in the food and cosmetics industries and it can also be used in inks and dyes. Walnut husks have also been used to produce a brown dye, used to dye hair or fabrics. The dye doesn’t require a fixant so the husks will stain the hands if handled without gloves. The husks of walnuts are often washed to remove the dyeing compounds, which can cause skin irritation as well as staining, before they are sold.