Enhanced oral bioavailability and anti-gout activity of [6]-shogaol-loaded solid lipid nanoparticles

[6]-Shogaol, an alkylphenol compound purified from the root and stem of ginger (Zingiber officinale), has attracted considerable interest due to its potential anticancer, antioxidative and antirheumatic properties. However, the oral bioavailability of [6]-shogaol has been severely limited because of its poor solubility. In this study, a significant quantity of high-purity [6]-shogaol (yield: 3.6%; purity: 98.65%) was extracted and encapsulated in solid lipid nanoparticles (SLNs) via high-pressure homogenization (encapsulation efficiency: 87.67%) to improve its solubility and oral bioavailability. The resulting [6]-shogaol-loaded solid lipid nanoparticles (SSLNs) were stable, homogeneous and well-dispersed. Its mean particle size and zeta potential were 73.56 +/- 5.62 nm and -15.2 +/- 1.3 mV, respectively. Importantly, the in vitro release profile and in vivo oral bioavailability of SSLNs were significantly improved compared with the free drug. Furthermore, the SSLNs could remarkably lower the uric acid level via inhibiting the activity of xanthine oxidase and reduce the production of interleukin-1 beta (IL-1 beta) and tumor necrosis factor (TNF-alpha) in the hyperuricemia/gouty arthritis rat model, when compared to the free [6]-shogaol. Collectively, SLNs could serve as a promising drug delivery system to improve the oral bioavailability of [6]-shogaol for effective treatment of gouty arthritis.