Evaluation of the in vivo acute antiinflammatory response of curcumin-loaded nanoparticles

Abstract

Curcumin is the main curcuminoid found in turmeric rhizomes and is a strong candidate to formulate foodstuff with specific properties. Among various bioactive properties of curcumin, its antiinflammatory activity is remarkable; on the other hand, its low water solubility leads to low absorption. Thus, new formulations need to be developed to improve its efficacy, and encapsulation is a promising alternative strategy in this regard. The objective of the present study was to obtain curcumin-loaded polyvinylpyrrolidone (PVP) nanoparticles and evaluate their acute in vivo antiinflammatory activity. Nanoparticles were obtained by complexation using the solid dispersion technique, and the characterization of nanoparticles showed that curcumin and PVP formed an amorphous solid solution. Encapsulated curcumin was colloidally stable in distilled water; this was attributed to the formation of hydrogen bonds between curcumin hydroxyl and PVP carbonyl groups. Rats were treated orally with single doses of curcumin and curcumin-loaded PVP nanoparticles, and antiinflammatory activity was evaluated by an experimental model of carrageenan-induced paw edema, myeloperoxidase (MPO) activity, and microcirculation in situ. Treatment with nanoparticles at 12.5 mg kg⁻¹ significantly reduced the intensity of edema and MPO activity, whereas pure curcumin only presented a significant effect at 400 mg kg⁻¹. Curcumin inhibited cell migration since rolling and adherent leukocytes were significantly reduced using nanoparticles at 50 mg kg⁻¹ and curcumin at 400 mg kg⁻¹. Compared to free curcumin, encapsulated curcumin was effective at lower doses; this might be due to the improved water affinity and colloidal stability of curcumin nanoparticles.