Tithoniaquinone A and Tithoniamide B: A New Anthraquinone and a New Ceramide from Leaves of Tithonia diversifolia

From the leaves of Tithonia diversifolia, four compounds were isolated and identified. Two of them, the anthraquinone tithoniquinone A (1) with an unusual substitution pattern on the anthraquinone skeleton, and the ceramide, named tithoniamide B (2a), are reported for the first time as natural products. Their structures were determined by comprehensive analyses of their 1D and 2D NMR and electron impact (EI) mass spectral data. The remaining two known compounds were identified as psoralen and l-quebrachitol. Preliminary studies showed that tithoniaquinone A (1) is strongly antibacterial and antifungal against Gram-positive Bacillus megaterium and Microbotryum violaceum, respectively, while psoralen has strong algicidal, fungicidal, and antibacterial activities.