Tamarix hohenackeri Bunge exerts anti-inflammatory effects on lipopolysaccharide-activated microglia in vitro

Effusol ameliorates ischemic stroke by targeting NLRP3 protein to regulate NLRP3 inflammasome-mediated pyroptosis

BACKGROUND

The significance of pyroptosis as an inflammatory mode of death in ischemic stroke (IS) has attracted much attention in recent years. Effusol is a dihydrophenanthrene component extracted from Juncus effusus L.. Previous studies have found that Juncus effusus L. has a good inhibitory effect against microglia activation. However, it is not clear whether effusol inhibits microglia over-activation and attenuates its mediated microglia pyroptosis in the treatment of IS.

PURPOSE

The aim is to examine how effusol influences the initiation and activation stages of pyroptosis, as well as the NLRP3 inflammasome, resulting from microglial over-activation triggered post-IS.

METHODS

This study investigated the impact of effusol on neurological severity and edema to assess its neuroprotective effects in IS. Mechanistically, immunofluorescence and western blotting were applied to explore the initiation and activation of the NLRP3 inflammasome. Finally, we employed the NLRP3 specific inhibitor, molecular docking, drug affinity responsive target stability (DARTS), and cellular thermal shift assay (CETSA) to further explore the underlying targets of effusol.

RESULTS

Effusol mitigated IS-induced damage and downregulated the expression of inflammatory factors at the mRNA level, the protein levels of toll-like receptor 4 (TLR4), nuclear transcription factor NF-κB p65, and key components of the NLRP3 inflammasome. Effusol also mitigated mitochondrial damage by increasing ATP levels and decreasing mitochondrial membrane potential. Importantly, effusol targets NLRP3 protein to inhibit pyroptosis, thereby suppressing the hyperactivation of NLRP3 inflammasome.

CONCLUSIONS

Effusol may be protective against IS by targeting NLRP3 proteins to inhibit NLRP3 inflammasome activation-mediated pyroptosis. This finding provides a theoretical basis and a prospective drug candidate for the treatment of effusol in IS.

Study on the Chemical Components and Anti-neuroinflammatory Activity of the Roots of Clausena excavate Burm. f

The ethanol extract of the roots of Clausena excavata gave two previously undescribed coumarins, clauexcatin A (1) and clauexcatin B (2), as well as a pair of new isomers, trans/cis-clauexcatin C (3a, 3b), along with thirty known compounds. Among these, compound 33 was isolated from this genus for the first time. The structures of these compounds were elucidated based on their physicochemical properties and spectroscopic data. The anti-neuroinflammatory activities were assessed using LPS-activated BV-2 microglial cells. Compounds 6, 8, 17, 24, 29, and 30 exhibited significant inhibition of nitric oxide release in a dose-dependent manner, with their inhibitory effects being 1.2 to 10.9 times greater than that of the positive control (minocycline).

Comparative study on chloroplast genome of Tamarix species

Tamaricaceae comprises about 120 species and has a long evolutionary history, Tamarix Linn accounts for approximately 75% of the total species in this family. It is the most widely distributed and diverse genus in the family. They have important ecological significance for transforming deserts and improving climate conditions. However, Tamarix is the most poorly classified genera among flowering plants owing to its large variability and high susceptibility to interspecific hybridization. In this study, the complete chloroplast genomes of three Tamarix species and one draft chloroplast genome were obtained in this study. Combined with eight chloroplast genomes deposited in GenBank, complete chloroplast sequences of 12 Tamarix species were used for further analysis. There are 176 non-SSR-related indels and 681 non-indel-related SSRs in the 12 Tamarix chloroplast genomes. The mononucleotide SSRs are the most prevalent among all types of SSRs. The mVISTA results indicate high sequence similarities across the chloroplast genome, suggesting that the chloroplast genomes are highly conserved, except for sample Tamarix androssowii (ENC850343). The IR regions and the coding regions are more conserved than the single-copy and noncoding regions. The trnF-ndhJ, ndhC-trnM-CAU, ycf1, and trnL-UAG-ndhF regions are the most variable and have higher variability than those of the universal DNA markers. Finally, the first phylogenetic tree of Tamaricaceae was constructed which confirmed the monophyly of Tamarix in Tamaricaceae. The first phylogenetic tree of Tamarix was based on the complete chloroplast genome to date, the changes in branch length and support rate can potentially help us clarify the phylogenetic relationships of Tamarix. All the obtained genetic resources will facilitate future studies in population genetics, species identification, and conservation biology of Tamarix.

