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In vitro antioxidant capacity of commercial dietary supplements.

Publication . Almeida, Ivone M.C.; Barreira, João C.M.; Oliveira, Beatriz; Ferreira, Isabel C.F.R.

Consumption of food rich in natural antioxidant compounds has been linked to a reduced risk of developing chronic oxidative stress-related diseases, including cancer and cardiovascular and neurodegenerative diseases. This therapeutic potential of antioxidants has lead, in recent years, to a dramatic growth of the market of functional foods and dietary supplements (DS) claiming “antioxidant power”, and to the widespread consumption of these products. In this work, the in vitro antioxidant activity (AA) of 6 DS (capsules/tablets), obtained from local markets, was determined by four different assays: scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, reducing power (RP), inhibition of lipid peroxidation using thiobarbituric acid reactive substances (TBARS) and β-carotene-linoleate model systems.

2011Conference object

Open access

Antioxidant potential of individual or combined dietary supplements

Publication . Almeida, Ivone M.C.; Barreira, João C.M.; Oliveira, Beatriz; Ferreira, Isabel C.F.R.

An antioxidant may be defined as a substance that when present at low concentrations, compared with those of the oxidizable substrate, significantly delays or inhibits its oxidation [1]. Nowadays there are several commercial dietary supplements which claim for antioxidant activity. In this work, the antioxidant activity (AA) of 17 dietary supplements (Table 1) available in different formulations (pills, capsules or bags), was evaluated by in vitro assays: scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, reducing power (RP) and inhibition of lipid peroxidation by preventing the formation of thiobarbituric acid reactive substances (TBARS). Furthermore, different combinations (8+10+17, 8+10, 8+17 and 10+17) of some samples were also tested in order to obtain potential synergistic effects. Linear discriminant analysis (LDA) was used to categorize the condensed formulations (pills and capsules), the infusion bags and the combined samples, according with their antioxidant activity. The Advanced Antioxidant Formula (AAF; sample 8) proved to have the highest antioxidant activity in all the assayed methods, either singly taken or included in mixtures. Furthermore, the mixtures containing this supplement revealed synergistic effects in 92% of the cases. The intake of antioxidant mixtures might provide some additional benefits.

2011Conference object

Open access

Dietary antioxidant supplements: benefits of their combined use

Publication . Almeida, Ivone M.C.; Barreira, João C.M.; Oliveira, Beatriz; Ferreira, Isabel C.F.R.

Several dietary supplements claim medicinal benefits due to their composition in hydrophilic and lipophilic molecules, natural extracts or synthetic compounds with antioxidant properties. In the present work, the antioxidant activity of selected supplements taken in pills, capsules or infusions were studied either individually or combined. Linear discriminant analysis (LDA) was used to categorize the condensed formulations (pills and capsules), infusion bags and combined samples according with their antioxidant activity measured by radical scavenging activity, reducing power and lipid peroxidation inhibition using brain homogenates as models. AAF proved to have the highest antioxidant activity in all the assayed methods, either singly taken or included in mixtures. Furthermore, the mixtures containing this supplement revealed synergistic effects in 92% of the cases. The intake of antioxidant mixtures might provide some additional benefits.

2011Journal article

Open access