Natural product emodin-based nanodrug delivery systems: Advancements and applications

Emodin, a natural anthraquinone derivative, possesses diverse pharmacological activities encompassing anticancer, antibacterial, anti-inflammatory, antiviral, antifibrosis, and antioxidant effects. Nevertheless, its clinical application is severely impeded due to its poor water solubility, inadequate stability, low bioavailability, and potential dose-dependent toxicity. To address these challenges, multiple nanoscale drug delivery systems have been developed for emodin, with great promise for improving its solubility and stability, enhancing bioavailability, and mitigating its toxicity. Currently, there is a noticeable research gap regarding the systematic summary of emodin nanoformulations and their application in various diseases. Therefore, we meticulously summarized and discussed the research progress and clinical translation of emodin nanodrug delivery systems against various diseases (anticancer, anti-inflammatory, antibacterial, antifibrotic, obesity, and others). Furthermore, the key challenges that hinder the translational application of emodin nanoformulations, as well as the future development directions of the emodin nanodrug delivery systems, are systematically analyzed and elaborated. This review provides a comprehensive reference for the rational design and optimization of nanoformulations for emodin and compounds sharing the same anthraquinone scaffold, including aloe-emodin, chrysophanol, rhein and physcion, thereby accelerating their clinical translation.