Bioactives Derived from Ripe Corn Tassels: A Possible New Natural Skin Whitener, 4-Hydroxy-1-Oxindole-3-Acetic Acid

John      J. Wille; Mark      A. Berhow

Abstract

Previously, we showed that extracts of ripe seasonal sweet corn tassels possess anti-irritant and anti-oxidant activities. The chemical identification of corn tassel bioactives was investigated by HPLC analysis. The hydroalcoholic extracts are composed primarily ( > 85%) phenolic-type compounds. The predominant component from C18 columns were concentrated by reverse phase chromatography and purified to greater than 97-99% by preparative HPLC chromatography. The chemical was determined by mass and NMR spectrometry to be 4-hydroxy-1-oxindole-3-acetic acid (Tasselin A) with a M.W of 207 daltons. Purified Tasselin A inhibits melanin production in sporulating cultures of the common bread mold. An anti-tyrosinase enzyme assay showed that it inhibits mushroom tyrosinase enzyme (IC50 = 0.75mM), and has both antioxidant, and skin anti-irritant activities. There are no prior reports of bioactives derived from corn tassels with potential skin whitening activity, nor are any corn tassel bioactivities currently employed as ingredients in personal care or skin care products.

Keywords: Anti-tyrosinase, bioactives, corn tassels, 4-hydroxy-2-oxindole-3-acetic acid, melanin inhibitor, skin whitener, HPLC, kojic acid, tasselin A, anti-irritant