Protective effects of polysaccharides and polyhydric alcohols in a dry mouth model in cultured cells

The goal of the study was to investigate the effects of 21 polysaccharides and 12 polyhydric alcohols on inhibition of dryness in oral mucosal epithelial cells in vitro. All the tested compounds are currently used in oral products.

Human gingival epithelial Ca9-22 cells were incubated in 96-well plates until the cells reached confluence. After removal of the culture medium, the cells were incubated with a solution containing one of 21 polysaccharides (seven semisynthetic and 14 natural polysaccharides) or 12 polyhydric alcohols for 15 min (short-term treatment). After removal of the sample solution, the cells were dried at 25°C and 30% humidity, and cell viability was measured to determine the effect of each compound on prevention of cell death due to drying. The effects of the polyhydric alcohols were also examined for 3 days (long-term treatment).

The semisynthetic polysaccharides ethylcellulose (EC), methylcellulose (MC), and hydroxypropylmethylcellulose (HPMC) and the natural polysaccharides xanthan and gellan gum significantly inhibited cell death due to drying. Hydroxypropylcellulose increased cell death under these conditions. Of the polyhydric alcohols, long-term treatment with glycosyltrehalose significantly inhibited cell death due to drying, but short-term treatment with glycosyltrehalose did not do so. Long-term treatment had an effect on cell proliferation that appeared to differ from the effect of short-term treatment.

Short-term treatment with EC, MC, HPMC, xanthan gum, and gellan gum and long-term treatment with glycosyltrehalose showed significant inhibition of cell death due to drying. These materials might have protective effects against dry mouth.