Characteristic terpenylated coumarins from Ferula ferulaeoides as potential inhibitors on overactivation of microglia

A total of 37 characteristic terpenylated coumarins (1-25), including 17 undescribed compounds (1-5, 6a/6b, 7-10, 11a/11b-13a/13b), have been isolated from the root of Ferula ferulaeoides. Meanwhile, twelve pairs of enantiomers (6a/6b, 11a/11b-15a/15b, 17a/17b, 18a/18b, 20a/20b-22a/22b, and 25a/25b) were chirally purified. The structures of these new compounds were elucidated using HRESIMS, UV, NMR, and calculated 13C NMR with a custom DP4 + analysis. The absolute configurations of all the compounds were determined for the first time using electronic circular dichroism (ECD). Then, their inhibitory effects on nitric oxide (NO) production were evaluated with LPS-induced BV-2 microglia. Compared with the positive control minocycline (IC50 = 59.3 μM), ferulaferone B (2) exhibited stronger inhibitory potency with an IC50 value of 12.4 μM. The immunofluorescence investigation indicated that ferulaferone B (2) could inhibit Iba-1 expression in LPS-stimulated BV-2 microglia.

Tamarixetin ameliorates cerebral ischemia-reperfusion injury via suppressing nicotinamide adenine dinucleotide phosphate oxidase 2/nucleotide-binding oligomerization domain like receptor family pyrin domain-containing 3 inflammasome activation

Tamarixetin, a natural dietary flavone, exhibits remarkable potential for the treatment of ischemic stroke. The present article aimed to explore the impact of tamarixetin on ischemic stroke and elucidate the underlying mechanisms. Effects of tamarixetin on ischemic stroke were evaluated in rats using the middle cerebral artery occlusion and reperfusion (MCAO/R) model, by assessing the neurological deficit scores, brain water content, brain infraction, and neuronal damage. The levels of proinflammatory cytokines, NLRP3 inflammasome activation, reactive oxygen species (ROS) production, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase expression were measured in MCAO/R rats and lipopolysaccharide-stimulated cells. Tamarixetin administration improved the neurological dysfunction and neuronal loss in MCAO/R rats. In addition, tamarixetin reduced microglial hyperactivation and proinflammatory cytokines expression in vivo and in vitro. Tamarixetin attenuated NF-κB p65 phosphorylation and promoter activity, reduced NLRP3 expression and caspase-1 cleavage, and downregulated IL-1β and IL-18 secretions to suppress NLRP3 inflammasome activation. The levels of superoxide anion, hydrogen peroxide, and ROS were also suppressed by tamarixetin. The downregulation of NADP+ and NADPH levels, and gp91phox expression indicated the ameliorative effects of tamarixetin on NADPH oxidase activation. In the gp91phox knockdown cells treated with lipopolysaccharide, the effects of tamarixetin on NADPH oxidase activation, ROS generation, and NLRP3 inflammasome activation were diminished. Moreover, tamarixetin protects neurons against microglial hyperactivation in vitro. Our findings support the potential of tamarixetin as a therapeutic agent for ischemic stroke, and its mechanism of action involves the inhibition of NADPH oxidase-NLRP3 inflammasome signaling.

Americanin B inhibits pyroptosis in lipopolysaccharide-induced septic encephalopathy mice through targeting NLRP3 protein

BACKGROUND

Sepsis is considered as a severe illness due to its high mortality. Sepsis can cause septic encephalopathy, thus leading to brain injury, behavioral and cognitive dysfunction. Pyroptosis is a type of regulated cell death (RCD) and takes a crucial part in occurrence and development of sepsis. Americanin B (AMEB) is a lignan compounds, which is extracted from Vernicia fordii. In our previous study, AMEB could inhibit microglial activation in inflammatory cell model. However, the function of AMEB in septic encephalopathy mice is uncertain. It would be worthwhile to ascertain the role and mechanism of AMEB in sepsis.

PURPOSE

Current study designs to certify the relationship between pyroptosis and septic encephalopathy, and investigate whether AMEB can restrain NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome activation and restrict pyroptosis by targeting NLRP3 in septic mice model.

STUDY DESIGN

C57BL/6 mice were utilized to perform sepsis model in vivo experiments. BV-2 cell lines were used for in vitro experiments.

