ScienceDaily (Feb. 23, 2008) — Scientists have found new evidence, using innovative techniques, to support the growing body of literature that indicates kava may have a negative effect on the liver. Kava is a plant native to the South Pacific that has been used as a ceremonial beverage in the region for thousands of years, and, more recently, as a natural treatment for medical conditions such as anxiety. In recent years, serious concerns about the dangers of kava and the effects on the liver have resulted in regulatory agencies, such as the US Food and Drug Administration and Australia's Therapeutic Goods Administration, banning or restricting the sale of kava and kava products.
Originally from Fiji, where kava drinking is common, Professor Iqbal Ramzan, Dean of Pharmacy at the University of Sydney, Australia, had previously published articles on the adverse effects of kava, and wanted to investigate further the effects kava had on the liver.
Leading a team of researchers from the University of Sydney, Professor Ramzan spent one year investigating the cellular effects of kava on the liver. Kava has been used in ceremonies and for recreational and social purposes in the South Pacific since ancient times, much like alcohol, tea or coffee is in other societies today.
In the 1980s other medicinal uses for kava began to emerge and it was marketed in herbal form as a natural way to treat conditions such as anxiety, insomnia, tension and restlessness, particularly in Europe and North America.
More recently, evidence began to emerge about the adverse affect kava could have on the liver.
To test these theories, the University of Sydney study focused on the major kavalactone (the ingredient in kava believed to affect the liver) -- kavain -- and investigated the effects it had on the ultrastructure (or biological structure) of the liver.
This required the use of electron microscopes (which enable the examination of the interior of cells) provided by the Australian Key Centre for Microscopy and Microanalysis at the University of Sydney under the direction of its Deputy Director, Professor Filip Braet.
The study found that following kavain treatment the liver tissue displayed an overall change in structure, including the narrowing of blood vessels, the constriction of blood vessel passages and the retraction of the cellular lining.
Interestingly, kavain also adversely affected certain cells which function in the destruction of foreign antigens (such as bacteria and viruses), which make up part of the body's immune system.
In other words, the kavain treatment disturbed the basic structure of the liver, consequently seriously impacting the normal functioning of the liver.
The results of the University of Sydney's study clearly support earlier literature observations on kava's adverse affects on the functioning of the liver in general.
However, additional investigations into the effects of other major kavalactones on the liver, as well as studies on whether the effects of kava are reversible, are urgently needed.
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Influence of kavain on hepatic ultrastructure.Fu S, Korkmaz E, Braet F, Ngo Q, Ramzan I.
Faculty of Pharmacy, The University of Sydney, NSW 2006, Australia.
[email protected].
AIM: To investigate whether the major kavalactone kavain imposes adverse effects on the liver ultrastructure and function by affecting vascular and microvascular architecture and altering hepatocellular morphology. METHODS: Kavain solution (10 mug/mL or 43.5 mumol/L) was perfused for 2 h in isolated rat livers. After standard fixation and tissue preparation, the samples were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and light microscopy (LM). RESULTS: LM, SEM, and TEM examinations indicated kavain-treated rat livers (n = 4) displayed severe vascular and endothelial damage compared to control livers (n = 4). CONCLUSION: The data so far support the hypothesis that kavain induces adverse effects on liver; additional investigations with other kavalactones and their effects on liver are urgently needed.
PMID: 18203285 [PubMed - in process]