The anti-oxidant effects of melatonin derivatives on human gingival fibroblasts

- Structural modification of MLT at indole ring has shown benefits in protecting fibroblast cells from oxidative damage.
- The speculative mechanism to reduce oxidative damage is related with hydrogen atom transfer properties.
- MLT, AMLT and BMLT can be taken place inside the oral fibroblast cells to reduction of oxidative stress.

ObjectivesAim of this in vitro study was to evaluate the anti-oxidant activity of indole ring modified melatonin derivatives as compared with melatonin in primary human gingival fibroblast (HGF) cells.MethodsAnti-oxidant activity of melatonin (MLT), acetyl-melatonin (AMLT) and benzoyl-melatonin (BMLT) was evaluated by5 standard methods as follows: 2, 2-diphenyl-1-picrylhydrazyl (DPPH); ferric ion reducing antioxidant power (FRAP); superoxide anion scavenging; nitric oxide (NO) scavenging; and thiobarbituric acid reactive substances (TBARs).Evaluation of cellular antioxidant activity (CAA) and protectivity against H2O2 induced cellular damage was performed via MTT assay in HGF cells.ResultsAccording to the standard anti-oxidant assays, the antioxidant power of AMLT and BMLT were slightly less than MLT in FRAP and superoxide scavenging assays. In the NO scavenging and TBARs assays, BMLT and AMLT were more potent than MLT, whereas DPPH assays demonstrated that MLT was more potent than others. BMLT and AMLT had more potent anti-oxidant and protective activities against H2O2in HGF cells as compared with MLT.ConclusionsMLT derivatives demonstrated different anti-oxidant activities as compared with MLT, depending upon assays. These findings imply that N-indole substitution of MLT may help to improve hydrogen atom transfer to free radicals but electron transfer property is slightly decreased. Anti-oxidant and protective effects of melatonin derivatives (AMLT and BMLT) on human gingival fibroblasts imply the potential use of these molecules as alternative therapeutics for chronic inflammatory oral diseases.