Structural characterization of a galactoglucomannan with anti-neuroinflammatory activity from Ganoderma lucidum

According to traditional Chinese medicine theory, Ganoderma lucidum (G. lucidum) presents certain effects for nourishing nerves and calming the mind. G. lucidum polysaccharides (GLPs) have various biological activities; however, the structural characterization and the structure-activity relationship in anti-neuroinflammation of GLPs needs to be further investigated. In this work, the crude polysaccharide GL70 exhibited a remarkable impact on enhancing the spatial learning and memory function, as well as reducing the anxiety symptoms of the lipopolysaccharide (LPS)-induced rat model of Alzheimer's disease (AD). A galactoglucomannan (GLP70-1-2) was isolated from GL70, and characterized by monosaccharide composition, partial acid hydrolysis, methylation, and NMR analysis. The backbone of GLP70-1-2 was →6)-α-D-glcp-(1 → 6)-β-D-galp-(1 → [6)-β-D-manp-(1]3 → 4)-α-D-Glcp-(1 → 6)-α-D-glcp-(1 → 2)-β-D-galp-(1 → [4)-α-D-glcp-(1 → 6)-β-D-manp-(1 → 2)-β-D-galp-(1]2 → 6)-β-D-glcp-(1 → 6)-β-D-glcp-(1→ with two side chains attached to O-4 of →6)-β-D-galp-(1→ and O-3 of →6)-β-D-glcp-(1→, respectively. In addition, GLP70-1-2 exhibited remarkable efficacy in decreasing the level of pro-inflammatory factors in LPS-activated BV2 cells through the TLR4/MyD88/NF-κB pathway. Collectively, GLP70-1-2 exhibited significant anti-neuroinflammatory activity and may have the potential for developing as a drug for AD.

Least Absolute Shrinkage and Selection Operator-Based Prediction of the Binding Constant of p-Sulfonatocalix[6]/[8]arenes with Alkaloids

p-Sulfonatocalix[n]arenes (SCnA) have demonstrated great potential for drug encapsulation through host-guest complexation to improve solubility, stability, and bioavailability. In this study, the solubilization effect of SCnA (n = 4, 6, 8) on 95 active compounds derived from traditional Chinese medicine (TCM) was investigated. Based on the significant solubilization effect on alkaloids, SC6A/SC8A and 76 alkaloids were selected as the host and guest, respectively, to determine the binding constant by competitive fluorescence titration. LASSO regression was adopted to investigate the mechanism of the complex of SCnA with alkaloids. The binding constant of alkaloids-SC6A and alkaloids-SC8A was related to the alkaloid alkalinity. Also, the electronegativity, polarization, first ionization potential, hydrogen bond potential, the molecular size, and shape of alkaloids are critical properties to determine alkaloids-SC6A binding constant as well as electronegativity, polarization, hydrophobicity, and the molecular size and shape of alkaloids play an important role for the alkaloids-SC8A binding constant.

Plant triterpenoid saponins: biosynthesis, in vitro production, and pharmacological relevance

The saponins are a diverse class of natural products, with a broad scale distribution across different plant species. Chemically characterized as triterpenoid glycosides, they posses a 30C oxidosqualene precursor-based aglycone moiety (sapogenin), to which glycosyl residues are subsequently attached to yield the corresponding saponin. Based on the chemically distinct aglycone moieties, broadly, they are divided into triterpenoid saponins (dammaranes, ursanes, oleananes, lupanes, hopanes, etc.) and the sterol glycosides. This review aims to present in detail the biosynthesis patterns of the different aglycones from a common precursor and their glycosylation patterns to yield the functionally active glycoside. The review also presents recent advances in the pharmacological activities of these saponins, particularly as potent anti-neoplastic pharmacophores, antioxidants, or anti-viral/antibacterial agents. Since alternate production pedestals for these pharmacologically important triterpenes via cell and tissue cultures are an attractive option for their sustainable production, recent trends in the variety and scale of in vitro production of plant triterpenoids have also been discussed.

