Absolute Configuration of Bioactive Azaphilones from the Marine-Derived Fungus Pleosporales sp. CF09-1

Abstract

Investigation of the marine-derived fungus Pleosporales sp. CF09-1 cultured in modified PDB medium led to the isolation of six new azaphilone derivatives, pleosporalones B and C (1 and 2) and pleosporalones E−H (4−7), and one known analogue (3). The absolute configurations of C-2′ and C-3′ in 3 were assigned by a vibrational circular dichroism method. The C-11 relative configurations for the pair of C-11 epimers (4 and 5) were established by comparing the magnitude of the computed 13 C NMR chemical shifts (Δδ calcd ) with the experimental 13 C NMR values (Δδ exp ) for the epimers. Antiphytopathogenic and anti-Vibrio activities were evaluated for 1−7. Pleosporalone B (1) exhibited potent antifungal activities against the fungi Alternaria brassicicola and Fusarium oxysporum with the same MIC value of 1.6 μg/mL, which were stronger than the positive control ketoconazole among these compounds. Additionally, pleosporalone C (2) displayed significant activity against the fungus Botryosphaeria dothidea (MIC, 3.1 μg/mL). Compounds 6 and 7 displayed moderate anti-Vibrio activities against Vibrio anguillarum and Vibrio parahemolyticus, with MIC values of 13 and 6.3 μg/mL for 6 and 6.3 and 25 μg/mL for 7, respectively.

Recent advances in the chemistry and biology of azaphilones

“…BS4 37 Antimicrobial (Staphylococcus aureus: 5.0 mg mL À1 ) Colletotrichone C (56) Colletotrichum sp. BS4 37 Antimicrobial (Escherichia coli: 5.0 mg mL À1 ) Coniellin A (57) Coniella fragariae 9 Anti-tumor (MDA-MB-231: 21.5 mM, inhibit NF-kB activation: 4.4 mM) Coniellin B (58) Coniella fragariae 9 Anti-tumor (MDA-MB-231: 19.6 mM) Coniellin C (59) Coniella fragariae 9 Anti-tumor (MDA-MB-231: 21.0 mM) Coniellin D (60) Coniella fragariae 9 Anti-tumor (MDA-MB-231: 18.6 mM, inhibit NF-kB activation: 37.8 mM) Coniellin E (61) Coniella fragariae 9 Anti-tumor (MDA-MB-231: 79.3 mM, inhibit NF-kB activation: 29.4 mM) Coniellin F (62) Coniella fragariae 9 Anti-tumor (inhibit NF-kB activation: 70.7 mM) Coniellin G (63) Coniella fragariae 9 Anti-tumor (MDA-MB-231: 21.6 mM, inhibit NF-kB activation: 11.3 mM) Coniellins H-I (64)(65) Coniella fragariae 35 5 0 ,6 0 -Dihydroxyacetosellin (66) Epicoccum nigrum strain 749 38 Monakaocinol 67Monascus kaoliang 39 Monascuspirolide A (68) Monascus purpureus BCRC 38110 42 Anti-inammatory (inhibit NO production: 17.5 mM) Monascuspirolide B (69) Monascus purpureus BCRC 38110 42 Anti-inammatory (inhibit NO production: 23.5 mM) Thielavialides A-E (70)(71)(72)(73)(74) Thielavia sp. PA0001 40…”

“…And the absolute congurations of C-11 in both 137 and 138 were assigned via the GIAO 13 C NMR calculations, while the congurations of C-11 in 139 and 140 remained unassigned due to the impracticable calculations. 61 They displayed anti-Vibrio anguillarum activities with MIC values from 6.3 to 25 mg mL À1 . 61…”

“…CF09-1 yielded three new azaphilone derivatives carrying with aromatic A-ring, pleosporalones A-C (205-207). 61,85 Among them, 205 displayed strong antifungal activity against three plant pathogenic fungi with the MIC values ranging from 0.39 to 0.78 mM. 85 Additionally, 206 exhibited stronger antifungal activities against Alternaria brassicicola and Fusarium oxysporum with the same MIC value of 1.6 mg mL À1 than that of the positive control ketoconazole, whilst 206 displayed signicant activity against Botryosphaeria dothidea (MIC ¼ 3.1 mg mL À1 ).…”

“…85 Additionally, 206 exhibited stronger antifungal activities against Alternaria brassicicola and Fusarium oxysporum with the same MIC value of 1.6 mg mL À1 than that of the positive control ketoconazole, whilst 206 displayed signicant activity against Botryosphaeria dothidea (MIC ¼ 3.1 mg mL À1 ). 61…”

“…Chemical structures of deflectin-type azaphilones(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63)(64)(65).…”