Structural patterns of rhamnogalacturonans modulating Hsp-27 expression in cultured human keratinocytes

Healing efficiency of oligosaccharides generated from almond gum (Prunus amygdalus) on dermal wounds of adult rats

Almond gum is a naturally occurring polymer produced by almond trees and shrubs. Its abundance, as well as its low cost production makes it a potential feedstock for use in food and pharmaceuticals. In this regard, almond gum oligosaccharides were enzymatically generated, purified and their monosaccharide composition assessed using gas chromatography-flame ionization detector. Oligosaccharide analyses show that the most prominent residues were galactose and arabinose with traces of xylose, rhamnose, glucose and mannose. The glycosyl linkage positions were analyzed using gas chromatography - mass spectrometry showing a main chain composed of galactose units [→3)-Gal-(1→] branched mainly with arabinose residues [Ara-(1→]. The potent role of the generated oligosaccharides on rats wound healing was investigated. They have been applied either alone or supplemented, as active substance, with cream formulation, on full-thickness wound created on the dorsum of the rats. The effect of oligosaccharides was assessed by measuring the wound closure percentage, reaching an average of around 100% when applied alone or supplemented to cream formulation. The healing percentage for the control group was only 74.3% at the same day. The histological evaluation of skin sections visualized by light microscopy revealed an improved collagen deposition and an increased fibroblast and vascular densities.

Arabinogalactans from Mimosa tenuiflora (Willd.) Poiret bark as active principles for wound-healing properties: specific enhancement of dermal fibroblast activity and minor influence on HaCaT keratinocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Aqueous extracts from the bark of Mimosa tenuiflora (Willd.) Poirett (Mimosaceae), tradionally known as "tepescohuite", are widely used for wound-healing and burns in middle and South America. No pharmacological data are available on the influence of aqueous extracts and high molecular constituents on human skin cells.

MATERIALS AND METHODS

Tests were performed on human primary dermal fibroblasts and human HaCaT keratinocytes by quantification of mitochondrial activity (MTT, WST-1), proliferation (BrdU incorporation), necrosis (LDH) and gene expression profiling (RT-PCR).

RESULTS

Water extract WE (10 and 100 microg/mL) expressed loss of cell viability and proliferation in dermal fibroblasts. Ethanol-precipitated compounds EPC (10 microg/mL), isolated from WE significantly stimulated mitochondrial activity and proliferation of dermal fibroblasts. Minor stimulation of human kerationocytes by EPC was found only at 100 microg/mL level. The differentiation behavior of keratinocytes was not influenced by EPC. EPC had no influence on the expression of specific proliferation and differentiation related genes so that the mode of action remains unclear. By bioactivity-guided fractionation two arabinogalactan-enriched fractions (F2, F3) were isolated from EPC and identified as the stimulating principles of EPC against fibroblasts.

CONCLUSIONS

A significant in vitro stimulation of dermal fibroblast activity and proliferation by arabinogalactans from Mimosa tenuiflora provides a rational for the traditional use of the bark material for wound healing.