METHODS

In vivo sepsis model was established by lipopolysaccharide (LPS) intraperitoneal injection in male C57BL/6 J mice and in vitro model was exposed by LPS plus ATP in BV-2 cells. The survival rate was monitored on the corresponding days. NLRP3, apoptosis associated Speck-like protein (ASC), caspase-1, GasderminD (GSDMD), interleukin-1β (IL-1β) and interleukin-18 (IL-18) level were detected by western blotting and immunofluorescence analysis. Molecular docking, cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) experiments, RNAi transfection and quantitative real-time PCR were applied to confirm the potential target of AMEB.

RESULTS

The results suggested that AMEB could rise survival percentage and lighten brain injury in LPS-induced sepsis mice. In addition, AMEB could inhibit pyroptosis and the activiation of NLRP3 inflammasome. The inhibiting function of AMEB on the activiation of NLRP3 inflammasome is weakened following si-NLRP3 transfection. Moreover, AMEB exerted anti-pyroptosis effect via targeting NLRP3 protein.

CONCLUSIONS

Our findings first indicate NLRP3 is an effective druggable target for septic encephalopathy related brain injury, and also provide a candidate-AMEB for the treatment of septic encephalopathy. These emerging findings on AMEB in models of sepsis suggest an innovative approach that may be beneficial in the prevention of septic encephalopathy.

Phytochemical and pharmacological properties of the genus Tamarix: a comprehensive review

The genus Tamarix in the Tamaricaceae family consists of more than 100 species of halophyte plants worldwide that are mainly used to improve saline-alkali land and for coastal windbreaks, sand fixation, and afforestation in arid areas. A considerable number of species in this genus are also used as traditional medicines to treat various human diseases, especially in Asian and African countries. This review presents a comprehensive summary of 655 naturally occurring compounds derived from the genus Tamarix, categorized into flavonoids (18.0%), phenols (13.9%), tannins (9.3%), terpenoids (10.5%), essential oils (31.0%), and others (17.3%). The investigation revealed that the crude extracts and phytochemicals of this genus exhibited significant therapeutic potential, including anti-inflammatory, anti-Alzheimer, anticancer, antidiabetic, antibacterial, and antifungal activities. Six species of Tamarix have anticancer effects by causing cancer cell death, inducing autophagy, and stopping cell division. Seven species from the same genus have the potential for treating diabetes by inhibiting α-glycosidase activity, suppressing human islet amyloid polypeptide, regulating blood glucose levels, and modulating autophagy or inflammation. The focus on antibacterial and antidiabetic effects is due to the presence of volatile oil and flavonoid components. Extensive research has been conducted on the biological activity of 30 constituents, including 15 flavonoids, 5 phenols, 3 terpenoids, 1 tannin, and 6 others. Therefore, future research should thoroughly study the mechanisms of action of these and similar compounds. This is the most comprehensive review of the phytochemistry and pharmacological properties of Tamarix species, with a critical assessment of the current state of knowledge.

Chemical profile of the roots of Clausena lansium and their inhibitory effects of the over-activation in BV-2 microglial cells

From the 95% ethanol aqueous extract of the roots of Clausena lansium, six previously undescribed alkaloids (1, 2a, 2b, 15, 24a, 24b), a pair of prenylated phenylpropenols (26a, 26b), two coumarins (27, 28), and two undescribed sesquiterpenes (37, 38) were isolated and identified using spectroscopic and electron circular dichroism data, together with thirty-two known compounds. The absolute configurations of three alkaloids (3a, 3b, 4a) were determined for the first time. In vitro assay showed that alkaloids 7, 10, 12, 19, and furanocoumarins 34, 35 displayed inhibitory effects on the production of nitric oxide in lipopolysaccharide (LPS)-induced BV-2 microglial cells, which were stronger than that of the minocycline (positive control). RT-PCR results indicated that indizoline (7) could inhibit the expression of pro-inflammatory factors (IL-1β, TNF-α, and IL-6) in LPS-treated BV-2 cells.

Neuroprotective Effect of Lithospermum officinale Callus Extract on Inflamed Primary Microglial Cells

BACKGROUND

Plants that have therapeutic features for humans or animals are commonly referred to as "medicinal plants". They produce secondary metabolites with antioxidant, antimicrobial and/or anti-cancer effects. Lithospermum officinale, known as European stone seed, is a famous medicinal herb. However, due to the pyrrolizidine alkaloids (PzAl) in the root extract of L.officinal, there are therapeutic limitations to this herb.

