The ameliorative effect on chemotherapy-induced injury and tumor immunosuppressive microenvironment of the polysaccharide from the rhizome of Menispermum dauricum DC.

Combined medication has attracted increasing attention as an important treatment option for tumors due to the serious adverse effects of chemotherapy. In this study, as a new therapy strategy, a combination treatment of MDP (a polysaccharide from the rhizome of Menispermum dauricum DC.) with cyclophosphamide (CTX) was investigated. The results showed that combination treatment with MDP and CTX exerted a significantly synergistic anti-tumor effect in Lewis tumor-bearing mice, improved CTX-induced emaciation and hair loss, as well as increased the number of leukocytes, erythrocytes, hemoglobin, and platelets in the peripheral blood. In addition, compared with CTX alone, the thymus index and spleen index of the MDP + CTX group were increased, the number of CD3 + T cells, CD8 + T cells, white blood cells and B cells in spleen also increased significantly. MDP could also ameliorate the increase in liver and kidney index caused by CTX. In the Lewis lung cancer model, MDP showed a certain degree of anti-tumor effects, which may be related to its promotion of tumor-associated macrophages (TAMs) to M1 phenotype polarisation, enhancement of the number of T cells in tumor tissues and promotion of Th cells in tumor tissues to Th1 phenotype polarisation, thus alleviating the immunosuppressive microenvironment in tumor tissues. This study laid the foundation for the development of MDP as a polysaccharide drug for the treatment or adjuvant therapy of tumors and has important significance for the further clinical application of polysaccharides.

Extraction, structure and bioactivities of polysaccharide from root of Arctium lappa L.: A review.

Arctium lappa L. root is a well-known Chinese medicine with high medicinal and food values. Arctium lappa L. root polysaccharide (ALP), as the main component and bioactive substance, has a variety of biological activities, including anti-inflammatory, antioxidant, hypoglycemic, hypolipidemic, antithrombotic, immunomodulatory activity and improvement of intestinal flora. The biological activities of polysaccharides are closely related to their structures, and different extraction and purification methods will yield different polysaccharide structures. As a kind of natural polysaccharide, ALP has a broad application prospect in drug carrier. In this paper, we reviewed the research progress on the extraction, purification, structural characterization, biological activities, structure-activity relationship and drug carrier application of ALP, in order to provide basic reference for the development and application of medical and health care value. At the same time, the shortcomings of ALP research are discussed in depth, and the potential development prospect and future research direction are prospected.

Neuroprotective mechanism of ribisin A on H2O2-induced PC12 cell injury model.

Ribisin A has been shown to have neurotrophic activity. The aim of this study was to evaluate the neuroprotective effect of ribisin A on injured PC12 cells and elucidate its mechanism. In this project, PC12 cells were induced by H2O2 to establish an injury model. After treatment with ribisin A, the neuroprotective mechanism of ribisin A was investigated by methyl tetrazolium (MTT) assay, Enzyme-linked immunosorbent assay (ELISA), flow cytometric analysis, fluorescent probe analysis, and western blot. We found that ribisin A decreased the rate of lactate dehydrogenase (LDH) release, increased cellular superoxide dismutase (SOD) level, decreased the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), Ca2+ expression and reactive oxygen species (ROS). Moreover, ribisin A significantly increased mitochondrial membrane potential (MMP) and inhibited apoptosis of PC12 cells. Meanwhile, ribisin A activated the phosphorylation of ERK1/2 and its downstream molecule CREB by upregulating the expression of Trk A and Trk B, the upstream molecules of the ERK signaling pathway.

Neuroprotective effects of PRG on Aß25-35-induced cytotoxicity through activation of the ERK1/2 signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Phylloporia ribis (Schumach:Fr.)Ryvarden is a genus of needle Phellinus medicinal fungi, parasitic on the living rhizomes of hawthorn and pear trees. As a traditional Chinese medicine, Phylloporia ribis was used in folklore for long-term illness, weakness and memory loss in old age. Previous studies have shown that polysaccharides from Phylloporia ribis (PRG) significantly promoted synaptic growth in PC12 cells in a dose-dependent manner, exhibiting "NGF"-like neurotrophic activity. Aß25-35 damage to PC12 cells produced neurotoxicity and decreased cell survival, and PRG reduced the apoptosis rate, suggesting that PRG has neuroprotective effects. The studies confirmed that PRG had the potential to be a neuroprotective agent, but its neuroprotective mechanism remained unclear. AIM OF THE STUDY: We aimed to elucidate the neuroprotective effects of PRG in an Aß25-35-induced Alzheimer's disease (AD) model. MATERIALS AND METHODS: Highly-differentiated PC12 cells were treated with Aß25-35 (AD model) and PRG, and were assessed for cellular apoptosis, inflammatory factors, oxidative stress, and kinase phosphorylation. RESULTS: The results showed that the PRG groups effectively inhibited the neurotoxicity, mainly manifested by inhibiting mitochondrial oxidative stress, attenuating neuroinflammatory responses, and improving mitochondrial energy metabolism, eventually resulting in higher cell survival. The expression of p-ERK, p-CREB and BDNF proteins was increased in the PRG groups compared to the model group, which confirmed that PRG reversed the inhibition of the ERK pathway. CONCLUSION: We provide evidence for neuroprotection conferred by PRG and its mechanism by inhibiting ERK1/2 hyper-phosphorylation, prevention of mitochondrial stress, and subsequent prevention of apoptosis. The study highlights PRG as a promising candidate with neuroprotective effects, the potential of which can be harnessed for identifying novel therapeutic targets.

Extraction, structure and bioactivities of polysaccharides from Rehmannia glutinosa: A review.

