mahsima khoshneviszadeh

Tyrosinase enzyme has a key role in melanin biosynthesis by converting tyrosine into dopaquinone. It also participates in the enzymatic browning of vegetables by polyphenol oxidation. Therefore, tyrosinase inhibitors are useful in the fields of medicine, cosmetics, and agriculture. Many tyrosinase inhibitors having drawbacks have been reported to date; so, finding new inhibitors is a great need.

A variety of 6-hydroxy-3,4-dihydronaphthalenone chalcone-like analogs (C1-C10) have been synthesized by aldol condensation of 6-hydroxy tetralone and differently substituted benzaldehydes. The compounds were evaluated for their inhibitory effect on mushroom tyrosinase by a spectrophotometric method. Moreover, the inhibition manner of the most active compound was determined by Lineweaver-Burk plots. Docking study was done using AutoDock 4.2. The drug-likeness scores and ADME features of the active derivatives were also predicted.

Most of the compounds showed remarkable inhibitory activity against the tyrosinase enzyme. 6-Hydroxy-2-(3,4,5-trimethoxybenzylidene)-3,4-dihydronaphthalen-1(2H)-one (C2) was the most potent derivative amongst the series with an IC50 value of 8.8 μM which was slightly more favorable to that of the reference kojic acid (IC50 = 9.7 μM). Inhibitory kinetic studies revealed that C2 behaves as a competitive inhibitor. According to the docking results, compound C2 formed the most stable enzyme-inhibitor complex, mainly via establishing interactions with the two copper ions in the active site. In silico drug-likeness and pharmacokinetics predictions for the proposed tyrosinase inhibitors revealed that most of the compounds including C2 have proper drug-likeness scores and pharmacokinetic properties.

Therefore, C2 could be suggested as a promising tyrosinase inhibitor that might be a good lead compound in medicine, cosmetics, and the food industry, and further drug development of this compound might be of great interest.

Melanogenesis is a process of melanin synthesize, which is a primary response for the pigmentation of human skin. Tyrosinase is a key enzyme, which catalyzes a rate-limiting step of the melanin formation, natural products have shown potent inhibitors, but some of these possess toxicity. Numerous synthetic inhibitors have been developed in recent years may lead to the potent anti-tyrosinase agents. Therefore its inhibition may be an efficient way for the development of depigmenting agents. A novel series of 2-arylidine-1H-indene-1,3(2H)-dione analogs were designed, synthesized and screened for their in vitro tyrosinase inhibitory activity. 3d derivative bearing nitrothiophene revealed excellent anti-tyrosinase activity with an IC50 value of 3.55 μM comparable to kojic acid as a positive control. 3d as the most potent inhibitor and 3f as the least active derivative were subjected to in silico evaluations considering the 3D conformations, ΔGb of bindings and interactions within the active site of tyrosinase.

  Previous studies indicated that both Plantago major and Aloe vera have anti-inflammatory, tissue regeneration, antioxidant, and immune-stimulatory effects. It is assumed that a mixture of these two herbal medicines may provide a potent material in treatment of skin wound injuries. Therefore, in this study we investigated the effects of Plantago major and Aloe vera mixture in the process of wound healing in rat models according to stereological parameters. In an experiential study, 36 male Sprague-Dawley rats (200±20 g) were randomly assigned into three groups (n=12): The control group which received no treatment, gel base treated group, and the 5% Plantago major and 5% Aloe vera mixture gel treated group (PA group). Treatments were done every 24 hrs for 15 days. Wound closure rate, volume densities of the collagen bundles and the vessels, vessel’s length density and mean diameter, and fibroblast populations were estimated using stereological methods. PA treated group showed faster wound closure rate in comparison with control and gel-base groups (p<0.05). Numerical density of fibroblasts, volume density of collagen bundles, mean diameter, and volume densities of the vessels in PA group were significantly higher than the control and the gel-base treated groups (p<0.05). We showed that Plantago major and Aloe vera mixture has the ability to improve wound healing by enhancing fibroblast proliferation, collagen bundle synthesis and re-vascularization in skin injuries

