Natural anti-neuroinflammatory inhibitors in vitro and in vivo from Aglaia odorata.

Fifty compounds including seven undescribed (1, 13, 18-20, 30, 31) and forty-three known (2-12, 14-17, 21-29, 32-50) ones were isolated from the extract of the twigs and leaves of Aglaia odorata with anti-neuroinflammatory activities. Their structures were determined by a combination of spectral analysis and calculated spectra (ECD and NMR). Among them, compounds 13-25 were found to possess tertiary amide bonds, with compounds 16, 17, and 19-21 existing detectable cis/trans mixtures in 1H NMR spectrum measured in CDCl3. Specifically, the analysis of the cis-trans isomerization equilibrium of tertiary amides in compounds 19-24 was conducted using NMR spectroscopy and quantum chemical calculations. Bioactivity evaluation showed that the cyclopenta[b]benzofuran derivatives (2-6, 8, 10, 12) could inhibit nitric oxide production at the nanomolar concentration (IC50 values ranging from 2 to 100 nM) in lipopolysaccharide-induced BV-2 cells, which were 413-20670 times greater than that of the positive drug (minocycline, IC50 = 41.34 µM). The cyclopenta[bc]benzopyran derivatives (13-16), diterpenoids (30-35), lignan (40), and flavonoids (45, 47, 49, 50) also demonstrated significant inhibitory activities with IC50 values ranging from 1.74 to 38.44 µM. Furthermore, the in vivo anti-neuroinflammatory effect of rocaglaol (12) was evaluated via immunofluorescence, qRT-PCR, and western blot assays in the LPS-treated mice model. The results showed that rocaglaol (12) attenuated the activation of microglia and decreased the mRNA expression of iNOS, TNF-α, IL-1ß, and IL-6 in the cortex and hippocampus of mice. The mechanistic study suggested that rocaglaol might inhibit the activation of the NF-κB signaling pathway to relieve the neuroinflammatory response.

Pterostilbene nanoemulsion promotes Nrf2 signaling pathway to downregulate oxidative stress for treating Alzheimer's disease.

Pterostilbene, a stilbene compound, demonstrates neuroprotective effects through its antioxidant and anti-inflammatory properties. However, pterostilbene exhibits low bioavailability. We developed a pterostilbene nanoemulsion with better release stability and particle size. Behavioral tests, including the Y maze, new object recognition, and water maze, revealed that the pterostilbene nanoemulsion demonstrated a more significant effect on improving learning and memory function than pterostilbene. Immunofluorescence analysis revealed that pterostilbene nanoemulsion was more potent in safeguarding hippocampal neurons and inhibiting apoptosis and oxidative stress than pterostilbene. Further results from the Western blot and quantitative reverse transcription polymerase chain reaction indicated that the enhanced efficacy of pterostilbene nanoemulsion may be attributed to its stronger promotion of the nuclear factor erythroid 2-related factor 2 signaling pathway. Hence, enhanced drug delivery efficiency decreased dosage requirements and increased the bioavailability of pterostilbene, thereby potentially providing a safe, effective, and convenient treatment option for patients with Alzheimer's disease.

Inhibition of TLR4 Signaling by Isorhapontigenin Targeting of the AHR Alleviates Cerebral Ischemia/Reperfusion Injury.

Ischemic stroke is a major risk factor in human health, yet there are no drugs to cure cerebral ischemia/reperfusion injury (CIRI). Inflammation plays a fundamental role in the consequences of CIRI. Isorhapontigenin (ISOR) exhibits great anti-inflammatory activity; however, it is unclear whether ISOR can treat ischemic stroke through an anti-inflammation effect. Here, middle cerebral artery occlusion/reperfusion (MCAO/R) was used to investigate the effects of ISOR on CIRI. The in vitro activity was measured in BV-2 cells exposed to oxygen-glucose deprivation/reperfusion. As measured by neurological scores, brain water content, and infarction, neurological dysfunction was improved in the ISOR group. The neuronal death and microglial activation in the ipsilateral cortex were reduced by ISOR. TLR4 signaling was significantly inhibited by ISOR in vivo and in vitro. By reverse molecular docking, cellular thermal shift, and drug affinity-responsive target stability assays, an aryl hydrocarbon receptor (AHR) was found to be a target of ISOR. Furthermore, AHR knockdown blocked the effect of ISOR on TLR4 signaling, suggesting that ISOR may regulate TLR4-mediated inflammation through AHR, thereby protecting neurons from CIRI. This study demonstrated that ISOR is a promising drug candidate for the treatment of ischemic stroke and provided a theoretical basis for the development of the medicinal value of ISOR-derived foods, such as grapes.

