Albizia lebbeck is a tree that is native to Pakistan, India, Bangladesh, southern China, Thailand, Malaysia, and possibly Sri Lanka, Africa and northern Australia. It is known by a variety of names, including Siris, Powder-puff Tree, Lebbeck, Broome Rain Tree, Albizia and Woman’s Tongue Tree.
The name “albizia” is thought to have come from an 18th century Florentine nobleman, Filippo del Albizzi, who first cultivated the species.
The tree is deciduous, growing to 30 metres tall in native forests. In open situations, trees develop a spreading, sometimes multi-stemmed appearance, reaching to 25 metres tall and 30 metres across, with long, low branches. It is valued for its shade and also as a provider of quality hardwood. It’s also good for soil as it fixes nitrogen and has an extensive, shallow root system that makes it a good soil binder suited to soil conservation and erosion control.
The outer bark of albizia is rough, grey and flaky, while the inner bark is reddish. Leaves are pale green when young and grey when old, growing to 7–15cm. It’s the bark and leaves that are used medicinally and have been popular in Ayurvedic medicine for centuries.
Constituents
The bark contains saponins and tannins traditionally used for making soap and in tanning. Although the constituents of the bark are not well understood it is known to contain albiziasaponins (A, B and C), epicatechin, procyanidins, cardiac glycosides and stigmastadienone. There are no alkaloids present.
Uses
Despite its long use in Ayurvedic medicine for respiratory conditions, asthma, skin complaints and eczema, albizia has not been well studied in clinical trials. Still, there is enough evidence to suggest it is a very useful medicine, particularly for allergic conditions.
Allergy. Human and laboratory tests have shown that albizia has the capacity to heal allergies by its effect on mast cells.
Mast cells are immune cells that play a key role in defence against infection and also in the allergic response. Mast cells are present in most places in the body but typically they are in the tissue surrounding blood vessels and nerves, and are especially prominent near the boundaries between the outside world and your internal environment such as the skin, mucosa of the lungs, digestive tract, mouth, conjunctiva and nose. They are part of the first line of defence and they contain granules of chemicals called histamine and heparin.
When the mast cell binds to a foreign substance it will “degranulate”, meaning it will release these chemicals into the surrounding tissue. In the case of allergy, it involves an antibody mistakenly presenting a substance to a mast cell which then degranulates, releasing its histamine into the surrounding tissue and bloodstream. This triggers a dilation of surface blood vessels and a drop in blood pressure. The spaces between the surrounding cells then fill with fluid. Depending on the part of the body or the allergen involved, this heralds the onset of various allergy symptoms, some of the most common being itching, hives, sneezing, wheezing, nausea, diarrhoea and vomiting.
Albizia works by stabilising mast cells and stopping the release of histamine through degranulation. It’s believed that the saponins are responsible for this effect, which has been seen in many clinical studies. One such study was published in the journal Immunopharmacology and Immunotoxicology (2010 Jun;32(2):272-6) and it did show that albizia reduced both histamine release from mast cells and other chemicals that perpetuate the allergic response.
This quality of albizia makes its effective to treat hayfever, asthma and allergic skin reactions.
Memory. The saponins from albizia have also been shown to improve memory retention in mice, but this remains to be conclusively shown in human studies.
Serotonin and GABA. Studies have shown that albizia will increase brain levels of the calming neurotransmitter, serotonin. There is evidence, though, that different forms of extract of albizia will have contrasting effects on the neurotransmitter, GABA. A saponin-containing extract of albizia decreases brain levels of GABA, while an ethanolic extract increases GABA levels. GABA plays a role in regulating excitability in the nervous system, so the nature of your albizia is critically important.
Male fertility reduction. In animal-based studies the saponins from albizia have been shown to reduce the weight of the testes, reduce sperm concentration and decrease overall fertility.
Taking albizia
The lack of human clinical trials means a hard-and-fast dosage regime is difficult to establish for albizia. However, these recommendations are currently best practice. If you are using a 1:2 liquid extract, take 3–6mL daily. If using dried herb, the dosage is 3–6 grams a day.
Precautions
If you are taking anti-allergy medication, albizia could theoretically add to the effect of your existing medication. Additionally, if you are taking SSRI medication (selective serotonin reuptake inhibitors), albizia could in theory lead to excessive levels of serotonin, causing “serotonin syndrome”. Serotonin syndrome produces symptoms that can range from mild (shivering and diarrhoea) to severe (muscle rigidity, fever and seizures). Severe serotonin syndrome can be fatal if not treated. Mild forms of serotonin syndrome may go away within a day of stopping the medications causing the symptoms. It’s not known whether the reductions in male fertility that show in animal trials will translate to human beings. There is insufficient information to say whether it is safe to use in pregnancy.
References available on request.
