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Arabinogalactan protein JC from Jatropha curcas seed endosperm (mean molecular weight 140 kDa) was isolated by cold water extraction and characterized concerning sugar and amino acid composition. At 10 and 100 µg/mL JC stimulated mitochondrial activity (MTT test) of human skin cells (HaCaT keratinocytes, fibroblasts) and the ATP status of primary keratinocytes. JC did not influence the cellular proliferation, while primary keratinocytes were triggered into differentiation status. Investigations on a potential mode of action of JC were performed on complex organotypic skin equivalents. JC induced the production of HGF, KGF and TGFβ, with TGFβ being the main inductor for the differentiation-inducing effect of JC. Also the expression of GM-CSF was stimulated strongly by JC. This in vitro activity profile indicated JC to be a potent inductor of cellular differentiation via stimulation of growth hormones and TGF-β-induced cell signaling., (Copyright © 2010 Elsevier B.V. All rights reserved.)

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.

An arabinogalactan protein (F2) was isolated in 1.5% yield from the seeds of Ribes nigrum L. (Grossulariaceae) by aqueous extraction and a one-step anion exchange chromatography on DEAE-Sephacel with 24% galactose, 43% arabinose, and 20% xylose as main carbohydrate residues. Methylation analysis revealed the presence of a 1,3-/1,3,6-galactose backbone, side chains from arabinose in different linkages, and terminal xylose residues. The polysaccharide which turned out to be an arabinogalactan protein had a molecular weight of >10(6) Da and deaggregated under chaotropic conditions. The cellular dehydrogenase activities (MTT and WST-1 tests) of human skin cells (fibroblasts, keratinocytes) as well as the proliferation rate of keratinocytes (BrdU incorporation ELISA) were significantly stimulated by the polymer at 10 and 100 microg/mL. F2 had no influence on differentiation status of keratinocytes and did not exhibit any cytotoxic potential (LDH test). The biological activity of F2 was not dependent on the high molecular weight. Influence of the polysaccharide on the gene expression of specific growth factors, growth factor receptors, signal proteins and marker proteins for skin cell proliferation, and differentiation by RT-PCR could not be shown. Gene array investigations indicated an increased expression of various genes encoding for catabolic enzymes, DNA repair, extracellular matrix proteins, and signal transduction factors. Removal of terminal arabinose residues by alpha-L-arabinofuranosidase did not influence the activity toward skin cells, while the treatment with beta-D-galactosidase yielded an inactive polysaccharide. The FITC-labeled polysaccharide was incorporated in a time-dependent manner into human fibroblasts (laser scanning microscopy) via endosomal transport. This internalization of the polysaccharide was inhibited by Cytochalasin B.