Effects of pressed juices of common ice plant and nopal on human skin cells as a function of incubation time and filter pore size

Pressed juices from the common ice plant (Mesembryanthemum crystallinum L., Aizoaceae) are part of cosmetic formulations but little is known with respect to their bioactivity. In the present study pressed juices were passed through 1.2µm (McPI) or 0.2µm (McPII) filters prior to monitoring their effects on the proliferation and metabolic activity of human skin keratinocytes (HaCaT) and fibroblasts (NHDF). Incubation was carried out over 48h and 72h, respectively. Independent of the pressed juice and the experimental conditions applied, the metabolic activity determined by MTT reduction was not changed. While during 48h the proliferation of both skin cell types was not altered, a significant increase of proliferation rates was observed if NHDF and HaCaTs were incubated with McPI. On the other hand McPII selectively increased the proliferation of HaCaT keratinocytes. To conclude the effect of pressed juices of common ice plant predominantly influenced the cell proliferation of NHDF and HaCaTs in a time-dependent manner. In the case of keratinocytes, the biological activity also depended on the specific composition that was altered by pretreatment using different filter pore sizes.