Kola is a common name for a genus of about 125 species of evergreen trees and their trees are best known for their seeds or nuts which are rich in caffeine and used in the manufacturing of carbonated soft drinks known as kola beverages. They can relieve migraine, and can be used in states of depression, or weakness and even in the treatment of malaria fever . They can also be used to prepare tonic, as a remedy for dysentery, coughs, diarrhoea, vomiting and chest complaints (Burkill, 1995). Kola is one of the major sources of caffeine and taking kola nut by the mouth, in large doses is likely unsafe, due to its caffeine content and frequent chewing can lead to stained teeth [2–3]. Adisa, et al, (2010) also carried out a significant research and reported on the effects of aqueous extract of kola nut on the reproductive hormones in rat . The result of this study shows that kolanut extract significantly reduced plasma level of luteinizing hormone but significantly increased plasma testosterone level. The reduced plasma luteinizing hormone level reported in this study is in agreement with findings of Benie and Thieulant , where it was reported that kolanut extract exerted an inhibitory effect on luteinizing hormone release of rat’s pituitary cells, however our findings on plasma level of testosterone was in agreement with Leehayward , that caffeine increases plasma level of testosterone. But contrary to the findings of Rebecca and Elizabeth , who reported that bioavailable testosterone was negatively and independently associated with caffeine intake, while estrone was positively associated with high levels of caffeine consumption in post-menopausal women. The active chemical constituents of all the species of kola nut include: caffeine, glucoside, theobromine and kolatin which are stimulants .
The symptoms of caffeine intoxication are not unlike overdoses of other stimulants. It may include restlessness, fidgetiness, nervousness, excitement, euphoria, insomnia, flushing of the face, increased urination, gastrointestinal disturbance, muscle twitching, a rambling flow of thought and speech, irritability, irregular or rapid heartbeat, and psychomotor agitation . In cases of much larger overdoses, mania, depression, lapses in judgment, disorientation, disinhibition, delusions, hallucinations, and psychosis may occur, and rhabdomyolysis (breakdown of skeletal muscle tissue) can be provoked [10–11]. In large amounts, and most especially, over an extended period of time, caffeine can lead to a condition known as caffeinism . Caffeinism usually combines caffeine dependency with a wide range of unpleasant physical and mental conditions including irritability, anxiety, tremulousness, muscle twitching (hyperreflexia), insomnia, headaches, respiratory alkalosis, and heart palpitations [13–14]. Parvathy, et al., (2014) reported the chemical analysis of caffeine content in tea and coffee samples . Okolie, (2010) reported the effect of heat on caffeine isolated from kolanut . Caffeine has even been suggested as possible cause of cancer, though no studies have confirmed yet . Caffeine relaxes the internal anal sphincter muscles and thus should be avoided by those with fecal in continence . Caffeine citrate may confer a modest protective effect against some diseases, including Parkinson’s disease .
Antioxidants are compounds that inhibit oxidation or substances that at low concentrations prevents the oxidation of a substrate. A chemical reaction that can produce free radicals and chain reactions that may damage the cells of organisms, have antioxidants such as thiols or ascorbic acid (vitamin C) that may act to inhibit these reactions. The antioxidant capacity is a measure of the amount of a certain free radical captured by an antioxidant sample . To balance oxidative stress, plants and animals maintain complex systems of overlapping antioxidants, such as glutathione. The only dietary antioxidants are vitamins A, C, and E.
The aim of this research is to investigate the antioxidant activity of caffeine isolated from kolanut grown in Nsukka, eastern part of Nigeria. The choice of this research arises from the fact that kola nut contains most essential phytochemicals which are suspected to have antioxidant behaviour and is believed to possess numerous biological properties. Also it has been found that most of the physiological actions of kola are due to caffeine  and caffeine content of kola nut varies with difference in climatic and adaphic factors .