Dalbergia monetaria is an Amazonian plant whose bark is widely used to treat urinary tract infections. This paper describes a bio-guided study of ethanolic extracts from the bark and leaves of D. monetaria, in a search for metabolites active against human pathogenic bacteria. In vitro assays were performed against 10 bacterial strains, highlighting methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Fractioning of the extracts was performed using instrumental and classical techniques, and samples were characterized by UHPLC-HRMS/MS. Ethyl acetate fractions from bark and leaves showed similar antibacterial activities. EAFB is enriched in isoflavone C-glucosides and EAFL enriched in proanthocyanidins. Subfractions from EAFL presented higher activity and showed a complex profile of proanthocyanidins constructed by (epi)-cassiaflavan and (epi)-catechin units, including dimers, trimers and tetramers. The fragmentation pattern emphasized the neutral loss of cassiaflavan units by quinone-methide fission. Fraction SL7-6, constituted by (ent)-cassiaflavan-(ent)-cassiaflavan-(epi)-catechin isomers, showed the lowest MIC against the S. aureus and P. aeruginosa with values corresponding to 64 and 32 µg/mL, respectively. Cassiaflavan-proanthocyanidins have not been found previously in another botanical genus, except in Cassia, and the traditional medicinal use of D. monetaria might be related to the antibacterial activity of proanthocyanidins characterized in the species.

AbstractThree previously undescribed natural products, phomopsinin A – C (1 – 3), together with three known compounds, namely, cis-hydroxymellein (4), phomoxanthone A (5) and cytochalasin L-696,474 (6), were isolated from the solid culture of Phomopsis sp. CAM212, an endophytic fungus obtained from Garcinia xanthochymus. Their structures were determined on the basis of spectroscopic data, including IR, NMR, and MS. The absolute configurations of 1 and 2 were assigned by comparing their experimental and calculated ECD spectra. Acetylation of compound 1 yielded 1a, a new natural product derivative that was tested together with other isolated compounds on lipopolysaccharide-stimulated RAW 264.7 cells. Cytochalasin L-696,474 (6) was found to significantly inhibit nitric oxide production, but was highly cytotoxic to the treated cells, whereas compound 1 slightly inhibited nitric oxide production, which was not significantly different compared to lipopolysaccharide-treated cells. Remarkably, the acetylated derivative of 1, compound 1a, significantly inhibited nitric oxide production with an IC50 value of 14.8 µM and no cytotoxic effect on treated cells, thereby showing the importance of the acetyl group in the anti-inflammatory activity of 1a. The study of the mechanism of action revealed that 1a decreases the expression of inducible nitric oxide synthase, cyclooxygenase 2, and proinflammatory cytokine IL-6 without an effect on IL-1β expression. Moreover, it was found that 1a exerts its anti-inflammatory activity in lipopolysaccharide-stimulated RAW 264.7 macrophage cells by downregulating the activation of ERK1/2 and by preventing the translocation of nuclear factor κB. Thus, derivatives of phomopsinin A (1), such as compound 1a, could provide new anti-inflammatory leads.

In the last decade thiotaurine, 2-aminoethane thiosulfonate, has been investigated as an inflammatory modulating agent as a result of its ability to release hydrogen sulfide (H2S) known to play regulatory roles in inflammation. Thiotaurine can be included in the “taurine family” due to structural similarity to taurine and hypotaurine, and is characterized by the presence of a sulfane sulfur moiety. Thiotaurine can be produced by different pathways, such as the spontaneous transsulfuration between thiocysteine – a persulfide analogue of cysteine – and hypotaurine as well as in vivo from cystine. Moreover, the enzymatic oxidation of cysteamine to hypotaurine and thiotaurine in the presence of inorganic sulfur can occur in animal tissues and last but not least thiotaurine can be generated by the transfer of sulfur from mercaptopyruvate to hypotaurine catalyzed by a sulfurtransferase. Thiotaurine is an effective antioxidant agent as demonstrated by its ability to counteract the damage caused by pro-oxidants in the rat. Recently, we observed the influence of thiotaurine on human neutrophils functional responses. In particular, thiotaurine has been found to prevent human neutrophil spontaneous apoptosis suggesting an alternative or additional role to its antioxidant activity. It is likely that the sulfane sulfur of thiotaurine may modulate neutrophil activation via persulfidation of target proteins. In conclusion, thiotaurine can represent a biologically relevant sulfur donor acting as a biological intermediate in the transport, storage and release of sulfide.

