better living through chemistry

[rone]

From Bawls' page on guaraná:

The Guarana berry contains a naturally-occurring form of caffeine which is 2.5 times stronger than the caffeine found in coffee, tea, and soft drinks.

How is one form of caffeine 2.5 times stronger than another form of caffeine?

Comments

Re: These are not the stimulants you are seeking...

[eejitalmuppet.livejournal.com]

"Guarana contains a crystallizable principle called guaranine. It has the same chemical composition to caffeine, theine and cocaine, and the same physiological action, along with tannic acid, catechutannic acid starch, and a greenish fixed oil."

Oh boy, that's a doozy. Presumably they have the same chemical composition on the basis that each contains carbon, hydrogen, nitrogen and oxygen: on that basis, it's perfectly safe to drink methanol or ethylene glycol (good news for Russian vodka smugglers and Austian winemakers). As for physiological action, cocaine is a catecholamine uptake inhibitor, while xanthines are phosphodiesterase inhibitors (and adenosine antagonists). Perhaps the author of that page should be given caffeine as a local anaesthetic, in order to learn the difference...

As an aside, I found two structures for caffeine in my books. One, in "Heterocyclic Chemistry" by T L Gilchrist, matches the formula you gave. The other, in "Pharmacology" by H. P. Rang and M. M. Dale, shows a CH2 group instead of the carbonyl adjacent to the ring-fusing carbon (the "6" position for chemistry geeks). I'm inclined to trust the former, since I already know that Rang and Dale represent the wrong isomer for salbutamol (and there are two sources for the two-carbonyl formula).