Co-delivery of beta-caryophyllene and indomethacin in the oily core of nanoemulsions potentiates the anti-inflammatory effect in LPS-stimulated macrophage model

Abstract

The potentiation of pharmacological effects can be achieved through several strategies, such as the association of substances and delivery in nanostructured systems. In practice, potentiation can be measured by the law of mass action and joint evaluation of the combination index (CI) and dose-response curves. In this context, this study aimed to evaluate the anti-inflammatory effect of the association of β-caryophyllene and indomethacin in the free form and delivered in nanoemulsions using the in vitro model of LPS-stimulated murine macrophage. The results indicated potentiation of the anti-inflammatory effect of nanoemulsified substances compared to free substances, as well as synergistic action between the sesquiterpene and the selected NSAID. In comparison, the association of β-caryophyllene and indomethacin in the free form inhibited the production of nitric oxide by 50% at 48.60 µg/mL (CI = 0.21), while the nanoemulsified association of these substances resulted in an IC₅₀ of 1.45 µg/mL (CI = 0.14). In parallel, cytotoxicity assays on HaCaT and MRC-5 cell lines demonstrated the safety of IC₅₀-equivalent concentrations of the anti-inflammatory action, and no irritating effects on the chorioallantoic membrane of embryonated eggs were observed (HET-CAM assay). The results suggest that β-caryophyllene may be an alternative to replace an inert oily core in nanoemulsion systems when anti-inflammatory effects are desirable.

Keywords: Combination index; HET-CAM assay; Isobologram; RAW 264.7 cells; Safety profile.