Neuroprotective Effects of Taraxacum officinale Wigg. Extract on Glutamate-Induced Oxidative Stress in HT22 Cells via HO-1/Nrf2 Pathways

Neuroprotective potential of Betulinic acid against TIO2NP induced neurotoxicity in zebrafish

Betulinic acid (BA) is a natural triterpenoid extracted from Bacopa monnieri. BA has been reported to be used as a neuroprotective agent, but their molecular mechanisms are still unknown. Therefore, in this study, we attempted to investigate the precise mechanism of BA for its protective effect against Titanium dioxide nanoparticles (TiO2NP) induced neurotoxicity in zebrafish. Hence, our study observation showed that 10 µg/ml dose of TiO2NP caused a rigorous behavioral deficit in zebrafish. Further, biochemical analysis revealed TiO2NP significantly decreased GSH, and SOD, and increased MDA, AChE, TNF-α, IL-1β, and IL-6 levels, suggesting it triggers oxidative stress and neuroinflammation. However, BA at doses of 2.5,5,10 mg/kg improved behavioral as well as biochemical changes in zebrafish brain. Moreover, BA also significantly raised the levels of DA, NE, 5-HT, and GABA and decreased glutamate levels in TiO2NP-treated zebrafish brain. Our histopathological analysis proved that TiO2NP causes morphological changes in the brain. These changes were expressed by increasing pyknotic neurons, which were dose-dependently reduced by Betulinic acid. Likewise, BA upregulated the levels of NRF-2 and HO-1, which can reduce oxidative stress and neuroinflammation. Thus, our study provides evidence for the molecular mechanism behind the neuroprotective effect of Betulinic acid. Rendering to the findings, we can consider BA as a suitable applicant for the treatment of AD-like symptoms.

Farrerol attenuates glutamate-induced apoptosis in HT22 cells via the Nrf2/heme oxygenase-1 pathway

Farrerol is a flavonoid found in plants with a wide range of pharmacological effects, including protection and enhancement of nerve cell function, as well as antioxidant and antibacterial properties, among others. Neurodegenerative diseases are irreversible neurological disorders resulting from the loss of neuronal cells in the brain and spinal cord. In this experiment, we investigated the neuroprotective and antioxidant effects of farrerol on glutamate-induced HT22 cells. Our results showed that farrerol inhibited reactive oxygen species expression, apoptosis, mitochondrial damage, and the activation of caspases 3 and 9 in HT22 cells induced by glutamate. Additionally, farrerol potentially regulated the Nrf2/heme oxygenase-1 (HO-1) signaling pathway, as it attenuated the nuclear translocation of Nrf2 and promoted the expression of HO-1. These findings suggest that farrerol has potential as a new therapeutic option.

Induction of Nrf2-EpRE-mediated gene expression by hydroxyanthraquinones present in extracts from traditional Chinese medicine and herbs

Hydroxyanthraquinones that can be present in traditional Chinese medicine (TCM) and herbal extracts have claimed beneficial intestinal effects. We examined the ability of a panel hydroxyanthraquinones, and methanolic extracts from selected TCM and herbal granules to activate Nrf2-EpRE mediated gene expression using a reporter-gene assay. The results indicate that purpurin, aloe-emodin, 2-hydroxy-3-methylanthraquinone and rhein induced Nrf2 mediated gene expressions with a high induction factor (IFs>10), with BMCL₁₀ values (the lower confidence limit of the concentration giving 10% added response above background) of 16 μM, 1.1 μM, 23 μM and 2.3 μM, respectively, while aurantio-obtusin, obtusifolin, rubiadin 1-methyl ether and emodin were less potent (IFs<5), with BMCL₁₀ values for added response above background level of 4.6 μM, 15 μM, 9.8 μM and 3.8 μM, respectively. All TCM extracts and the herbal extracts of Aloe Vera, Polygonum multiflorum, Rubia (cordifolia) and Rheum officinale activated the Nrf2-EpRE pathway. Of the TCM extracts, Chuan-Xin-Lian-Kang-Yan-Pian was the most potent Nrf2-inducer. LC-MS/MS analysis indicated the presence of selected hydroxyanthraquinones in the extracts and herbs, in part explaining their Nrf2-EpRE mediated activity. In conclusion, different hydroxyanthraquinones have different potencies of Nrf2 activation. The Nrf2 activation by extracts from TCM and herbs can be partially explained by the presence of selected hydroxyanthraquinones.

