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Metals are important cofactors in the metabolic processes of cyanobacteria, including photosynthesis, cellular respiration, DNA replication, and the biosynthesis of primary and secondary metabolites. In adaptation to the marine environment, cyanobacteria use metallophores to acquire trace metals when necessary as well as to reduce potential toxicity from excessive metal concentrations. Leptochelins A-C were identified as structurally novel metallophores from three geographically dispersed cyanobacteria of the genus Leptothoe. Determination of the complex structures of these metabolites presented numerous challenges, but they were ultimately solved using integrated data from NMR, mass spectrometry and deductions from the biosynthetic gene cluster. The leptochelins are comprised of halogenated linear NRPS-PKS hybrid products with multiple heterocycles that have potential for hexadentate and tetradentate coordination with metal ions. The genomes of the three leptochelin producers were sequenced, and retrobiosynthetic analysis revealed one candidate biosynthetic gene cluster (BGC) consistent with the structure of leptochelin. The putative BGC is highly homologous in all three Leptothoe strains, and all possess genetic signatures associated with metallophores. Postcolumn infusion of metals using an LC-MS metabolomics workflow performed with leptochelins A and B revealed promiscuous binding of iron, copper, cobalt, and zinc, with greatest preference for copper. Iron depletion and copper toxicity experiments support the hypothesis that leptochelin metallophores may play key ecological roles in iron acquisition and in copper detoxification. In addition, the leptochelins possess significant cytotoxicity against several cancer cell lines.

Phenolic compounds are the main special metabolites of Cyperaceae species from phytochemical, pharmacological, and chemotaxonomical points of view. The present study focused on the isolation, structure determination, and pharmacological investigation of constituents from Carex praecox. Twenty-six compounds, including lignans, stilbenes, flavonoids, megastigmanes, chromenes, and phenylpropanoids, were identified from the methanol extract of the plant. Five of these compounds, namely, carexines A–E, are previously undescribed natural products. All compounds were isolated for the first time from C. praecox. The ACE-inhibitory activity of seven stilbenoid compounds was tested, and (–)-hopeaphenol proved to be the most active (IC50 7.7 ± 0.9 μM). The enzyme–kinetic studies revealed a mixed-type inhibition; therefore, domain-specific studies were also conducted. The in silico docking of (–)-hopeaphenol to the ACE affirmed some favorable interactions. In addition, the antiproliferative and antibacterial effects of some compounds were also evaluated. [ABSTRACT FROM AUTHOR]

In this work, we developed multifunctional hydrogel nanoparticles (NPs) that can encapsulate anticancer drugs and imaging contrast agents as well. Mitomycin C (MMC) and rhodamine B (RB) were selected as models for anticancer drugs and imaging contrasting agents, respectively. Both MMC and RB were linked to the succinated polyvinyl alcohol polymer (PVA-SA). The selected labeled hydrogel NPs ((0.5% RB)-PVA-SA NPs and (1.5% RB)-PVA-SA NPs) improved the RB quantum yield from 29.8% to a minimum of 42.7%. Moreover, they showed higher emission stability compared to free RB when they were repeatedly excited at 554 nm for 2 h. Furthermore, the dye polymeric interactions significantly increased the RB fluorescence lifetime by approximately twofold. All these optical properties pave the way for our labeled hydrogel NPs to be used in imaging-guided therapy. For the labeled MMC-loaded NPs, the MMC-binding efficiency was found to be exceedingly high in all synthesized samples: a minimum of 92% was achieved. In addition, the obtained pH-dependent drug release profiles as well as the cytotoxicity evaluation demonstrated the high potential of releasing MMC under acidic cancerous conditions. Moreover, the in vitro cellular uptake experiment confirmed the accumulation of MMC NPs throughout the cytoplasm. [ABSTRACT FROM AUTHOR]

Chemotherapy is a known treatment modality that improves the long-term survival of breast cancer patients. However, due to the resistance to numerous anticancer drugs, alternative chemotherapeutic strategies are required. Regarding antimetabolic drugs, several compounds have proven anticancer properties, such as statins. The present study aimed to investigate the in vitro effects of V9302, a competitive antagonist of glutamine flux, on different subtypes of breast cancers (estrogen, progesterone, and HER2 receptor-positive or negative, and Pgp-negative and Pgp-overexpressing). The interactions of V9302 with standard chemotherapeutic drugs (doxorubicin and cisplatin) were also determined by MTT staining on breast cancer cell lines. Furthermore, the influence of V9302 on the cell cycle of MCF-7 and its Pgp-overexpressing counterpart KCR was monitored by flow cytometry. It was shown that V9302 exerted synergistic interactions with doxorubicin in all breast cancer cell lines. In cell cycle analysis, the KCR cell line was more sensitive to V9302. After 48 h, cell proliferation was completely blocked, and elevated G1, suppressed S, and decreased G2/M could be detected. Inhibition of glutamate transport can be assumed to block resistance related to Pgp. [ABSTRACT FROM AUTHOR]

The aim of our study was to characterize the composition and certain bioactivities of the essential oil of Ambrosia artemisiifolia. Eighty organic compounds were identified in the essential oils obtained by hydrodistillation and microwave-assisted isolation. Germacrene D was the main component in both oils. The essential oil obtained by hydrodistillation exerted antibacterial activity against two S. aureus strains, with MIC values of 0.015% for the methicillin-susceptible strain and 0.25% for the methicillin-resistant strain. In the biofilm formation assay, a dose-dependent inhibition was observed in case of the K. pneumoniae ATCC 600,703. In the ethidium bromide accumulation assay, a dose-dependent inhibition activity was observed against the bacterial efflux pump of the Gram-negative bacteria E. coli ATCC 25,922. The essential oil displayed strong in vitro cytotoxicity against the multidrug-resistant (MDR) Colo 320 cancer cell line with an IC50 value of 0.0103%. The essential oil showed strong inhibition on the proliferation of the doxorubicin-sensitive Colo 205 cells (IC50 values of 0.054%) and in the case of MDR Colo 320 colonic adenocarcinoma cells (IC50 values of 0.008%). This is the first report of the cytotoxic and antiproliferative activities of the essential oil from these species. [ABSTRACT FROM AUTHOR]