Open AccessCorrelation of Phytochemical, Metal Contents and Antioxidant Activities of Black Glutinous Rice Bran and Potential Chemoprevention
Author(s) -
Paradorn Ngamdee,
Uthai Wichai,
Sudarat Jiamyangyuen
Publication year - 2016
Publication title -
food technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.744
H-Index - 67
eISSN - 1334-2606
pISSN - 1330-9862
DOI - 10.17113/ftb.54.03.16.4346
Subject(s) - chemistry , black rice , food science , bran , antioxidant , phytochemical , flavonoid , anthocyanin , cultivar , quercetin , biochemistry , botany , biology , raw material , organic chemistry
In this work total anthocyanin content (TAC), total flavonoid content (TFC), total phenolic content (TPC) and minerals found in five black glutinous rice cultivars (MS, SK, PY, PC and KK) from Thailand were analyzed. The antioxidant activity of anthocyanin-rich black glutinous rice bran extracts against nitric oxide radical (NO˙), superoxide radical (O 2 ˙Ż) and lipid peroxyl radical (LOO˙) was also determined. Potential chemopreventive property of rice bran extract was screened based on cellular bioassays for phase II detoxification enzyme induction. Quinone reductase (QR) induction in murine hepatoma cells was used as a marker for this effect. Rice bran extract of cultivar KK had the highest TAC, of SK the highest TFC and of PC the highest TPC. The best antioxidants against NO˙, O 2 ˙Ż and LOO˙ were cultivars KK, MS, and SK, respectively. Overall, TAC, TFC and TPC had a combinatorial effect on the antioxidant activities of all extracts; none of them dominated. Minerals may not play a role in the antioxidant activity of the extracts because most correlations between them and the antioxidant activity were unpredictable. However, rice bran contained high mass fractions of some essential minerals on dry mass basis, including Zn (103-133 µg/g), Se (11-18 µg/g) and Cu (3.8-7.1 µg/g). Chemopreventive study indicated that PC cultivar was the most potent chemopreventor with the lowest concentration of an inducer needed to double the QR activity (CD value) of 0.7 µg/mL. These findings showed that black glutinous rice bran is rich in phytochemicals and some essential minerals, and has a potential chemopreventive property.