99 years ago, a Japanese researcher was looking into some puzzling stuff. A broth of kelp, when boiled down, yielded some brown crystals that tasted like, well, essence of savoriness. “Savory” is one of those flavors that is hard to pinpoint - for salty, sweet, sour, bitter, we have archetypes - sugar, sodium chloride, lemon juice, and alkaloids, which you don’t taste on their own very often. As Barry Sharpless noted, he won’t taste a compound with a nitrogen atom in it - these are the bulk of our alkaloids, many of which are psychotropic (not nearly all, though). The best everyday example of a bitter compound I can think of is tonic water, which is bitter due to the alkaloid quinine.

Anyway, savoriness, or “umami,” as he put it, is hard to pinpoint. Those crystals he found came close, which were those of the much-maligned monosodium glutamate, or MSG:

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Here’s a quacky one for you. If you lived through the 70’s, you remember this as Laetrile. Amygdalin is a cyanide compound found in almond, peach pits, and some other stone fruits. Fun fact: “amygdala,” like in your brain, comes from the same Greek root as amygdalin. Here, it describes the source of the compound, in “amygdala,” it describes the shape of the structure. Sort of like naming the pituitary “Mr. Peanut,” then translating it into a dead tongue for some added class.

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This is the yellow pigment in turmeric, the spice responsible for curries being nuclear holocaust yellow.

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Here’s a neat and weekend-appropriate one. I’ve alluded to the fact that your body processes small amounts of endogenous alcohol in the course of metabolism. As such, you have evolved some enzymes to process ethanol. The enzymes are meant for ethanol, since that’s what organisms saw for the most part in the course of evolution. As we’ve seen with drugs and poisons, though, other molecules can fit just fine into the active pocket of an enzyme and it can do its business on them, too. Sometimes this works in your favor, sometimes not. In the case of alcohol, it’s great. If you didn’t have a processing enzyme, it would be much more harmful than it is; it would have to wait around to pass through your urine (it could fit into a few other enzymes, but not very well; I believe this is the major alternative pathway).

What happens is your body takes alcohol and begins to oxidize it. Ethanol turns into acetaldehyde, which turns into acetic acid, which your body knows how to handle fine. The ethanol to acetaldehyde step is catalyzed by the enzyme alcohol dehydrogenase and requires one NAD+ (nicotinamide adenine dinucleotide, an endogenous oxidizing agent involved in glycolysis. The acetaldehyde to acetate step also requires NAD+ and is catalyzed by aldehyde dehydrogenase.
Relative to Anglos, many Asians have a paucity of aldehyde dehydrogenase, causing acetaldehyde to build up when ethanol is consumed. This causes the flushed face seen in many Asians after even moderate alcohol consumption. In all populations, NAD+ is limiting; your body simply does not have that much. It is regenerated, but slowly, so even after moderate alcohol consumption, NADH (the metabolite of NAD+) to NAD+ regeneration is the limiting step in the alcohol to acetate cycle. This is poorly understood — understandably. Not many research dollars get routed to hangover prevention, since it’s essentially a nuisance and considered a “disease of excess.”
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GHB stands for gamma-hydroxybutyrate. It has received buckets of terrible press in recent years that would certainly have resulted in lawsuits in both directions if it was a patented pharmaceutical. Let’s take a look at the structure, then we will take a look at the days of yore when GHB was a blameless little molecule you bought at GNC (or you could get from Aldrich for organic synthesis). Then, we’ll take a look at the subsequent demonization and where we stand today.

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Have you ever wondered whether you would swim faster in syrup or water? I hadn’t, either, until I found out someone had actually brought a swimming pool up to to Mrs. Butterworth’s-level viscosity and had people swim in it. Then I became intensely curious.

Proell admits he was slightly taken aback when he first heard Cussler’s proposal to dump 700 pounds of guar gum, a thickening agent, into one of the University’s pools. Fortunately, though, he recognized the proposal’s educational merits.

“Cussler is persuasive, but we didn’t need much persuading. We all agreed that we had an opportunity here to be part of the University’s educational mission. [The experiment] involved movement through water. [I]n aquatics, that’s our business. It intrigued us.”

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A lot of people have heard of “noble gases” - this is that rightmost column of the periodic table: Helium, Neon, Argon, Krypton, and Xenon. They exist pretty much on their own; it is very hard to make a compound out of them, and when you manage to, they’re fleeting sorts of things, waiting to react with whatever’s around.

Another series of noble compounds exists; the noble metals. These are named “noble” for the same reason - their relative lack of reactivity (the idea being that there are “noble” metals that hold onto their electrons in a dignified fashion, and “base” metals that deign to react with the other peasant molecules). Because of their lack of reactivity, they occur as the “native” metal much more often than the base metals (which occur as ores).

All that aside, when you want a metal that won’t react, you’re pretty good with platinum. Platinum is also very high-melting, so the development of a crucible made of platinum was a help, since various things could be heated in it without reacting with their vessel. These are curious objects. If you have any platinum jewelry, you know it really doesn’t wear. Unless it’s polished, though (and Pt crucibles usually are just brushed), it just looks like stainless steel. It doesn’t look like as expensive or special as it is until you pick it up - then you realize it’s denser than gold, and nearly twice as dense as lead - and maybe you are holding something a little bizzare.

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Here is another distinctly unfriendly-looking molecule, arsphenamine. For 30-40 brutish years, this was our single best treatment for syphilis. We owe this distinct pleasure to Paul Ehrlich, father of chemotherapy (coined the term, along with “Magic Bullet.”) In the early 20th century, he was working on histology, or staining cells. He reasoned that if we had compounds that stained only certain types of cells, maybe we could find one that would kill certain cells. Like syphilis spirochetes.

While this was a primitive theory of selectivity, Elrich used it to good effect, and six hundred five dead ends later, he released arsphenamine upon the world:

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Mercury is a weird one. It’s quite toxic, and you’ll do well not to handle it casually, but as the metal it’s actually not that bad. If a thermometer breaks, you can probably clean up the area as best you can, then sprinkle zinc dust or sulfur (disputed, see here) on it to keep it from evaporating. If you spill it in, say, an oven, like in the lab, or spill a great deal, it can be a bigger problem - some labs have mercury bubblers with literally pounds of the stuff in them - for most applications, you can use mineral oil, but especially in academic labs, you see a lot of mercury still floating around.

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Capsaicin is a molecule expressed by chiles (genus capsicum - this includes all pepper fruits, from jalapeno to habanero). It induces the familiar burning sensation. It, or its cousin, dihydrocapsaicin, is responsible for the hotness in essentially all hot sauces. Here is its structure:

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