(Ilex paraguariensis)
INTRODUCTION :
Yerba mate has probably been used ritually as a stimulant since the year 1000 in South America. Yerba mate leaves were found in precolobian graves in Peru. The Guaranì and Caingang Indians value the leaves for their transcendent properties and employed it shamanically. In many South American cultures Yerba mate is often used medicinally and as an aphrodisiac.6
The Yerba mate leaves that are sold on the market are sometimes interchanged with the closely related I. brevicuspis, I. dumosa.
Effects :
Yerba mate has stimulating and agitating effects: it enhances alertness, physical capacities and improves mood. Euphoria can be experienced simultaneously with the stimulating effects when higher doses are taken. Yerba mate does not cause a typical caffeine effect due to the presence of two other main active constituents (theobromine and chlorogenic acid).6
Autonomic changes: elevation of body temperature, increase of bloodpressure and respiratory rate, diuretic prperties, insomnia and a supressed appitite.
Duration :
The effects appear within half an hour after ingestion of the tea and last for 3-5 hours.
Dosage and preparation :
After harvesting the leaves and small twigs from the plant, they are heated for a short time to retain their original green colour; when the plant material is dried slowly it turns black.
The plant material is prepared into an aqueous infusion and imbibed as a tea: the leaves are covered with hot water and drawn for 5-10 minues. Cold water infusions also cause stimulating effects. Two grams of dried leaves are considered to be a normal dose for one cup of tea. It appears that the stimulating effects are stronger as the tea is drawn for a shorter time.
The Indians in paraguay add dried Stevia rebaudiana foliage (this plant contains sweet tasting diterpenes) to the tea as a sweetening.
Botanical aspects :
I. paraguariensis belongs to Aquifoliaceae and is native to the South-American continent; it is now spread out all over Paraguay, Northern Argentina, Uruguay, Brazil and Bolivia.
Although the shrub can be propogated via seeds and cuttings, seed propagation is difficult due to the 6 months germinating period of the seeds.
Because its appearance is very similar to that of I. Aquifolium these two species are sometimes interchanged.
 Figure: I. Paraguariensis seeds
Phytochemistry :
The foliage of I. paraguariensis contains methylxanthines (0.4-1.6 % caffeine, 0.3-0.45 % theobromine and traces of theophiline), vitamin C, an aromatic oil, an enzymatic compound, the caffeoylquinic acids 3,5-, 4,5- and 3,4-dicaffeoylquinic acid, neo-chlorogenic acid and kryptochlorogenic acid (the hydroxyl of quinic acid in position 3 is esterfied with caffeic acid). Saponines and the flanonoids isoquercetine, kampferolglycoside and rutoside have also been isolated from Yerba mate.
Tabel …: Methylxanthine derivatives
Trivial name Formal name
Caffeine 1,3,7-trimethylxanthine
Theophylline 1,3-dimethylxanthine
Theobromine 3,7-dimethylxanthine
Tabel..: Flavonoids
Trivial names Formal names
Kaempferol 3,5,7,4'-tetrahydroxy flavone
Isoquercetin (=quercetine-3-O-glucoside) 3-O-glucoside-5,7,4',5'-tetrahydroxyflavone
Pharmacology :
The pharmacological activity of Yerba mate is an simultaneous effect of the methylxanthines, the flavonoids and the chlorogenic acids; the psychostimulant effects are caused by caffeine and theobromine, the euphoric and anxiolytic aspects are caused by the flavonoids and the chlorogenic acids exhibit antimutagenic activity.
The methylxanthines alter the biochemistry of the body on tree different levels: (1) they inhibit phosphodiesterase, (2) they block (P-1) adenosine receptors (A1, A2A) and (3) they cause the release of Ca2+ from the storage vesicles into the cytoplasma. 1 The first alteration results in an increased cAMP 2nd messenger activity, the second causes physical stimulation and the third, contraction of the smooth- and skeleton muscles.
Approximately 95 % of the methylxantines are metabolised through hydroxylation at carbon 8 and demethylation by Cytochrome-P-450 (A1, A2), but oxidation by Xanthinoxidase is also a common inactivation pathway.
The flavonoids, kaempferol and quercetine, act (like apigenine, chrisine and flavon itself) as agonists on benzodiazepine receptors 6,9. The allosteric modulation of the GABA-receptor-proteins results in a more frequent activation of the Cl-ionchannels in the neuronal membrane, so that chloride ions are more easily transfered from the exterior of the nerve endings into the interior, which in turn leads to a decreased firing rate of the neurons.2,8
The flavonoids are metabolised in the gastrointestinal lumen and liver and are substrate for P-glycoproteins (MRP1 and MRP2), glucuronosyltransferases (UGT) and sulfotranferases (SULT)1.
The chlorogenic acids aren't psychoactive, but appear to inhibit the mutagenic activity of cigarette smoke condensate7. They are also responsible for the increased concentration of gastric juice and abdominal pains which can occur at higher doses6
Modifiers :
- Sympathomimetic amines (ephedrine, amphetamine) intensify the effects of the methylxanthines2,6.
- MAO-inhibitors in combination with caffeine can cause hyperreactivity and suspiciousness.
- A combination of alcohol and flavonoids (which are benzodiazepine agonists) may lead to dangerous synergic interactions.
References
1. [Erlund]
2. [Forth/ Henschler/ Rummel/ Fostermann/ Starke, 2001]
3. [Hoffmann/ Schultes, 1973]
4. [Mohring/ Morrill/ Neckers/ Hammond, 1999]
5. [Karrer, 1950]
6. [Ratsch, 1998]
7. [Romert/ Jansson/ Curvall/ Jenssen, 1994] [Snyder, 1996]
8. [Wolfman/ Paladini/ Medina/ Levi de stein/ Calvo/ Diaz, 1999]
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