Water-Soluble Polysaccharides Extracted from Pueraria lobata Delay Aging of Caenorhabditis elegans under Heat Stress.

Pueraria lobata is a perennial legume, commonly used as a food source in China. The polysaccharides extracted from P. lobata have demonstrated various biological activities. However their anti-aging effects and the underline mechanisms are largely unknown. In this study, water-soluble polysaccharides (WSPS) from P. lobata were extracted and demonstrated antioxidant activity against DPPH radicals and hydroxyl radicals in vitro. Using nematode Caenorhabditis elegans as a model, we found that WSPS remarkably prolonged the survival, increased growth and locomotion under heat stress. To investigate the possible mechanism, the levels of reactive oxygen species (ROS) and lipid peroxidation product malondialdehyde (MDA) were determined. WSPS significantly decreased ROS and MDA levels which is consistent with increased activity of superoxide dismutase (SOD). Meanwhile, WSPS upregulated the expression of stress resistance genes sod-1, sod-5, hsf-1, hsp-12.6, hsp-16.2, skn-1 and gst-4. Together, these results suggest that the anti-aging activity of WSPS under heat stress was mediated most likely by activation of the target genes of heat-shock transcription factor (HSF)-1 and skinhead (SKN)-1, and thus inducing endogenous ROS scavenging response.

Highly efficient removal and detoxification of phenolic compounds using persulfate activated by MnOx@OMC: Synergistic mechanism and kinetic analysis.

Persulfate-based advanced oxidation technology exhibits great potential for hazardous organic pollutant removal from wastewater. Acceleration of pollutant degradation needs to be elucidated, particularly for heterogeneous catalytic systems. In this study, manganese oxide ordered mesoporous carbon composites (MnOx@OMC) were prepared by nano-casting method and used for persulfate activation to degrade phenol. Kinetics analysis indicate that the rate of phenol degradation using MnOx@OMC composites was improved by 34.9 folds relative to that using a mixture of MnOx and OMC. The phenol toxicity towards Caenorhabditis elegans could be totally reduced within 8 min. The different roles of MnOx and OMC in persulfate activation were confirmed to validate their synergistic effect. MnOx provided major active sites for persulfate activation in accordance with the surface Mn3+/Mn4+ cycle to induce SO4•- radicals. The OMC matrix provided the adsorption sites to enrich phenol molecules on the catalytic surface and promote the interfacial electron transfer process for persulfate activation. Moreover, a novel kinetic model with two distinct kinetic stages was established to verify the effects of phenol and persulfate on phenol removal.