Cheersical Education

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DMS-Woah?!: From Oxidant to Analgesic?

with 8 comments

Edit: Props to Pat Knerr for forwarding along the SI article.

Every chemistry teacher has moments when students ask…odd questions. I had one such moment last week, when a student hung around after class to ask me what I knew about DMSO (yes organickers, that DMSO). A friend had advised the student to use DMSO on a running-related injury. Organic chemists know DMSO as the world’s most annoying NMR solvent and an oxidant…was there any truth to these claims of pain relief? After lowering the figurative raised eyebrow, I decided to investigate.

A Lewis structure of dimethyl sulfoxide

A Lewis structure of dimethyl sulfoxide.

DMSO is perhaps the world’s most famous sulfoxide, and it sits on the oxidation ladder between the abhorrent dimethyl sulfide (Me2S) and dimethyl sulfone (Me2SO2). The latter has an interesting medical history of its own, as we’ll see shortly. DMSO may be used as a polar solvent in organic reactions, but it also finds application in the Swern oxidation and other alkoxysulfonium-based oxidations—organickers, check out the Pfitzner-Moffatt oxidation too. All those applications, of course, have nothing to do with the medicinal effects of DMSO. Could a choice reagent for oxidations also have anti-inflammatory and analgesic effects?

Let’s start with Exhibit A, a 1981 report from Sports Illustrated describing the use of DMSO by athletes for pain relief. Here’s a quote from a winner of the New York Marathon:

“I used to go the usual route when I got a strain or a sprain,” he said, “ice, ultrasound, acupuncture, whirlpool, massage, heat. But I’ve been using DMSO for about three years now, and it’s the answer. A strain like this used to keep me from training for four or five days, but with DMSO I can run full strength again in 24 to 48 hours. That’s important when you’re peaking for a race.”

Tommy LaSorda used DMSO to relieve arthritis pain, but Lou Piniella (then still a player) called it “nothing special.” Midwesterners, are you listening yet?! The article goes on to list contradictory opinions of both players and physicians.

DMSO is quite the polar molecule, thanks to its S–O bond. It hardly has a “complex molecular structure,” despite SI’s description—replace the carbon in acetone with sulfur, and voilà! Because DMSO is so polar, it has the ability to dissolve water and all kinds of other polar molecules at sites of inflammation. DMSO rapidly penetrates the skin and may carry all kinds of polar compounds with it. As it zips through the skin and the bloodstream, DMSO whisks away water, making healing easier (or so the story goes). Users report the taste of oysters in their mouths mere seconds after topical application of DMSO, due to the production of foul-smelling dimethyl sulfide in the lungs.

Although this mechanism of action is purely physical (no chemical change to be found), DMSO may have some chemical benefits in humans as well. Since it can be oxidized, DMSO has the potential to scavenge for reactive oxygen species (ROS) and protect against “oxidative stress”—in other words, it may act as an antioxidant. The compound has also been shown to trap free radical species. DMSO’s great permeability is associated with some dangers, too, as it can easily carry highly toxic compounds into the bloodstream.

The Protein Data Bank includes a useful summary page on DMSO. The compound has been crystallized in the active site of (bacterial) DMSO reductase, a metal-dependent enzyme that converts DMSO to dimethyl sulfide. Similar studies of DMSO’s interactions with human enzymes are non-existent, however. The current body of work on DMSO makes it clear that its mechanism of action in the body is far from well understood!

A Lewis structure of dimethyl sulfone, DMSO2.

A Lewis structure of dimethyl sulfone, DMSO2.

One last word on dimethyl sulfone, (CH3)2SO2 (popularly known as methylsulfonylmethane, or “MSM”). Oxidation of DMSO in the body produces this metabolite. Interestingly, dimethyl sulfone readily crosses the blood-brain barrier. However, unlike everyone’s favorite barrier crosser ethanol, short exposure to dimethyl sulfone appears to have no negative physiological effects. MSM has been used in combination with drugs such as glucosamine that treat arthritis and joint pain. The compound can act as an analgesic and anti-inflammatory itself (probably by the exact same mechanism as DMSO).

In conclusion, I wouldn’t bathe in DMSO. However, this compound isn’t as toxic as its structure and name might lead the more chemophobic to believe. Its mechanism of action appears to involve a simple physical effect. That said, the verdict is still out on DMSO’s chemical effects, and its permeability and knack for carrying other molecules around with it imply that it should be used only on clean skin in moderate amounts. Finally, IANAD (I am not a doctor)!

References & Further Reading

A Miracle! Or Is It A Mirage? – Sports Illustrated, April 20, 1981

BMB Reports 2010, 43, 622. (doi: 10.5483/BMBRep.2010.43.9.622)

Histochem. Cell Biol. 2000113, 341. (doi: 10.1007/s004180000151)

NMR Biomed. 200518, 331. (doi: 10.1002/nbm.966)

Dimethyl sulfoxide on the Human Metabolome Database

Dimethyl sulfoxide on Wikipedia

Dimethyl sulfoxide on the Protein Data Bank

Dimethyl sulfone summary page

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Written by mevans

February 16, 2013 at 8:54 pm

8 Responses

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  1. I was just writing an abstract about DMSO. DMSO was first synthesized by Alexander Zaitsev by oxidation of dimethyl sulfide (DMS) with nitric acid (HNO3). By the second half of the 20th century it was discovered that DMSO was a biologically useful compound and can act as a ligand in metal complexes. There is also a website of Dr.Stanley Jacob’s and it is called dmso.org . http://www.dmso.org/

    pcelsus

    February 17, 2013 at 2:39 am

    • Very cool! Thanks for the resource. No idea DMSO had its own website!

      mevans

      February 17, 2013 at 2:40 am

      • You are welcome. When I first saw it, I was surprised too.

        pcelsus

        February 17, 2013 at 2:51 am

  2. I remember learning about DMSO’s home remedy uses via the strange case of Gloria Ramirez, the “Toxic Lady.” http://en.wikipedia.org/wiki/Gloria_Ramirez

    Nick

    February 17, 2013 at 3:36 am

  3. The main concern with topical application of DMSO is that it is such a good, almost universal solvent. That is, if you have anything on your skin where you apply the DMSO, as you say, it will be transported straight into your bloodstream. It is common for people to taste soap when they get DMSO on themselves, but imagine the myriad things you could have on your skin ready to be zipped through to your bloodstream…

    Renée Webster (@reneewebs)

    February 17, 2013 at 5:31 am

  4. I have not heard of this. Where would I purchase if I wanted to try it?

    Lori evans

    February 17, 2013 at 4:25 pm

    • It’s not terribly hard to find on the Web; if you search for it on Amazon you’ll find it. Also, it’s available at some farm supply stores as it’s used to treat animal injuries as well.

      mevans

      February 17, 2013 at 4:56 pm

  5. For the record, the student used DMSO and is now a believer in its anti-inflammatory properties. Anecdotally, it works!

    mevans

    February 18, 2013 at 4:10 am


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