The chemical study of the ascidian Aplidium haouarianum has led to the isolation of the new metabolites haouamines A (1) and B (2) which belong to a novel class of alkaloids. The structure of 1 was established by interpretation of its spectroscopic data and those of the N-methyl derivative 3, and confirmed by X-ray crystallographic analysis. The structure of 2 was deduced by spectroscopic study of its peracetyl derivative 2a. In solution each haouamine exists as an unseparable mixture of two interconverting isomers derived by the presence of a highly strained 3-aza-[7]-paracyclophane moiety in their structures. Compound 1 exhibits a selective cytotoxic activity against the HT-29 human colon carcinoma cell line.
The sponge Spongia agaricina from Tarifa, Cadiz, Spain, contains two new 9,11-secosterols, [3-0-deacetylluffasterol B (1) and 3-0-deacetyl-22,23-dihydro-24,28-dehydroluffasterol B (2)] and two new sesterterpenoids [12,16-di-epi-12-0-deacetyl-16-0-acetylfuroscalarol (3) and 16-epi-scalarolbutenolide (4)], in addition to the known compounds 5-15. The structures of all compounds were elucidated by interpretation of' spectroscopic data. The metabolites 1-3 showed significant cytotoxicity against four tumor cell lines (C50 1 microgram/mL).
A chemical study of the alga Cystoseira usneoides has led to the isolation of six new meroterpenoids, cystodiones A-F (1-6), together with six known related compounds (7-12). The structures of the new metabolites have been established by spectroscopic techniques. In antioxidant assays all of the tested meroterpenes, and in particular cystodiones A (1) and B (2), 6-cis-amentadione-1'-methyl ether (7), and amentadione-1'-methyl ether (8), exhibited strong radical-scavenging activity. In anti-inflammatory assays, usneoidone Z (11) and its corresponding 6E isomer (12) showed significant activity as inhibitors of the production of the proinflammatory cytokine TNF-α in LPS-stimulated THP-1 human macrophages.
The sponge Cacospongia scalaris from Tarifa Island,
Spain, contains in addition to five known
compounds (1−5), the new scalarane
sestertepenes 18-epi-scalaradial (6),
19-dihydroscalaradial
(7), 12-epi-acetylscalarolide (8), and
16-acetylfuroscalarol (9) together with three
uncommon
norscalaranes norscalaral A (10), norscalaral B
(11), and norscalaral C (12). The structures
were
elucidated by interpretation of spectral data.
18-epi-Scalaradial (6) represents the
missing
stereoisomer on structure−activity studies carried out with compounds
of this series and did not
react with methylamine. The new compounds isolated from C.
scalaris showed significant in vitro
cytotoxicity against five tumor cell lines with
18-epi-scalaradial showing the greatest activity
(ED50
= 0.2 μg/mL).
The sponge Reniera fulva from Algeciras Bay, Spain,
contains, in addition to the five acetylenic
compounds described previously, a new long-chain acetylene named
fulvinol (1). Its highly
symmetric structure was elucidated by interpretation of spectral data,
and its absolute
configuration was established using the Mosher method. Fulvinol
(1) exhibited cytotoxicity
against four tumor cell lines (ED50 = 1
μg/mL).
The chemical study of two sponges of the genus Dysidea collected in the Gulf of California has led to the isolation of the new merosesquiterpenes 20-O-acetyl-21-hydroxy-ent-isozonarol (2), 20-O-acetylneoavarol (3), ent-yahazunol (4), and dysienone (5), together with the known compounds 1 and 6-9. The structures of the new metabolites have been established by spectroscopic techniques. The absolute configuration of compounds 5 and 6 has been investigated by application of a procedure developed by Riguera et al. Compounds 2 and 5 showed cytotoxic activity against three human tumor cell lines.
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