Mammalian target of rapamycin (mTOR) is a phosphoinositide 3-kinase-related protein kinase which controls cell growth and is frequently deregulated in many cancers. Therefore, mTOR inhibitors are used as antineoplastic agents for cancer treatment. In this study, 1,2,4-triazine derivatives containing different arylidene-hydrazinyl moieties were designed and synthesized. Cytotoxicity of the compounds was evaluated on HL-60 and MCF-7 cell lines by MTT assay. S1, S2 and S3 exhibited good cytotoxic activity on both cell lines with an IC50 range of 6.42 - 20.20 μM. In general, substitution of a five-membered heterocyclic ring containing NO2, such as 5-nitrofuran-2-yl, resulted in the best potency. Molecular docking analysis was performed to study the possible interactions and binding modes of all the triazine derivatives with mTOR receptor. The most promising compound, S1, was well accommodated within the active site and had the least estimated free energy of binding (even less than the inherent ligand of the protein, PDB ID: 4JT6). It is concluded from both MTT assay and docking studies that the arylidene moiety linked to the hydrazinyl part of the structure had a prominent role in cytotoxicity and mTOR inhibitory activity.

Nicotinamide (NA), the active form of vitamin-B3, is hypothesized to have positive effects on the process of wound healing; it has anti-inflammatory, antioxidant, and immunomodulatory properties, as well as an epithelization inducing action.

In the present study, we aimed to determine the effects of topical administration of NA on skin wounds, based on histomorphometrical and pathological criteria.

In this study, 36 male Sprague-Dawley rats (220 ± 20 g each), with 1 cm2 circular full-thickness wounds on their backs were divided into three groups (n = 12): NA group, was treated daily with a Nicotinamide 2% gel , untreated group (control), and base group, which were treated with the vehicle (base) of the gel (carboxymethylcellulose). Skin biopsies were prepared for microscopic analyses. Inflammation, granulation tissue formation, ulceration, epithelization, wound closure rate, fibroblast proliferation, collagen synthesis, and vascularization were studied criteria.

The results revealed that besides improving the wound healing by its anti-inflammatory, antioxidant, and epithelization inducing effects, NA also improved tissue regeneration through the increment of fibroblast proliferation, collagen synthesis, and vascularization.

In spite of the few reported side effects, NA can be introduced as an effective agent on the wound healing process, an adjuvant therapy and possibly a treatment by itself. However, its chemical characteristics, as well as possible adverse effects warrants further research.

Wounds and wound healing have always been one of the most important subjects that experimental researches were dedicated to. Simvastatin has been used for long as a common lipid lowering agent which was reported to have some pleiotropic effects such as antioxidation, anti-inflammation and immunomodulation. In this study we aimed to determine the effect of simvastatin on wound healing process in laboratory rats by means of stereological and histopathological analyses. 36 male Sprague-Dawley rats (220 ± 20 g) with a 1 cm2 circular full-thickness wound on their back were divided into three groups: SS group that received a gel with 2% concentration of simvastatin; UW group that received no treatment but daily irrigation with normal saline; Base group that was treated with the gel base. Duration of the study was 12 days and at the end, wound closure rate, grade of inflammation, granulation-tissue formation, ulceration, epithelization, fibroblast proliferation, collagen-bundles synthesis, and vascularization were determined. Outcome of this study revealed that Simvastatin improves the wound healing by its anti-inflammatory and epithelization induction effect as well as statistically significant induction of fibroblast proliferation and collagen bundle synthesis which were reported by our stereological and histopathological investigations. Results of the present study demonstrated that topical Simvastatin enhances the wound healing process through affecting different aspects of tissue regeneration; however, further researches are needed to find the exact mechanism, advantages and disadvantages of this chemical agent.