Volume 78, December 30, 2015, Pages 116-123
a
MEtRiCS, Departamento de Ciências e Tecnologia da Biomassa,
Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa,
Campus de Caparica, Caparica, Portugal
b Department of Analytical Chemistry, Faculty of Sciences, University of Granada, c/Fuentenueva s/n, Granada, Spain
c Functional Food Research and Development Center (CIDAF), Health Science Technological Park, Avenida del Conocimiento s/n, Granada, Spain
b Department of Analytical Chemistry, Faculty of Sciences, University of Granada, c/Fuentenueva s/n, Granada, Spain
c Functional Food Research and Development Center (CIDAF), Health Science Technological Park, Avenida del Conocimiento s/n, Granada, Spain
Abstract
Kenaf (. Hibiscus
cannabinus L.) is a short day, annual, herbaceous plant producing high
quality cellulose. Kenaf is a valuable fiber crop that is cultivated for
its fibrous stem. Recently, seeds and leaves have been also considered
as a source of industrial products, such as biopharmaceuticals. However,
their pharmacological effects and chemical composition are still poorly
studied.In this context, the aim of this work was to identify the
phenolic compounds and to evaluate the antioxidant activity of kenaf
leaves extracts, comparing two varieties, Everglades 41 and Tainung 2,
produced in Portugal. The
identification of the phenolic compounds in the leaves was done using
advanced analytical techniques such as high-performance liquid
chromatography coupled to electrospray ionization and quadrupole
time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS). Parallel to this,
in vitro antioxidant activity and total phenolic content of extracts
were also determined. The antioxidant activity was evaluated with the
use of two assays (oxygen radical absorbance capacity assay-ORAC and
DPPH assay) and the total phenolic content by the Folin-Ciocalteu
method.HPLC-ESI-QTOF-MS analyses enabled to tentatively identify 29
compounds in both varieties, mainly chlorogenic acids and quercetin and
kaempferol derivatives. Some of the compounds found in the kenaf leaves
were related before to the Hibiscus genus. Results of Folin-Ciocalteu,
DPPH and ORAC assays showed that Everglades 41 leaves were richer in
phenolic compounds presenting a higher antioxidant potential than
Tainung 2 leaves. This study indicates that kenaf leaves can be
considered as potentially new source of antioxidants but its future use
in food and nutraceutical matrices still need to be tested and
evaluated. © 2015 Elsevier B.V.
Author keywords
Antioxidant capacity; HPLC-ESI-QTOF-MS; Kenaf; Kenaf leaves; Phenolic compounds
Indexed keywords
Engineering controlled terms: Agents; Antioxidants;
Assays; Chemical compounds; Chromatography; Electrospray ionization;
Flavonoids; Hemp; High performance liquid chromatography; Ionization of
liquids; Liquid chromatography; Mass spectrometry; Phenols
Antioxidant capacity; ESI-QTOF-MS; Kenaf; Kenaf leaves; Phenolic compounds
Engineering main heading: Plants (botany)
Species Index: Hibiscus; Hibiscus cannabinus