ETHNOPHARMACOLOGIC RELEVANCE: Rehmannia glutinosa (Gaertn.) DC. (RG) is a widely used herb for clearing heat and cooling the blood. Polysaccharides from Rehmannia glutinosa (Gaertn.) DC. (RGPs) have a variety of biological activities, including antioxidation, hypoglycemia, immune enhancement, hematopoiesis promotion, and antianxiety. AIM OF THE STUDY: This review provides up-to-date and comprehensive information on the extraction and separation methods, structural characteristics, and pharmacological activities of RGPs. A more in-depth study on the structure and clinical pharmacology of the RGPs was investigated. To further explore the pharmacological effects of RGPS, and lay a foundation for the safe clinical application and expansion of application scope. MATERIALS AND METHODS: Use Google Scholar, Scifinder, PubMed, Springer, Elsevier, Wiley, Web of Science and other online database search to collect the literature on extraction, separation, structural analysis and pharmacological activity of RGPs published before December 2022. The key words are "extraction", "isolation", "purification" and "pharmacological action" and "Rehmanniae polysaccharide". RESULTS: Rehmannia glutinosa has been widely used in the treatment of diabetes since ancient times, and is known as one of the "Four Sacred Medicines" for the treatment of diabetes, along with Ginseng, Psidium Guajava and Pueraria Mirifica. The active ingredients of Rehmannia glutinosa that have been studied more in the treatment of diabetes are Rehmannia glutinosa polysaccharide and Rehmannia glutinosa oligosaccharide. The content of polysaccharides varies due to different extraction methods, and separation and purification methods. RGPs have a wide range of pharmacological activities, including antitumor, immunomodulatory, neuroprotective effect, hypoglycemic activity, cardioprotective and antioxidant activities. These pharmacological properties lay a foundation for the treatment of tumors, inflammation, hyperglycemia, myocardial ischemia, oxidative stress and other diseases with RGPs. CONCLUSION: Based on its effects of promoting hematopoiesis, antitumor and enhancing immunity, RGPs have been clinically applied in the treatment of chronic aplastic anemia and esophageal cancer, but other effects of RGPs have not been reflected in the clinical practice. In the future, more in-depth research can be conducted on the molecular structure analysis, toxicity, side effects and clinical pharmacological effects of RGPs to further explore the pharmacological effects of RGPs and to lay the foundation for safe clinical application and expansion of application scope.

Preparation methods, structural characteristics, and biological activity of polysaccharides from Salvia miltiorrhiza: A review.

ETHNOPHARMACOLOGICAL RELEVANCE: Salvia miltiorrhiza is a traditional Chinese medicine with the application of more than a two-thousand-year history. It is a common medicine used in the clinical treatment of cardiovascular and cerebrovascular diseases and is listed as the top grade in Shennong's Classic of Materia Medica. Polysaccharide is an important chemical component of Salvia miltiorrhiza and has a variety of biological activities. AIM OF THE STUDY: In this review, we summarized the preparation methods, structural characteristics, and biological activities of Salvia miltiorrhiza polysaccharides, as well as discussed current research problems, providing support for further research, development, and utilization. MATERIALS AND METHODS: By inputting the search term "Salvia miltiorrhiza polysaccharides", relevant research information was obtained from databases such as Google Scholar, PubMed, VIP, Web of Science, and China Knowledge Network (CNKI). RESULTS: It has been found that the monosaccharide composition of Salvia miltiorrhiza polysaccharides containing glucose (Glc), galactose (Gal), mannose (Man), and arabinose (Ara) has antioxidant, anti-tumor, liver protection, and other activities. CONCLUSIONS: We summarized the preparation methods, structural information, and biological activities of Salvia miltiorrhiza polysaccharides in this review and discussed the issues that are currently being researched. Although this product has a wide range of biological activities and has high development and utilization potential, its structure information and structure-activity relationship require further investigation.

Broadband absorption and efficiency enhancement of an ultra-thin silicon solar cell with a plasmonic fractal.

We report in this work that quantum efficiency can be significantly enhanced in an ultra-thin silicon solar cell coated by a fractal-like pattern of silver nano cuboids. When sunlight shines this solar cell, multiple antireflection bands are achieved mainly due to the self-similarity in the fractal-like structure. Actually, several kinds of optical modes exist in the structure. One is cavity modes, which come from Fabry-Perot resonances at the longitudinal and transverse cavities, respectively; the other is surface plasmon (SP) modes, which propagate along the silicon-silver interface. Due to the fact that several feature sizes distribute in a fractal-like structure, both low-index and high-index SP modes are simultaneously excited. As a whole effect, broadband absorption is achieved in this solar cell. Further by considering the ideal process that the lifetime of carriers is infinite and the recombination loss is ignored, we demonstrate that external quantum efficiency of the solar cell under this ideal condition is significantly enhanced. This theoretical finding contributes to high-performance plasmonic solar cells and can be applied to designing miniaturized compact photovoltaic devices.

Influence of the interlayer on coupling of surface plasmons in a sandwiched structure with periodic array of nanoapertures.

In this work, we investigate the optical properties of a multilayer structure, where a SiO2 film is sandwiched by silver films with periodic array of sub-wavelength apertures. Due to the coupling of surface plasmons (SPs) between different layers, electric and magnetic resonances have been observed. By varying the thickness of the interlayer SiO2, we can modify relative phase of the SPs resonance and control the shifts of transmission peaks. Experimentally the multilayers are fabricated by magnetron sputtering and the array of apertures is milled by focused-ion-beam facility. The measured optical transmission spectra reasonably agree with our numerical calculation, which bases on three-dimensional finite-difference time-domain method. To understand the shifts of the peaks, we present a phenomenological explanation, considering the transmission peaks as energy levels, and the coupling of localized surface plasmons as perturbation. These results may have potential applications in designing plasmonic devices and tuning electromagnetic wave in nanophotonics.