Qualitative and quantitative analysis of anthocyanins and other phenolic
compounds from a purple corn extract was performed. The purple corn extract had
cyanidin-3-glucoside, pelargonidin-3-glucoside, peonidin-3-glucoside and its respective
acylated anthocyanin-glucosides. Cyadinin-3glucoside was the main constituent (44.4 ??
4.7%) followed by the acylated cyanidin-3-glucoside (26.9 ?? 8.0%). Other phenolic
compounds present in the purple corn corresponded to protocatechuic acid, vanillic acid,
and p-coumaric acid. In addition, quercetin derivatives, a hesperitin derivative and pcoumaric
and ferulic acid derivatives were found.
Fractionation of phenolic compounds yielded two main fractions, an
anthocyanin-rich water fraction (WF) and an ethyl acetate fraction (EAF). Evaluation of
antimutagenic activity in both fractions revealed higher antimutagenic activity in the
ethyl acetate fraction compared to the anthocyanin-rich fraction. On the other hand,
antioxidant activity of the anthocyanin-rich fraction was higher compared to the ethyl
acetate fraction.
Further fractionation of the anthocyanin-rich fraction in a Toyopearl HW40 gel
permeation column yielded five sub-fractions which showed no difference in
antimutagenic activity except for the water sub-fraction WF-V. All the sub-fractions
were active as antimutagens and antioxidants. Further fractionation of the ethyl acetate
fraction yielded four sub-fractions that showed to be active as antimutagens and
antioxidants. Ethyl acetate sub-fraction EAF-IV was the most active as an antimutagen.
HPLC-DAD characterization of that sub-fraction revealed mainly the presence of a
quercetin derivative with UV-visible spectral characteristics similar to rutin but with a
little longer retention time.
The mechanism of antimutagenic action by the phenolic compounds present
either in the anthocyanin-rich fraction or the ethyl acetate fraction and sub-fraction EAFIV
seems to be a contribution of a direct action on the enzymes involved in the
activation of the mutagen and to the scavenging activity of the mutagen nucleophiles, as
demonstrated by our assays.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/2343 |
| Date | 29 August 2005 |
| Creators | Pedreschi, Romina Paola |
| Contributors | Cisneros-Zevallos, Luis |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | 487058 bytes, electronic, application/pdf, born digital |
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