OBJECTIVE

This research was devoted to the evaluation of the anti-inflammatory capacity of methanolic extracts of L. officinale callus (LoE) (fresh cells) on rat microglial cells, the immune cells of the Central Nervous System, which play an essential role in the responses to neuroinflammation.

METHODS

Primary microglia were obtained from neonatal Wistar rats (1 to 3-days old), and then treated with various concentration of CfA and methanolic extracts of 17 and 31-day-old L. officinale callus before LPS-stimulation. In addition to HPLC analysis of the extracts, viability, nitric oxide production, and evaluation of pro-inflammatory genes and cytokines in the inflamed microglia were investigated by MTT, Griess methos, qrt-PCR, and ELISA.

RESULTS

Methanolic extract of the 17-day-old callus of L. officinale exhibited anti-inflammatory effects on LPS-stimulated microglial cells much higher than observed for CfA. The data were further supported by the decreased expression of Nos2, Tnf-α, and Cox-2 mRNA and the suppression of TNF-α and IL-1β release in the activated microglial cells pretreated with the effective dose of LoE (0.8 mg mL-1).

CONCLUSION

It was assumed that the better anti-neuroinflammatory performance of LoE than CfA in LPS-activated primary microglia could be a result of the synergism of the components of the extract and the lipophilic nature of RsA as the main phenolic acid of LoE. Considering that LoE shows a high antioxidant capacity and lacks PzAl, it is anticipated that LoE extract might be considered a reliable substitute to play a key role in the preparation of neuroprotective pharmaceutical formulas, which require in vivo research and further experiments.

Crebanine ameliorates ischemia-reperfusion brain damage by inhibiting oxidative stress and neuroinflammation mediated by NADPH oxidase 2 in microglia

BACKGROUND

The urgent challenge for ischemic stroke treatment is the lack of effective neuroprotectants that target multiple pathological processes. Crebanine, an isoquinoline-like alkaloid with superior pharmacological activities, presents itself as a promising candidate for neuroprotection. However, its effects and mechanisms on ischemic stroke remain unknown.

METHODS

The effects of crebanine on brain damage following ischemic stroke were evaluated using the middle cerebral artery occlusion and reperfusion (MCAO/R) model. Mechanism of action was investigated using both MCAO/R rats and lipopolysaccharide (LPS)-activated BV-2 cells.

RESULTS

We initially demonstrated that crebanine effectively ameliorated the neurological deficits in MCAO/R rats, while also reducing brain edema and infarction. Treatment with crebanine resulted in the up-regulation of NeuN+ fluorescence density and down-regulation of FJB+ cell count, and mitigated synaptic damage. Crebanine attenuated the hyperactivation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) by downregulating NADP+ and NADPH levels, suppressing gp91phox and p47phox expressions, and reducing p47phox membrane translocation in Iba-1+ cells. Additionally, crebanine reduced the quantity of Iba-1+ cells and protein expression. Correlation analysis has demonstrated that the inhibition of NOX2 activation in microglia is beneficial for mitigating I/R brain injuries. Moreover, crebanine exhibited significant antioxidant properties by down-regulating the expression of superoxide anion and intracellular reactive oxygen species in vivo and in vitro, and reducing lipid and DNA peroxidation. Crebanine exerted anti-inflammatory effect, as evidenced by the reduction in the expressions of nitric oxide, interleukin 1β, tumor necrosis factor α, interleukin 6, and inducible nitric oxide synthase. The effect of crebanine was achieved through the suppression of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPK) signaling pathway. This is supported by evidence showing reduced NF-κB p65 promoter activity and nucleus translocation, as well as suppressed IκBα phosphorylation and degradation. Additionally, it inhibited the phosphorylation of ERK, JNK, and p38 MAPKs. Importantly, the anti-oxidative stress and neuroinflammation effects of crebanine were further enhanced after silencing gp91phox and p47phox.

CONCLUSION

Crebanine alleviated the brain damages of MCAO/R rats by inhibiting oxidative stress and neuroinflammation mediated by NOX2 in microglia, implying crebanine might be a potential natural drug for the treatment of cerebral ischemia.

