Interaction of Over-the-Counter Drugs with Curcumin: Influence on Stability and Bioactivities in Intestinal Cells
ABSTRACT Curcumin, a major constituent in rhizomes of Curcuma longa L., has shown various biological activities. It has widely been used as a food additive to provide potential health benefits. In the present study, we investigated changes in chemical stability and cytotoxic properties of curcumin and commonly consumed over-the-counter (OTC) drugs including ibuprofen, acetylsalicylic acid (Asp), and acetaminophen (AAP), through their interactions. Stability of curcumin was significantly improved in phosphate-buffered saline or 0.01 N HCl containing each OTC drug; Asp showed the most prominent effect. Stability of Asp or AAP during 24 h incubation with curcumin was not changed significantly. Cytotoxic effects of curcumin were enhanced in the presence of the OTC drugs on INT 407 normal intestinal and HCT 116 colon cancer cells. Relative cytotoxicity of curcumin (>10 μM) under the drug-treated conditions was significantly higher. Cellular uptake of curcumin in HCT 116 cells increased significantly when incubated with Asp or AAP. Intracellular thiol levels of the cells treated with curcumin were further reduced in the presence of the OTC drugs. The present study provides information that commonly consumed OTC drugs affect chemical stability of curcumin in physiological conditions, and certain bioactivities of curcumin can be altered through their interactions.
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ABSTRACT: The results of TG/DTG when curcumin was used as the food colouring agent indicated that the processing temperature of the food should not exceed 190 °C. The decomposition process of curcumin involved two stages. The results of Eα values, determined by an advanced isoconversional method, showed that the two stages were both single-step processes. The most probable mechanisms of the two stages were estimated by using comparative and nonlinear model-fitting methods. The mechanisms obtained from the two methods are the same, which are the assumed random nucleation and its subsequent growth for stage I and one-dimensional diffusion for stage II, respectively. The values of pre-exponential factor A for both stages were obtained on the basis of Ea and g(α). Besides, some thermodynamic functions (ΔS≠, ΔH≠ and ΔG≠) of the transition state complexes for the two stages were also calculated.Food Chemistry 07/2014; 155:81–86. DOI:10.1016/j.foodchem.2014.01.034 · 3.26 Impact Factor