Assessing the activity of natural food antioxidants - Oxidation in Foods and Beverages and Antioxidant Applications - page 334

Table 14.1 Descriptors for the prioritization of antioxidants with regard to hydro/lipophilicity

Descriptor Method/Tool Antioxidant compounds Reference

Theoretical approach
log P a

COSMO model Eugenol related compounds 1

Hydroxycinnamic acids and halogenated derivatives 2±7

Phenolic, ascorbic, uric acids

Chem Draw program Oleuropein and related compounds

log P simulation of partition in water/n-octanol Simple phenols and phenolic acids

(1:1, v/v mixture) Ferulic acid and related compounds

Caffeic acid amide and ester analogues

Dipole moment Gaussian Inc program Caffeic acid and related monopherols 8

Experimental approach
log P

Mixtures of water or buffer/n-octanol (1:1, v/v), Gallic acid derivatives 9±13

UV-Vis, room temperature or incubation Echinochrome

Caffeic acid and related monophenols
Natural and synthetic phenolic antioxidants
Hydroxytyrosol acetate and olive phenols

K p b

Phospholipid/water (varying liposome quantity), 7-Hydroxyflavone 14±16

incubation 30 ëC, fluorescence Catechin and derivatives, norlignans, hydroxytyrosol, oleuropein

Galloylated catechins

log P Liposome/buffer, Hydroxycinnamic acid derivatives 17, 18

derivative spectroscopy (2 d derivative) Dietary flavonoids

log P HPLC, retention times (calibration with

compounds of known log P values)

Caffeic acid, ferulic acid, Trolox, myricetin 19

% distribution Water/methyl linoleate (9:1 w/w, 1% Tween 20),

HPLC, ultrafiltration Hydroxybenzoic and hydroxycinnamic acids 20

R f c TLC Phenolic acids and flavonoids 21

% in the aqueous 20% w/w olive oil in water emulsion Gallic acid, quercetin, catechin 22

phase (thawing, Folin-Ciocalteu in the aqueous phase)

Tributyrin/Brij 30/water emulsions

P W and P O d (derivatization method with arenediazonium ion, -Tocopherol 23

without physical isolation of phases)

a Logarithm of partition coefficient in water/n-octanol (1:1, v/v) mixture, b phospholipid/water partition coefficient; c retention factor, d partition constants in water (w) and
oil (o) phase.