dihydrothiophene-condensed congeners, oxalicumones AÀE (72–76) (Fig. 5), as
well as five cyclopentane-condensed chromones, coniochaetones GÀK (77–81).
Oxalicumone A (72) showed cytotoxicity against the A375 and SW-620 cell lines
with IC 50 values of 11.7 and 22.6 μM, while its (R)-MTPA ester displayed cytotoxicity against the A375, SW-620, and HeLa carcinoma cell lines with IC 50 values of
8.9, 7.8, and 18.4 μM, respectively [41]. Oxalicumones D and E (75 and 76)
exhibited significant cytotoxicity against eight tested cell lines (H1975, U937,
K562, BGC823, MOLT-4, MCF-7, HL60, and Huh-7) with IC 50 values all below
10 μM [42, 43]. Penicitor B (82) was isolated from the solid rice medium fermentation of Penicillium sp. SCS-KFD08 associated with the marine worm Sipunculus
nudus from Haikou Bay. Penicitor B (82) exhibited anti-quorum sensing activity at a
dose of 50 μg/well in the Chromobacterium violaceum CV026 well diffusion assay
[23]. 7-Hydroxy-2-(2-hydroxypropyl)-5-pentylchromone (83) was obtained from
the solid rice medium fermentation of Aspergillus sp. SCSIO XWS02F40 that was
associated with the sponge Callyspongia sp. collected from the sea near Xuwen
County, Guangdong Province. The pentylbenzene moiety of compound 83 is rare in
Nature (Fig. 5) [31].
2.4 Anthraquinones and Hydroanthraquinones
Cultivation of Aspergillus versicolor EN-7, which was isolated from the brown alga
Sargassum thunbergii collected along the Qingdao coastline of Shandong Province,
O
S
O
OH
OH
O
O
O
O
76 (oxalicumone E)
O
S
OH O
OH
O
O
OH
O
O
O
S
OH O
OH
O
O
OH
O
O
O
O
OH
COOCH 3
COOCH 3
OH
72 (oxalicumone A)
73 (oxalicumone B)
74 (oxalicumone C)
O
O
OH
HO
77 R = OH (coniochaetone G)
78 R = H (coniochaetone H)
O
O
OH
HO
R
79 R = OH (coniochaetone I)
80 R = OMe (coniochaetone J)
O
O
OH
OH
OH
81 (coniochaetone K)
O
S
O
OH
OH
OH
O
HO
O
O
75 (oxalicumone D)
O
O
O
HO
O
82 (penicitor B)
O
OH
O
HO
83
R
Fig. 5 Structures of γ-pyrones including xanthones and chromones (part 2)
Secondary Metabolites from Marine-Derived Fungi from China
91