Xanthine oxidase inhibitory constituents from the roots of Ampelopsis japonica.

Bioassay-guided purification of the xanthine oxidase (XOD) inhibitory extract of the roots of Ampelopsis japonica resulted in the isolation of two new triterpenoids (1-2), designated Ampejaponoside A and B, along with sixteen known compounds (3-18). The structures of Ampejaposide A and B were elucidated by comprehensive analysis of spectroscopic data with the structures of the known compounds 3-18 confirmed by comparison the spectral data with corresponding values reported in literatures. All the isolates were evaluated for their XOD inhibitory activity in vitro. As a result, compounds 2, 8, and 14-16 displayed significant XOD inhibitory effect, particularly 16 being the most potent with an IC50 value of 0.21 µM, superior to positive substance allopurinol (IC50 1.95 µM). Molecular docking uncovered a unique interaction mode of 16 with the active site of XOD. The current study showed that the triterpenoids and polyphenols from A. japonica could serve as new lead compounds with the potential to speed up the development of novel XOD inhibitors with clinical potential to treat hyperuricaemia and gout.

Bioactive Diarylheptanoids from Alpinia coriandriodora.

Eight new diarylheptanoids, coriandralpinins A-H (1-8), were isolated from the rhizomes of Alpinia coriandriodora, an edible plant of the ginger family. Their structures, including the absolute configurations, were established by extensive spectroscopic analysis and ECD calculations. Compounds 1-8 have a 1,5-O-bridged diarylheptanoid structure featuring polyoxygenated aryl units. When evaluated for intracellular antioxidant activity using t-BHP stressed RAW264.7 macrophages, all these compounds scavenged reactive oxygen species (ROS) in a concentration-dependent manner. Compounds 3 and 5 also showed inhibitory activity against NO release in LPS-induced RAW 264.7 cells. Six known flavonols, 7,4'-di-O-methylkaempferol, 7-O-methylquercetin, 7,4'-di-O-methylquercetin, 7,3',4'-tri-O- methylquercetin, kaempferol 3-O-ß-D-(6-O-α-L-rhamnopyranosyl)glucopyranoside, and 3-O-ß-D-glucopyranuronosylquercetin were also isolated and characterized from the rhizomes.

[Microbial Community of Granular Sludge in an ANAMMOX-EGSB Reactor Under Saline Conditions].

High-throughput sequencing technology was used to investigate changes in the microbial community in granular sludge under salinity conditions of 0, 15, and 30 g·L-1 in an ANAMMOX-EGSB reactor under stable operation. The study found that when the influent salinity was increased to 15 g·L-1 and 30 g·L-1, the nitrogen removal performance of the reactor decreased slightly, but was restored with the extension of the running time. After the performance of the reactor became stable, the abundance of the ANAMMOX bacteria under the three salinity conditions was 10.33%, 20.90%, and 35.87%, of which Candidatus Kuenenia was the dominant genus. Planctomycetes, Proteobacteria, and Chloroflexi accounted for a high proportion in the granular sludge, and their cumulative abundance exceeded 80%, making them the dominant phyla of the reactor. Under saline conditions, the abundance of the Planctomycetes bacteria increased, the abundance of the Proteobacteria bacteria decreased, and the abundance of the Chloroflexi bacteria was relatively stable. Electron microscopy showed a large number of filamentous bacteria and extracellular polymers were present on the surface of the granular sludge under saline conditions. The increased abundance of the denitrifying bacteria enhanced the cooperative denitrification, the presence of aerobic microorganisms and denitrifying bacteria facilitated the maintenance of anaerobic conditions inside the reactor, and the increased abundance of Chloroflexi and Bacteroidetes was beneficial to maintain the stability of the granular sludge structure. These results showed that the ANAMMOX bacteria could be adapted to saline conditions by acclimation, and that the associated bacteria provided support for the function of the ANAMMOX bacteria under saline conditions.

Underlying mechanisms of ANAMMOX bacteria adaptation to salinity stress.

Dealing with nitrogen-rich saline wastewater produced by industries remains challenging because of the inhibition of functional microorganisms by high salinity. The underlying mechanisms of anaerobic ammonium-oxidizing bacteria (AnAOB) exposed to salinity stress should be studied to investigate the potential of anaerobic ammonium oxidation (ANAMMOX) for applications in such wastewater. In this study, the total DNA from granular sludge was extracted from an expanded granular sludge bed (EGSB) reactor operated at 0, 15 and 30 g/L salinity and subjected to high-throughput sequencing. The nitrogen removal performance in the reactor could be maintained from 86.2 to 88.0% at less than 30 g/L salinity level. The microbial diversity in the reactor under saline conditions was lower than that under the salt-free condition. Three genera of AnAOB were detected in the reactor, and Candidatus Kuenenia was the most abundant. The predictive functional profiling based on the Clusters of Orthologous Groups of proteins (COGs) database showed that the inhibition of AnAOB under saline conditions was mainly characterised by the weakening of energy metabolism and intracellular repair. AnAOB might adapt to salinity stress by increasing their rigidity and intracellular osmotic pressure. The predictive functional profiling based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database revealed that the inhibition of AnAOB was mainly manifested by the weakening of intracellular carbohydrate and lipid metabolism, the blockage of intracellular energy supply and the reduction of membrane transport capacity. AnAOB might adapt to salinity stress by strengthening wall/membrane synthesis, essential cofactors (porphyrins) and energy productivity, enhancing intracellular material transformation and gene repair and changing its structure and group behaviour. The stability of the nitrogen removal performance could be maintained via the adaptation of AnAOB to salinity and their increased abundance.

Xylarodons A and B, new hexaketides from the endophytic fungus Xylaria sp. SC1440.

Two new hexaketides, xylarodons B (1) and C (2), were isolated from solid cultures of the endophytic fungus Xylaria sp. SC1440. The structures of these compounds were elucidated on the basis of detailed 1D, 2D NMR, and HRESIMS analysis. Their absolute configurations were established by experimental and TDDFT calculated ECD spectra. The isolated compounds were evaluated for cytotoxic and tyrosinase inhibitory activity.