Avenanthramides, polyphenols from oats, exhibit anti-inflammatory and anti-itch activity

Arch Dermatol Res. 2008 Nov;300(10):569-74. doi: 10.1007/s00403-008-0858-x. Epub 2008 May 7.

Abstract

Oatmeal has been used for centuries as a soothing agent to relieve itch and irritation associated with various xerotic dermatoses; however few studies have sought to identify the active phytochemical(s) in oat that mediate this anti-inflammatory activity. Avenanthramides are phenolic compounds present in oats at approximately 300 parts per million (ppm) and have been reported to exhibit anti-oxidant activity in various cell-types. In the current study we investigated whether these compounds exert anti-inflammatory activity in the skin. We found that avenanthramides at concentrations as low as 1 parts per billion inhibited the degradation of inhibitor of nuclear factor kappa B-alpha (IkappaB-alpha) in keratinocytes which correlated with decreased phosphorylation of p65 subunit of nuclear factor kappa B (NF-kappaB). Furthermore, cells treated with avenanthramides showed a significant inhibition of tumor necrosis factor-alpha (TNF-alpha) induced NF-kappaB luciferase activity and subsequent reduction of interleukin-8 (IL-8) release. Additionally, topical application of 1-3 ppm avenanthramides mitigated inflammation in murine models of contact hypersensitivity and neurogenic inflammation and reduced pruritogen-induced scratching in a murine itch model. Taken together these results demonstrate that avenanthramides are potent anti-inflammatory agents that appear to mediate the anti-irritant effects of oats.

MeSH terms

  • Animals
  • Avena*
  • Cells, Cultured
  • Dermatitis, Contact / drug therapy
  • Dermatitis, Contact / etiology
  • Dermatitis, Contact / metabolism
  • Disease Models, Animal
  • Diterpenes / adverse effects
  • Flavonoids / pharmacology
  • Flavonoids / therapeutic use*
  • Humans
  • Inflammation / drug therapy*
  • Inflammation / etiology
  • Inflammation / metabolism
  • Interleukin-8 / metabolism
  • Keratinocytes / drug effects
  • Keratinocytes / metabolism
  • Mice
  • Mice, Inbred ICR
  • NF-kappa B / metabolism
  • Oxazolone / adverse effects
  • Phenols / pharmacology
  • Phenols / therapeutic use*
  • Phytotherapy*
  • Polyphenols
  • Pruritus / drug therapy*
  • Pruritus / etiology
  • Pruritus / metabolism
  • Signal Transduction / physiology
  • ortho-Aminobenzoates / pharmacology
  • ortho-Aminobenzoates / therapeutic use*

Substances

  • Diterpenes
  • Flavonoids
  • Interleukin-8
  • NF-kappa B
  • Phenols
  • Polyphenols
  • ortho-Aminobenzoates
  • Oxazolone
  • avenanthramide-2C
  • resiniferatoxin