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In this study, the response surface methodology was used to optimize the ultrasonic extraction of polysaccharides from Radix pueraria lobata. The first parameter of interest was ultrasonic extraction to investigate its effect on the polysaccharide content within Radix pueraria lobata. Based on single-factor experiments analysis, the independent variables including time, solid–liquid, and times were used for further optimization of the extraction of RPL polysaccharides by Box-Behnken design (BBD). Optimal conditions showed that the maximum polysaccharide content was 1.235 mg/g. The molecular weight (Mw), Fourier transformation infrared (FT-IR) spectroscopy, and proton nuclear magnetic resonance (HNMR) spectroscopy were used for structural characterization in this study. The scavenging activities of Radix Pueraria lobata against DPPH, ABTS, and OH were remarkable, and they were concentration dependent.

Polybrominated diphenyl ethers (PBDEs), a group of typical brominated flame retardants (BFRs), have drawn an increasing concern due to their widespread manufacture, usage and disposal around the world and the frequent detection in a variety of environmental media. In the present study, we investigated the molecular mechanism of the partitioning equilibrium of PBDEs between gas and atmospheric particles, and developed a new temperature-dependent predictive model for the gas/particle partition coefficient ( K P ) of these chemicals. Quantum chemical computations were implemented at B3LYP/6-31G (d,p) level of theory based on the neutral electronic ground state of PBDE congeners by Gaussian 09 software package. The model performance was assessed by different validation strategies and the application domain was defined by Williams Plot. Mechanism analysis indicated that the interactions of dispersion, electrostatic and hydrogen bond play crucial roles in the partitioning of PBDEs between the two phases. The developed model can be used to estimate the K P values of PBDEs for which experimental measurements are restricted. Therefore, this work provides an alternative method in a regulatory context of PBDEs. [ABSTRACT FROM AUTHOR]