Sunday, January 31, 2010

Polyphenols: Cinnamic acid

Cinnamic acid is a precursor of a group of polyphenols called hydroxycinnamic acid derivatives, such as p-coumaric acid, caffeic acid, ferulic acid, and sinapic acid. It is a powerful anti-oxidant, and offers UV protection as well as a reduction in inflammation, redness, and water retention. It is found in great quantities in shea butter and cinnamon.

As an UV protector, you can find it as octylmethoxycinnamate or Tinosorb OMC used to up to 10%. It is an oil soluble sunscreen that works to protect skin from UVB rays. It's generally found in anhydrous products like lip sticks or sports sunscreens. The cinnamic acid we find in shea butter, for instance, can behave as a mild sunscreen, but I wouldn't trust it for that purpose without testing!

Cinnamic acid can behave like an AHA (alpha-hydroxy acid), which means it can penetrate the skin and help with cell regeneration under the skin (more on AHAs in the future). Some call it anti-aging as it can help to reduce the look of fine lines and wrinkles through this mechanism, but it can lead to slightly thinned skin and a slight increase in transepidermal water loss with use over time. But the wonderful and moisturizing fatty acids we find in something like shea butter are more than enough to compensate for these concerns!

Cinnamic acid and cinnamic aldehyde can cause contact urticaria, which is a skin irritation syndrome which results in an immediate type reaction of the skin or mucous membrane. It can be as subtle as itching and redness or as severe as weals or flares on the skin. As little as 0.01% cinnamic aldehyde can produce this result in sensitive people. (This may be one of the reasons someone is sensitive to shea butter.)


Hippy at Heart said...

Brilliant article. I find all your info riveting.

Why might somebody be sensitive to jojoba though? I know somebody who practically peels if this oil comes anywhere near her.

Susan Barclay-Nichols said...

Sorry, but I have no immediate ideas on the jojoba oil mystery. You can get some information about jojoba oil in this post. Perhaps her skin doesn't like the sinking in? Or perhaps she is sensitive to one of the fatty acids? Or maybe she is sensitive to the polyphenols like tannins? I really don't know, sorry!

Kim said...

In this post, you write "reduction in inflammation, redness, and water retention" So this polyphenol decreases water retention? Is this bad or good?

Susan Barclay-Nichols said...

Hi Kim. This is water rentention in the sense of bloating or feeling full of water, not in the sense of water in our skin. I would consider that something that appeals to me when I'm making products.