Synthesis and evaluation of isoprenylation-resveratrol dimer derivatives against Alzheimer's disease

A series of resveratrol dimer derivatives against Alzheimer's disease (AD) was obtained by structural modification and transformation using resveratrol as substrate. Biological analysis revealed that these derivatives had moderate inhibitory activity against human monoamine oxidase B (hMAO-B). In particular, 3 and 7 showed the better inhibitory activity for hMAO-B (IC50 = 3.91 ± 0.23 μM, 0.90 ± 0.01 μM) respectively. Compound 3 (IC50 = 46.95 ± 0.21 μM for DPPH, 1.43 and 1.74 trolox equivalent by ABTS and FRAP method respectively), and 7 (IC50 = 35.33 ± 0.15 μM for DPPH, 1.70 and 1.97 trolox equivalent by ABTS method and FRAP method respectively) have excellent antioxidant effects. Cellular assay shown that 3 and 7 had lower toxicity and were resistant to neurotoxicity induced by oxidative toxins (H2O2, rotenone and oligomycin-A). More importantly, the selected compounds have neuroprotective effects against ROS generation, H2O2-induced apoptosis and a significant in vitro anti-inflammatory activity. The results of the parallel artificial membrane permeability assay for blood-brain barrier indicated that 3 and 7 would be predominant to cross the blood-brain barrier. In this study, mouse microglia BV2 cells were used to establish cell oxidative stress injury model with H2O2 and to explore the protective effect and mechanism of 3 and 7. In general, 3 and 7 can be considered candidates for potential treatment of AD.

Anti-neuroinflammatory effect of Sophoraflavanone G from Sophora alopecuroides in LPS-activated BV2 microglia by MAPK, JAK/STAT and Nrf2/HO-1 signaling pathways

BACKGROUND

Neuroinflammation plays a vital role in Alzheimer's disease (AD) and other neurodegenerative conditions. Sophora alopecuroides is widely used in traditional Uighur's medicine for the treatment of inflammation. Sophoraflavanone G (SG), a major flavonoid found in the S. alopecuroides, has also been reported to exhibit anti-inflammatory activity both in vitro and in vivo. However, the effect of S. alopecuroides and SG on microglia-mediated neuroinflammation has not been investigated.

PURPOSE

The present study was designed to evaluate the anti-neuroinflammatory effect of S. alopecuroides and SG against lipopolysaccharide (LPS)-activated BV2 microglial cells and to explore the underlying mechanisms.

METHODS

We measured the production of pro-inflammatory mediators and cytokines, and analyzed relevant mRNA and protein expressions by qRT-PCR and Western Blot.

RESULTS

S. alopecuroides extract (SAE) and SG inhibited the LPS-induced release of nitric oxide (NO), prostaglandin E₂ (PGE₂), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β). Additionally, SG reduced gene expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α, IL-6 and IL-1β, and further decreased the protein expressions of iNOS and COX-2. Mechanism studies found that SG down-regulated phosphorylated mitogen-activated protein kinases (MAPKs), phosphoinositide-3-kinase (PI3K)/AKT and Janus kinase/signal transducer and activator of transcription (JAK/STAT), and up-regulated heme oxygenase-1 (HO-1) expression via nuclear translocation of nuclear factor E2-related factor 2 (Nrf2). In addition, SG inhibited the cytotoxicity of conditioned medium prepared by LPS-activated BV2 microglia to neuronal PC12 cells and improved cell viability.

CONCLUSION

S. alopecuroides and SG displayed anti-neuroinflammatory activity in LPS-activated BV2 microglia. SG was able to inhibit the neuroinflammation by MAPKs, PI3K/AKT, JAK/STAT and Nrf2/HO-1 signaling pathways and might act as a natural therapeutic agent to be further developed for the treatment of various neuroinflammatory conditions.

Antimalarial diterpenoid dimers of a new carbon skeleton from Aphanamixis grandifolia

Chemical investigation into the minor constituents of Aphanamixis grandifolia yielded three new diterpenoid dimers, aphadilactones E-G (1-3) featuring a new carbon skeleton. Their structures and absolute configurations were fully established by comprehensive spectroscopic data analysis and ECD calculation. Discovery of another two new dimers (4 and 5) suggested the structure of recently reported aphanamene A to be re-investigated. Compounds 1-5 showed moderate antimalarial activities with low micromolar IC50 values.

Limonoids from the fruits of Aphanamixis polystachya (Meliaceae) and their biological activities

Seven new prieurianin-type limonoids, aphapolynins C-I (1-7), and a new aphanamolide-type limonoid, aphanamolide B (8), along with seventeen known compounds, were isolated from the fruits of Aphanamixis polystachya. The structures of these compounds were established on the basis of spectroscopic studies. The absolute configurations were determined by combination of electronic circular dichroism (ECD) calculation, CD exciton chirality method, and single crystal X-ray diffraction. All these isolates were evaluated for their cytotoxicities against three human cancer cell lines, for their inhibitory effects on lipopolysaccharide (LPS) induced RAW264.7 murine macrophages, and for their fungicidal, herbicidal, and insecticidal activities. Compounds 1, 14, 16, and 17 exhibited significant fungicidal activities; 1 and 25 in particular showed good insecticidal activities. The α,β-unsaturated lactone and 14,15-epoxy ring moieties were essential for the insecticidal activity.