A quote from Ed Rosenthal out of a cannabis culture issue says:
"Eating a slightly overripe mango about 30 minutes before smoking marijuana increases the intensity of the high. The reason is that Myrcene, one of the odor moleculesin mangos, easily crosses the blood-brain barrier and transports THC across the barrier too. Myrcene is one of the most prevalent odor compounds in marijuana. It has traces of clove, earthy and fruity odors. It is found in mangos and in other fruits as well. I think that one of the differences in perceived potency of different marijuana varieties is the amount of myrcene they contain. Increasing the amount of myrcene in the blood system results in more THC getting to the brain. Anecdotally, people who have tested this theorem report that they agree with it".
Now I don't agree with a lot of what Ed says, but the man does know his marijuana.