A New Antioxidant Decalin Polyketide from Freshwater‐Sediment‐Derived Fungus Penicillium sp. Strain S1a1

Abstract

Chromatographic workup for EtOAc (ethyl acetate) extract of an OSMAC (One Strain MAny Compounds)‐modified solid rice culture of the freshwater‐sediment‐derived fungus, Penicillium sp. (S1a1), afforded one new decalin polyketide derivative, tanzawaic acid Z1 (1). The chemical structure of the new derivative was unambiguously established based on extensive 1D (one‐) and 2D (two‐dimensional) NMR (Nuclear Magnetic Resonance) spectroscopic data along with ESI‐HRMS (ElectroSpray Ionization‐High Resolution Mass Spectrometry). Moreover, the relative configuration was determined based on NMR spectroscopic data including a ROESY (Rotational Overhauser Effect SpectroscopY) spectrum. The absolute configuration was suggested on the basis of the specific optical rotation, and biogenetic considerations in comparison with related previously isolated known metabolites from the same fungal strain. In addition, the antioxidant, antibacterial and cytotoxic activities of the new derivative were evaluated. Compound 1 proved to exert a promising antioxidant activity.

Arohynapene A Produced by <i>Penicillium steckii</i> JB-NW-2-1 Isolated from <i>Avicennia marina</i> (Forssk.) Vierh and Its Cytotoxic Activities

“…This result was supported by the comparison between literature as shown in Table 1, where this compound has previously been isolated from the endophytic fungi Penicillium sp. FO-2995 derived from a water sample in Tanegashima, Kagoshima, Japan, and anticoccidial activity with MIC 35.0 μM [20][21][22][23].…”

Freshwater Fungi as a Source of Chemical Diversity: A Review

“…A chemical study of the ethyl acetate extract of a solid rice medium culture yielded three new [penitanzchroman (114) and tanzawaic acids Y (115) and Z (116)] and six known tanzawaic acid derivatives [arohynapene A (117) and tanzawaic acids A (118), B (119), E (120), M (121), and N (122)], three isochromans [(3S)-6-hydroxy-8-methoxy-3,5dimethylisochroman (123), (3S,4R)-6-hydroxy-8-methoxy-3,5-dimethylisochromanol (124), and (1S,3S)-1,6-dihydroxy-3,5-dimethyl-8-methoxyisochroman (125)], and two benzoquinones [anserinones A (126) and B (127)]. 139 Furthermore, investigation of the same fungus using the OSMAC (one-strain many-compounds) approach 140 afforded tanzawaic acid Z1 (128). The in vitro antioxidant activity of this compound using the DPPH assay yielded an IC 50 value of 2.8 μM, which is on par with the positive control, quercetin (i.e., IC 50 value of 5.7 μM).…”

“…The in vitro antioxidant activity of this compound using the DPPH assay yielded an IC 50 value of 2.8 μM, which is on par with the positive control, quercetin (i.e., IC 50 value of 5.7 μM). 140 Penicillium spp. are widespread and reported to grow in diverse habitats, including freshwater environments, and are typically classified as freshwater immigrant species.…”

“…Furthermore, investigation of the same fungus using the OSMAC (one-strain many-compounds) approach afforded tanzawaic acid Z1 ( 128 ). The in vitro antioxidant activity of this compound using the DPPH assay yielded an IC 50 value of 2.8 μM, which is on par with the positive control, quercetin (i.e., IC 50 value of 5.7 μM) …”