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Antioxidant and free
radical scavenging activities of plant extracts used in
traditional medicine in Mexico
F.
Ruiz-Terán, A. Medrano-Martínez and A. Navarro-Ocaña*
Departamento de Alimentos y Biotecnología, Facultad de
Química, Universidad Nacional Autónoma de México, Circuito
Exterior, Ciudad Universitaria, México, D.F., 04510, México.
*Corresponding author. E-mail:
arturono@servidor.unam.mx. Tel: 52-55-56225346. Fax:
52-55-56220609.
Abbreviations:
DPPH, 1,1-Diphenyl-2-picrylhydrazyl-hydrate; TPME, total
amount of phenol in the methanol extract; BHA, butylated
hydroxyanisole; TBHQ, tert-butyl hydroquinone; TPC,
total phenolic content introduction.
Accepted
25 April, 2008 |
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Twenty-two species of medicinal plants collected in the
Mexican state of Morelos were selected to evaluate their
free radical scavenging and antioxidant activities. The
extracts from the aerial parts of the plants were obtained
using hexane, acetone and methanol (66 extracts). The
initial qualitative screening of antioxidants was made using
two TLC methods against the stable DPPH
(1,1-diphenyl-2-picrylhydrazyl-hydrate) and β-carotene-linoleic
acid bleaching assay. All the extracts displayed antioxidant
activity. However, the methanol extracts appeared to have
the highest antioxidant activity, so they were examined
further. The quantitative assays against DPPH radical,
β-carotene-linoleic acid bleaching and total amount of
phenols in the methanol extracts (TPME) showed nine plants
as having the highest scavenging and antioxidant activities.
For the nine methanolic extracts analysed, a clear relation
between the total phenolic content of the extracts and their
antioxidant activity was found. Plants such as Annona
squamosa and Sapium macrocarpum showed two times
more antioxidant activity than the commercial BHA (butylated
hydroxyanisole) antioxidant. Moreover,
some methanolic extracts of the plants showed
activities comparable to commercial antioxidants BHA and
TBHQ (tert-butylhydroquinone), thus making it
possible to consider some of the studied plants as a
potential source of antioxidants of natural origin.
Key
words: Antioxidant activity, Mexican plants, total phenol
content. |
