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Background & Objective: Abnormal production of melanin pigment which causes melasma, freckles, ephelides, and age spots, are esthetic problems. Polyphenol oxidase (PPO), a copper-containing enzyme, is involved in melanin biosynthesis and the abnormal accumulation of melanin pigments. Thus, its inhibitors are of great importance in the medical and cosmetic fields. The aim of this study was to investigate some salicylaldehyde Analogues as Polyphenol oxidase inhibitors. Material & Methods: In the present study, thirty five derivatives of salicylaldehyde scaffold were subjected to molecular docking studies to investigate the mode of interaction of the compounds with tyrosinase active site. Docking study was performed by AutoDock 4.2 program and the resulting docking poses were analyzed in AutoDockTools, DS Visualizer 3.5 and Ligplot softwares. Results: Among the all studied compounds, Ligand 4-isopropylsalicylaldehyde displayed good docking results. In fact, this compound had the most negative ΔGbind (-4.01 Kcal/mol) that indicated favorable interactions with the key amino acid residues at active site of Polyphenol oxidase. Docking results for this compound are in accordance with the docking results of Co-crystallized ligand (tropolone). In this compound, the oxygen of a carbonyl group has an efficient metal-ligand interaction with the Cu2+ ion in the active site. Conclusion: The presence of non-polar moiety in salicylaldehyde Analogues increases the inhibitory property.

Background & Objective: Tyrosinase is a key enzyme in pigment synthesis.Overproduction of melanin in parts of the skin results in hyperpigmentation diseases. Thus, its inhibitors are highly important in the medical, cosmetic and agricultural fields. The aim of this research is the bioinformatical study of tyrosinase inhibition by a number of hydroxy nitrodiphenyl ether derivatives. Material & Methods: This is a descriptive-analytic study. In order to investigate the mode of interaction of the compounds with tyrosinase active site, the chemical structures of all compounds were designed using ChemDraw program, then transferred into Hyperchem software for energy minimization. Docking study was performed by AutoDock 4.2 program and the resulting docking poses were analyzed in AutoDockTools, DS Visualizer 3.5 and Ligplot software. Results: Among the all studied compounds, the best docking results were related to 4-Hydroxy- 2'-nitrodiphenyl etherdisplayed. In fact, this compound had the most negative ΔGbind (-12.79 Kcal/mol) that indicated favorable interactions with the key amino acid residues at active site of tyrosinase. Docking results for this compound are in accordance with those of co-crystallized ligand (tropolone). In this compound, the oxygen of nitro group has an efficient metal-ligand interaction with the Cu2+ ions in the active site. Conclusion: Finally, in respect to high effectiveness and docking results, we can conclude that the compound 4-Hydroxy- 2'-nitrodiphenyl ether may be regarded as an effective anti-tyrosinase inhibitor.

Background & Objective: Tyrosinase is a key enzyme in pigment synthesis.Overproduction of melanin in parts of the skin results in hyperpigmentation diseases. Thus, its inhibitors are highly important in the medical, cosmetic and agricultural fields. The aim of this research is the bioinformatical study of tyrosinase inhibition by a number of hydroxy nitrodiphenyl ether derivatives. Material & Methods: This is a descriptive-analytic study. In order to investigate the mode of interaction of the compounds with tyrosinase active site, the chemical structures of all compounds were designed using ChemDraw program, then transferred into Hyperchem software for energy minimization. Docking study was performed by AutoDock 4.2 program and the resulting docking poses were analyzed in AutoDockTools, DS Visualizer 3.5 and Ligplot software. Results: Among the all studied compounds, the best docking results were related to 4-Hydroxy- 2'-nitrodiphenyl etherdisplayed. In fact, this compound had the most negative ΔGbind (-12.79 Kcal/mol) that indicated favorable interactions with the key amino acid residues at active site of tyrosinase. Docking results for this compound are in accordance with those of co-crystallized ligand (tropolone). In this compound, the oxygen of nitro group has an efficient metal-ligand interaction with the Cu2+ ions in the active site. Conclusion: Finally, in respect to high effectiveness and docking results, we can conclude that the compound 4-Hydroxy- 2'-nitrodiphenyl ether may be regarded as an effective anti-tyrosinase inhibitor.

Background & Objectives: Dental pulp stem cells (DPSCs) are alternate source of mesenchymal stem cells. Subsequent to tooth avulsion and fracture, DPSCs can play a prominent role in tissue regeneration. This study was conducted to evaluate the effect of soymilk and milk on survival of dental pulp stem cells. Materials & Methods: DPSCs were isolated from 16 freshly extracted incisors of 5 rabbits. The 3rd passage was seeded in 24 well plates, and after 3 days, soymilk, cow milk, HBSS, and distilled water were replaced with culture media. After 45 minutes, 1.5, 3, and 6 hours, the viability of DPSCs were investigated. Mesenchymal nature of stem cells was investigated by RT-PCR. The cell viability was determined by Trypan blue exclusion. Karyotyping was done to evaluate the cytogenetic stability of cells. Results: The viability of DPSCs in all media were significantly more than distilled water at all intervals. After 6 h, the viability of DPSCs in soymilk, cow milk, and HBSS were 100,000±0.00, 100,000±0.00, and 74.74±5.70, respectively. After 6 h, both soymilk and cow milk maintained cells significantly better than HBSS. Conclusion: Like cow milk, soymilk is a suitable alternative transfer media for avulsed and broken teeth that can increase the survival of DPSCs.