Pramote Mahakunakorn

Anti‐Inflammatory Activities of Melatonin Derivatives in Lipopolysaccharide‐Stimulated RAW 264.7 Cells and Antinociceptive Effects in Mice

Preclinical Research

Protective Effect of Crocodile Hemoglobin and Whole Blood Against Hydrogen Peroxide-Induced Oxidative Damage in Human Lung Fibroblasts (MRC-5) and Inflammation in Mice

A putative protective effect of cHb and cWb against H2O2-induced oxidative damage was evaluated in detail using MRC-5 cells. In addition, the carrageenan (Carr)-induced mouse paw edema model and the cotton pellet-induced granuloma model were employed to examine the in vivo anti-inflammatory activity of cHb and cWb in mice. It was demonstrated that both cHb and cWb treatments significantly increased cell viability and inhibited morphology alterations in MRC-5 cells exposed to H2O2. Orally administered cHb and cWb significantly reduced Carr-induced paw edema volume and cotton pellet-induced granuloma formation. Moreover, cHb and cWb decreased the expression levels of important pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α), while only cWb was found to increase the expression of the anti-inflammatory cytokine IL-10 significantly. Finally, the activity of antioxidant enzymes (SOD, CAT, and GPx) in the liver improved after cHb and cWb treatment under acute and chronic inflammation. Taken collectively, the results of this study suggest that both cHb and cWb protect against hydrogen peroxide-induced damage in fibroblast cells. Moreover, cHb and cWb were found to exhibit anti-inflammatory activity in both the acute and chronic stages of inflammation and appear to enhance antioxidant enzyme activity and decrease lipid peroxidation in the livers of mice. Therefore, this study indicates that cHb and cWb have great potential to be used in the development of dietary supplements for the prevention of oxidative stress related to inflammatory disorders.

In Vitro and in Vivo Wound Healing Properties of Plasma and Serum from Crocodylus siamensis Blood

The plasma and serum of Crocodylus siamensis have previously been reported to exhibit potent antimicrobial, antioxidant, and anti-inflammatory activities. During wound healing, these biological properties play a crucial role for supporting the formation of new tissue around the injured skin in the recovery process. Thus, this study aimed to evaluate the wound healing properties of C. siamensis plasma and serum. The collected data demonstrate that crocodile plasma and serum were able to activate in vitro proliferation and migration of HaCaT, a human keratinocyte cell line, which represents an essential phase in the wound healing process. With respect to investigating cell migration, a scratch wound experiment was performed which revealed the ability of plasma and serum to decrease the gap of wounds in a dose-dependent manner. Consistent with the in vitro results, remarkably enhanced wound repair was also observed in a mouse excisional skin wound model after treatment with plasma or serum. The effects of C. siamensis plasma and serum on wound healing were further elucidated by treating wound infections by Staphylococcus aureus ATCC 25923 on mice skin coupled with a histological method. The results indicate that crocodile plasma and serum promote the prevention of wound infection and boost the re-epithelialization necessary for the formation of new skin. Therefore, this work represents the first study to demonstrate the efficiency of C. siamensis plasma and serum with respect to their wound healing properties and strongly supports the utilization of C. siamensis plasma and serum as therapeutic products for injured skin treatment.

Intranasal melatonin nanoniosomes: pharmacokinetic, pharmacodynamics and toxicity studies

AIM Intranasal melatonin encapsulated in nanosized niosomes was preclinically evaluated. METHODOLOGY A formula of melatonin niosomes (MN) was selected through physicochemical and cytotoxic data for pharmacokinetic, pharmacodynamics and toxicity studies in male Wistar rats. RESULTS Intranasal MN was bioequivalent to intravenous injection of melatonin, providing therapeutic level doses. Acute and subchronic toxicity screening showed no abnormal signs, symptoms or hematological effects in any animals. Transient nasal irritations with no inflammation were observed with intranasal MN, leading it to be categorized as relatively harmless. CONCLUSION The intranasal MN could deliver melatonin to the brain to induce sleep and provide delayed systemic circulation, relative to intravenous injection and also distribute to peripheral tissue.

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

OBJECTIVES Aim 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. METHODS Anti-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. RESULTS According 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. CONCLUSIONS MLT 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.

Prolonged Anti-inflammatory Activity of Topical Melatonin by Niosomal Encapsulation

Melatonin, encapsulated and non-encapsulated, in a topical gel, was comparatively investigated for its in vitro permeation and in vivo anti-inflammatory properties. An average size of the melatonin-encapsulated niosomes of 197 nm with a zeta potential of-78.8 mV and an entrapment efficiency of 92.7% was incorporated into a gel base. In vitro skin permeation of the same gel base incorporated with non-encapsulated melatonin or melatonin niosomes at 5% was comparatively evaluated through porcine skin using Franz diffusion cells and analyzed by spectroflurometry at λex 278 and λem 348 nm. From the same gel base, the permeation rate of non-encapsulated melatonin was about 2.5 times greater than that of melatonin-encapsulated niosomes. In comparison to piroxicam gel and hydrocortisone cream used as the positive controls, topical applications of melatonin and melatonin niosome gels tested in croton oil-induced ear edema in mice suggested that its anti-inflammatory activities were prolonged by the niosomal encapsulation. Similarly, analgesic effect of melatonin was prolonged by niosomal encapsulation using tail flick test in mice. Therefore, its immediate permeation through the skin was retarded by niosomal encapsulation which could also prolong its rapid decline in exerting anti-inflammatory and analgesic activities in vivo.