Ursolic acid is a triterpenoid compound present in many plants. This study examined the antimicrobial activity of ursolic acid against mutans streptococci (MS) isolated from the Korean population. The antimicrobial activity was evaluated by the minimum inhibitory concentration (MIC) and time kill curves of MS. The cytotoxicity of ursolic acid against KB cells was tested using an MTT assay. The MIC90 values of ursolic acid for Streptococcus mutans and Streptococcus sobrinus isolated from the Korean population were 2 μg/ml and 4 μg/ml, respectively. Ursolic acid had a bactericidal effect on S. mutans ATCC 25175 T and S. sobrinus ATCC 33478 T at > 2 × MIC (4 μg/ml) and 4 × MIC (8 μg/ml), respectively. Ursolic acid had no cytotoxic effect on KB cells at concentrations at which it exerted antimicrobial effects. The results suggest that ursolic acid can be used in the development of oral hygiene products for the prevention of dental caries.

We assessed the environmental risk of herbicide resistant transgenic rice (Protox) on non-target herbivore, grasshoppers (Oxya japonica japonica Thunberg). We conducted life-history experiments of grasshoppers with measuring their body weight, body length, eating amount, and feces amount between non-transgenic rice (nTR; Dongjin rice) and transgenic rice (TR; Protox rice) under laboratory conditions (Temp. 25Ð, R.H. 50-70%, Photoperiod L16:D8) in 2007. The growth of grasshoppers appeared to increase at each measuring date. We also compared the growth rate of grasshoppers between nTR and TR to examine the transgenic impact on the herbivore and we found there was no statistically signifi cant difference between the two plant types (P>0.05). We found that body weight and body length for grasshoppers were highly correlated at each of the two types of plants, nTR (0.962) and TR (0.960). The correlation of eating amount and feces amount of grasshoppers were higher nTR (0.830) than TR (0.782). The energy effi ciency of the grasshopper was not a signifi cant between nTR and TR (P> 0.05). But the molt timing of the grasshoppers for TR difference was faster than for nTR. Conclusively life-history of the grasshoppers but molt timing was not a signifi cant difference between nTR and TR. Therefore, we could conclude there was not any environment risk on herbivore from our result.

뻐ny studìes have shown the anti-proli ferative effects of irondeprivation on cancer cell s‘ but the effects 01' iron-chelators on oral cancer have not been clearly elucidated , To investigate the effects of an iron chelato r, desferrioxamine( 01"O).on the growth of ilIllTIortali zed human o1'al ke ratinocytes(IHOK), primary oraJ cancer cel ls(HN4)‘ metastatic oral cancer cell s(HN12) , and human skin keratìnocytes(HaCaT) in the MTr assay, three-dimensional(3D) raft cul tmes, Western blott ing, cell cycJ e analysis‘ nuclear staining‘ and cytochrome c expression for apoptosis s ig naling pathway were used OFO inhibited the growth of immortalized IHOK and HaCaT and mal ignant HN4 and HN12 keratinocytes in a time- and dose-dependent manner according to the MTT assay, The 3D organotypic cu l tu re also revealed that OF'O-treated cells showed less epithelial maturation, less surface keratinizati on‘ and de creased epithelia l thickness, The major mechanìsm of growth inhìbition with the micromolar 0 1"0 treatment was by the induction of apoptosis‘ which was supported by nuclear OAPI staining, ONA fragmentation analysis, and J10w cytometric analysis for sub-Gl phase ar rest and Annexin V-1"ITC stainìng, Furthermore‘ Bax expression in creased together with p53 and p21WAF1!CIPl, whìle the Bcl-2 expression decreased in the immortalized and malig nant keratinocytes treated with 01"0 , Time-dependent cytochrome c from mitochondria was observed in D1"O-treated [l-IOK and 0 1'머 cancel‘ ceJJ s, and was accompanied by the activation of caspase-3 in IHOK cells. These resu lts demonstrate that 0 1"0 has growth inhibitory effects on immortalized and malignant oral keratinocyLes Lhrough the induction of apoptosis and suggest that further evaluation of OFO as a potcntial thcrapcutic agent for human oral precancerous and cancerous lesions is warranted