Two new gingerol derivatives from the rhizome of Curcuma xanthorrhiza D.Dietr

A phytochemical investigation of the EtOAc-soluble extract from the rhizomes of Curcuma xanthorrhiza D.Dietr. led to the isolation of five gingerol derivatives, including two news, xanthorrhiza A (3) and xanthorrhiza B (5). These compounds were purified through column chromatography, and their structures were elucidated through spectral analysis. Bioactivity testing revealed that xanthorrhiza B (5) exhibited the strongest tyrosinase inhibitory activity with an IC₅₀ value of 61.0 μM, as strong as a positive control, kojic acid (IC₅₀: 44.6 µM). Additionally, the α-glucosidase inhibitory activity of 8-dehydrogingerdione (2) was the most potent than that of evaluated compounds, with an IC₅₀ value of 19.5 μM, and more potent than a positive control, acarbose (IC₅₀: 185.2 μM).