Isoamericanin A improves lipopolysaccharide-induced memory impairment in mice through suppression of the nicotinamide adenine dinucleotide phosphateoxidase-dependent nuclear factor kappa B signaling pathway

Alzheimer's disease (AD) is the most frequent cause of dementia in the elderly. Isoamericanin A (ISOA) is a natural lignan possessing great potential for AD treatment. This study investigated the efficacy of ISOA on memory impairments in the mice intrahippocampal injected with lipopolysaccharide (LPS) and the underlying mechanism. Y-maze and Morris Water Maze data suggested that ISOA (5 and 10 mg/kg) ameliorated short- and long-term memory impairments, and attenuated neuronal loss and lactate dehydrogenase activity. ISOA exerted anti-inflammatory effect demonstrating by the reduction of ionized calcium-binding adapter molecule 1 positive cells and suppression of marker protein and pro-inflammation cytokines expressions induced by LPS. ISOA suppressed the nuclear factor kappa B (NF-κB) signaling pathway by inhibiting IκBα phosphorylation and NF-κB p65 phosphorylation and nuclear translocation. ISOA inhibited superoxide and intracellular reactive oxygen species accumulation by reducing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation, demonstrating by suppressing NADP+ and NADPH contents, gp91phox expression, and p47phox expression and membrane translocation. These effects were enhanced in combination with NADPH oxidase inhibitor apocynin. The neuroprotective effect of ISOA was further proved in the in vitro models. Overall, our data revealed a novel pharmacological activity of ISOA: ameliorating memory impairment in AD via inhibiting neuroinflammation.

Chemical profiling and cytotoxic potential of the n-butanol fraction of Tamarix nilotica flowers

BACKGROUND

Cancer represents one of the biggest healthcare issues confronting humans and one of the big challenges for scientists in trials to dig into our nature for new remedies or to develop old ones with fewer side effects. Halophytes are widely distributed worldwide in areas of harsh conditions in dunes, and inland deserts, where, to cope with those conditions they synthesize important secondary metabolites highly valued in the medical field. Several Tamarix species are halophytic including T.nilotica which is native to Egypt, with a long history in its tradition, found in its papyri and in folk medicine to treat various ailments.

METHODS

LC-LTQ-MS-MS analysis and ¹H-NMR were used to identify the main phytoconstituents in the n- butanol fraction of T.nilotica flowers. The extract was tested  in vitro for its cytotoxic effect against breast (MCF-7) and liver cell carcinoma (Huh-7) using SRB assay.

RESULTS

T.nilotica n-butanol fraction of the flowers was found to be rich in phenolic content, where, LC-LTQ-MS-MS allowed the tentative identification of thirty-nine metabolites, based on the exact mass, the observed spectra fragmentation patterns, and the literature data, varying between tannins, phenolic acids, and flavonoids. ¹H-NMR confirmed the classes tentatively identified. The in-vitro evaluation of the n-butanol fraction showed lower activity on MCF-7 cell lines with IC₅₀ > 100 µg/mL, while the higher promising effect was against Huh-7 cell lines with an IC₅₀= 37 µg/mL.

CONCLUSION

Our study suggested that T.nilotica flowers' n-butanol fraction is representing a promising cytotoxic candidate against liver cell carcinoma having potential phytoconstituents with variable targets and signaling pathways.

Pharmacological Properties of Trichostatin A, Focusing on the Anticancer Potential: A Comprehensive Review

Trichostatin A (TSA), a natural derivative of dienohydroxamic acid derived from a fungal metabolite, exhibits various biological activities. It exerts antidiabetic activity and reverses high glucose levels caused by the downregulation of brain-derived neurotrophic factor (BDNF) expression in Schwann cells, anti-inflammatory activity by suppressing the expression of various cytokines, and significant antioxidant activity by suppressing oxidative stress through multiple mechanisms. Most importantly, TSA exhibits potent inhibitory activity against different types of cancer through different pathways. The anticancer activity of TSA appeared in many in vitro and in vivo investigations that involved various cell lines and animal models. Indeed, TSA exhibits anticancer properties alone or in combination with other drugs used in chemotherapy. It induces sensitivity of some human cancers toward chemotherapeutical drugs. TSA also exhibits its action on epigenetic modulators involved in cell transformation, and therefore it is considered an epidrug candidate for cancer therapy. Accordingly, this work presents a comprehensive review of the most recent developments in utilizing this natural compound for the prevention, management, and treatment of various diseases, including cancer, along with the multiple mechanisms of action. In addition, this review summarizes the most recent and relevant literature that deals with the use of TSA as a therapeutic agent against various diseases, emphasizing its anticancer potential and the anticancer molecular mechanisms. Moreover, TSA has not been involved in toxicological effects on normal cells. Furthermore, this work highlights the potential utilization of TSA as a complementary or alternative medicine for preventing and treating cancer, alone or in combination with other anticancer drugs.

