(Piper methysticum)
INTRODUCTION :
Piper methisticum is a tall perennial, which is native to the South Pacific Islands. The native nobles and working class use this local euphoriant/ aphrodisiac for pleasure, the priests use it ceremoniously. 3
Kava's psychoactive effects are caused by kawa-pyrones (kawaines). Kawa-pyrones, which are present in all plant material (roots, branches, fresh foliage), have local anaesthetic properties and can be used as an antidote against strychnine or strycnos nux-vormica poisoning.
Effects :
Euphoria, disturbed vision, out of the body experiences,
makes speech more fluently, increases sensibility to subtle sounds and improves appetite.
Large doses: dilated pupils, visual and auditory changes (often of a pleasant kind), difficulty in walking. Kava doesn't cause hangover effects.
Duration :
The effects appear within an hour after ingestion and last for 3-6 hours.
Dosage and preparation :
Kava can be chewed, or can be prepared as a beverage.
Depending on the purpose, 2-15 grams is needed.
Botanical aspects :
P. methysticum is a member of Piperaceae. Its geographical origin is unknown because this plant does not occur wild. It appears that the plant was introduced from Polynesia to Hawai since prehistoric times.
P. methysticum is a bushy, evergreen shrub that has heart-shaped foliage (30 cm length) and usually grows two meters in height. Male flowers are green-white of colour and female flowers are not known. The fleshy rhizome can weigh 2-10 kg.
Reproduction follows through cuttings or through rhizome division. When a twig of 15-20 cm is sticked into a humid soil, the new roots will apear within a week.
 Figure: P. methysticum
Phytochemistry :
The plant material contains more than 5% alkaloids (1.8% kawaine, 1.2% methysticine, 1% desmethoxy-yangonine, 0.6% yangonine and 0.5% dihydrokawaine. 4 Samples showed trace amounts of dihydrokawaine-5-ol, 11,12-dimethoxyhydrokawaine, 11-hydroxy-12-methyoxykawaine, 11-methoxy-nor-yangonine.
The kawa- pyrones present in kava-kava are structurally related to the Lonchocarpus-alkaloids and are not water soluble, but are soluble in alcohol (alcoholtinctures).
 
Tabel 1.23: Kawalactones
Pharmacology :
Kawa-pyrones (= kawa-lactones) probably act in vivo as agonists on barbiturate- and benzodiazepines-receptors. Thus, the kavapyrones work via similar mechanisms as meprobamate and benzodiazepines: the agonists on barbiturate- and benzodiazepine receptors both exhibit allosteric modulation of the GABA-receptor-proteins; the barbiturate receptor agonists increase the activation time of the Cl--ionchannels and the benzodiazepine receptor agonists increase the frequency of Cl--ionchannel activation.2,4
The local anaesthetic properties are very similar to those of cocaine and it's derivates. 2
Modifiers :
- Intensfies the effects of alcohol.
- Antagonizes the effects of dopamine, apomorphine, ephedrine and amphetamines (apomorphine is present in sassafras and ephedrine in various Ephedra species).
- In combination with Hypericum perforatum it has mild anti-depressing properties.
- Kava-pyrones prolong chloroform-, ether-, N2O- and barbiturate narcoses.
Dangerous combinations :
do NOT use when pregnant, or chronically.
References
1. [Gottlieb]
2. [Hoffer/ Osmond, 1967]
3. [Hoffmann/ Schultes, 1973]
4. [Ratsch, 1998]
5. [Snyder, 1996]
6. [Stafford, 1974] |
