TITLE:
Influence of Polyphenolic Contents on the Antioxidant Properties of Hibiscus sabdariffa Extract (HSE), Aged Garlic Extract (AGE) and Garlic Tablet (GT) in Vitro
AUTHORS:
Abiodun Olusoji Owoade, Adewale Adetutu, Olubukola Sinbad Olorunnisola
KEYWORDS:
Hibiscus sabdariffa, Aged Garlic Extract, Antioxidants, Phenolic Compounds
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.7 No.6,
May
24,
2016
ABSTRACT: This study compared the antioxidant properties of Hibiscus sabdariffa extract (HSE),
commercial aged garlic extract (AGE,
Kyolic) and garlic tablet (GT). The
results indicate that HSE, AGE and GT are effective antioxidant as xanthine/xanthine
oxidase generated superoxide ions are significantly inhibited in the presence
of 20% (v/v) diethyl ether extract of HSE, AGE and GT by 100%, 66.39% and
18.61% respectively, while
uric acid production is not affected byAGEand GT. However, at 2.5% and 5.0% (v/v) reaction volumes,HSEsignificantly inhibits uric acid production by
9.5% and 33.0% respectively, and this suggests that components ofHSEinhibit xanthine oxidase activity while AGE and
GT scavenge superoxide. In addition, it is
also found that the three extracts scavenge ABTS radical cations in
dose-dependent manner. In all cell free assays, HSE is found to be more
effective as an antioxidant when compared with AGE and GT under the same experimental
conditions. Chromatographic and colorimetric analyses suggest thatHSEhas numerous different types of phenolic
compounds with higher amount of phenolic compounds (14.9 mg/g) when compared
withAGE(2.8 mg/g) and GT (3.6
mg/g) catechin equivalent respectively. Therefore, the effectiveness of antioxidant
activities of these three extracts may be related to their phenolic content.