ABSTRACT
BACKGROUND: Curcumin was found to accelerate gastric ulcer healing by the main mechanism, i.e., the suppression of iNOS mediated inflammation. Although Tetrahydrocurcumin (THC) is claimed to be an active antioxidant element of curcumin, its antiulcer activity has not been systematically examined. The utility of Self-Microemulsifying Drug Delivery Systems (SMEDDSs) for curcumin and THC formulations in the liquid form was also found to increase the rate and extent of release of curcumin- and THC-SMEDDS. Nevertheless, the beneficial antiulcer effect of these nanoproducts has not yet been evaluated. OBJECTIVE: This study aimed to evaluate and compare the antiulcer efficacy of curcumin- and THCSMEDDS through the inhibition of the iNOS/NO system in the rat model. METHODS: Antiulcer efficacy was compared in terms of the ability to accelerate healing of gastric ulcer including the efficient inhibitory action on inflammatory NO production in activated macrophages and iNOS mRNA expression at the ulcerated area. RESULTS: THC was found to have less ulcer healing capacity than curcumin with a lack of significant inhibitory effect on the iNOS/NO system. The SMEDDS used in the study significantly increased the inhibitory efficacy of THC on iNOS/NO production and iNOS mRNA expression compared to the inhibitory potency of curcumin. An oral administration of curcumin- or THC-SMEDDS once a day was appropriate for exerting a comparable curative efficacy to a twice-daily oral administration of curcumin or THC. CONCLUSION: The SMEDDS used in the study was observed to enhance the inhibitory efficacy of the antiulcer drug on the iNOS/NO system, leading to a reduction of daily dosing and dosing frequency.
Subject(s)
Curcumin/analogs & derivatives , Curcumin/therapeutic use , Emulsifying Agents/therapeutic use , Nitric Oxide Synthase Type II/antagonists & inhibitors , Nitric Oxide/antagonists & inhibitors , Stomach Ulcer/drug therapy , Administration, Oral , Animals , Curcumin/pharmacology , Drug Compounding/methods , Emulsifying Agents/pharmacology , Macrophages/drug effects , Macrophages/metabolism , Male , Nitric Oxide/metabolism , Nitric Oxide Synthase Type II/metabolism , Rats , Rats, Wistar , Stomach Ulcer/chemically induced , Stomach Ulcer/metabolismABSTRACT
BACKGROUND: Oral inflammatory ulcers are one of the common complaints of patients attending out-patient clinics. Previous in vivo studies had shown that an Aqueous M. citrifolia Fruit Extract (AMFE) possessed anti-inflammatory and ulcer healing activities. Therefore, a standardized topical bioadhesive gel containing AMFE-phytosome was developed and determined for its oral ulcer healing efficacy in a rabbit model. METHODS: The AMFE phytosome (AMFE-P) was prepared by a complexation method with the required amount of AMFE: Phosphatidylcholine: Tween 80 to weigh ratio of 2:1:0.2. Poloxamer 407 was used as a gelling agent. The oral ulcer was induced in male New Zealand white rabbits by topical application of acetic acid. Each test compound was applied to the ulcer for 10 days beginning on the second day after the ulcer induction. Complete ulcer healing on the specimen obtained on day 12 was observed histologically using the histological scoring protocol. RESULTS: The optimized gel containing AMFE-P equivalent to AMFE 10%w/w (10%AMFE-P gel) showed the best bioadhesive gel quality, a smooth and homogeneous texture with an optimum viscosity and pH range used in human oral cavity, a good physical and chemical stability and the highest percentage cumulative release of total phenolic and scopoletin content. It was found that a daily application of 10% AMFE-P gel exerted a superior ulcer healing efficacy and a significantly rapid ulcer healing process than a twice daily application of topical gel containing AMFE 10%w/w or chlorhexidine 0.2%. CONCLUSION: These findings demonstrated that 10% AMFE-P gel has potential as a safe and effective alternative therapeutic agent for oral ulcers.