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Myrothecol A (1), a rare 10,13-cyclo macrocyclic trichothecene, and two known compounds (2 and 3) were isolated from the fungus Myrothecium roridum, which was obtained from the gut of a locust Atractomorpha sinensis Bolivar. Their structures and absolute configurations were determined through HRESIMS (high resolution electrospray ionization mass spectroscopy), NMR (nuclear magnetic resonance), ECD (electronic circular dichroism), and Mo2(OCOCH3)4-induced ECD experiments. Compounds 1−3 exhibited potent cytotoxic effects against human tumor cell lines MGC803 and NCI-H1975 with IC50 values between 68 nM and 28.72 μM. These results suggested that macrocyclic trichothecenes could be a kind of potential precursors for the anti-cancer drug development.

Three new macrocyclic trichothecenes possessing rare 6′-ketal moieties, roridoxins A–C (1–3), and five known compounds (4–8) were isolated from the insect-associated fungus Myrothecium roridum. Their structures were confirmed by a combination of NMR and HRESIMS data, while their absolute configurations were unambiguously determined by single-crystal X-ray analysis and electronic circular dichroism experiments. Trichothecenes 1 and 3 showed potent antifungal activities against four strains of phytopathogenic fungi. In addition, 1, 3, 5, and 6 were found to significantly inhibit the cell growth of Candida albicans with minimal inhibitory concentration values from 8.8 to 18.5 μg/mL. Moreover, they were able to inhibit the biofilm formation of C. albicans better than the positive control.

In this study, the effects of Tween 40 and ethanol supplementation on the secretion, structure and antioxidant activities of exopolysaccharide (EPS) from Inonotus rickii were investigated. It was observed that Tween 40 and ethanol displayed a stimulatory effect on EPS secretion. The EPSs obtained by the addition of Tween 40 (EPS-T), ethanol (EPS-E) and control (EPS-C) were purified by Sepharose CL-6B gel chromatography and molecular weights of EPS-T, EPS-E and EPS-C were estimated to be 22.1, 30.0, and 40.5 kDa, respectively. Monosaccharide composition analysis indicated that EPS-T, EPS-E and EPS-C were mainly composed of mannose and glucose. Furthermore, EPS-E exhibited better OH• and DPPH scavenging activities than those of EPS-C and EPS-T, which might be associated with its molecular characterization.

A new polysaccharides fraction (PSF) was isolated from the extraction of flue-cured tobacco stem with hot water and purified through ethanol precipitation, deproteinization and Sepharose CL-6B colu...

In this study, several surfactant and organic solvents were supplied to enhance the production of polysaccharides (EPSs) from Scorias spongiosa. The EPSs were purified by Sepharose CL-6B gel filtra...

The effect on different three carbon source (i.e. glucose, fructose and sucrose) on production, chemical characterization and antioxidant activity of exopolysaccharide (EPS) produced by Phellinus vaninii Ljup was investigated in this study. Amongst carbon sources examined, glucose and sucrose were favorable for the mycelia growth, while the maximum EPS yield was achieved when sucrose was employed. The predominant carbohydrate compositions in EPSs identified were gluconic acid, glucose, mannose and galactose acid. Then, FT-IR spectral analysis revealed prominent characteristic groups in EPSs. EPSs molecule exist as nearly globular shape form in aqueous solution. The variation also affects antioxidant activities by investigated by using hydroxyl and DPPH radical scavenging assay. Sucrose was best carbon source from the viewpoint of antioxidant activity due to the relatively high contents of galactose in the EPS with moderate molecular weight and polydispersity.Key words: Phellinus vaninii

Polysaccharides are ideal green synthetic raw materials to improve the biocompatibility of metal nanoparticles. However, polysaccharides generally have weak reducibilities, being challenging supports for the direct preparation of Ag nanoparticles. In this work, gold nanoclusters were prepared using a triple helix glucan (Lentinan) via microwave-assisted synthesis and subsequently employed as seeds for the synthesis of a series of Ag-Au alloy nanoparticles (Ag-AuNPs). The results showed that gold nanoclusters can remarkably speed up the preparation of Ag-AuNPs without the addition of any other chemicals. The particle size of Ag-AuNPs increased at increasing Ag contents in the alloy. Results of UV-vis, transmission electron microscope (TEM) and inductively coupled plasma mass spectrometry (ICP-MS) suggested that Ag+ was quickly reduced to irregular silver nanoparticles (with gold nanoparticles as seeds), then gradually form more regular nano-alloys. Additionally, X-ray diffraction (XRD) and zeta potential results suggested that Ag-AuNPs could entrap the hydrophobic cavity of triple helix polysaccharides during the renaturation process. The nanocomposites exhibited good antifungal activity and low cytotoxicity to RAW264.7, Hela and LO2 cell lines in vitro.

In this investigation we developed an optimal fermentation medium to produce an exopolysaccharide (EPS) with antioxidant activity from Rigidoporus microporus. Lactose and tryptone were chosen as the optimal carbon and nitrogen sources, respectively, for EPS production, with a 6-day cultivation cycle. After removing proteins through the use of the Sevag method, one EPS fraction was purified from the culture filtrates by gel filtration chromatography on a Sepharose CL-6B column. The preliminary chemical structure of the EPS fraction was determined by Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry, and nuclear magnetic resonance. The results indicated that the main structure of the EPS consisted of β-glucopyranose and mannopyranose. Furthermore, conformational parameters such as molecular weight (Mw), intrinsic viscosity ([η]), mean-square radii of gyration (Rg), and hydrodynamic radius (Rh) of the EPS were characterized using a size exclusion chromatography-multiangle light scattering-refractive index viscometry method. It showed that the EPS was a kind of water-soluble polysaccharide with a moderate molecular weight (34.1 × 104) and a flexible, linear random coil chain structure. The antioxidant activity tests suggested that the EPS has great potential application as a natural antioxidant material in foods and medicines.

Two new compounds, versicolones A and B (1 and 2), and three known pyrone derivatives (3−5) were isolated from the insect-associated fungus Aspergillus versicolor. Their structures were elucidated through a combination of HRESIMS and NMR spectroscopic analysis. Versicolone A (1) was revealed as a coumarin derivative with the rare 5-alkyl side chain substitution. Compound 5 exhibited significant antioxidant activity with EC50 value of 8.0 μM in the ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) assay, which was more than 2-fold potency of the positive control trolox.