Novel Aloe-Emodin Derivatives as Potential Anticancer Agents: Synthesis, Characterization and Cytotoxic Activity

The fusion of heterocycles onto an anthraquinone scaffold represents a promising strategy to optimize anticancer activity. This study has the aim to synthesize and characterize novel anthra[1,2-b]furan compounds based on the natural product aloe-emodin. Six novel anthra[1,2-b]furans bearing phenyl, n-hexane, and methoxy carbonyl substituents were synthesized starting from aloe-emodin. The synthetic route employed involved acetyl protection of aloe-emodin, electrophilic aromatic halogenation, subsequent Castro-Stephens coupling, spontaneous intramolecular cyclization, and deprotection of hydroxyl groups. These newly synthesized compounds were evaluated for their cytotoxic activity against various cancer cell lines, including lung adenocarcinoma (A5492), colorectal carcinoma (HCT116), hepatocellular carcinoma (HepG2), ovarian cancer (Skov3), and breast cancer (MCF-7), using the CCK8 assay. The anthra[1,2-b]furan derivative 10c, which contains a methoxy carbonyl group, demonstrated excellent potency against lung (A549) and breast (MCF-7) cancer cell lines, with IC₅₀ values of 0.49 and 2.91 µM, respectively. This preliminary cytotoxic finding shows compound 10c as a promising hit for further investigations towards a promising lead compound.