alkaloids, versiquinazolines AÀK (506–516). Versiquinazolines A, B, G, and K
(506, 507, 512, and 516) displayed inhibitory activities against thioredoxin with IC 50
values of 20, 12, 13, and 13 μM, respectively (Fig. 29) [158].
Fumiquinazoline L (517) (Fig. 30) was obtained from the liquid glucose potato
medium fermentation of Scopulariopsis sp. TA01-33, a fungus associated with the
gorgonian Carijoa sp. collected from the Weizhou coral reef in the South China Sea
[159]. Neosartin C (518) was isolated from the liquid GPY medium cultivation of
N
N
NH
O
O
O
502 (versicomide A)
N
N
NH
O
O
O
503 (versicomide B)
N
N
NH
O
O
O
504 (versicomide C)
O
N
N
NH
O
O
505 (versicomide D)
O
O
N
N
N
N
O
O
O
COOMe
OH
512 (versiquinazoline G)
N
N
O
O
N
N
O
HO
513 (versiquinazoline H)
N
N
N
O
O
506 R 1 = Me, R 2 = H
(versiquinazoline A)
507 R 1 = R 2 = CH 2
(versiquinazoline B)
N
O
N
O
R 2
R 1
N
N
NH
O
O
508 (versiquinazoline C)
N
H
O
N
O
N
N
NH
O
O
509 R 1 = Me, R 2 = H
(versiquinazoline D)
510 R 1 = R 2 = CH 2
(versiquinazoline E)
N
NH
OH
O
R 1
R 2
N
N
NH
O
O
511 (versiquinazoline F)
N
N
O
O
N
N
NH
O
O
514 (versiquinazoline I)
OH
N
H
N
N
O
O
NH OR
O
515 R = Me
(versiquinazoline J)
516 R = H
(versiquinazoline K)
N
H
O
O
N
H
O
OH
OH
O
497 R 1 = Me, R 2 = H (22-O-(N-Me-L-valyl)aflaquinolone B)
498 R 1 = H, R 2 = Me (22-O-(N-Me-L-valyl)-21-epi-aflaquinolone B)
O
O
N
N
N
O
O
O
O
500 (terremide C)
R 1
R 2
N
H
O
O
R 1
499 R 1 = OH, R 2 = H (3-methoxyviridicatol)
501 R 1 = H, R 2 = OH (9-hydroxy-3-methoxyviridicatin)
R 2
Fig. 29 Structures of quinolone and quinazoline derivatives (part 1)
128
Z. Liu et al.