The growing interest in the efficacy of phytomedicines and herbal supplements but also the increase in legal requirements for safety and reliable contents of active principles drive the development of analytical methods for the quality control of complex, multicomponent mixtures as found in plant extracts of value for the pharmaceutical industry. Here, we describe an ultra-performance liquid chromatography method (UPLC) coupled with quadrupole time of flight mass spectrometry (qTOF-MS) measurements for the large scale analysis of H. perforatum plant material and its commercial preparations. Under optimized conditions, we were able to simultaneously quantify and identify 21 metabolites including 4 hyperforins, 3 catechins, 3 naphthodianthrones, 5 flavonoids, 3 fatty acids, and a phenolic acid. Principal component analysis (PCA) was used to ensure good analytical rigorousness and define both similarities and differences among Hypericum samples. A selection of batches from 9 commercially available H. perforatum products available on the German and Egyptian markets showed variable quality, particularly in hyperforins and fatty acid content. PCA analysis was able to discriminate between various preparations according to their global composition, including differentiation between various batches from the same supplier. To the best of our knowledge, this study provides the first approach utilizing UPLC-MS-based metabolic fingerprinting to reveal secondary metabolite compositional differences in Hypericum extract.

Multi-component reactions of building blocks with more than one MCR-reactive group will give rise to oligomeric MCR products. The proper choice of at least two bifunctional building blocks will give either a polymeric or a cyclic product. Apart from polymerization, repetitive or consecutive Ugi reactions have been used to produce linear MCR-heterooligomers with such building blocks.

The present paper describes the phytochemical and anti-staphylococcal activity investigation of the dichloromethane extract of the Brazilian plant Zizyphus joazeiro Mart. The purification steps were guided by bioassays against 17 bacterial strains of clinical sources, including methicillin-resistant (MRSA) and ‐sensitive (MSSA) Staphylococcus aureus as well as MRSA (ATCC 33591) and MSSA (ATCC 29213) reference strains. One of the more active fractions is comprised of three lupane-type triterpenes, the methylbetulinate (1) as well as the known betulinic (2) and alphitolic (3) acids and, for the first time in the Z. joazeiro, two ceanothane type triterpenes, the methylceanothate (4) and the epigouanic acid A (5). These substances were assayed against one clinical (PVL+) and the reference strains of S. aureus as well as the ATTC 12228 strain of S. epidermidis, in concentrations that varied from 128 to 0.125 µg/mL in order to establish the minimum inhibitory concentration (MIC) of the drugs. The minimum bactericide concentration (MBC) was also evaluated to distinguish the bactericidal from bacteriostatic activity of the crude fractions and single compounds. Compounds 3 and 4 possess the highest antibacterial activity. They inhibit all bacteria tested at 32 µg/mL and 16 µg/mL, respectively, while the other compounds showed no activity at 128 µg/mL. In contrast to single compounds, the triterpenoid fraction showed bactericidal activity at 256 µg/mL. Structural elucidations are based on 1D and 2D NMR spectroscopy as well as HR‐FT‐ICR‐MS experiments.

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Geranylgeraniol (GGOH) is an acyclic diterpene that posesses apoptotic activity to cancer cells [1]. It has been proposed to be the main intermediate of the biosynthetic pathway of plaunotol, an antipeptic ulcer drug from Croton stellatopilosus [2]. Our enzymological studies showed that GGOH is formed from the dephosphorylation of geranylgeranyl pyrophosphate (GGPP), through sequential monodephosphorylation [3], by the action of GGPP phosphatase enzyme [4]. As part of our interest in manipulating the gene of GGPP phosphatase for the production of GGOH in Escherichia coli system, we began with cloning of cDNA encoding prenyl diphosphate phosphatase from C. stellatopilosus. The degenerated primers were designed from the alignment of amino acid sequences of prenyl diphosphate phosphatase in database. The full-length gene was obtained by RACE-PCR. The cDNA contained an open reading frame encoding 888 amino acids with a calculated molecular mass of 33.6 kDa. The phosphatase motif [5] was included in the deduced amino acid sequence consisting of KX6RP, PSGH, and SRX5HX3D. Its amino acid sequence showed 71% identity to phosphatidic acid phosphatase from Vigna unguiculata. The topology prediction of the enzyme indicated that it was a transmembrane protein with 6 transmembrane regions. The recombinant prenyl diphosphate phosphatase and its 4 designed truncated genes were expressed in Escherichia coli BL21(DE3)RIL. Detection of their phosphatase activities by using [1-3H]GGPP and farnesyl pyrophosphate ([1-3H]FPP) as substrates showed that their enzymatic products of [1-3H]GGOH and [1-3H]FOH, respectively, were formed in the assay mixture. The results suggested the potential of GGOH production by the recombinant E. coli although the expression of the recombinant gene was still in low level.

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Two new triterpenoids, named gouanic acid A (1) and gouanic acid B (2), were isolated from the aerial parts of Gouania ulmifolia, along with six known compounds. The structures of the new compounds were determined by spectroscopic methods, mainly NMR (1D and 2D) and mass spectrometry. The new compounds did not show significant antimicrobial activities.