Five new ceramides, neritinaceramides A (
1), B (
2), C (
3), D (
4) and E (
5), together with six known ceramides (
6–
11), two known alkyl glycerylethers (
12 and
13) and a known nucleoside (
14), were isolated from marine bryozoan
Bugula neritina, which inhabits the South China Sea. The structures of the new compounds were elucidated as (2
S,3
R,3′
S,4
E,8
E,10
E)-2-(hexadecanoylamino)-4,8,10-octadecatriene-l,3,3′-triol (
1), (2
S,3
R,2′
R,4
E,8
E,10
E)-2-(hexadecanoylamino)-4,8,10-octadecatriene-l,3,2′-triol (
2), (2
S,3
R,2′
R,4
E,8
E,10
E)-2-(octadecanoylamino)-4,8,10-octadecatriene-l,3,2′-triol (
3), (2
S,3
R,3′
S,4
E,8
E)-2-(hexadecanoylamino)-4,8-octadecadiene-l,3,3′-triol (
4) and (2
S,3
R,3′
S,4
E)-2-(hexadecanoylamino)-4-octadecene-l,3,3′-triol (
5) on the basis of extensive spectral analysis and chemical evidences. The characteristic C-3′
S hydroxyl group in the fatty acid moiety in compounds
1,
4 and
5, was a novel structural feature of ceramides. The rare 4
E,8
E,10
E-triene structure in the sphingoid base of compounds
1–
3, was found from marine bryozoans for the first time. The new ceramides
1–
5 were evaluated for their cytotoxicity against HepG2, NCI-H460 and SGC7901 tumor cell lines, and all of them exhibited selective cytotoxicity against HepG2 and SGC7901 cells with a range of IC
50 values from 47.3 μM to 58.1 μM. These chemical and cytotoxic studies on the new neritinaceramides A–E (
1–
5) added to the chemical diversity of
B.
neritina and expanded our knowledge of the chemical modifications and biological activity of ceramides.
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