C O M M U N I C A T I O N S
Supporting Information Available: Experimental procedure and
characterization data for 1 and 3-11, along with any intermediates.
This material is available free of charge via the Internet at http://
pubs.acs.org.
References
(1) Hecht, S. M. Pharm. Biol. 2003, 41, S68 and references therein.
(2) Starck, S. R.; Deng, J.-K.; Hecht, S. M. Biochemistry 2000, 39, 2413.
(3) (a) Erasto, P.; Bojase-Moleta, G.; Majinda, R. T. Phytochemistry 2004,
65, 875. (b) Martini, N. D.; Katerere, D. R. P.; Eloff, J. N. J. Ethnopharm.
2004, 93, 207. (c) Khan, M. S. Y.; Hasan, S. M. Indian J. Chem., Sect.
B 2003, 42, 1970. (d) Tang, S.; Bremner, P.; Kortenkamp, A.; Schlage,
C.; Gray, A. I.; Gibbons, S.; Heinrich, M. Planta Med. 2003, 69, 247.
(4) (a) Dumontet, V.; Van Hung, N.; Adeline, M. T.; Riche, C.; Chiaroni,
A.; Sevenet, T.; Gueritte, F. J. Nat. Prod. 2004, 67, 858. (b) Kobayakawa,
J.; Sato-Nishimori, F.; Moriyasu, M.; Matsukawa, Y. Cancer Lett. 2004,
208, 59. (c) Sonoda, M.; Nishiyama, T.; Matsukawa, Y.; Moriyasu, M. J.
Ethnopharm. 2004, 91, 65. (d) Fu, Y.; Hsieh, T.; Guo, J.; Kunicki, J.;
Lee, M. Y.; Darzynkiewicz, Z.; Wu, J. M. Biochem. Biophys. Res.
Commun. 2004, 322, 263. (e) Hsu, Y. L.; Kuo, P. L.; Liu, C. F.; Lin, C.
C. Cancer Lett. 2004, 212, 53. (f) Takahashi, T.; Takasuka, N.; Ligo, M.;
Baba, M.; Nishino, H.; Tsuda, H.; Okuyama, T. Cancer Sci. 2004, 95,
448.
(5) (a) Lee, J. S.; Kim, H. J.; Lee, Y. S. Planta Med. 2003, 69, 859. (b)
Jassim, S. A.; Naji, M. A. J. Appl. Microbiol. 2003, 95, 412. (c) Chiang,
L. C.; Chiang, W.; Liu, M. C.; Lin, C. C. J. Antimicrob. Chemother. 2003,
52, 194. (d) Li, Y. L.; Ma, S. C.; Yang, Y. T.; Ye, S. M.; But, P. H. J.
Ethnopharm. 2002, 79, 365. (e) Zembower, D. E.; Lin, Y. M.; Flavin, M.
T.; Fa-Ching, C.; Korba, B. E. AntiViral Res. 1998, 39, 81.
(6) Sawadjoon, S.; Kittakoop, P.; Kirtikara, K.; Vichai, V.; Tanticharoen, M.;
Thebtaranonth, Y. J. Org. Chem. 2002, 67, 5470. Compound 1 was also
isolated from Horsfieldia amygdaline; see: Katuhiko, H.; Akio, K.;
Hirokazu, Y.; Akira, M.; Akira, I.; Akinori, S.; Shengji, P.; Yanhui, L.;
Chun, W. Patent WO 9208712, 1992.
(7) (a) Chang, Y. C.; Kuo, S. C.; Lin, Y. L.; Wang, J. P.; Huang, L. J. Bioorg.
Med. Chem. Lett. 2001, 11, 1971. (b) Kurosawa, W.; Kan, T.; Fukuyama,
T. J. Am. Chem. Soc. 2003, 125, 8112. (c) Le Stang, S.; Meier, R.;
Rocaboy, C.; Gladysz, J. A. J. Flourine Chem. 2003, 119, 141. (d) Vanden
Eynde, J. J.; Mailleux, I. Synth. Commun. 2001, 31, 1. (e) Ruenitz, P. C.;
Arrendale, R. F.; Schmidt, W. F.; Thompson, C. B.; Nanavati, N. J. Med.
Chem. 1989, 32, 192. (f) Wu, G.; Geib, S. J.; Rheingold, A. L.; Heck, R.
F. J. Org. Chem. 1988, 53, 3238.
(8) (a) Hatayama, K.; Yokomori, S.; Kawashima, Y.; Saziki, R.; Kyogoku,
K. Chem. Pharm. Bull. 1985, 33, 1327. (b) Jung, S. H.; Cho, S. H.; The,
H. D.; Lee, J. F.; Ju, J. H.; Kim, M. K.; Lee, S. H.; Ryu, J. C.; Kim, Y.
Eur. J. Med. Chem. 2003, 38, 537. (c) Tunoori, A. R.; Dutta, D.; Georg,
G. I. Tetrahedon Lett. 1998, 39, 8751. (d) Dewick, P. M. Synth. Commun.
1981, 11, 853.
Figure 1. Relaxation of supercoiled plasmid DNA by 1 in the presence of
20 µM Cu2+: (lane 1) DNA + 20 µM Cu2+; (lane 2) DNA + 50 µM 1,
(lanes 3-8) DNA + 20 µM Cu2+ + 50, 10, 2, 0.5, 0.1 and 0.05 µM 1,
respectively; (lane 9) DNA alone.
dodecan-1-one17 with 9 in THF gave the desired 2,4-trans isomer
10 in good yield (77%) and excellent diastereoselectivity (g95:5).