Sesquiterpene coumarins isolated from Ferula bungeana and their anti-neuroinflammatory activities

This is the first study to profile natural sesquiterpene coumarins (SCs) in Ferula bungeana, a medicinal plant of the genus Ferula in China. Eight undescribed sesquiterpene coumarins (1-8), along with six known ones (9-14) were obtained from the whole plant of F. bungeana. These unreported SCs (1-8) enriched the structural diversity of natural SCs, especially these with the hydroxy or carbonyl group at C-7' and a hydroperoxy group at C-7' or C-8'. Compounds (9-14) were reported for the first time from this plant. The in vitro anti-neuroinflammatory activity assay showed that compounds 2 and 9 showed stronger inhibitory effect on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglia, compared with positive control minocycline, and compounds 5 and 10 showed moderate inhibitory effects.

Recent Progress on the Salt Tolerance Mechanisms and Application of Tamarisk

Salinized soil is a major environmental stress affecting plant growth and development. Excessive salt in the soil inhibits the growth of most plants and even threatens their survival. Halophytes are plants that can grow and develop normally on saline-alkali soil due to salt tolerance mechanisms that emerged during evolution. For this reason, halophytes are used as pioneer plants for improving and utilizing saline land. Tamarisk, a family of woody halophytes, is highly salt tolerant and has high economic value. Understanding the mechanisms of salt tolerance in tamarisk and identifying the key genes involved are important for improving saline land and increasing the salt tolerance of crops. Here, we review recent advances in our understanding of the salt tolerance mechanisms of tamarisk and the economic and medicinal value of this halophyte.

Structural elucidation of spiro cyclohexandienonyl naphthalenes with potential anti-neuroinflammatory activities from Caragana acanthophylla Kom

Four undescribed spiro cyclohexandienonyl naphthalenes (acanthophyllas A-D) and a revised compound were isolated from the roots of Caragana acanthophylla Kom. (Fabaceae). They were identified using extensive spectroscopic data and via chemical methods. Three of them were resolved into their enantiomers, and their absolute configurations were confirmed by comparing the experimental and calculated electronic circular dichroism spectra. Moreover, the anti-inflammatory activities of the compounds were investigated by evaluating their inhibitory effects on nitric oxide production in lipopolysaccharide-stimulated BV-2 cells. Some compounds showed significant inhibitory activities with IC₅₀ values of 8.8-13.4 μM (minocycline, IC₅₀ 7.8 μM), indicating that they might serve as potential therapeutic agents for neurodegenerative diseases.

Pterostilbene alleviates cerebral ischemia and reperfusion injury in rats by modulating microglial activation

Ischemic stroke is a severe neurological disease without known effective therapy. Microglia-mediated neuroinflammation plays an important role in ischemic stroke. Therefore, finding a safe and effective microglial activation inhibitor might lead to an effective therapeutic strategy against ischemic stroke. In this project, our goal was to explore both the mechanism and effect of pterostilbene in MCAO/R rats. The potential effect of pterostilbene on ischemic stroke was tested using MCAO/R rats and its effect on microglial activation was tested in LPS-stimulated BV-2 cells. In vivo, pterostilbene decreased the neurological scores, brain water content and infarct volume in MCAO/R rats. Pterostilbene increased the number of mature neurons, decreased the number of activated microglia, and reduced iNOS and IL-1β mRNA expression. Pterostilbene inhibited phosphorylated-IκBα expression, thus promoting IκBα expression and inhibiting ROS overexpression. In vitro, pterostilbene inhibited the expression of inflammatory cytokines and suppressed NAPDH activity as well as activation of both the NF-κB pathway and ROS production. To our knowledge, our study is the first to demonstrate that pterostilbene-mediated alleviation of cerebral ischemia and reperfusion injury in rats may be correlated with the inhibition of the ROS/NF-κB-mediated inflammatory pathway in microglia, indicating the potential for the use of pterostilbene as a candidate therapeutic compound for ischemic stroke.

