Perennial Spotted Rockrose as a Source of Ellagitannins with Therapeutic Interest: Influence of Drying and Extraction Conditions
Artigo de Conferência
Visão geral
Visão geral
resumo
The ellagitannins are a diverse class of hydrolysable tannins, a type of polyphenols present in
some fruits, medicinal plants, nuts and seeds. They are complex derivatives of ellagic acid
characterized by one or more hexahydroxydiphenoyl moieties esterified to a sugar, usually
glucose [1]. These compounds play an important role in human nutrition and are endowed with
numerous biological properties, including antioxidant, anti-inflammatory, anticancer, antiatherosclerotic,
antihepatotoxic, antibacterial and anti-HIV replication activities [1-3], being
therefore interesting molecules for medicinal and therapeutic applications. A previous work of our
research team highlighted the perennial spotted rockrose (Tuberaria lignosa (Sweet) Samp.) as
a rich source of ellagitannins, namely punicalagin [2]. In this study, the influence of drying and
extraction conditions on the ellagitannins content from perennial spotted rockrose flowering
aerial parts was evaluated. Wild specimens were gathered in the Northeast region of Portugal
and then freeze-dried immediately after gathering or shade-dried in a dark and dry place at
room temperature for 30 days. Subsequently, dried samples were extracted adding them to
boiling water and left to stand at room temperature for 5 min, or boiling them for 5 min plus 5
min at room temperature. The ellagitannins analysis was performed by HPLC-DAD-ESI/MS.
The effects of drying and extraction conditions were evaluated by analysis of variance (ANOVA)
using the General Linear Model procedure. The most abundant ellagitannins were punicalagin
isomers and punicalagin gallate isomers, being the highest levels detected in freeze-dried
samples. Additionally, higher amounts of these compounds were achieved with longer
extraction time (5 min + 5 min), in both shade- and freeze-dried samples. Thus, from the
obtained results, it might be concluded that freeze-drying and longer extraction time are the
preferable conditions to obtain high levels of ellagitannins with therapeutic interest from
perennial spotted rockrose samples.
