Denigrins A–C: new antitubercular 3,4-diarylpyrrole alkaloids from <i>Dendrilla nigra</i>

<div><p>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 <i>Dendrilla nigra</i> 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 <i>Mycobacterium tuberculosis</i> H37Rv.</p></div>