Distribution patterns and environmental risk assessments of microplastics in the lake waters and sediments from eight typical wetland parks in Changsha city, China.

The quality of water in urban parks is closely related to people's daily lives, but the pollution caused by microplastics in park water and sediments has not been comprehensively studied. Therefore, eight typical parks in the urban area of Changsha, China, were selected, and Raman spectroscopy was used to explore the spatial distributions and compositions of the microplastics in the water and sediments, analyze their influencing factors, and evaluate their environmental risks. The results showed that the abundances of surface water microplastics in all parks ranged from 150 to 525 n L-1, and the abundances of sediment microplastics ranged from 120 to 585 n kg-1. The microplastics in the surface water included polyethylene terephthalate (PET), chlorinated polyethylene (CPE), and fluororubber (FLU), while those in the sediments included polyvinyl chloride (PVC), wp-acrylate copolymer (ACR), and CPE. Regression analyses revealed significant positive correlations between human activities and the abundances of microplastics in the parks. Among them, the correlations of population, industrial discharge and domestic wastewater discharge with the abundance of microplastics in park water were the strongest. However, the correlations of car flow and tourists with the abundance of microplastics in park water were the weakest. Based on the potential ecological risk indices (PERI) classification assessment method, the levels of microplastics in the waters and sediments of the eight parks were all within the II-level risk zone (53-8,549), among which the risk indices for Meixi Lake and Yudai Lake were within the IV risk zone (1,365-8,549), which may have been caused by the high population density near the park. This study provides new insights into the characteristics of microplastics in urban park water and sediment.

Bioassay-guided isolation and characterisation of α-glucosidase inhibitors from Sanghuangporus baumii.

Bioassay-guided fractionation of the isopropanol extract of the medicinal mushroom Sanghuangporus baumii led to the isolation and characterisation of a new acorane-type sesquiterpenoid bauminene (1) and seven known compounds 2-8. The planar structure of 1 was elucidated on the basis of extensive spectroscopic analysis, including 1D, 2D NMR and HR-ESI-MS. The relative configuration of 1 was determined by a combination of ROESY experiment, density functional theory calculation of 13C NMR, and DP4+ probability analysis, while the absolute configuration of 1 was established by comparative electronic circular dichroism (ECD) spectra analysis. In the in vitro bioassay, compounds 1-8 exhibited potent to moderate α-glucosidase inhibitory activity with IC50 values ranging from 6.8 ± 0.68 to 221.4 ± 6.57 µM. The presences of these bioactive constituents in the sclerotia of S. baumii may be related to the use of the fungus as 'Sanghuang' for the adjuvant treatment of DM.