by Mala Coomar
Within the Pacific Islands, two main varieties of kava are recognized: Tudei Kavas (Piper wichmanii) and Noble Kavas (Piper methysticum). Tudei kava is the ancestor to Noble kava and is not traditionally consumed due to its unpleasant effects like nausea and lethargy. Tudei kavas have undesirable chemotypes and high concentrations of compounds that can produce negative reactions. There are some debates about its use medicinally, but it is never recommended for frequent or recreational use.
Noble kavas are the desirable varieties of kava that are traditionally regularly consumed and used in properly prepared kava beverages either from the fresh root or its dried, powdered form. Some Pacific Islander countries, like Vanuatu, even ban the export of Tudei kava so that only Noble kava varieties can be legally exported.
Kava is evidently an integral part of the culture of the Pacific Islands when it comes to social, ceremonial, and political contexts. Outside the Pacific Islands, the contemporary use of kava extends beyond ritualized circumstances. Kava has been viewed and marketed as everything from a casual, social beverage to a prescription-free alternative to benzodiazepines or “Nature’s Xanax.”
• chewing fresh kava root
• drinking beverages made from fresh kava root
• drinking beverages made from dried and powdered kava root
• consuming products made from kava extracted with organic solvents also referred to as “kava extracts”
The pharmacological differences between Tudei kavas and Noble kavas are relatively well-known, but the same cannot be said regarding the pharmacological differences between the more contemporary methods of consuming kava—even when strictly speaking about products made from Noble kavas.
Although negative health effects reported from kava use can possibly be attributed to the usage of Tudei kavas in dietary supplements, they can also be attributed to usage of kava extract—even if it is Noble kava—that has been extracted with organic solvents like acetone and ethanol. Products containing kava extracted with organic solvents are often marketed and presented as health/dietary supplements or through alternative/complementary medicine and are distinct from the traditional kava beverage. Products containing kava extracted with organic solvents are also relatively new and only found outside the Pacific Islands. Because of this, their long-term physiological effects are not thoroughly known and there is not universal agreement on whether or not they are safe to consume.
The differences in kava products are evident not only in their conception but at their molecular level. Understanding kava at the molecular level can shed light not only on the effects kava can have upon consumption but how and why those effects may vary.
The kava plant, Piper methysticum, has been found to contain more than 40 compounds belonging to the classes of kavapyrones, alkaloids, steroids, chalcones, long-chained fatty acids, and alcohols.
Kava alkaloids are present only in the parts of the kava plant that are exposed to sunlight. Properly prepared kava beverages are made only from the root of the plant and would not contain any alkaloids, some of which may be toxic. Negative health effects associated with kava could also be attributed to the improper or illegal usage of the stem and leaves in kava products.
Dried kava rootstock consists of approximately 43% starch, 20% fibre, 12% water, 3.2% sugars, 3.6% proteins, 3.2% minerals, and 3-20% kavalactones. Kavalactones, in particular, are a class of lactone compounds found in the kava plant and are recognized as being responsible for the effects it may have on the body.
Kavalactones are 4-methoxy-2-pyrones with phenyl or styryl substitutes at the 6th position. The general structure of kavalactones can be seen below.
Consensus on the pharmacology of kavalactones has not been reached yet, but the prevailing view is that their pharmacological actions are benzodiazepine-like. In other words, the effects of kavalactones on the body can be likened to that of benzodiazepines in that they are anxiety-reducing, hypnotic, sedative, and anticonvulsant. Kavalactones are poorly soluble in water, their absorption varies, and they are lipophilic—they better combine with fats (hence why coconut milk is favorable solvent when preparing kava beverages with dried/powdered kava root).
Although they are lipophilic, kavalactones—like benzodiazepines—absorb in the body remarkably rapidly. Kavalactones are then eliminated from the body in part by the kidneys (metabolites and unchanged pyrones) and in part by the feces (unchanged pyrones).
