Five new farnesyl-α-nitropyrroles, nitropyrrolins A-E (1-5), were isolated from the saline culture of the marine actinomycete strain CNQ-509. This strain belongs to the "MAR4" group of marine actinomycetes, which have been demonstrated to be a rich source of hybrid isoprenoid secondary metabolites. The structures of the nitropyrrolins are composed of α-nitropyrroles with functionalized farnesyl groups at the C-4 position. These compounds are the first examples of naturally-occurring terpenyl-α-nitropyrroles. Chemical modifications, including one-step acetonide formation from an epoxide, and application of the modified Mosher method, provided the full stereostructures and absolute configurations of these compounds. Several of the nitropyrrolins, nitropyrrolin D in particular, are cytotoxic toward HCT-116 human colon carcinoma cells, but show weak to little antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA).As part as our continuing interest in the chemistry and biomedical potential of sedimentderived marine actinomycetes, we have isolated a variety of new actinomycete taxa, which show the capacity to produce unique secondary metabolites.1 These taxa include the chemically prolific genera Salinispora2 and "Marinispora",3 members of which produce new structural classes of secondary metabolites including salinosporamide A,4 a potent proteasome inhibitor that recently completed phase I clinical trial for the treatment of cancer.5 Another group of marine-derived actinomycetes, designated as MAR 4, is proving to be of significant chemical interest.1 To date, at least 15 strains belonging to this group have been isolated from diverse marine sediments. Previous chemical studies of cultured MAR4 strains led to the discovery of a broad range of polyketide-terpenoid secondary metabolites including marinone,6 compounds in the napyradiomycin series7 and azamerone. 8 Further chemical analysis of the cultured MAR4 strain CNQ-509, isolated from a marine sediment sample collected off La Jolla, CA, has led to the discovery of a new set of hybrid * To whom Correspondence should be addressed. Tel: + 1 858 534 2133. Fax: +1 858 558 3702. wfenical@ucsd.edu. ‡ Scripps Institution of Oceanography. † Korea Institute of Science and Technology, Gangneung, Korea § Contributed equally to this work.Supporting Information Available: Spectroscopic data sets (1D and 2D NMR, ESI MS, UV/VIS, HRMS, etc) for 1-5, 1 H NMR spectra for 6 and (S)-Mosher ester of 11, 1 H NMR and 1 H-1 H COSY spectra for 9a, 9b, 12a, 12b, 13a, 13b, 14a and 14b, 1 H NMR and 2D NOESY spectra for 10 and 11, and 1 H and 13 C NMR spectra for 7 and 8. This material is available free of charge via the Internet at http://pubs.acs.org polyketide-terpenoid metabolites composed of sesquiterpenoid and α-nitropyrrole components. These compounds, nitropyrrolins A-E (1-5), are unusual examples illustrating rare pyrrole nitration in the α position with linear sesquiterpenoid substitution. The structures of these new compounds, including their absolu...

The isolation, detection and quantification of betulinic acid in Doliocarpus schottianus are described. The isolation from the plant extract was made by column chromatography and centrifugal TLC, and betulinic acid was characterized by spectrometric methods. The detection and quantification were made by HPLC using a C18 column eluted with acetonitrile: water and detected at 210 nm. The results showed that the metabolite accumulates in the bark of the plant, but very small concentrations were also found in the leaves and wood.

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Two chromomycin SA analogs, chromomycin SA3 and chromomycin SA2, along with deacetylchromomycin A3 and five previously reported chromomycin analogs were isolated from a marine-derived Streptomyces sp. The structures of the new compounds were determined by spectroscopic methods including 1D and 2D NMR techniques, HRMS and chemical methods. Chromomycin SA3 and chromomycin SA2 are the first naturally occuring chromomycin analogs with truncated side-chains. Biological evaluation of chromomycin analogs for cytotoxicity against two non-small cell lung cancer (NSCLC) cell-lines, A549 and HCC44, demonstrated a decrease in cytotoxicity for the truncated sides chain chromomycin analogs.

A new technique to deconvolute complex (1)H NMR spectra of small molecules has been developed that utilizes shape selective pulses to simultaneously decouple multiple protons. A limitation in the assignment of the relative configuration of small molecules is the ability to accurately obtain coupling constants. Other methods such as the E.COSY and the 2D J-resolved are available to obtain complicated coupling constants; the multiple homonuclear decoupling method (MDEC) described is a rapid and simple technique. Three examples of increasing spectral complexity, menthol, cholesteryl acetate and a C(16) fatty acid, demonstrate the utility of the technique. Increasing the experimental utility, the single pulse MDEC experiment can be incorporated in other 1D experiments, such as a 1D-TOCSY to solve specific problems.

Erythrolic acids A-E (1–5) are five unusual meroterpenoids isolated from the bacterium Erythrobacter sp. derived from a marine sediment sample collected in Galveston, TX. The structures were elucidated by means of detailed spectroscopic analysis and chemical derivatization. The erythrolic acids contain a 4-hydroxybenzoic acid appended with a modified terpene side chain. The side chain modifications include oxidation of a terminal methyl substituent and in the case of 1–4 addition of a 2-carbon unit to give terpene side chains of unusual length; C22 for 1 and 2, C17 for 3 and C12 for 4. The relative and absolute configurations of the meroterpenoids were determined by coupling constant, NOE and Mosher’s analysis. In vitro cytotoxicity towards a number of non-small cell lung cancer (NSCLC) cell lines revealed only modest activity for erythrolic acid D (4) (2.5 μM against HCC44). The discovery of these unusual diterpenes, along with the previously reported erythrazoles, demonstrate the natural product potential of a previously unstudied group of bacteria for drug discovery. The unusual nature of the terpene side chain, we believe, involves an oxidation of a terminal methyl group to a carboxylic acid and subsequent Claisen condensation with acetyl-CoA.

Candidatus Liberibacter spp. is the pathogen associated with Huanglongbing (HLB), a disease with an economic impact in the order of billions of dollars to the worldwide citrus industry. A key point to reduce HLB economic losses lies on early detection on asymptomatic stages of the infection by new detection methods as it is still not possible to cultivate Candidatus Liberibacter spp. in vitro, and the polymerase chain reaction (PCR) method used nowadays is not manageable in large scale. In this study, we search for metabolic biomarkers from Citrus sinensis leaves in different disease stages using a combined approach of NMR spectroscopy and chemometrics. Chemometric clustering was observed, providing excellent tools for class discrimination, with high accuracy, therefore enabling metabolic profile differentiation on disease early stages. Around 20 different key biomarkers, metabolites responsible for the clustering of each group, were identified using 2D NMR experimental data.

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