Extracts from the seeds of Annona muricata yielded three new Annonaceous acetogenins: muricatetrocin A ( = (SS)-3-{ (2R)-2-hydroxy-9-{(2R,SS)-tetrahydro-S-[(1 S,4S,5S)-1,4,S-trihydroxyheptadecyl]furan-2-yl}nonyl)-S-methylfuran-2(5H)-one; l), muricatetrocin B ( = (SS)-((2R)-2-hydroxy-9-{(2S,SS)-tetrahydro-5-[(lS,4~,SS)-1,4,S-trihydroxyheptadecyl]furan-2-yl~nonyl}-S-methylfuran-2(5H)-one; 2), and gigantetrocin B ( = (5S)-3-{(2R)-Z-hydroxy-7-{(2S, 5s)-tetrahydro-5-[( 1 S, 4R, SR)-l, 4, S-trihydroxynonadecyl]furan-2-yl}heptyl~-S-methylfuran-2(5H)-one; 3). Their C-skeletons were deduced by mass spectrometry. Configurations were determined by 'H-NMR of ketal derivatives and 2D-NMR experiments utilizing Mosher esters. A previously described compound, gigantetrocin A ( = (SS)-3
-{(2R)-2-hydroxy-7-{(2S,SS)-tetrahydro-5-[( lS,4S,SS)-I,4,S-trihydroxynona-
decyl]furan-2-yl}heptyl}-5-methylfuran-2-(S~)one; 4), was also isolated and is new to this species. Compounds 1-4 were all selectively cytotoxic for the HT-29 human colon-tumor cell line with potencies at least 10 times that of adriamycin.
') , )
This compound was previously called gigantetrocin . Arbitrary numbering according to Schemes I and 2 ; systematic names are given in the Exper. Purr. ));3.85(dt,J=5.9,6.7,H-C(10));5.04(dq,J=7.1, 1.4,H-C(34)); 7.17 (d, J = 1.4, H-C(33).
3.78(q,J=7.0,H-C(13));3.82(~,H-C(