Effects of noni on cellular viability and osteogenic differentiation of gingiva-derived stem cells demonstrated by RNA sequencing and quantitative PCR

Noni fruit (Morinda citrifolia) has been widely used in traditional medicine across tropical and subtropical regions, and is now being paid more attention in Western medicine. The present study aimed to investigate the effects of noni extract on the change in the cellular morphology, maintenance of cellular viability and enhancement of osteogenic differentiation of stem cells. Stem cells obtained from gingiva were cultured where noni extracts existed at concentrations ranging from 10-200 ng/ml. Evaluations of cell morphology and cellular viability were performed. Alkaline phosphatase activity assays were performed to assess the osteogenic differentiation. Alizarin Red S staining was performed to evaluate the calcium deposits in the culture, with the addition of noni extract. Global gene expression was analyzed via next-generation mRNA sequencing. Gene ontology and pathway analyses were performed to determine the associated mechanisms. Validation procedures were performed via quantitative (q)PCR analysis. The addition of noni at concentrations ranging from 10-200 ng/ml did not produce significant morphological changes. There were significantly higher values of cellular viability, with the highest value at 100 ng/ml compared with the control (P<0.05). Furthermore, significantly higher values of alkaline phosphatase activity was noted in the 10 and 100 ng/ml groups compared with the 0 ng/ml group on day 7 (P<0.05). Alizarin Red S staining revealed calcium deposits in each group. In addition, the highest value for Alizarin Red S staining was observed at 100 ng/ml compared with the unloaded control (P<0.05). qPCR analysis demonstrated that the mRNA expression levels of RUNX2, BSP, OCN and COL1A1 increased following treatment with noni. Taken together, the results of the present study suggest that noni extract has enhancing effects on gingiva-derived mesenchymal stem cells, by enhancing cellular viability and osteogenic differentiation.