苝衍生物光催化氧化硫醚的研究

本文通过对苝酐进行化学修饰,合成了两种具有较好溶解性和强可见光吸收的苝衍生物:PMI-(iPr)2An(PSⅡ)和PMI-((iPr)2An)2(PSⅢ)。在可见光照射下,以PSⅡ和PSⅢ作为光敏剂,氧气为氧化剂,实现了高转化率和高选择性的硫醚到亚砜的氧化。在优化反应条件下,PSⅢ对苯基硫醚衍生物光催化氧化的转化率和选择性均接近100%。活性中间体的清除实验和电子顺磁共振实验表明,该体系中单重态氧(~1O_2)和超氧自由基同时对硫醚的氧化起作用。     

Defensive Mechanisms in Cucurbits against Melon Fly (Bactrocera cucurbitae) Infestation through Excessive Production of Defensive Enzymes and Antioxidants

Melon fly (Bactrocera cucurbitae) is the most common pest of cucurbits, and it directly causes damage to cucurbit fruits in the early developmental stage. The infection of fruit tissues induces oxidative damage through increased generation of cellular reactive oxygen species. The effects of melon fly infestation on the production of defensive enzymes and antioxidant capabilities in five cucurbit species, namely, bottle gourd, chayote, cucumber, snake gourd, and bitter gourd, were investigated in this study. The total phenolic and flavonoid content was considerably higher in melon fly infestation tissues compared to healthy and apparently healthy tissues. The chayote and bottle gourd tissues expressed almost 1.5- to 2-fold higher phenolic and flavonoid contents compared to the tissues of bitter gourd, snake gourd, and cucumber upon infestation. Defensive enzymes, such as peroxidase (POD), superoxide dismutase (SOD), polyphenol oxidase (PPO), and catalase (CAT), were high in healthy and infected tissues of chayote and bottle gourd compared to bitter gourd, snake gourd, and cucumber. The activity of POD (60–80%), SOD (30–35%), PPO (70–75%), and CAT (40–50%) were high in infected chayote and bottle gourd tissue, representing resistance against infestation, while bitter gourd, snake gourd, and cucumber exhibited comparatively lower activity suggesting susceptibility to melon fly infection. The antioxidant properties were also high in the resistant cucurbits compared to the susceptible cucurbits. The current research has enlightened the importance of redox-regulatory pathways involving ROS neutralization through infection-induced antioxidative enzymes in host cucurbit resistance. The melon fly infestation depicts the possible induction of pathways that upregulate the production of defensive enzymes and antioxidants as a defensive strategy against melon fly infestation in resistant cucurbits.     

Anti-Inflammatory CeO2 Nanoparticles Prevented Cytotoxicity Due to Exogenous Nitric Oxide Donors via Induction Rather Than Inhibition of Superoxide/Nitric Oxide in HUVE Cells

The mechanism behind the cytoprotective potential of cerium oxide nanoparticles (CeO₂ NPs) against cytotoxic nitric oxide (NO) donors and H₂O₂ is still not clear. Synthesized and characterized CeO₂ NPs significantly ameliorated the lipopolysaccharide (LPS)-induced cytokines IL-1β and TNF-α. The main goal of this study was to determine the capacities of NPs regarding signaling effects that could have occurred due to reactive oxygen species (ROS) and/or NO, since NP-induced ROS/NO did not lead to toxicity in HUVE cells. Concentrations that induced 50% cell death (i.e., IC50s) of two NO donors (DETA-NO; 1250 ± 110 µM and sodium nitroprusside (SNP); 950 ± 89 µM) along with the IC50 of H₂O₂ (120 ± 7 µM) were utilized to evaluate cytoprotective potential and its underlying mechanism. We determined total ROS (as a collective marker of hydrogen peroxide, superoxide radical (O₂^•−), hydroxyl radical, etc.) by DCFH-DA and used a O₂^•− specific probe DHE to decipher prominent ROS. The findings revealed that signaling effects mediated mainly by O₂^•− and/or NO are responsible for the amelioration of toxicity by CeO₂ NPs at 100 µg/mL. The unaltered effect on mitochondrial membrane potential (MMP) due to NP exposure and, again, CeO₂ NPs-mediated recovery in the loss of MMP due to exogenous NO donors and H₂O₂ suggested that NP-mediated O₂^•− production might be extra-mitochondrial. Data on activated glutathione reductase (GR) and unaffected glutathione peroxidase (GPx) activities partially explain the mechanism behind the NP-induced gain in GSH and persistent cytoplasmic ROS. The promoted antioxidant capacity due to non-cytotoxic ROS and/or NO production, rather than inhibition, by CeO₂ NP treatment may allow cells to develop the capacity to tolerate exogenously induced toxicity.     

Polyphenolic Extracts from Spent Coffee Grounds Prevent H2O2-Induced Oxidative Stress in Centropomus viridis Brain Cells

Oxidative stress in aquatic organisms might suppress the immune system and propagate infectious diseases. This study aimed to investigate the protective effect of polyphenolic extracts from spent coffee grounds (SCG) against oxidative stress, induced by H₂O₂, in C. viridis brain cells, through an in vitro model. Hydrophilic extracts from SCG are rich in quinic, ferulic and caffeic acids and showed antioxidant capacity in DPPH, ORAC and FRAP assays. Furthermore, pretreatment of C. viridis brain cells with the polyphenolic extracts from SCG (230 and 460 µg/mL) for 24 h prior to 100 µM H₂O₂ exposure (1 h) significantly increased antioxidant enzymes activity (superoxide dismutase and catalase) and reduced lipid peroxidation (measured by MDA levels). These results suggest that polyphenols found in SCG extracts exert an antioxidative protective effect against oxidative stress in C. viridis brain cells by stimulating the activity of SOD and CAT.     

