Compositions for enhancing brain activity

A method for maintaining the attention, alertness, concentration, and memory-enhancing effect of a product comprising caffeine or theobromine, while reducing side effects of said caffeine or theobromine, said method comprising replacing all or part of the caffeine or theobromine in said product with a composition comprising:

• a) an effective amount of an extract of Cyperus esculentus peel, Cyperus esculentus rhizomes, or a combination thereof;
• b) an effective amount of mangiferin, norathyriol, or an extract comprising mangiferin or norathyriol;
• or
• c) a synergistic mixture of (a) and (b).