Kellerin from Ferula sinkiangensis exerts neuroprotective effects after focal cerebral ischemia in rats by inhibiting microglia-mediated inflammatory responses

ETHNOPHARMACOLOGICAL RELEVANCE

Ferula sinkiangensis K. M. Shen is a traditional Chinese medicine that has a variety of pharmacological properties relevant to neurological disorders and inflammations. Kellerin, a novel compound extracted from Ferula sinkiangensis, exerts a strong anti-neuroinflammatory effect by inhibiting microglial activation. Microglial activation plays a vital role in ischemia-induced brain injury. However, the potential therapeutic effect of kellerin on focal cerebral ischemia is still unknown.

AIM OF THE STUDY

To explore the effect of kellerin on cerebral ischemia and clarify its possible mechanisms, we applied the middle cerebral artery occlusion (MCAO) model and the LPS-activated microglia model in our study.

MATERIALS AND METHODS

Neurological outcome was examined according to a 4-tiered grading system. Brain infarct size was measured using TTC staining. Brain edema was calculated using the wet weight minus dry weight method. Neuron damage and microglial activation were observed by immunofluorescence in MCAO model in rats. In in vitro studies, microglial activation was examined by flow cytometry and the viability of neuronal cells cultured in microglia-conditioned medium was measured using MTT assay. The levels of pro-inflammatory cytokines were measured by qRT-PCR and ELISA. The proteins involved in NF-κB signaling pathway were determined by western blot. Intracellular ROS was examined using DCFH-DA method and NADPH oxidase activity was measured using the NBT assay.

RESULTS

We found that kellerin improved neurological outcome, reduced brain infarct size and decreased brain edema in MCAO model in rats. Under the pathologic conditions of focal cerebral ischemia, kellerin alleviated neuron damage and inhibited microglial activation. Moreover, in in vitro studies of LPS-stimulated BV2 cells kellerin protected neuronal cells from being damaged by inhibiting microglial activation. Kellerin also reduced the levels of pro-inflammatory cytokines, suppressed the NF-κB signaling pathway, and decreased ROS generation and NADPH oxidase activity.

CONCLUSIONS

Our discoveries reveal that the neuroprotective effects of kellerin may largely depend on its inhibitory effect on microglial activation. This suggests that kellerin could serve as a novel anti-inflammatory agent which may have therapeutic effects in ischemic stroke.

Natural potential neuroinflammatory inhibitors from Stephania epigaea H.S. Lo

Stephania epigaea H. S. Lo is a folk medicine widely distributed in the south of China, especially in Yunnan and Guangxi province. An in vitro anti-neuroinflammatory study showed that total alkaloids of it can potently inhibit LPS-induced NO releasing of BV2 cells with an IC₅₀ value of 10.05 ± 2.03 μg/mL (minocycline as the positive drug, IC₅₀ 15.49 ± 2.14 μM). The phytochemical investigation of the total alkaloids afforded three new phenanthrene (1-3), two lactams (4a, 4b), and nine aporphine derivatives (5-13). The final structure of 1 was identified by computer-assisted structure elucidation (ACD/Structure Elucidator software and the ¹³C NMR calculation with GIAO method) due to many possibilities of the substituent pattern. All isolates were evaluated for their anti-neuroinflammatory effects, and as a result, 5, 8, 10, and 11 exhibited stronger inhibitory activities than the minocycline. The results suggested S. epigaea could provide potential therapeutic agents for neurodegenerative diseases.

Inflammatory mechanism of cerebral ischemia-reperfusion injury with treatment of stepharine in rats

BACKGROUND

Increasing evidence has shown that microglia-induced neuroinflammation is involved in the pathogenesis of ischemic stroke. Stepharine, one of the alkaloids extracted from Stephania japonica (Thunb.) Miers, exhibited strong inhibitory effect on microglial overactivation. However, it is not known whether it has the potential to prevent ischemic stroke.

METHODS

The neuroprotective and anti-neuroinflammatory effects of stepharine were investigated in vivo and in vitro, using a rat model of middle cerebral artery occlusion (MCAO) and lipopolysaccharide (LPS)-stimulated BV-2 cells, respectively.

