2.2 α-Pyrones Including Isocoumarins
The fungus Neosartorya pseudofischeri was obtained from the inner tissue of the
starfish Acanthaster planci collected from the Hainan Sanya National Coral Reef
Reserve. Fermentation of this fungus in liquid GPY medium gave 6,8-dihydroxy-3[(1E,3E)-penta-1,3-dien-1-yl]isochroman-1-one (23) (Fig. 2) [19]. The halotolerant
endophytic fungus Aspergillus sp. F00785 was obtained from the marine alga
Enteromorpha prolifera collected in Jinjiang Saltern, Fujian Province. Three
asperentin-type compounds including 6-O-α-D-ribosylasperentin (24), 6-O-α-Dribosyl-8-O-methylasperentin (25), and 5-hydroxy-6-O-methylasperentin (26) were
isolated following fermentation of this fungus in potato dextrose agar (PDA)
O
O
O
HO
HO
HO
OH O
O
O
O
O
HO
HO
HO
O
O
O
24 (6-O-α-D-ribosylasperentin)
O
OH O
O
O
OH
26 (5-hydroxy-6-O-methylasperentin)
O
R 1 R 2
OH
OH
O
OH
O
27 R 1 = Cl, R 2 = H (peyroisocoumarin A)
28 R
1 = Cl, R
2 = Cl (peyroisocoumarin B)
29 R
1 = OH, R
2 = H (peyroisocoumarin C)
O
O
OH O
OH
OH
30 (peyroisocoumarin D)
O
OH
OH
O
OH
HO
31 (isocitreoisocoumarinol)
O
O
OH
HO
23
O
O
OH
HO
32 (pestaloisocoumarin A)
O
O
OH
HO
AcO
33 (pestaloisocoumarin B)
O
HO
O
OH O
34 (penicitor A)
O
OR 1
R 3
R 2
O
35 R
1 = R
2 = H, R 3 = OH (penicitide A)
36 R
1 = H, R
2 = R 3 = OH (penicitide B)
O
O
O
HN
O
O
O
OH
39 (isopyrophen)
40 (aspergillusol)
O
O
O
O
O
OH
O
O
HO
41 (asteltoxin B)
O
O
OH
HO
OH O
42 (communol A)
O
OH
OH
O
37
O
OAc
O
OH
38
CH 2 OH
25 (6-O-α-D-ribosyl-8-O-methylasperentin)
Fig. 2 Structures of α-pyrones including isocoumarins (part 1)
Secondary Metabolites from Marine-Derived Fungi from China
85