In Captain Cook’s 1768 recount of his voyage in the Southern Seas, he wrote of his discovery of an intoxicating ceremonial drink prepared from Piper methysticum (better known as Kava):
“the Kava first causes a numbing and then astringent effect in the mouth. This is then followed by a relaxed, sociable state where the muscles are relaxed from the drink and fatigue and anxiety are lessened. Eventually a deep, relaxing sleep arrives and the person that has had the kava awakes refreshed and without a hangover or any after-effects of the herb.”
Given the proven anxiolytic activities of Kava root, it is most commonly used to calm anxiety, stress, restlessness and treat insomnia. It’s also used for the treatment of ADHD symptoms, epilepsy, psychosis, depression, migraines and other headaches, chronic fatigue syndrome, the common cold and other respiratory tract infections, tuberculosis and muscle pain.
As an antibacterial-agent it is beneficial for urinary tract infections (UTIs), pain and swelling of the uterus, venereal disease, menstrual discomfort and as a mouthwash for canker sores and toothaches. Kava has also exhibited remarkable antifungal activity against a wide range of pathogenic fungi (although not the Candida species, unfortunately).
The main active constituents in the Kava root and rhizome are the resinous compounds called kava lactones. Good quality Kava rhizome contains between 5.5% and 8.3% Kava lactones, which comprise mainly of kavain, dihydrokavain (DHK) and methysticine. Several others are also present but in lower quantities.
Clinical studies in Germany have demonstrated Kava to be a safe, non-addictive anti-anxiety herb with an efficacy comparable to benzodiazepenes (such as Diazepam and Valium). Both Kava’s muscle relaxant effects on smooth and skeletal muscle and anticonvulsant effects are also well documented along with its analgesic activities. As an analgesic, DHK was superior to aspirin but considerably less potent than morphine. The Kava lactones have potencies similar to the action of a local anaesthetic.
Kava’s early studies demonstrated the ability of good quality kava extracts to induce sleep in a variety of tests. The amygdala complex in the limbic structures of the brain represented the most preferential sites of action for both the kavain and kava extract.
Generalised Anxiety Disorder is a chronic and pervasive condition that generates high levels of psychological stress and is typically difficult to treat long term. Several countries including Australia have approved kava preparations for the treatment of nervous anxiety, insomnia and restlessness on the basis of detailed pharmacological data and favourable clinical studies.
Flavokavains are secondary metabolites found in the kava root that may have anticancer properties. Studies compared the toxicity of kava and monitored the results of cellular adaptation in the human hepatocyte cell line. To test for subsequent resistance to oxidative stress, cells were pretreated, and some results showed significant cell death, giving reason to believe that kava root has potential as a chemopreventive or chemotherapeutic agent.
It may also reduce the size of tumors found in the prostate – a study published in Oncotarget was conducted demonstrating that elements within the kava plant may inhibit the growth of certain deficient cell lines. Interestingly, some agents found in kava may be a promising inhibitor for targeting degradation in prostate cancer prevention and treatment. This makes kava root an excellent addition to improve health overall and to possibly reduce the chances of prostate cancer in certain individuals.
The long-term use of Kava is not recommended as it has been shown to induce liver damage in some cases. High quality, TGA approved Kava should only be used under the strict guidance of a registered Naturopath/Herbalist.