RESULTS

In vivo, stepharine (500 μg/kg) suppressed neurological deficits scores, brain water content and cerebral infarct volume induced by MCAO. Moreover, stepharine (500 μg/kg) inhibited NeuN⁺ cells loss and Iba-1⁺ cells increase in the MCAO ischemic cortex. In vitro, stepharine (10, 30 μM) substantially inhibited nitric oxide release as well as the mRNA and protein expression of pro-inflammatory mediators [inducible nitric oxide synthase, interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-1β] in LPS-activated BV-2 cells. LPS-induced increase of TLR4 expression, IκBα phosphorylation, and NF-κB p65 nuclear translocation was inhibited by stepharine (10, 30 μM). Molecular docking analysis showed that stepharine directly interacted with TLR4. SPR assay further confirmed that stepharine could bind to the TLR4/MD2 complex. Meanwhile, stepharine exhibited neuroprotective effects on SH-SY5Y cells cultured with LPS-treated conditioned medium.

CONCLUSION

Our study demonstrated for the first time that stepharine improved the outcomes in MCAO rats, reduced neuronal loss, and suppressed microglial overactivation via the inhibition of TLR4/NF-κB pathway. These results suggest that stepharine might be a potential therapeutic agent for the treatment of ischemic stroke.

Bioactive sesquiterpene coumarins from the resin of Ferula sinkiangensis targeted on over-activation of microglia

Nine undescribed (1-4, 6-10) sesquiterpene coumarins, together with a new natural one (5) and ten known ones (11-20), were isolated from the low polarity fraction of the 95% ethanol extract of the resin of Ferula sinkiangensis. Their structures were elucidated based on the comprehensive analysis of HRESIMS, 1D and 2D NMR data. The absolute configurations were determined by comparison of experimental and calculated ECD spectra. All the identified SCs were evaluated for their anti-neuroinflammatory activities in LPS-induced BV-2 cells. Ferusingensine G (8) displayed a significant inhibitory effect on nitric oxide (NO) production with an IC₅₀ value of 1.2 μM. The results suggested that natural SCs might be served as potential neuroinflammatory inhibitors.

The genus Tamarix: Traditional uses, phytochemistry, and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Tamarix L., with the common name of tamarisk, consists of more than 60 species of halophyte plants which are used for medicinal purposes such as infections, wounds, and liver and spleen disorders by local people mostly in Asian and African countries.

AIM OF THE REVIEW

In spite of the potential health benefits of Tamarix spp., the plant is not yet well-known in modern medicine; thus, the aim of the present review is to provide a critical appraisal of the current state of the art regarding the ethnomedicinal uses, phytochemistry, and pharmacological properties of Tamarix spp.

MATERIALS AND METHODS

Electronic databases (Medline, Cochrane library, Science Direct, and Scopus) were searched with the words "Tamarix" and "Tamarisk" to collect all available data regarding different Tamarix species from the inception until May 2019.

RESULTS

Tamarix spp. is traditionally used for gastrointestinal disorders, wounds, diabetes, and dental problems. Phenolic acids, flavonoids, and tannins constitute the main phytochemicals of these plants. Preclinical pharmacological evaluations have demonstrated several biological activities for Tamarix spp. including antidiabetic, hepatoprotective, wound healing, and anti-inflammatory; however, no clinical evidence have yet been provided to support the health benefits of these plants.

CONCLUSIONS

Tamarix spp. are plants rich in polyphenolic compounds with valuable medicinal properties; though, there are several methodological problems such as lack of a mechanistic approach and taxonomic ambiguities in the current available data. High-quality preclinical studies, as well as well-designed clinical trials are necessary to confirm the safety and efficacy of these plants in humans.

Anti-inflammatory, antiallergic and COVID-19 protease inhibitory activities of phytochemicals from the Jordanian hawksbeard: identification, structure–activity relationships, molecular modeling and impact on its folk medicinal uses

On Wednesday 11th March, 2020, the world health organization (WHO) announced novel coronavirus (COVID-19, also called SARS-CoV-2) as a pandemic.

Natural Inhibitors on Over-Activation of Microglia from Herbals

Neuroinflammation manifested by over-activation of microglial cells plays an essential role in neurodegenerative diseases. Short-term activation of microglia can be beneficial, but chronically activated microglia can aggravate neuronal dysfunction possibly by secreting potentially cytotoxic substances such as tumor necrosis factor-alpha (TNF-α) and nitric oxide (NO), which can result in dysfunction and death of neurons. Therefore inhibiting over-activation of microglia and the production of cytotoxic intermediates may become an effective therapeutic approach for neuroinflammation. In this paper, we review our continuous research on natural inhibitors of over-activated microglia from traditional herbals, including flavonoids, lignans, sesquiterpene coumarins, and stilbenes.