Curcumin loaded and co-loaded nanosystems: A review from a biological activity enhancement perspective.

BACKGROUND Curcumin is a natural phenolic compound exhibiting multiple bioactivities that have been evaluated in vitro, in vivo as well as through clinical studies in humans. Some of them include antimicrobial, antioxidant, anti-inflammatory and central nervous system protective effects. Further, curcumin is considered a Generally Recognized as Safe substance because of its low toxicity. However, its molecular structure is susceptible to changes in pH, oxidation, photodegradation, low aqueous solubility and biotransformation compromising its bioavailability, drawbacks that have been successfully addressed through nanotechnology. OBJECTIVE The present review systematizes findings on the enhancement of curcumin's beneficial effects when it is loaded and co-loaded into different types of nanosystems covering liposomes, polymeric and solid-lipid nanoparticles, nanostructured lipid carrier, lipid-polymeric hybrids, self-assembled and protein-based core-shell systems in relation to its antimicrobial, antioxidant, anti-inflammatory and central nervous system protective bioactivities. CONCLUSION Curcumin is a versatile molecule capable of exerting antimicrobial, antioxidant, anti-inflammatory and central nervous system protective effects in an enhanced manner using the possibilities offered by the nanotechnology - based approach. Its enhanced bioactivities are associated with increments in solubility, stability, bioavailability as well as in improved intracellular uptake and cell internalization. These advantages, in addition to curcumin's low toxicity, indicate the potential of curcumin to be loaded and co-loaded into nanosystems capable to provide a controlled release and targeted administration.