Kavalactones have been shown to have anxiolytic properties via modulation of gamma-aminobutyric acid (GABA) receptors and other excitatory neurotransmitters, as well as inhibition of monoamine oxidase B and inflammation. A pharmacological report on kavalactones found that they “facilitate the functioning of GABA A receptors, in a manner that is similar to benzodiazepines” although they “do not appear to bind to benzodiazepine receptors.”
So far, 18 different kavalactones have been identified. 15 of them are active, but six of them—kavain, methysticin, 7,8-dihydromethysticin, yangonin, desmethoxyyangonin and 5,6- dihydrokawain— make up 96% of the effects kava has on the body.
The fact there is no consensus on the pharmacology of kavalactones could be, in part, due to the fact that their effects can drastically vary.
Kavalactones are a chemical compound and their structures and effects can drastically vary depending on the variety of kava plant, whether the kava root is fresh or dried and powdered, how old the dried and powdered kava is, and whether the kava was extracted with organic solvents. The strength and effects of the kavalactones also depend on the method of preparation and whether or not the kava is consumed with other drugs, food, alcohol, caffeine, and physical activity.
Fresh kava has a higher concentration of kavalactones than dried kava. Chewing on fresh kava root or drinking kava beverages prepared with water and fresh kava root results in stronger psychoactive effects than drinking kava prepared with dried, powdered kava root.
The psychoactive effects of kava beverages made from powdered kava also depend on how the kava powder was stored and how old it is. One study investigated the stability of kavalactones in powdered kava root stored in screw-capped glass bottles at room temperature and found that after 39 months of storage, 93.9% of dihydrokavain, 81.6% of kavain, 72.4% of dehydrokavain, 54.9% of tetrahydroyangonin, 25.8% of dihydromethysticin, 32.1% of yangonin and 29.5% of methysticin had deteriorated in the samples.
Outside of the Pacific Islands, “kava” has also been used to refer to the organic solvent extracts of the plant for use in medicinal products. Acetone or ethanol is used to extract kava and is used in complementary medicines/dietary supplements. These kava extracts generally contain 30% kavalactones and can be presented as capsules, powders/teas, liquids, and in combination products containing a variety of herbs and/or vitamins. As such, kava extracts have a different effect on the body and react differently than kava beverages made with fresh or dried and powdered kava root mixed with water/nut milks.
Organic solvent extractions of kava are compositionally different than traditionally prepared kava beverages made with water and fresh kava root as well as kava beverages prepared with dried, powdered kava and water/nut milks.
For instance, glutathione is present in fresh as well as dried and powdered kava root but not in organic solvent extractions of kava. Glutathione—made up of three amino acids—occurs naturally in kava root and may play an important role in the metabolism of kavalactones. Kava extracts are likely to contain only kavalactones and no proteins, amino acids—including glutathione—or sugars. Glutathione is present in healthy individuals but genetic deficiencies are possible. In these cases, the high concentration of kavalactones in organic solvent extractions of kava combined with the absence of glutathione can result in toxicity and possible tissue damage.
A report on kava from the New Zealand government found that, “[t]he use of non-traditional methods of preparation can change the [kava] component profile, which may potentially affect the toxicity of the kava preparation” and that “[d]ifferent extraction techniques and preparation methods may result in extracts where the presence and relative concentration of each kavalactone is altered considerably compared to the kava root and the traditionally prepared kava beverage.” The report goes on to say that “traditional methods of preparation in water are considerably safer than kava prepared in organic solvents (ethanol, acetone and hexane).”
Quality control is very important when it comes to kava beverages in order to ensure there is no contamination from the improper and illegal use of the stems and leaves from the kava plant or the use of Tudei kava. Organic solvent extraction of kavalactones may not to be subject to the same quality control as dried and powdered kava root and thus should be treated with caution.
Kava extracted with organic solvents is a contemporary product that is not found in the Pacific Islands and which is compositionally and pharmacologically different than the traditional kava beverage prepared with fresh kava root or powdered kava root mixed with water/nut milk.
Because of these differences, it is important to be aware of the various kind of kava and to be mindful about choosing which kava to consume as well as how to consume it.
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