Background:
The biodegradable and biocompatible nature of pectin-based films is of particular
interest in wound dressing applications, due to its non-toxicity, pH-sensitivity and gelling activity. An approach
to improve the mechanical properties, the release profile of bioactive compounds as well as the performance
in wet environments of pectin-based films is mixing with other biopolymers.
Objective:
To prepare hydrocolloid films based on crosslinked pectin / starch blend loaded with bioactive extracts
from leaves of G. tinctoria and U. molinae with controlled release of bioactive compounds and healing
property.
Method:
The hydrocolloid films were characterized by FTIR, SEM, and TGA-FTIR techniques and their tensile
properties, water uptake, and polyphenolic release profile in aqueous media were evaluated. The dermal
anti inflammatory activity of the hydrocolloid films was assessed by the mouse ear inflammation test. The
wound healing property of the loaded hydrocolloid films was explored in a rat model and in a clinical trial (sacrum
pressure ulcer).
Results:
The films showed an adequate water-uptake capacity between 100-160%. The release of active compounds
from the hydrocolloid films followed the Korsmeyer-Peppas equation. The mechanical properties of
hydrocolloid films were not affected by the plant extracts within the concentration range used. The incorporation
of the bioactive extracts in the polysaccharide films inhibited the topical edematous response by about
50%. The topical application of the loaded hydrocolloid film on the pressure ulcer is completely closed after
17 days without showing any adverse reaction.
Conclusion:
A novel hydrocolloid matrix was produced from crosslinked starch-pectin, which exhibited suitable
chemical-physical properties to be used as a carrier of plant extracts with wound healing properties.
Background
Gunnera tinctoria has been collected by Mapuche-Pewenche people for food and medicinal purposes. The high polyphenol content of methanolic extract from G. tinctoria leaves with chemical constituents such as ellagic acid and quercetin derivatives suggests its application to prevent endothelial dysfunction and oxidative stress. The aim of this study was to provide evidence of the protective effect of this extract on endothelial function by reducing oxidative stress induced by high d-glucose and H2O2, as well as by stimulating nitric oxide (NO) levels in human umbilical vein endothelial cells (HUVECs).
Results
A methanolic extract with a high content of polyphenols (520 ± 30 mg gallic acid equivalents/g dry extract) was obtained from G. tinctoria leaves. Its main constituent was ellagic acid. The results of Ferric reducing antioxidant power and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays of the extract confirmed its antioxidant activity by inhibition pathway of radical species. The incubation of HUVECs with the extract decreased the apoptosis and reactive oxygen species (ROS) synthesis induced by high extracellular concentration of d-glucose or hydrogen peroxide. The extract increased endothelial NO levels and reduced vasoconstriction in human placental vessels.
Conclusions
This study provides evidence about the antioxidant and endothelial protective properties of methanolic G. tinctoria leaf extract. The extract improves the availability of NO in HUVECs, inhibiting the production of ROS and vasoconstriction.
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