Pterostilbene participates in TLR4- mediated inflammatory response and autophagy-dependent Aß1-42 endocytosis in Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD), the most prevalent form of dementia, remains untreatable. One of the factors that contributes to its progression is microglia-mediated inflammation. Pterostilbene, a compound isolated from Chinese dragon's blood, can reduce inflammation caused by overactive microglia. However, its effects on AD transgenic animals and the possible underlying mechanism remain unknown. METHODS: We evaluated the effect of pterostilbene on learning and memory difficulties in transgenic APP/PS1 mice. We used immunofluorescence to detect microglial activation and Aß aggregation. We explored the cellular mechanism of pterostilbene by establishing LPS- stimulated BV2 cells and oAß1-42- exposed HEK 293T cells that overexpress TLR4 and/or MD2 via lentivirus. We applied flow cytometry and immunoprecipitation to examine how pterostilbene regulates TLR4 signaling. RESULTS: Pterostilbene enhanced the learning and memory abilities of APP/PS1 mice and reduced microglial activation and Aß aggregation in their hippocampus. Pterostilbene alleviated oAß1-42-induced inflammation, which required the involvement of MD2. Pterostilbene disrupted the binding between TLR4 and MD2, which may further prevent TLR4 dimerization and subsequent inflammatory response. Moreover, pterostilbene restored the impaired endocytosis of oAß1-42 through an autophagy-dependent mechanism. CONCLUSION: This is the first demonstration that pterostilbene can potentially treat AD by blocking the interaction of TLR4 and MD2, thereby suppressing TLR4-mediated inflammation.

Triad3A-Dependent TLR4 Ubiquitination and Degradation Contributes to the Anti-Inflammatory Effects of Pterostilbene on Vascular Dementia.

Pterostilbene, a methylated stilbene derived from many plant foods, has significant anti-inflammatory activity. Meanwhile, vascular dementia (VaD) is the second most common subtype of dementia, in which inflammation is one of the major pathogenic contributors. However, the protective effect of pterostilbene on VaD is not well understood. In this work, we investigated the effect of pterostilbene on VaD and explored its underlying mechanisms using in vivo and in vitro models. Y-maze and Morris water maze tests showed pterostilbene-attenuated cognitive impairment in mice with bilateral common carotid artery occlusion (BCCAO). The hippocampal neuronal death and microglial activation in BCCAO mice were also reduced by pterostilbene treatment. Further, pterostilbene inhibited the expression of TLR4 and downstream inflammatory cytokines in these mice, with similar results observed in an oxygen-glucose deprivation and reperfusion (OGD/R) BV-2 cell model. In addition, its anti-inflammatory effect on OGD/R BV-2 cells was partially blocked by TLR4 overexpression. Moreover, Triad3A-TLR4 interactions were increased by pterostilbene following enhanced ubiquitination and degradation of TLR4, and the inhibitory effect of pterostilbene on inflammation was blocked by Triad3A knockdown in OGD/R-stimulated BV-2 cells. Together, these results reveal that pterostilbene could reduce vascular cognitive impairment and that Triad3A-mediated TLR4 degradation might be the key target.

The effect of cadmium exposure on diversity of intestinal microbial community of Rana chensinensis tadpoles.

Cadmium is a natural and widely distributed toxicant, and can be commonly found in environment. Intestinal microbiota plays a very important role in maintaining its host's health. The effects of cadmium on the intestinal microbiota composition and stability of amphibians are little known. We exposed Rana chensinensis (R. chensinensis) embryos to different concentrations of cadmium (0, 112 and 448 µg Cd L-1) until they reached Gosner stage 38, and analyzed their microbial communities using 16S rRNA amplicon sequencing. By measures of both alpha and beta diversity, intestinal microbial communities were significantly differentiated in 448 µg Cd L-1 exposure groups. Cadmium exposure significantly altered the intestinal microflora diversity and composition of R. chensinensis. At the phylum level, it is worth noting that Fusobacteria and Spirochaetae were not detected in 448 µg Cd L-1 exposure groups. Firmicutes rapidly decreased in 448 µg Cd L-1 exposure group. At the genus level, Succinispira (Firmicutes), Desulfovibrio (Proteobacteria) and Fusobacterium (Fusobacteria) vanished in 448 µg Cd L-1 exposure groups. Our results demonstrate that cadmium exposure changed the composition and decreased the community diversity of intestinal microbiota of R. chensinensis tadpoles. Our study may provide a new framework based on intestinal microbiota to evaluate the response of amphibians to environmental chemicals pollution.

The morphological changes and molecular biomarker responses in the liver of fluoride-exposed Bufo gargarizans larvae.

The goal of the current study was to evaluate the negative influences of fluoride on liver of Bufo gargarizans larvae. B. gargarizans larvae were treated with 42.4mgF-/L for 0, 24, 48 and 72h at Gosner stage 37. The morphological changes and responses of molecular biomarkers involved in lipid metabolism, oxidative stress and apoptosis were examined in liver. Disappearance of cell boundaries, degeneration of hepatic parenchyma cells and significant increase in the number of melanomacrophage centres and the quantity of lipid droplets were found in the liver treated with 42.4mgF-/L for 72h. In addition, in the relative expression of acetyl CoA carboxylase 1 (ACC-1), fatty acid elongase 1 (FAE-1), sterol carrier protein 2 (SCP-2), and carnitine palmitoyltransferase-1 (CPT-1), decrease was observed after 24, 48 and 72h of 42.4mgF-/L exposure. Furthermore, the transcript levels of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were downregulated in tadpoles exposed for 24, 48 and 72h to 42.4mgF-/L, while the transcript level of heat shock protein 90 (HSP90) was upregulated at 42.4mgF-/L for 72h. Also, mRNA expression of Bcl-2-associated transcription factor 1(BCLAF1) and thyroid hormone receptors (TRα and TRß) was significantly upregulated in tadpoles treated with 42.4mgF-/L for 72h. Therefore, our results suggested that the liver injury induced by fluoride might result from disruption of lipid metabolism, oxidative damage and apoptosis.