Preclinical studies of the antitumor effect of curcumin-loaded polymeric nanocapsules: A systematic review and meta-analysis

Curcumin, a plant-derived compound, has various well-known biological effects (anti-inflammatory, antioxidant, antitumor, among others) as well as some important limitations for formulators, such as poor water solubility and low oral bioavailability. Its nanoencapsulation is reported to overcome these drawbacks and to improve its in vivo efficacy. Here, data from preclinical in vivo studies evaluating the antitumor efficacy of curcumin-loaded polymeric nanocapsules are collected, analyzed, and discussed as a systematic review. Meta-analyses are performed to assess the contribution of this nanoencapsulation compared with nonencapsulated curcumin. Eighteen studies (116 animals) meet the inclusion criteria. The evidence that curcumin-loaded polymeric nanocapsules inhibits tumor growth (SMD: -3.03; 95% CI: -3.84, -2.21; p < 0.00001) and decreases tumor weight (SMD: -3.96; 95% CI: -6.22, -1.70; p = 0.0006) in rodents is established, regardless of the solid tumor model. To assess the quality of the studies included in the review a bias risk analysis was performed using the SYRCLE's RoB tool. Therefore, encapsulation in polymeric nanocapsules represents an important tool to improve the antitumor effects of curcumin, and this systematic review paves the way for future clinical studies and the translation of curcumin formulations into novel nanomedicines for human cancer treatment.