A new meroterpene, chrysomutanin (1), two new meroterpenoids (4 and 5) together with nine known ones were isolated from the diethyl sulphate (DES) mutant 3d10-01 of the marine-derived fungus Penicillium chrysogenum S-3-25. The structures of the isolated compounds were determined by their spectroscopic data, and the absolute configuration of 1 was determined by Rh₂-induced electrical circular dichroism (ECD) analysis or by comparison of the measured ECD with that of the known compounds. The cytotoxic activity was preliminarily evaluated against five human cancer cell lines. HPLC-UV analysis showed that compounds 1–12 were all newly produced by the mutant, and were not detected from the initial strain S-3-25. Chrysomutanin (1) is a new member with a chain sesquiterpene unit to the family of meroterpenes. Present results confirm that DES mutagenesis strategy is an effective method to exploit the dormant metabolites of fungi.

Natural products are irreplaceable reservoirs for cancer treatments. In this study, 12 phenanthrene compounds were extracted and isolated from Dendrobium officinale. Each chemical structure was identified using comprehensive NMR analysis. All compounds were evaluated for their cytotoxic activities against five tumor cell lines, i.e., HeLa, MCF-7, SK-N-AS, Capan-2 and Hep G2. Compound 5, 1,5,6-trimethoxy-2,7-dihydroxyphenanthrene, displayed the most significant cytotoxic effect against HeLa and Hep G2 cells, with an IC₅₀ of 0.42 and 0.20 μM. For Hela cells, further experiments demonstrated that compound 5 could obviously inhibit cell migration, block cell cycle in the G0/G1 phase and induce apoptosis. Expression measurements for p53 indicated that knock down of p53 by siRNA could mitigate the apoptosis induced by compound 5. Therefore, the compound 5 is a potential candidate drug for HeLa cells in cervical cancer.