These studies are showing more and more that an increased intake of antioxidants (typically A, E, C- but includes others) may reduce post workout soreness, recovery time and boost your immune system.
here are some of the articles. (first one is a long read. second one is very short)
HYPERplasia The Magazine
Nutrition Strategies For Speeding Recovery Post-Workout - Triathlon Training Log
Also, here are some remedies for post workout soreness ( i thought the caffeine one was very interesting):
Don't Be Sore! - MSN Health & Fitness - Diet & Fitness
it has also been reported that many Brazilian fighters eat acai berries as an integral part of their diet to help minimize down time and speed recovery.
overall, i think it's a nice little tweak to the workout diet. my antioxidants come largely from fruits but many supplements are now including green tea complexes as a source of caffeine and antioxidants for just this purpose.