Penicillanthone and penicillidic acids A–C from the soil-derived fungus Penicillium aculeatum PSU-RSPG105

Abstract

A new xanthone (penicillanthone, 1) and three new diphenyl ether derivatives (penicillidic acids A–C, 2–4) together with 14 known compounds (5–18) were isolated from the soil-derived fungus Penicillium aculeatum PSU-RSPG105. The structures were elucidated by spectroscopic analyses. The absolute configuration of compound 1 was determined using the Snatzke's method whereas those of compounds 2–4 was established by comparison of their optical rotations with those of structurally related compounds. Compound 5 exhibited mild antimycobacterial activity against Mycobacterium tuberculosis with an MIC value of 25 μg mL⁻¹ and was noncytotoxic to noncancerous Vero cells. In addition, altenusin (12) displayed moderate antibacterial activity against methicillin-resistant Staphylococcus aureus with an MIC value of 32 μg mL⁻¹ and mild activity towards Vero cells with an IC₅₀ value of 19.46 μM.