Anti-Inflammatory Efficacy of Fabricated Rhein Micelles

Rhein is a potential anti-inflammatory agent, but its poor water solubility significantly restricts its clinical application. In this study, rhein micelles (RMs) with improved water solubility were fabricated on Pluronic F127 (F-127). Transmission electron microscopy showed that the as-prepared RMs displayed a mean diameter of approximately 20 nm and a spherical morphology. The encapsulation efficiency of the micelles towards drugs varied from 81.38 ± 4.35% to 24.87 ± 4.32%. The RMs exhibited a burst release during the first 6 h and a following sustained release up to 96 h with a biphasic drug release pattern as suggested by the drug release assay. Cytotoxicity assessment showed that the RMs caused no change in cell viability at drug concentrations below 40 μM after 24 and 48 h of incubation. In RAW264.7 macrophages, the RMs inhibited the lipopolysaccharide-induced activation of p65/NF-κB, which in turn suppressed the transcription of its downstream inducible nitric oxide synthase, and cytokine genes such as interleukin-1β and tumor necrosis factor-α . Simultaneously, the RMs led to reduced cytokine secretions, including cyclooxygenase-2, prostaglandin E2, nitric oxide, and interleukin-6 in a dose-dependent manner. The RMs reported herein may be a promising candidate for developing anti-inflammatory therapeutic formulations.