Acetate deprotection using methanolic K2CO3, followed by thio-
acylation with phenyl chlorothionoformate in MeCN at 60 °C, gave
the desired deoxygenation precursor. The thioester was treated
immediately with SnBu3H in the presence of catalytic AIBN in
toluene at reflux to furnish the deoxygenation product 11 (65%,
three steps).18 Complete deprotection proceeded smoothly using
Pearlman’s catalyst (Pd(OH)2/C) in 1:1 THF/MeOH to afford (+)-
myristinin A (1) in 75% yield.19
Single-strand breakage of supercoiled (Form I) pSP64 plasmid
DNA by 1 was observed in the presence of Cu2+ in a dose-
dependent manner (Figure 1). The concentration of Cu2+ was kept
constant at 20 µM while 1 was tested at 50 µM-50 nM
concentrations. Concentration-dependent plasmid relaxation was
readily apparent within 2.5 h (Figure 1). Investigations at lower
concentrations of 1 revealed the accumulation of DNA cleavage
in a steady fashion over a period of a few days. Under these
conditions, cleavage was readily apparent at 10 pM concentration.
The potency of DNA cleavage by Cu2+ + 1 in replicate experiments
over an extended time period argues that 1 must produce a
concentration of DNA breaks that greatly exceeds its own molar
concentration, i.e., that it cleaves DNA “catalytically”. This property
is the subject of ongoing study.
In addition to its potent DNA-damaging ability, 1 was also shown
to inhibit DNA polymerase â (IC50 2.8 µM), a DNA repair enzyme
important in base excision repair. Inhibition of this enzyme has
been shown to result in potentiation of the cytotoxic activity of
bleomycin (BLM), indicating the potential for polymerase inhibitors
to allow lower doses of DNA-damaging antitumor agents to be
administered.1 In fact, in cultured A549 cells, a sublethal concentra-
tion of 1 strongly potentiated the cytotoxicity of BLM.20 Moreover,
polymerase â was shown to be overexpressed in cells exposed to
DNA-damaging agents, further validating the enzyme as a potential
target for cancer chemotherapy.21 Typically DNA polymerase â
inhibitors only prevent DNA repair, thereby limiting their potential
use to that of adjuvants with known DNA-damaging agents. In
contrast, the unique dual biological activity of 1 offers the additional
prospect of use as a single agent capable of mediating DNA damage
and blocking repair of the induced lesions.
(9) (a) Claisen, L.; Clapare`de, A. Chem. Ber. 1881, 14, 2460. (b) Schmidt, J.
G. Chem. Ber. 1881, 14, 1459.
(10) Minami, N.; Kijima, S. Chem. Pharm. Bull. 1979, 27, 1490.
(11) Sharpless, K. B.; Amberg, W.; Beller, M.; Chen, H.; Hartung, J.;
Kawanami, Y.; Lu¨bben, D.; Manoury, E.; Ogino, Y.; Shibata, T.; Ukita,
T. J. Org. Chem. 1991, 56, 4585. This established the absolute stereo-
chemistry at the position corresponding to C-2 in myristinin A and that
of (+)-myristinin A as 2S,4R. The assignment was supported by the CD
spectrum of the alcohol precursor of 7 (van Rensburg, H.; Steynberg, P.
J.; Burger, J. F. W.; van Heerden, P. S.; Ferreira, D. J. Chem. Res., Synop.
1999, 450).
(12) Li, L.; Chan, T. H. Org. Lett. 2001, 3, 739.
(13) (a) Dess, D. B.; Martin, J. C. J. Org. Chem. 1983, 48, 4155. (b) Dess, D.
B.; Martin, J. C. J. Am. Chem. Soc. 1991, 113, 7277.
(14) Tu¨ckmantel, W.; Kozikowski, A. P.; Romanczyk, L. J., Jr. J. Am. Chem.
Soc. 1999, 121, 12073.
(15) Saito, A.; Nakajima, N.; Tanaka, A.; Ubukata, M. Tetrahedron 2002, 58,
7829.
(16) Kozikowski, A. P.; Tu¨ckmantel, W.; Hu, Y. J. Org. Chem. 2001, 66, 1287.
(17) Synthesized in three steps from phloroglucinol; see Supporting Information.
In summary, the first stereoselective synthesis, structure confir-
mation, and absolute stereochemistry of (+)-myristinin A are
described. Also described are the remarkable properties of this
compound as a potent DNA-damaging agent and polymerase â
inhibitor. Further chemical and biological evaluation of 1 is
underway and will be reported in due course.
(18) Robins, M. J.; Wilson, J. S.; Hansske, F. J. Am. Chem. Soc. 1983, 105,
4059.
(19) Synthetic and natural 1 afforded identical 1H and 13C NMR and HRMS
data and the same mobility on C18 reversed phase HPLC. The optical
rotation of synthetic ([R]23D +57.8 (c 0.40, MeOH)) and natural 1 ([R]22
D
+60.6 (c 0.13, MeOH)) were comparable.
(20) BLM alone (2.5 µM) produced 3.1% growth inhibition, whereas 27 µM
Acknowledgment. We thank Dr. Craig J. Thomas for helpful
discussions during the course of this work. This work was supported
by NIH Research Grant CA50771, awarded by the National Cancer
Institute.
1 produced 1.8%. In combination 22.2% growth inhibition occurred.
(21) Canitrot, Y.; Cazaux, C.; Fre`chet, M.; Bouayadi, K.; Lesca, C.; Salles,
B.; Hoffmann, J.-S. Proc. Natl. Acad. Sci. U.S.A. 1998, 95, 12586.
JA042727J
9
J. AM. CHEM. SOC. VOL. 127, NO. 12, 2005 4141