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The phytochemical investigation of Grazielia gaudichaudeana aerial parts yielded 15 compounds, including diterpenes, triterpenes, sterols and flavonoids. With exception to ent‐kaurenoic acid diterpenes, the compounds isolated are being described for the first time in this species. Some unusual 1H‐NMR chemical shifts of 18‐nor‐ent‐labdane (7–9) led us carry out a conformational analysis by theoretical calculations in order to support the experimental data. Moreover, due to the limitation of studies focused on pharmacological potential of Grazielia gaudichaudeana, the present study was carried out to investigate the antioxidant, antiproliferative, antiviral, antileishmanial and antimicrobial activities from the extract, fractions and isolated compounds obtained from this species. Ethyl acetate fraction showed significant activity in the antiproliferative assay, with GI50 range of 3.9 to 27.2 μg mL−1. Dichloromethane fraction, rich in diterpenoids, inhibited all human tumor cell lines tested, and the nor‐labdane 7 showed potent cytotoxic activity against glioma and ovary cancer cell lines.

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Streptomyces sp. 4054, isolated from marine sediments, produced a new butenolide, mycenolide A (1), along with five known butenolide derivatives (2-6). The structures of the compounds were established based on 1D-and 2D-NMR spectroscopic analysis, circular dichroism, and mass spectrometry data. The antimicrobial activity of the crude extract of the marine bacteria Streptomyces sp. 4054 was evaluated, showing good results against Bacillus subtilis and MRSA.

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Marine strains of Bacillus are known to produce secondary metabolites different from that accumulated by their terrestrial counterparts, for example, lipopeptides such as surfactins, iturins and fengycins, which exhibit a variety of biological activities. Another important class of lipopeptides are pumilacidins, identified specially from Bacillus pumilus strains, usually by using liquid chromatography-mass spectrometry (LC-MS) techniques. In this work, five knowns pumilacidins were isolated from the solid culture of the marine-derived bacterium Bacillus sp. 4040. The structures of compounds, pumilacidins A-E, were determined using a combination of mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy and comparison with reported data. The 1 H and 13 C NMR data of pumilacidin B is being described here for the first time. All compounds were evaluated against five microorganisms, but no antimicrobial activity was detected.