Eleven manzamine type alkaloids, two β-carbolines, and five nucleosides have been isolated from an Indonesian sponge. Among these are the previously characterized 12,34-oxamanzamine A, 12,34-oxamanzamine E, manzamine A (1), 8-hydroxymanzamine A, 6-deoxymanzamine X, manzamine E (2), manzamine X, manzamine F (4), norharman, thymine, 2′,3′-didehydro-2′,3′-dideoxyuridine, uracil, thymidine, and 2′-deoxyuridine. The structures for the five new compounds have been assigned as 32,33-dihydro-31-hydroxymanzamine A (3), 32,33-dihydro-6-hydroxymanzamine A-35-one (5), des-N-methylxestomanzamine A (6), 32,33-dihydro-6,31-dihydroxymanzamine A (7), and 1,2,3,4-tetrahydronorharman-1-one (8), on the basis of NMR and X-ray data. The bioactivity and SAR of the manzamines against malaria, TB, and leishmania are also presented. The structural revision of two previously reported pyrazoles as uracil and thymine is also discussed.Manzamines are unique β-carboline alkaloids isolated from Indo-Pacific sponges and characterized by having an intricate nitrogen-containing polycyclic system. In 1986, Higa and co-workers first reported manzamine A from the Okinawan sponge of the genus Haliclona. 1 These compounds exhibit a diverse range of bioactivities including cytotoxicity, 1 insecticidal, 2 and antibacterial 3 as well as the exciting curative activity against malaria in animal models. 4,5 Since the first report of manzamine A, an additional 40 manzamine-type alkaloids have been reported from nine different sponge genera. 6,7 In our continuing search for manzamine-related alkaloids with significant activity against infectious diseases, we have identified several novel manzamine alkaloids from an Indonesian sponge, and herein we describe their structure determination and biological activity.
*To whom correspondence should be addressed. Tel: (662) 915-5730. Fax: (662) 915-6975. mthamann@olemiss.edu. Supporting Information Available: Copies of 1 H and 13 C NMR spectra for all new compounds, HMQC spectra for 3, 5-7, HMBC spectra for 5-8, and X-ray data for 3. This material is available free of charge via the Internet at http://pubs.acs.org. (Table 1) includes aromatic proton resonances similar to those of manzamine E. 12 Spectral data of how 3 differs from manzamine E (2) includes the presence of 13 CH carbons (manzamine E has 12 CH carbons) and the absence of the low-field C-31 carbonyl carbon signal of manzamine E. In place of the carbonyl carbon compound 3 has a signal at 70.9 ppm, which correlates with a multiplet at 4.05 ppm in the HMQC spectrum. The presence of this new OH-functionality is confirmed by a number of long-range 1 H-13 C correlations H 2 -29 and H 2 -33 to C-31, Figure 1
HHS Public Access
Author ManuscriptAuthor Manuscript
Author ManuscriptAuthor Manuscript C-12, C-24, C-25, C-26, and C-34 of 3 were elucidated to be the same as those of manzamine E by NOESY data as well as comparable 13 C chemical shifts. In addition both compounds were isolated from the same sponge and possessed dextrorotation. The relative config...