Kinetic stability and bioavailability of curcumin nanoemulsions stabilized with krill oil phospholipids

Abstract

Curcumin is a phenolic compound with widely reported bioactive properties. However, its low water solubility leads to low stability and bioavailability. Krill oil (KO) is a rich source of phospholipids naturally structured with omega-3 fatty acids (FA) that emerges as a suggested vehicle for curcumin. This study was aimed to prepare curcumin nanoemulsions (NE) using KO phospholipids as a surfactant to improve the absorption of curcumin after oral ingestion. NE were formulated with i) purified krill phospholipids (PCK), and ii) NE with crude KO without the addition of co-surfactants. As a reference, a NE was formulated using soy phosphatidylcholine (PC). Using 8 % of PCK and 4 cycles of ultrasound, NE with unimodal particle size dispersion were formed. The physicochemical analysis of the NE was monitored for 70 days at 4 and 30 °C; the nanoemulsified curcumin followed first-order degradation kinetics with a half-life (t1/2) for PC, KO, and PCK of 396, 328, and 162 days, respectively. TBARS values reached a maximum of 30 μM for KO and PCK NE, but according to the ABTS method, they had better antioxidant activities (>4.9 μM Trolox). Concerning pharmacokinetics, KO NE displayed the best bioavailability data with an AUC of 684.54 ± 72.62 ng h/mL, increasing five times more its absorption with respect to non-nanoemulsified curcumin. According to our data, NEs can guarantee the stability of curcumin during storage at 4 °C and improve its absorption after oral intake. Indeed, self-emulsified KO NEs enhance the bioavailability of curcumin to the same or better extent than soy PC conventional, but with the advantage of providing functional ingredients (omega-3 FA and astaxanthin).