Impact of Dilution and Polymerization on Cytotoxicity of Dentin Adhesives to Human Gingival Fibroblasts: Early Exposure Time.

Background and aims. The aim of this study was to evaluate the effect of dilution and curing methods of an etch-and-rinse adhesive and a self-etching primer from the same manufacturer at early exposure time on cytotoxicity of primary human gingival fibroblasts. Materials and methods. Primary human gingival fibroblasts were exposed to different dilutions of Adper Single Bond (ASB) and Adper Prompt L-Pop (APL) (3M ESPE, USA). They were evaluated in unpolymerized mode for 20 s, 5 min and 24 h and in polymerized mode for 24 h and 48 h. Cytotoxicity was evaluated using three cytotoxic tests (MTT, cell counting and DNA condensation). Data was analyzed by a one-way ANOVA and Post Hoc Tukey HSD test. Results. Cytotoxicity tests revealed that unpolymerized APL was more cytotoxic compared to ASB after 20 s (P<0.05). By increasing the time to 5 min and 24 h, ASB was more cytotoxic than APL with lower dilutions. Polymerized ASB was more toxic than APL. Conclusion. Both adhesives were cytotoxic in different dilutions, times and curing modes. Cytotoxicity of the unpolymerized self-etching primer (APL) was more than etch-and-rinse adhesive (ASB) in 20 s, which is important clinically and dentists should be aware of the harmful effects and try to minimize it by curing and rinsing soon after composite resin insertion. ASB was more cytotoxic at 5 min and 24h.

Tyrosinase inhibitor and radical scavenger fractions and isolated compounds from aerial parts of Peucedanum knappii Bornm.

In this study, we investigated tyrosinase inhibitory and radical scavenger activities of the hydroalcoholic extract from Peucedanum knappii Bornm aerial parts, together with its fractions. The EtOAc fraction showed the highest antioxidant and anti-tyrosinase activity was selected for the isolation and identification of major active compound(s). Two flavonol glycosides, named rhamnetin-3-O-ß-D-glucopyranoside (1) and isorhamnetin-3-O-ß-D-glucopyranoside (2) were isolated from the EtOAc fraction. Compound 1 showed the most active radical scavenging and potential anti-tyrosinase activity with SC50 values of 2.9 µg mL(-1) on the DPPH test and IC50 27.95 µg mL(-1) in mushroom tyrosinase method. Therefore, isolated flavonoids from P. knappii can be considered as antioxidant and effective tyrosinase inhibitors.