Anti Caries Effects of Extracts from Geranium strictipes R. Kunth

Geranium strictipes R. Kunth has played a crucial part in traditional Chinese medicine for curing dysentery, hemostasis and anti-caries. In this work, we investigated the anti caries effect of the extract from G. strictipes. Streptococcus mutans and cariogenic diet (keyes 2000) were employed to accelerate enamel caries of rats. 32 rats were randomly divided into four groups, and each group was treated with following solution: 2 mg/mL G. strictipes ethyl acetate extract (GSEAE), 2 mg/mL G. strictipes n-butanol extract (GSNBE), 0.1% (wt.) NaF and distilled water (DW), respectively. After 30 days, the incisor hardness of rats was examined by Vickers micro-hardness (VMH) tester. Polarizing microscope (PLM) and confocal laser scanning microscope (CLSM) were used to monitor the incisor lesion. The incisor enamel hardness of GSNBE, GSEAE and NaF group were higher than that of DW group (p < 0.05). There was no statistical difference between the 4 groups (p > 0.05) about dentin hardness. The remineralization zone was observed in GSNBE, GSEAE and NaF group, but negative in DW group. Furthermore, the lesion average fluorescence values of GSNBE, GSEAE and NaF group were lower than that of DW group. Our experimental results suggest that the remineralization gener-ally occurs at the junction of enamel and dentin. G. strictipes extract was beneficial to prevent caries in rats through promoting remineralization. We believe that this work can be further extended to the caries cure of other animals even to our human tooth health.