Talanta 78 (2009) 1219–1226
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Talanta
journal homepage: www.elsevier.com/locate/talanta
Review
Automatic flow injection based methodologies for determination of scavenging
capacity against biologically relevant reactive species of oxygen and nitrogen
Luís M. Magalhães, Marlene Lúcio, Marcela A. Segundo
∗
, Salette Reis, José L.F.C. Lima
REQUIMTE, Servic ¸o de Química-Física, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha 164, 4099-030 Porto, Portugal
article info
Article history:
Received 31 July 2008
Received in revised form 31 January 2009
Accepted 3 February 2009
Available online 13 February 2009
Keywords:
Antioxidants
Reactive oxygen species
Reactive nitrogen species
Flow injection analysis
abstract
Redox reactions are the heart of numerous biochemical pathways found in cellular chemistry, generating
reactive oxygen species (ROS) and reactive nitrogen species (RNS), that includes superoxide anion radical
(O
2
•-
), hydrogen peroxide (H
2
O
2
), hydroxyl radical (HO
•
), singlet oxygen (
1
O
2
), hypochlorite anion (OCl
-
),
peroxynitrite anion (ONOO
-
) and nitric oxide radical (NO
•
). The measurement of scavenging capacity
against these reactive species presents new challenges, which can be met by flow injection analysis (FIA).
In the present review several methods based on FIA and also on its predecessors computer-controlled
techniques (sequential injection analysis, multisyringe flow injection analysis, multicommutated and
multipumping flow systems) are critically discussed. The selectivity and applicability of the methodology,
the generation and detection of the target reactive species, the benefits and limitations of automation
when compared to batch methods are some of the issues addressed.
© 2009 Elsevier B.V. All rights reserved.
Contents
1. Introduction ........................................................................................................................................ 1219
2. Flow-based methods for determination of scavenging capacity against specific ROS ............................................................ 1220
2.1. Superoxide anion radical (O
2
•-
) ............................................................................................................ 1220
2.2. Hydrogen peroxide (H
2
O
2
) ................................................................................................................. 1223
2.3. Hydroxyl radical (HO
•
) ..................................................................................................................... 1223
2.4. Singlet oxygen (
1
O
2
) ........................................................................................................................ 1224
2.5. Hypochlorite anion (OCl
-
) ................................................................................................................. 1224
3. Flow-based methods for determination of scavenging capacity against specific RNS ............................................................ 1224
3.1. Peroxynitrite anion (ONOO
-
) ............................................................................................................... 1224
3.2. Nitric oxide radical (NO
•
) ................................................................................................................... 1225
4. Several species simultaneously .................................................................................................................... 1225
5. Conclusions ........................................................................................................................................ 1226
Acknowledgements ................................................................................................................................ 1226
References ......................................................................................................................................... 1226
1. Introduction
Redox reactions are the heart of numerous biochemical path-
ways found in cellular chemistry, including biosynthesis and
regulation [1]. They are also important for understanding the
oxidative stress phenomena and radical/antioxidant effects. In a
biological context, the chemical terms “oxidant” and “reductant”
∗
Corresponding author. Tel.: +351 222078994; fax: +351 222078961.
E-mail address: msegundo@mail.ff.up.pt (M.A. Segundo).
are usually replaced by pro-oxidant and antioxidant, respectively
[2]. Therefore, pro-oxidant is a substance that can induce oxidative
damage to various biological targets (oxidizable substrates) such
as nucleic acids (e.g. base modification, single and double-strand
breaks), lipids (e.g. peroxidation, fatty acid loss), and proteins (e.g.
oxidation of specific amino acid residues, formation of carbonyls).
On the other hand, an antioxidant is a substance that, when present
at low concentrations compared with those of an oxidizable sub-
strate, significantly delays or prevents oxidation of that substrate
[3].
In general these pro-oxidants are referred to as reactive oxy-
gen species (ROS) and reactive nitrogen species (RNS) that can have
0039-9140/$ – see front matter © 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.talanta.2009.02.006