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Methylxanthines are chemical compounds which are derivatives of xanthine with one or more methyl groups, including: One methyl group: 1-Methylxanthine;
Xanthine (/ ˈ z æ n θ iː n / or / ˈ z æ n θ aɪ n /, from Ancient Greek ξανθός xanthós ' yellow ' for its yellowish-white appearance; archaically xanthic acid; systematic name 3,7-dihydropurine-2,6-dione) is a purine base found in most human body tissues and fluids, as well as in other organisms. [2]
Around thirty plant species are known to contain caffeine. [220] Common sources are the "beans" (seeds) of the two cultivated coffee plants, Coffea arabica and Coffea canephora (the quantity varies, but 1.3% is a typical value); and of the cocoa plant, Theobroma cacao; the leaves of the tea plant; and kola nuts.
7-Methylxanthine (7-MX), also known as heteroxanthine, is an active metabolite of caffeine (1,3,7-trimethylxanthine) and theobromine (3,7-dimethylxanthine). [ 1 ] [ 2 ] It is a non-selective antagonist of the adenosine receptors .
Paraxanthine is the primary metabolite of caffeine in humans and other animals, such as mice. [3] Shortly after ingestion, roughly 84% of caffeine is metabolized into paraxanthine by hepatic cytochrome P450 , which removes a methyl group from the N3 position of caffeine.
The characteristic signals, distinguishing theophylline from related methylxanthines, are approximately 3.23δ and 3.41δ, corresponding to the unique methylation possessed by theophylline. The remaining proton signal, at 8.01δ, corresponds to the proton on the imidazole ring, not transferred between the nitrogen.
Theobromine has no significant stimulant effect on the human central nervous system. [4] It is a bronchodilator and causes relaxation of vascular smooth muscle. [4] It is not currently used as a prescription drug. [5] The amount of theobromine found in chocolate is small enough that chocolate can, in general, be safely consumed by humans.
Natural phenols are a class of molecules found in abundance in plants. Many common foods contain rich sources of polyphenols which have antioxidant properties only in test tube studies. As interpreted by the Linus Pauling Institute, dietary polyphenols have little or no direct antioxidant food value following digestion. [7]