Search Results (4)

Natural bioresources, predominantly plants, have always been regarded as the richest source of drugs for diseases threatening humanity. Additionally, microorganism-originating metabolites have been extensively explored as weapons against bacterial, fungal, and viral infections. However, the biological potential of metabolites produced by plant endophytes still remains understudied, despite significant efforts reflected in recently published papers. Thus, our goal was to evaluate the metabolites produced by endophytes isolated from Marchantia polymorpha and to study their biological properties, namely anticancer and antiviral potential. The cytotoxicity and anticancer potential were assessed using the microculture tetrazolium technique (MTT) against non-cancerous VERO cells and cancer cells—namely the HeLa, RKO, and FaDu cell lines. The antiviral potential was tested against the human herpesvirus type-1 replicating in VERO cells by observing the influence of the extract on the virus-infected cells and measuring the viral infectious titer and viral load. The most characteristic metabolites identified in the ethyl acetate extract and fractions obtained by use of centrifugal partition chromatography (CPC) were volatile cyclic dipeptides, cyclo(l-phenylalanyl-l-prolyl), cyclo(l-leucyl-l-prolyl), and their stereoisomers. In addition to the diketopiperazine derivatives, this liverwort endophyte also produced arylethylamides and fatty acids amides. The presence of N-phenethylacetamide and oleic acid amide was confirmed. The endophyte extract and isolated fractions showed a potential selective anticancer influence on all tested cancer cell lines. Moreover, the extract and the first separated fraction noticeably diminished the formation of the HHV-1-induced cytopathic effect and reduced the virus infectious titer by 0.61–1.16 log and the viral load by 0.93–1.03 log. Endophytic organisms produced metabolites with potential anticancer and antiviral activity; thus, future studies should aim to isolate pure compounds and evaluate their biological activities. Full article

For exploring structurally diverse metabolites and uniquely metabolic mechanisms, we systematically investigated the chemical constituents and putative biosynthesis of Janibacter sp. SCSIO 52865 derived from the deep-sea sediment based on the OSMAC strategy, molecular networking tool, in combination with bioinformatic analysis. As a result, one new diketopiperazine (1), along with seven known cyclodipeptides (2–8), trans-cinnamic acid (9), N-phenethylacetamide (10) and five fatty acids (11–15), was isolated from the ethyl acetate extract of SCSIO 52865. Their structures were elucidated by a combination of comprehensive spectroscopic analyses, Marfey’s method and GC-MS analysis. Furthermore, the analysis of molecular networking revealed the presence of cyclodipeptides, and compound 1 was produced only under mBHI fermentation condition. Moreover, bioinformatic analysis suggested that compound 1 was closely related to four genes, namely jatA–D, encoding core non-ribosomal peptide synthetase and acetyltransferase. Full article

Chemical investigations of Aquimarina sp. MC085, which suppressed TGF-β-induced epithelial–mesenchymal transition (EMT) in A549 human lung cancer cells, led to the isolation of compounds 1–3. Structural characterization using spectroscopic data analyses in combination with Marfey’s analysis revealed that they were two diketopiperazines [cyclo(l-Pro-l-Leu) (1) and cyclo(l-Pro-l-Ile) (2)] and one N-phenethylacetamide (3). Cyclo(l-Pro-l-Leu) (1) and N-phenethylactamide (3) inhibited the TGF-β/Smad pathway and suppressed the metastasis of A549 cells by affecting TGF-β-induced EMT. However, cyclo(l-Pro-l-Ile) (2) downregulated mesenchymal factors via a non-Smad-mediated signaling pathway. Full article

Bacteria-derived allelopathic effects on microalgae blooms have been studied with an aim to develop algicidal products that may have field applications. However, few such studies have been conducted on macroalgae. Therefore, a series of experiments was conducted to investigate the impacts of different concentrations of cell-free filtrate of the bacteria Bacillus cereus BE23 on Ulva prolifera. Excessive reactive oxygen species (ROS) were produced when these cells were exposed to high concentrations of filtrate relative to f/2 medium. In such conditions, the antioxidative defense system of the macroalga was activated as shown by activities of the enzymes superoxide dismutase (SOD) and catalase (CAT) and upregulation of the associated genes upMnSOD and upCAT. High concentrations of filtrate also inhibited growth of U. prolifera, and reduced chlorophyll a and b, the photosynthetic efficiency (Fv/Fm), and the electron transport rate (rETR). Non-photochemical quenching (NPQ) was also inhibited, as evidenced by the downregulation of the photoprotective genes PsbS and LhcSR. Collectively, this evidence indicates that the alteration of energy dissipation caused excess cellular ROS accumulation that further induced oxidative damage on the photosynthesis apparatus of the D1 protein. The potential allelochemicals were further isolated by five steps of extraction and insolation (solid phase–liquid phase–open column–UPLC–preHPLC) and identified as N-phenethylacetamide, cyclo (L-Pro-L-Val), and cyclo (L-Pro-L-Pro) by HR-ESI-MS and NMR spectra. The diketopiperazines derivative, cyclo (L-Pro-L-Pro), exhibited the highest inhibition on U. prolifera and may be a good candidate as an algicidal product for green algae bloom control. Full article