Effects of the Controlled Differential Sieving process (CDSp) on the antioxidant properties of Syzygium aromaticum

Abstract: The effect of particle size on the antioxidant properties of Syzigium aromaticum flower buds was evaluated. The powder from the flower buds of Syzigium aromaticum was fractionated by Controlled Differential Sieving process (CDSp), obtaining five fractions. An in vitro study permited to determine the content of bioactive phytochemical
compounds and to evaluate the antioxidant properties of each fraction through the evaluation of the anti-radical power DPPH, the ferric reducing antioxidant power and the reducing power of the ABTS radical. Furthermore, the evaluation of antioxidant properties in vivo was focused on the evaluation of biomarkers of oxidative stress in particular superoxide dismutase, catalase and malondialdehyde after induction of oxidative stress by a High-Fat Diet. The results from this study showed that the contents of phenolic compounds, notably polyphenols, flavonoids and anthocyanidins, decrease with the particle size of the fractions. To this end, the fraction <100μm presents the highest contents of polyphenols (251.85 ± 2.80), flavonoids (51.70 ± 0.81) and proanthocyanidins (2.46 ± 0.025). Furthermore, this fraction offers the best anti-radical powers with inhibition percentages of (96.79±2.22 mg/mL) and (97.72±0.78) respectively for the DPPH
and ABTS test. It also revealed a much higher ferric reducing antioxidant power (21.39±0.06 mg EAA/gMS). Concerning the antioxidant activities in vivo, the fraction <100μm best improved the antioxidant status in the blood with values of 0.97 ± 0.35mEQ/ gMS for SOD, 6.14± 0.25 mgEAG/ gMS for catalase and 0.91 ± 0.01 mg/100g for MDA. The lowest in vivo antioxidant activity was reported by the unsieved powder but still remained significantly close to the results of the normal control. Thus, PTC fractionation influences the distribution of bioactive molecules and consequently on biological activity.

Keywords: Controlled Differential, Sieving, antioxidant properties Syzygium aromaticum