Avaliação da atividade antimicrobiana de microcristais de curcumina

Abstract

Phenolic compound extracted from the rhizome of Curcuma longa, curcumin is a crystalline pigment, insoluble in water, susceptible to factors such as pH, temperature, oxidation and light. This weakness hampers its use in various applications, which is a problem since curcumin has several interesting pharmacological effects such as anti-inflammatory, antimicrobial, antioxidant, and many studies indicate its performance in blocking carcinogenesis. Thus, it becomes necessary to develop methods for the use of this potential. In this study, curcumin was converted into microcrystals by the modified method of non-solvent preciptation. For the preparation of microcrystals three formulations were tested, with or without stabilizers: 1) PVP + curcumin; 2) curcumin + calcium caseinate and 3) curcumin without the addition of stabilizer. The formulation that showed better characteristics to be analyzed in the light microscope was curcumin without adding a stabilizer, and that this formulation was chosen for the antimicrobial activity tests. A comparison of the antimicrobial activity exhibited by the two compounds by means of modified dilution technique in agar was done before four microorganisms: S. aureus, E. coli, P. aeruginosa and B. cereus. Free curcumin and curcumin microcrystals were able to inhibit growth of all the microorganisms. In addition, the minimum inhibitory concentrations (MIC) obtained demonstrate the increased efficiency of microcrystals regarding curcumin in nature, and the main explanation for this is the reduced particle size of the microcrystals. Characterization analyzes by Differential Scanning Calorimetry (DSC) confirm that the only physical modifications suffered by the material was a reduction in the size of the crystals. These results demonstrate that the production of curcumin microcrystals is an alternative that facilitates and enhances its use.