Effects of a slight acidic arabinoxylan from Plantago ovata seed husk on human skin cells
The Plantago ovata, Forssk, Plantaginaceae, seed husk has a high content of water-soluble polysaccharide identified as an arabinosyl (galactosyluronic acid) rhamnosylxylan further denominated as P1. The P1 activity on the cell proliferation, migration and cell cycle of keratinocytes (NHEK, HaCaT) and fibroblasts (NHDF) was analyzed by flow cytometry. Internalization studies were done to elucidate the effectiveness of P1. Enzymatic hydrolysis was done to investigate the necessary structure responsible for the biologic activity. Subfractions of P1 were obtained using α-L-arabinofuranosidase (P11-P18), endo-1,4-ß-xylanase (P21-P24) and both enzymes in combination (P31-P36).
P1 significantly increased the proliferation rates of NHEK, HaCaT and NHDF independent of the used concentration. The scratch assay revealed that the migration of NHDF was also significantly enhanced while this effect was not observed using keratinocytes. Both skin cell types internalized P1 rapidly during 3h of incubation and also triggered the NHDF and NHEK in the S and G2 phase after 6h and 3h of incubation. After enzymatic hydrolysis all the subfractions maintain the cell proliferation promoting effect on HaCaT whereas the subfractions P13-P18 and P31-P36 were more effective than P1. Subfractions P15-P16 and P31-P36 had no effect on NHDF but subfractions P11-P14 and P18 increased the effect.