Geniposidic Acid from Eucommia ulmoides Oliver Staminate Flower Tea Mitigates Cellular Oxidative Stress via Activating AKT/NRF2 Signaling

Eucommia ulmoides Oliver staminate flower (ESF) tea enjoys a good reputation in folk medicine and displays multiple bioactivities, such as antioxidant and antifatigue properties. However, the underlying biological mechanisms remain largely unknown. In this study, we aimed to investigate whether ESF tea can mitigate cellular oxidative stress. Crude ethyl alcohol extract and its three subfractions prepared by sequential extraction with chloroform, n-butyl alcohol and residual water were prepared from ESF tea. The results of antioxidant activity tests in vitro manifested n-butyl alcohol fraction (n-BUF) showed the strongest antioxidant capacity (DPPH: IC50 = 24.45 ± 0.74 µg/mL, ABTS: IC50 = 17.25 ± 0.04 µg/mL). Moreover, all subfractions of ESF tea, especially the n-BUF, exhibited an obvious capacity to scavenge the reactive oxygen species (ROS) and stimulate the NRF2 antioxidative response in human keratinocytes HaCaT treated by H2O2. Using ultra-high-performance liquid chromatography, we identified geniposidic acid (GPA) as the most abundant component in ESF tea extract. Furthermore, it was found that GPA relieved oxidative stress in H2O2-induced HaCaT cells by activating the Akt/Nrf2/OGG1 pathway. Our findings indicated that ESF tea may be a source of natural antioxidants to protect against skin cell oxidative damage and deserves further development and utilization.

Implantable Electronic Medicine Enabled by Bioresorbable Microneedles for Wireless Electrotherapy and Drug Delivery.

A combined treatment using medication and electrostimulation increases its effectiveness in comparison with one treatment alone. However, the organic integration of two strategies in one miniaturized system for practical usage has seldom been reported. This article reports an implantable electronic medicine based on bioresorbable microneedle devices that is activated wirelessly for electrostimulation and sustainable delivery of anti-inflammatory drugs. The electronic medicine is composed of a radio frequency wireless power transmission system and a drug-loaded microneedle structure, all fabricated with bioresorbable materials. In a rat skeletal muscle injury model, periodic electrostimulation regulates cell behaviors and tissue regeneration while the anti-inflammatory drugs prevent inflammation, which ultimately enhance the skeletal muscle regeneration. Finally, the electronic medicine is fully bioresorbable, excluding the second surgery for device removal.

Novel mechanisms of selenite reduction in Bacillus subtilis 168：Confirmation of multiple-pathway mediated remediation based on transcriptome analysis.

Selenite biotransformation by microorganisms is an effective detoxification and assimilation process. Bacillus subtilis is a probiotic bacterium that can reduce Se(IV) to SeNPs under aerobic conditions. However, current knowledge on the molecular mechanisms of selenite reduction by B. subtilis remains limited. Here, the reduction of Se(IV) by probiotic bacterium Bacillus subtilis 168 was systematically analysed, and the molecular mechanisms of selenium nanoparticle (SeNPs) formation were characterised in detail. B. subtilis 168 reduced 5.0 mM selenite by nearly 40% in 24 h, and the produced SeNPs were spherical and localised intracellularly or extracellularly. FTIR (Fourier transform infrared) spectroscopy suggested the presence of proteins, lipids, and carbohydrates on the surface of the isolated SeNPs. Transcriptome data analysis revealed that the expression of genes associated with the proline metabolism, glutamate metabolism, and sulfite metabolism pathways was significantly up-regulated. Gene mutation and complementation revealed the ability of PutC, GabD, and CysJI to reduce selenite in vivo. In vitro experiments demonstrated that PutC, GabD, and CysJI could catalyse the reduction of Se(IV) under optimal conditions using NADPH as a cofactor. To the best of our knowledge, our study is the first to demonstrate the involvement of PutC and GabD in selenite reduction. Particularly, our findings demonstrated that the reduction of Se(IV) was mediated by multiple pathways both in vivo and in vitro. Our findings thus provide novel insights into the molecular mechanisms of Se(VI) reduction in aerobic bacteria.

Speeding up selenite bioremediation using the highly selenite-tolerant strain Providencia rettgeri HF16-A novel mechanism of selenite reduction based on proteomic analysis.

Selenite in the environment is extremely biotoxic, thus, the biotransformation of selenite into selenium nanoparticles (SeNPs) by microorganisms is gaining increasing interest. However, the relatively low selenite tolerance and slow processing by known microorganisms limit its application. In this study, a highly selenite-resistant strain (up to 800 mM) was isolated from coalmine soil and identified as Providencia rettgeri HF16. Remarkably, 5 mM selenite was entirely transformed by this strain within 24 h, and SeNPs were detected as early as 2 h of incubation, which is a more rapid conversion than that described for other microorganisms. The SeNPs were spherical in shape with diameters ranging from 120 nm to 295 nm, depending on the incubation time. Moreover, in vitro selenite-reduction activity was detected in the cytoplasmic protein fraction with NADPH or NADH serving as electron donors. Proteomics analysis and key enzyme activity tests revealed the presence of a sulfite reductase-mediated selenite reduction pathway. To our knowledge, this is the first report to identify the involvement of sulfite reductase in selenite reduction under physiological conditions. P. rettgeri HF16 could be a suitable and robust biocatalyst for the bioremediation of selenite, and would accelerate the efficient and economical synthesis of selenium nanoparticles.