High molecular weight plant heteropolysaccharides stimulate fibroblasts but inhibit keratinocytes

• Species of Amorphophallus with at least 50% GM content stimulated fibroblasts and inhibited keratinocytes.
• The biological activity of KGM on fibroblasts is dependent on high molecular weight components.
• KGM maintained fibroblast and adipose derived stem cell metabolic activity under media starvation conditions.

Konjac glucomannan (KGM) is a natural polysaccharide of β(1-4)-d-glucomannopyranosyl backbone of d-mannose and d-glucose derived from the tuber of Amorphophallus konjac C. Koch. KGM has been reported to have a wide range of activities including wound healing. In this study we examined KGM extracts prepared from five plant species, (Amorphophallus konjac Koch, Amorphophallus oncophyllus, Amorphophallus prainii, Amorphophallus paeoniifolius and Amorphophallus elegans) for their effects on cultured human keratinocytes and fibroblasts. Extracts from A. konjac Koch, A. oncophyllus and A. prainii (but not from A. paeoniifolius or A. elegans) stimulated fibroblast proliferation both in the absence and presence of serum. However, these materials inhibited keratinocyte proliferation. The fibroblast stimulatory activity was associated with high molecular weight fractions of KGM and was lost following ethanol extraction or enzyme digestion with β-mannanase. It was also reduced by the addition of concanavalin A but not mannose suggesting that these heteropolysaccharides are acting on lectins but not via receptors specific to mannose. The most dramatic effect of KGM was seen in its ability to support fibroblasts for 3 weeks under conditions of deliberate media starvation. This effect did not extend to supporting keratinocytes under conditions of media starvation but KGM did significantly help support adipose derived stem cells under media starvation conditions.

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