Effects of Anthocyanins and Melatonin From Purple Waxy Corn By-Products on Collagen Production by Cultured Human Fibroblasts

Cob and silk of purple waxy corn ( Zea mays L. Ceratina Kulesh) are underutilized sources of anthocyanins, which could be extracted by various solvents: water, ethanol, methanol, 50% ethanol, and 50% methanol. Anthocyanin and melatonin levels were investigated. The quantifications of anthocyanins as cyanidin-3-glucoside, pelargonidin-3-glucoside, and peonidin-3-glucoside were determined by high-performance liquid chromatography combined with mass spectrometry (HPLC-MS/MS), and melatonin by HPLC-fluorescence. The ability of collagen production upon exposure to human skin fibroblasts from the different macerates of the cob and silk was also studied. All cob extracts showed higher level of anthocyanins than silk extracts. The 50% ethanol extract of cob showed the highest cyanidin-3-glucoside level at 2.42 ± 0.03 mg/g dried weight, whereas that of silk showed the highest content of cyanidin-3-glucoside at 1.95 ± 0.04 mg/g dried weight. Although cob extracts contained more anthocyanins than silk extracts, silk extracts could stimulate collagen production more than cob extracts. Therefore, the collagen production was likely due to the amount of melatonin in the silk extracts, which contained greater quantities than those of the cob, and the lipophilicity of melatonin or the hydrophilicity of anthocyanins also affected the ability of cell permeation. Thus, anthocyanins and melatonin levels should be considered for the biological activity study.