Talk:Theanine

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Is L-Theanine also known by another name? I having trouble finding it at GNC's or CVS pharmacies. --JoelM do a GOOGLE search and you will find it everywhere..

I think its a relatively new discovery, either that or the tea companies have just started to exploit it all of a sudden because I'm constantly hearing it on the radio over here at the moment. Like tea companies advertising it, telling you to drink their tea because of it. Which is ironic considering that it was always in the tea.. so in reality they're just aiming for a placebo effect? Because lets face it, everyone has had tea at least once in their life (well at least most people.) But now they think that if they tell us that tea contains this special ingredient, everyone will start buying it. Which is true, but a dodgy marketing scheme. Javsav 16:29, 28 August 2006 (UTC)

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[edit] Theanine research

Does anyone know any specifics about theanine's neuropharmacological properties? All I could find was one reference to "micromolar affinities" to several neurotransmitters. However, I'm sure there have been studies that give specific its particular neurochemical interactions. Jolb 20:06, 9 February 2007 (UTC)

[edit] Caffiene buzz

Someone put this in: It is theorized that the GABA-binding properties of theanine reduce the caffeine buzz delivered in black tea versus that of coffee. Of course, there was no citation, so I put a {{cn}} next to it. It was sitting there for a while, so I decided to do some research on this, and I found the following:

The objective of this study was to determine the effect of caffeine level in tea and coffee on acute physiological responses and mood. Randomised full crossover design in subjects after overnight caffeine abstention was studied. In study 1 (n = 17) the caffeine level was manipulated naturalistically by preparing tea and coffee at different strengths (1 or 2 cups equivalent). Caffeine levels were 37.5 and 75 mg in tea, 75 and 150 mg in coffee, with water and no-drink controls. In study 2 (n = 15) caffeine level alone was manipulated (water, decaffeinated tea, plus 0, 25, 50, 100, and 200 mg caffeine). Beverage volume and temperature (55 degrees C) were constant. SBP, DBP, heart rate, skin temperature, skin conductance, and mood were monitored over each 3-h study session. In study 1, tea and coffee produced mild autonomic stimulation and an elevation in mood. There were no effects of tea vs. coffee or caffeine dose, despite a fourfold variation in the latter.

(Quinlan P, Lane J, Moore K, Aspen J, Rycroft J, O'Brien D (2000). "The acute physiological and mood effects of tea and coffee: the role of caffeine level". [1])

Therefore, I'm going to remove sentence. Jolb 19:36, 14 February 2007 (UTC)

You should really look at what physiologic responses they measured. A lot of times studies like this are either done poorly, or they only look at a narrow spectrum of measurable variables. If compounds aside from caffeine are psychoactive in green tea, then some measurements will pick these up on the clinical level while others won't...--Xris0 04:29, 17 August 2007 (UTC)

[edit] Contradiction

I've added a contradiction template, because the article says that L-theanine increases serotonin levels (and cites a study), but then says it lowers serotonin levels (and cites a study). So which is it? or is something missing from the article such as spontaneous hypertension causing abnormally high levels of serotonin (in which case, the article should mention it). --Mark PEA 10:39, 9 March 2007 (UTC)

I noticed that before, but I thought it maybe had something to do with spontaneous hypertension? I decided to let it go and trust the person who added that. However, when you added the contradiction tag, I did some research.

Antioxidant activity of 5-hydroxytryptophan, 5-hydroxyindole, and DOPA against microsomal lipid peroxidation and its dependence on vitamin E.

* Cadenas E, Simic MG, Sies H.
Department of Pathology II, University of Linkoping, Sweden.
The antioxidant capacity of 5-hydroxy-tryptophan, 5-hydroxy-indole, and DOPA (3,4-dihydroxy-phenylalanine) was tested in the Fe-induced lipid peroxidation of liver microsomes of normal- and vitamin E-deficient rats, using ascorbate as a reductant. Lipid peroxidation was monitored as low-level chemiluminescence, indicative of generation of electronically-excited states arising from the recombination of secondary lipid peroxyl radicals. The lag phase (tau 0) preceding the rise in chemiluminescence intensity was used as indicator of antioxidant efficiency, in the absence (tau 0) and the presence (tau) of these polar compounds. The increase in duration of the lag phase exerted by these hydroxy compounds was expressed and quantified as the relationship: tau-tau 0. The tau-tau 0 values were considerably higher in the presence of vitamin E and almost negligible in the absence of tocopherol. It is postulated that the observed increased protection against lipid peroxidation by the above 5-hydroxy derivatives is displayed in a fashion dependent on the presence of vitamin E and probably involving recovery of the chromanoxyl radical by means of an electron-transfer process.
PMID: 2498167 [PubMed - indexed for MEDLINE]
The study really has no relevance here, but it clearly says that serotonin (5-hydroxy-tryptophan) is completely different from 5-hydroxy-indole. Jolb 13:40, 9 March 2007 (UTC)
Ah right, I understand now. Of course, serotonin is 5-hydroxy-indole-ethyl-amine, and I didn't have access to the full article, so assumed it meant biochemicals that were homologous 5-hydroxyindole, such as serotonin, that's why I was confused and added the contradict tag, but now that the serotonin statement has been removed it makes sense now. --Mark PEA 18:09, 9 March 2007 (UTC)

[edit] Occurrence

It would be nice to have a section which shows the theanine content ranges of tea and other beverages, for comparison. I've seen supplements and theanine-infused juice drinks already appearing in supermarkets.

--BadZen 15:09, 7 May 2008

[edit] Suntheanine

I've once again removed a reference to Suntheanine® as the supposed generic name of theanine. Suntheanine® is clearly not a generic name (hence the ® symbol) -- it's a brand name, which is pretty much the opposite of a generic name. "Theanine" is the generic name. Also, http://www.suntheanine.com/, which was given as a reference, is not a reliable source by wikipedia standards, and that web site also pretty clearly indicates that Suntheanine is a brand of L-theanine, hence not a generic name. Also, wikipedia does not, in general, list brand names under which chemicals may be available, unless such brand names are notable, and I see no evidence that this brand is notable. Finally, wikipedia generally does not include the ® symbol when mentioning brands. I suppose I could see adding a section about commercial preparations to the article, and such a section might mention this brand, but I see no reason to mention a brand in the overview of a naturally-occurring chemical. Klausness (talk) 21:16, 20 May 2008 (UTC)

Support for a little change. Thanks for correcting me, by the way. 98.227.189.232 (talk) 22:32, 1 June 2008 (UTC)