Resonant Raman‐based cytochrome C biosensor as a tool for evaluating the oxidative properties of the diesel exhaust particulate matter

Air pollution mostly originating from car exhaust and industrial emissions is seriously endangering human health. The study of toxic effects of particulate matter (PM) is a subject of very active research that covers a broad field from biology to chemistry and technology. The main issue of these works is the understanding of the oxidative properties of PM. In this paper, we present a quantitative analytical method based on the resonance Raman spectroscopy of cytocrome c that can be used to monitor the oxidative reactions that may take place between biological samples and PM. Copyright © 2016 John Wiley & Sons, Ltd.     

Enhanced skin anti-inflammatory and moisturizing action of gold nanoparticles produced utilizing Diospyros kaki fruit extracts

Inflammatory skin diseases (ISD) cause very severe itchy skin and dryness which is now a days an important issue which has to be taken care. Nanotechnology plays a main role in manufacturing cosmetic ingredients at a nanoscale size. Among different nanoparticles, gold (Au) is one of the non-toxic materials synthesized organically or inorganically. For synthesizing nanoparticles (NPs), using inorganic methods may cause some toxicity to cells, but using organic synthesis like plant extract is less toxic and environmentally friendly. Therefore, we synthesized DK-AuNPs using Diospyros kaki fruit extract. UPLC-MS/MS was used to evaluate phytochemicals responsible for converting salt into nanoparticles. The DK-AuNPs were characterized to confirm the formation of NPs. Furthermore, we analyzed the activity of DK-AuNPs on human keratinocytes (HaCaT cells). The DK-AuNPs showed 98.2 % cell survival upto 200 µg/mL against HaCaT cells. Additionally, compared to DK treatment, DK-AuNPs therapy decreased ROS production in TNF-α/IFN-γ (T + I) stimulated HaCaT cells by 68.7 %, whereas DK treatment reduced ROS generation by 27.8 %. Moreover, the skin anti-inflammatory potential and moisturizing effect of DK-AuNPs were analyzed using HaCaT cells. Furthermore, skin inflammatory activity biomarkers were downregulated through the MAPK/NFκB signaling pathway and showed significant inhibition by DK-AuNPs. Also, the skin moisturizing biomarkers such as HAS (1–3) were upregulated and HYAL (1–2) were downregulated by PI3K/AKT/NFκB through HAS2 regulation. Therefore, skin anti-inflammatory and moisturizing activity were enhanced by treatment with DK-AuNPs. In summary, we conclude that the DK-AuNPs could be a new alternative for skin disease.     

Basic characterization and Alzheimer’s disease relieving property of a glucose riched polysaccharide from Cibotium barometz

The water-soluble polysaccharides from plants have attracted ever-increasing attention in the field of food and drug due to their various activities and low toxicity. CBP50-1, as a purified fraction of polysaccharide from the rhizome of Cibotium barometz (CBP), mainly consisted of glucose (55.45%) and xylose (25.27%). CBP50-1 showed excellent antioxidant activity for scavenging 2,2?Diphenyl?1?picryl?hydrazy (DPPH) radical and hydroxyl radical, further inhibiting lipid peroxidation. CBP50-1 significantly improved the survival rate of Caenorhabditis elegans under thermal and oxidative stress. Furthermore, CBP50-1 reduced the paralysis and oxidative damage induced by amyloid-beta (Aβ) and increased the antioxidant enzyme activity in Alzheimer’s disease (AD) model C. elegans CL4176 through c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) signal pathway. Thus, CBP50-1 had a potential application in health industries.     

Camellia sinensis: Insights on its molecular mechanisms of action towards nutraceutical,anticancer potential and other therapeutic applications

The Camellia sinensis plant provides a wide diversity of black, green, oolong, yellow, brick dark, and white tea. Tea is one of the majorly used beverages across the globe, succeeds only in the water for fitness and pleasure. Generally, green tea has been preferred more as compared to other teas due to its main constituent e.g. polyphenols which contribute to various health benefits. The aim of this updated and comprehensive review is to bring together the latest data on the phytochemistry and pharmacological properties of Camellia sinensis and to highlight the therapeutic prospects of the bioactive compounds in this plant so that the full medicinal potential of Camellia sinensis can be realised. A review of published studies on this topic was performed by searching PubMed/MedLine, Scopus, Google scholar, and Web of Science databases from 1999 to 2022. The results of the analysed studies showed that the main polyphenols of tea are the four prime flavonoids catechins: epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC), and epicatechin (EC) along with the beneficial biological properties of tea for a broad heterogeneity of disorders, including anticancer, neuroprotective, antibacterial, antiviral, antifungal, antiobesity, antidiabetes and antiglaucoma activities. Poor absorption and low bioavailability of bioactive compounds from Camellia sinensis are limiting aspects of their therapeutic use. More human clinical studies and approaching the latest nanoformulation techniques in nanoparticles to transport the target phytochemical compounds to increase therapeutic efficacy are needed in the future.