Meroterpenoids from a Medicinal Fungus <i>Antrodia cinnamomea</i>

<i>Antrodia cinnamomea,</i> a medicinal fungus indigenous to Taiwan, has been shown to exhibit a broad spectrum of bioactivities for the treatments of alcoholic intoxication, diarrhea, abdominal pain, and fatigue, and a number of active principles have been identified. Among the bioactive entities, clinical trials of antroquinonol and 4-acetyl antroquinonol B are being carried out for curing cancer, hypercholesterolemia, and hyperlipidemia. The total synthesis of antroquinonol has been achieved; however, investigating the structure–activity relationship of this class of compounds remained difficult due to the lack of available analogues. Twenty antroquinonols isolated from <i>A. cinnamomea</i> IFS006 are reported herein. Their structures were elucidated using spectral analysis and by comparison with literature values. Of these, 11 antroquinonol analogues, namely, antroquinonols N–X (<b>1</b>–<b>11</b>), were previously unreported. The growth inhibitory activity of all the antroquinonol analogues was evaluated against human A549 and PC-3 cancer cell lines, and antroquinonol A exhibited the most potent activity, with GI₅₀ values of 5.7 ± 0.2 and 13.5 ± 0.2 μM, respectively. Antroquinonols V (<b>9</b>) and W (<b>10</b>) also showed growth inhibitory activity against A549 cells with GI₅₀ values of 8.2 ± 0.8 and 7.1 ± 2.1 μM, respectively, compared to 5-fluorouracil (GI₅₀ = 4.2 ± 0.2 μM)