Variations in extraction protocol lead to differences in monosaccharide composition and bioactivity on human keratinocytes as shown by polysaccharides from banana and plum fruits

In precede investigations polysaccharides have been shown to exhibit different bioactivities on the cell physiology of primary keratinocytes dependent on their monosaccharid composition related to the plant, which was used for extraction. The intention of the present study was that the way of polysaccharide precipitation leads to a varition of monosaccharide composition and different bioactivities, too.

For the investigations water extracts from banana (Musa paradisica var. sapientum, Musaceae) and plum (Prunus domestica L., Rosaceae) fruits were splitted and carbohydrates were obtained by two ways of precipitation: 1. the water extracts were dropped into ethanol and 2. ethanol was dropped into the extracts to a final ethanol concentration of 80%. Subsequently polysaccharides were examined by chemical and chromatographic methods and incubated with human keratinocytes.

The analysis of monosaccharides by Dionex HPLC, GC/FID revealed that the polysaccharides obtained after dropping of ethanol in the extracts contained up to 20% more uronic acid determined as galacturonic acid by TLC than the polysaccharides obtained by method 1. Further the amounts of fructose, galactose and arabinose rose up to 26% (Fruc), 20% (Gal) and 10% (Ara). Differences in the protein content were not observed. Investigation of keratinocyte cell physiology after incubation with the polysacchrides exhibited that the polysaccharides obtained after dropping of ethanol in the water extract triggered the cell proliferation and cell viability to a greater extend than the others, which had no or only minor effects. Further polysacchrides aquired by method 2 reduced the amount of necrotic cells. The obtained data show that slight variations in extrac