Molecule of the week (I)

Most people like chili peppers, they're hot and spicy, but just what makes them so hot. The answer is Capsaicin (see above) and related molecules that are mostly found in the pithy material surrounding the seeds inside.

Some chilis are clearly hotter than other and there is actually a scale, called the Scoville scale that can be used to benchmark the "hotness" of chilis. A Poblano pepper comes in at around 1,000 to 1,500, the famous Jalapeno (the ones you put on nachos) come in at around 2,500 to 8,000. Pretty hot you think, oh no, there's hotter! Try the Serrano pepper at 10,000 to 23,000 or better still the habanero at a skyrocketing 100,000 to 350,000, just try eating a fistful of these, go on i dare ya!

Just why are chilis hot anyway you might ask? The answer lies in that the spiciness aids in seed dispersal. How so? What creature (besides humans of course) would bite into a jalapeno and say to itself: hmmm... food! Well, the answer is birds, yes birds. The thing about birds is that their physiology is different. Instead of getting that burning, irritating sensation that humans alone among mammals seem to like, they experience an analgesic effect, probably something like taking codeine, cocaine or maybe even heroin. Anyway, the like it, scoff down the chilis and thus disperse the seeds.

To mammals, the above mentioned capsaicin molecule is actually toxic, it can kill, far more toxic than cocaine but perfectly legal (just let's seem them try to ban chili peppers!) It registers at about 15,000,000 on the Scoville scale. Fortunately enough though, there isn't enough in any amount of chilis that you could possibly eat to actually kill you, and it's not addictive either (or maybe it is?) But what about the pure molecule itself, that could do it! Easily! Sells for about €100 a gram from Aldrich. Try snorting a line of this stuff and you're dead baby!