Theanine and
caffeine, 2 naturally occurring components in
tea, have repeatedly been shown to deliver unique cognitive benefits when consumed in combination. In this study, we assessed the beneficial synergistic effects of concurrent treatment with
theanine and
caffeine against cerebral damage in rats.
Theanine and
caffeine had no effect on physiological variables, including pH, partial pressures of
oxygen (PaO2) and
carbon dioxide (PaCO2), mean arterial blood pressure, plasma
glucose, or regional cerebral blood flow. Treatment with
theanine (1 mg/kg body mass,
intraperitoneal injection) alone significantly reduced
cerebral infarction induced by
cerebral ischemia-reperfusion, but
caffeine (10 mg/kg,
intravenous administration) alone only had a marginal effect. However, the combination of
theanine plus
caffeine resulted in a significant reduction of
cerebral infarction and
brain edema compared with
theanine monotherapy. Meanwhile, increased
malondialdehyde levels as well as decreased
superoxide dismutase activity,
glutathione peroxidase activity, and
glutathione levels observed in the cerebral cortex after
cerebral ischemia-reperfusion were significantly ameliorated by the combination
therapy. Furthermore, the elevated inflammatory response levels observed in the cortex after
cerebral ischemia-reperfusion were markedly attenuated by the combined treatment. Thus, it is suggested that the neuroprotective potential of a combination
therapy with
theanine and
caffeine against
cerebral ischemia-reperfusion is partly ascribed to their
antioxidant and anti-inflammatory properties.