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The cytotoxic activities of extracts (50 μg/ml) from 48 fungal strains, recovered from sediments of Pecém's offshore port terminal (Northeast coast of Brazil), against HCT-116 colon cancer cell lines were investigated. The most promising extract was obtained from strain BRF082, identified as Dichotomomyces cejpii by phylogenetic analyses of partial RPB2 gene sequence. Thus, it was selected for bioassay-guided isolation of the cytotoxic compounds. Large-scale fermentation of BRF082 in potato dextrose broth, followed by chromatographic purification of the bioactive fractions from the liquid medium, yielded gliotoxin (4) and its derivatives acetylgliotoxin G (3), bis(dethio)bis(methylsulfanyl)gliotoxin (1), acetylgliotoxin (5), 6-acetylbis(dethio)bis(methylsulfanyl)gliotoxin (2), besides the quinazolinone alkaloid fiscalin B. All isolated compounds were tested for their cytotoxicities against the tumor cell lines HCT-116, revealing 4 and 3 as the most cytotoxic ones (IC50 0.41 and 1.06 μg/ml, resp.).

Metabolomic profiles were explored to understand environmental and taxonomic influences on the metabolism of two congeneric zoanthids, Palythoa caribaeorum and P. variabilis, collected across distinct geographical ranges. Integrated mass spectrometry data suggested the major influence of geographical location on chemical divergence when compared to species differentiation.

Five new diterpenes derivatives named as ornatin A, B, C, D and E, in addition to six known related diterpenes were isolated from the aerial parts of cultivated specimens of Plectranthus ornatus. The structures were elucidated using a combination of 1D/2D nuclear magnetic resonance (NMR) spectroscopy, high-resolution electrospray ionization mass spectrometry (HRESIMS) and comparison with published NMR data of analogous compounds. All isolated compounds were assayed against four human cancer cell lines, and Gram-positive and Gram-negative bacteria strains. None of them showed any cytotoxic activity, but ornatin C, D, E and three related diterpenes displayed marginal bactericidal or bacteriostatic effects against the Gram-positive strains. Keywords: Plectranthus ornatus, diterpenes, ent-clerodanes, bacteriostatic IntroductionThe genus Plectranthus L'Her (Lamiaceae, subfamily Nepetoideae, tribe Ocimeae, subtribe Plectranthinae) comprises approximately 300 species largely distributed over the African, Asian and Australian continents. 1 Plectranthus is a large genus well known by its diversity of ethnobotanical uses, being especially indicated to treat digestive disorders, skin diseases, infections and respiratory problems. 2 In general, are rich source of essential oils, terpenoids and phenol compounds. 3 Pharmacological properties such as anti-inflammatory, 4 antioxidant, 5 antimicrobial, 6 anti-tumoral 7 and diuretic 8 have been demonstrated for several isolated compounds from Plectranthus, corroborating with its larger medicinal uses.Plectranthus ornatus Codd (syn. Coleus comosus Hochst. ex Gurke) is a perennial and aromatic herb, widespread around the new world. 9 In the northeast of Brazil, P. ornatus, popularly known as "malva santa" or "boldo miúdo", is cultivated as a very important medicinal plant, indicated as analgesic and particularly to treat gastric disorders. 10 Several antimicrobial labdanes, ent-clerodanes, and halimane-type diterpenoids have been previously isolated from P. ornatus. 11 As part of a multidisciplinary program, where the efforts are devoted to study medicinal plants or congeners, in order to unveil their pharmacological or biological properties, herein we describe the isolation and characterization of five new diterpenes derivatives together with six known compounds from the aerial parts of cultivated specimens of P. ornatus, as well as the results of pharmacological and biological assays with the isolated secondary metabolites (Figure 1). Ávila et al. 1015 Vol. 28, No. 6, 2017 Experimental General experimental proceduresOptical rotations were measured on a PerkinElmer 341 digital polarimeter. Infrared (IR) spectra were obtained on a PerkinElmer FT-IR spectrum 1000 spectrometer. Accurate mass spectra were acquired on a liquid chromatography-mass spectrometry ion-trap and time-of-flight (LCMS-IT-TOF, Shimadzu) spectrometer. Nuclear magnetic resonance (NMR) spectra were performed either on Bruker DPX-300 or DRX-500 spectrometers. Open column chromatography (CC) were carried out wit...

A Streptomyces sp. (BRA-384) was selected among nine strains of bacteria isolated from the zoanthids Palythoa caribaeorum due to the high cytotoxic activity presented by its EtOAc extract (inhibitory concentration mean (IC 50) of 2 ng mL-1) against colon cancer cell line. From the EtOAc extract of BRA-384 three new chemical entities (A 6 , A 7 and A 8) and one dextrorotatory chromomycin (A 5), a promising class of anticancer compounds, were identified. The cytotoxicity of chromomycins A 5 to A 8 was tested against five tumor cell lines (HCT 116 (human colon adenocarcinoma), MCF-7 (human breast carcinoma), PC-3M (human metastatic prostate cancer), 501-mel (human metastatic melanoma) and MM200 (metastatic melanoma)). All chromomycins were highly potent showing IC 50 values from 0.2 to 133 nM. Chromomycin A 5 was consistently the most potent over all tested cells (IC 50 values from 0.2 in MM200 to 7.9 nM in PC-3M), inclusive when compared to the standard chemotherapeutic agent doxorubicin, that presented IC 50 values ranging from 147 to 568 nM against MM200 and MCF-7, respectively.