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Chemical diversity is vital to antitubercular drug discovery as it ensures a novel bioactivity profile. Marine sponges have so far provided more than 1000 new bioactive molecules. Ethyl acetate extract of the marine sponge Dendrilla nigra on bioactivity-guided screening yielded three new compounds denigrins A–C, with potent antitubercular activity. Spectral and chemical analyses confirmed that these three compounds belong to the 3,4-diaryl pyrrole alkaloid category. The presence of monohydroxy substitution on benzene rings is not very common in lamellarin and related 3,4-diaryl pyrrole alkaloids isolated from marine invertebrates. Among these, denigrin C showed highest potency (minimum inhibitory concentration 4 μg/mL) against Mycobacterium tuberculosis H37Rv.

A new compound, (2 S)- p-hydroxyphenethyl 2-bromo-2-methyldodeconate (1) and 7,3′-dimethoxy-5,4′-dihydroxy flavone, together with lupeol and stigmasterol were isolated from the stem bark of Citharexylum fruticosum (Verbenaceae). The structures of the compounds were established on the basis of the interpretation of NMR (1H, 13C, COSY and HMBC) spectra, as well as low and high-resolution mass spectrometric data. In this paper, we report on the structure elucidation of 1.

Nine polyhydroxysterols were isolated from the lipid extract of two Sclerophytum sp. soft corals collected in the Andaman and Nicobar Islands. Of these, three compounds (7a, b, and 8) had previously been isolated from the southern Japan soft coral Sarcophyton glaucum. Compound 1 was identified as lobosterol having a novel 6-keto-A/B-cis ring juncture. The structures of the five new compounds were determined as 25-deacetyllobosterol (2), (24S)-24-methylcholest-7-ene-3β, 5α, 6β, 25-tetrol 25-monoacetate (3), (24S)-24-methylcholest-22E-ene-3β, 5α, 6β, 25-tetrol (4), (24S)-24-methylcholestane-3β, 5α, 25-triol-6-one 25-monoacetate (5a) and its C-25 deacetoxy analog (6), from the spectral data and by chemical conversion.

3β, 7β-Dihydroxy-24-methylenecholesterol (1) and three new polyhydroxysterol glycosides (2a, 3a and 4) were isolated from the lipid extract of an Alcyonium sp. soft coral which was collected in the Andaman and Nicobar Islands. Isolation of steroidal glycosides from soft corals is rare, if not unprecedented. Spectroscopic and chemical degradation studies indicated the new glycosides to be 24-methylenecholest-5-ene-3β, 16β-diol-3-O-α-L-fucoside (2a) and its 7β- (3a) and 7α-hydroxy (4) derivatives.

Chemical examination of the marine sponge Iotrochota baculifera of the Indian Ocean furnished a sphingolipid (1), a new glycosphingolipid (iotroridoside-B, 2) and a four-component mixture of sphingolipids (3a-d) with two new components. Structure elucidation was carried out by spectral and chemical methods.