New nitrogenous bisabolene-type sesquiterpenes from a micronesian marine sponge, axinyssa species

Halipanasterol, a New Sterol Isolated From the Marine Sponge Halichondria panicea

A new sterol (1) and 8 known (2-9) compounds were isolated from the methanol extract of the Vietnamese marine sponge Halichondria panicea (Pallas, 1766) by various chromatographic methods. Their chemical structures were determined as 5 α,6 α-epoxy-(22 E)-ergosta-3 β,7 α-diol-8,22,25-triene (1), (22 E)-ergosta-7,22,25-triene-3 β,5 α,6 β-triol (2), 3 β-hydroxycholest-5ene-7-one (3), cholesterol sulfate (4), 3-formamidotheonellin (5), para-hydroxybenzylideneacetone (6), indole-3-carbaldehyde (7), thymidine (8), and adenosine (9) by using a combination of HR-ESI-MS, 1D and 2D NMR spectral data, as well as by comparison with the previous literature. This is the first report of these compounds from H panicea. Compounds 1 and 2 exhibited cytotoxic effects on Hep-G2, SK-Mel-2, LU-1, and MCF-7 cell lines with IC50 values of 9.27 ± 1.25, 11.34 ± 1.18, 15.45 ± 1.47, and 10.85 ± 1.19 µM (for 1), and 6.45 ± 0.77, 9.74 ± 1.03, 7.08 ± 0.64, 5.61 ± 0.39 µM (for 2), compared to the positive control compound, ellipticine, 1.60 ± 0.37, 2.53 ± 0.51, 1.82 ± 0.20, and 2.17 ± 0.66 µM, respectively.

Bisabolane-type sesquiterpenoids: Structural diversity and biological activity

Bisabolane-type sesquiterpenoids, a class of monocyclic sesquiterpenoids, are widely distributed in nature and have a variety of biological activities. To provide a reference for the further research and development of these compounds, the phytochemical and biological properties of natural bisabolane-type sesquiterpenoids (356 compounds in total) isolated between 1985 and 2020 from 24 families, primarily Compositae, Zingiberaceae, Aspergillaceae, Halichondriidae, and Aplysiidae were reviewed. In vitro and in vivo studies have indicated that antibacterial, anti-inflammatory, and cytotoxic effects are the most commonly reported pharmacological properties of bisabolane-type sesquiterpenoids. Owing to their extensive significant effects, a lot of traditional medicines containing this type of compounds have been used for a long history. Thus, bisabolane-type sesquiterpenoids are a rich source of important natural products, which show great potential for the development of new drugs.

Halichonic Acid B, a Rearranged Nitrogenous Bisabolene-Type Sesquiterpene from a Marine Sponge Axinyssa sp

A new rearranged nitrogenous bisabolone-type sesquiterpene, halichonic acid B (1), was isolated from a marine sponge Axinyssa sp. together with halichonic acid (2) and (6R,7S)-7-amino-7,8-dihydro-α-bisabolene (3). The structure of 1 was determined by extensive NMR and MS analyses, revealing an unprecedented carbon framework, and its absolute configuration was elucidated by time-dependent density-functional theory (TDDFT)-based electronic circular dichroism (ECD) spectrum calculation. We propose that 1 and 2 may be biosynthesized in the same pathway, involving the reaction between farnesyl pyrophosphate and glycine, followed by cyclization.

Marine Isonitriles and Their Related Compounds

Marine isonitriles represent the largest group of natural products carrying the remarkable isocyanide moiety. Together with marine isothiocyanates and formamides, which originate from the same biosynthetic pathways, they offer diverse biological activities and in spite of their exotic nature they may constitute potential lead structures for pharmaceutical development. Among other biological activities, several marine isonitriles show antimalarial, antitubercular, antifouling and antiplasmodial effects. In contrast to terrestrial isonitriles, which are mostly derived from α-amino acids, the vast majority of marine representatives are of terpenoid origin. An overview of all known marine isonitriles and their congeners will be given and their biological and chemical aspects will be discussed.

Isothiocyanate sesquiterpenes from a sponge of the genus axinyssa

The chemical study of a sponge of the genus Axinyssa collected in the Gulf of California has led to the isolation of the new bicyclic sesquiterpenes axinisothiocyanates A-L ( 1- 12) together with the known compounds (1 R,6 S,7 S,10 S)-10-isothiocyanato-4-amorphene ( 13), (4 R*,5 R*,7 S*,10 R*)-4-isocyanoeudesm-11-ene, (-)-epipolasin A, and (+)-aristolone. The structures of the new metabolites have been established by spectroscopic techniques, including the analysis of pyridine-induced 1H NMR chemical shifts. The cytotoxic activity has been tested against three human tumor cell lines.

Stereochemical determination and bioactivity assessment of (S)-(+)-curcuphenol dimers isolated from the marine sponge Didiscus aceratus and synthesized through laccase biocatalysis

Electrospray ionization mass spectrometry-guided isolation of extracts from Didiscus aceratus led to the discovery of several new derivatives of the bioactive bisabolene-type sponge metabolite (S)-(+)-curcuphenol (1). The compounds obtained by this method included a mixture of known (2) and new (3) dihydroxylated analogs as well as a novel family of dimeric derivatives, dicurcuphenols A-E (4-8), and dicurcuphenol ether F (9). Dimers 4-9 were also subsequently obtained through a hemisynthetic method in which 1 was incubated with the enzyme laccase. Atropisomeric dimers 5 and 6 were subjected to vibrational circular dichroism analysis thereby establishing their absolute biaryl axial chirality as P and M, respectively. In contrast to 1, metabolites 2-9 exhibited weak or no cytotoxic or lipoxygenase inhibitory effects.

(-)-Axinyssene: a novel cytotoxic diterpene from a Japanese marine sponge Axinyssa sp

[structure: see text] A novel diterpene, (-)-axinyssene, was isolated from the Japanese marine sponge Axinyssa sp. The structure of (-)-axinyssene was determined on the basis of spectroscopic and synthetic evidence to be 1-methyl-4-[(4E)-5',9'-dimethyl-1'-methylene-4',8'-decadienyl]-(4S)-cyclohexene. (-)- and (+)-axinyssene showed mild cytotoxicity against acute promyelocytic leukemia, HL-60 cells.