Recent Developments in Chemical Synthesis and Biological Activities of Aloe-Emodin Derivatives

Aloe-emodin is an anthraquinone with a wide range of medicinal applications, including anti-angiogenic, anticancer, antimicrobial, antiviral, anti-inflammatory, and antioxidant activities. In this review, the functionalization of aloe-emodin using various synthetic methods, including alkylation, condensation, esterification, the Finkelstein reaction, and the Kabachnik–Fields reaction was reported. The biological activity of the synthesized aloe-emodin derivatives is discussed, with a focus on their potential future applications as anticancer agents, enzyme inhibitors, anti-inflammatory agents, and antimicrobial agents. This review also discusses the structure–activity relationship (SAR) and the mechanism of action (e.g., molecular docking studies, cell membrane-disrupting capacity, and apoptosis studies). This review highlights the many contributions made towards the design and development of novel, biologically active aloe-emodin derivatives.