Caffeine Case Study

1. Introduction

Caffeine (1, 3, 7-trimethylxantheine) is a xanthine derivative and member of a class of drugs known as methylxanthines (Sutor, 1958). Caffeine is a plant alkaloid and was isolated from plants as a white crystalline substance for the first time in 1820 by Ferdinand Runge. Simillar compound was isolated from tea (Camellia sinensis) in 1827 by Oudry. However, in 1832 Pfaff and Liebig identify caffeine as a purine compound, and IUPAC name 1,3,7-trimethylxanthine was denominated (Mazzafera, 2004). Caffeine is the most widely consumed psychoactive drug in the world (Dews, 1984). It is present in leaves, seeds, and fruits of many plant species of which coffee, tea, guarana, cocoa and yerba mate are the most well known (Ashihara et

In coffee plants, leaves which are not fully expanded have high capacity to biosynthesize caffeine (Fujimori and Ashihara, 1994). Caffeine presence in plants has two roles, chemical defence and allelopathic role. Caffeine in fruits, young leaves and flower buds acts to protect soft tissues from predators such as insect larvae and beetles and acts in chemical defence (Frischknecht et al., 1986). Caffeine act as allelopathic agent, when in seed coats it is released into the soil and inhibits the germination of other seeds (Silva et al., 2013; Suzuki and Waller, 1987). Allelopathic property of caffeine has been well utilized in horticulture. Transgenic crops containing caffeine has been produced, which may save labor and agricultural costs and also alleviate the environmental load of pesticides in future (Uefuji et al., 2005). Moreover, repellant effect of caffeine has been reported for snails and slugs (Hollingsworth et al., 2002). Caffeine presence is not only limited to coffee and tea plants, 0.9% of dry weight in citrus flower is of caffeine, which is broken down during production of honey (Kretschmar and Baumann, 1990). In plants, caffeine is synthesized from primary metabolites by de novo synthesis or

Degradation of caffeine occurs simultaneously in matured plant parts via N-demethylation to dimethylxanthine (theobromine and theophylline), followed by demethylation to monomethylxanthine and later demethylated to xanthine (Ahihara et al 2008). Methylxanthine derivatives like theophylline, theobromine, paraxanthine, 7 methyl xanthine and uric acid are metabolic products of caffeine (Fig. 1.1). Caffeine is used in many pharmaceutical preparations like apectol, anacin, dristan, vivarin, darvon, excedrin, percodan, soma, synalogos, butabital, norgesic and prolamine (Seegers et al., 1981; Thomas, 2004). Theobromine is used primarily as a diuretic, myocardial stimulant, or vasodilator (Stavric, 1988). 7-Methylxanthine has been shown to improve the quality of sclera collagen, and has been suggested for treatment and/or prevention of axial myopia, glaucoma, and macular degeneration (Trier et al., 1999). Uric acid and methyluric acids are used in obesity reducing pharmaceuticals, skin cosmetics, and anti-dandruff preparations (Madyastha and Sridhar, 1998). Theophylline is used in the treatment of airway diseases (Banner, 1995).

1.1. Advantages of caffeine. Caffeine is widely used for awakening and counteract fatigue induced by the restriction of sleep (Goldstein, 1964). Caffeine reduces risk