Antimicrobial and antioxidant activities of two polyketides from lichen-endophytic fungus Preussia sp.

Two compounds, compounds 1 and 2, were isolated from Preussia sp. The molecular structures of both compounds were elucidated by analyzing one-dimensional (1D) and 2D nuclear magnetic resonance data along with high-resolution mass spectrometry data. Compound 1 was obtained as novel in structure, and compound 2 was recently reported elsewhere. Compound 1 did not show antioxidant and antimicrobial activities and brine shrimp toxicity, while compound 2 showed strong antioxidant activity (DPPH reduction capacity; IC50=3 μg/mL) and brine shrimp toxicity (LD50=50 μg/mL).