Novel Prenylated Indole Alkaloids with Neuroprotection on SH-SY5Y Cells against Oxidative Stress Targeting Keap1–Nrf2

Oxidative stress has been implicated in the etiology of Parkinson’s disease (PD). Molecules non-covalently binding to the Keap1–Nrf2 complex could be a promising therapeutic approach for PD. Herein, two novel prenylated indole alkaloids asperpenazine (1), and asperpendoline (2) with a scarce skeleton of pyrimido[1,6-a]indole were discovered from the co-cultivated fungi of Aspergillus ochraceus MCCC 3A00521 and Penicillium sp. HUBU 0120. Compound 2 exhibited potential neuroprotective activity on SH-SY5Y cells against oxidative stress. Molecular mechanism research demonstrated that 2 inhibited Keap1 expression, resulting in the translocation of Nrf2 from the cytoplasm to the nucleus, activating the downstream genes expression of HO-1 and NQO1, leading to the reduction in reactive oxygen species (ROS) and the augment of glutathione. Molecular docking and dynamic simulation analyses manifested that 2 interacted with Keap1 (PDB ID: 1X2R) via forming typical hydrogen and hydrophobic bonds with residues and presented less fluctuation of RMSD and RMSF during a natural physiological condition.

Discovery of alkaloids from the leaves of Isatis indigotica Fortune with neuroprotective activity

Seven alkaloids including five undescribed ones (1a/1b, 2, 3 and 5) were obtained from the leaves of Isatis indigotica Fortune. Their structures were established by extensive spectroscopic analyses. The absolute configurations of compounds 1a, 1b, 3 and 5 were determined by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra. Subsequently, the neuroprotective effects of all the isolates against H₂O₂-induced injury in SH-SY5Y cells were evaluated in vitro by MTT assay. Moreover, Annexin V-FITC/PI double staining was performed, while the activities of antioxidant enzymes (SOD, CAT and GSH-Px) for compounds 1a and 1b were measured.

Traditional plants from Asteraceae family as potential candidates for functional food industry

Traditional plants have been used in the treatment of disease and pain due to their beneficial properties such as antioxidant, antiinflammation, analgesic, and antibiotic activities. The Asteraceae family is one of the most common groups of plants used in folk medicine. The species Achillea millefolium, Arnica montana, Bellis perennis, Calendula officinalis, Chamaemelum nobile, Eupatorium cannabinum, Helichrysum stoechas, and Taraxacum officinale have been used in different remedies in Northwest Spain. Besides health benefits, some of them like C. nobile and H. stoechas are already employed in cooking and culinary uses, including cocktails, desserts, and savory dishes. This study aimed to review the current information on nutritive and beneficial properties and bioactive compounds of these plants, which are not mainly used as foods but are possible candidates for this purpose. The report highlights their current uses and suitability for the development of new functional food industrial applications. Phenolic compounds, essential oils, and sesquiterpene lactones are some of the most important compounds, being related to different bioactivities. Hence, they could be interesting for the development of new functional foods.

Protective Effects of Taraxacum officinale L. (Dandelion) Root Extract in Experimental Acute on Chronic Liver Failure

BACKGROUND

Taraxacum officinale (TO) or dandelion has been frequently used to prevent or treat different liver diseases because of its rich composition in phytochemicals with demonstrated effect against hepatic injuries. This study aimed to investigate the possible preventing effect of ethanolic TO root extract (TOERE) on a rat experimental acute on chronic liver failure (ACLF) model.

METHODS

Chronic liver failure (CLF) was induced by human serum albumin, and ACLF was induced in CLF by D-galactosamine and lipopolysaccharide (D-Gal-LPS). Five groups (n = 5) of male Wistar rats (200-250 g) were used: ACLF, ACLF-silymarin (200 mg/kg b.w./day), three ACLF-TO administered in three doses (200 mg, 100 mg, 50 mg/kg b.w./day).

RESULTS

The in vivo results showed that treatment with TOERE administered in three chosen doses before ACLF induction reduced serum liver injury markers (AST, ALT, ALP, GGT, total bilirubin), renal tests (creatinine, urea), and oxidative stress tests (TOS, OSI, MDA, NO, 3NT). Histopathologically, TOERE diminished the level of liver tissue injury and 3NT immunoexpression.

CONCLUSIONS

This paper indicated oxidative stress reduction as possible mechanisms for the hepatoprotective effect of TOERE in ACLF and provided evidence for the preventive treatment.

Potential neuroprotection of wheat alkylresorcinols in hippocampal neurons via Nrf2/ARE pathway

5-n-Alkylresorcinols (ARs) are abundant in wheat bran and potentially antioxidative, although the neuroprotective mechanism is not fully understood. The neuroprotective effect of wheat bran ARs on H2O2-induced neuronal cells and the relationship between neuroprotection and the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant-response element (ARE) pathway were investigated in this study. Seven homologs were identified in the purified ARs by high-performance liquid chromatography-tandem mass spectrometry. Pretreatment with 80 μg mL-1 ARs alleviated 23% HT22 cell death and the up-regulation of intracellular reactive oxygen species level and malondialdehyde under H2O2 stimulation. The neuroprotection effect was proved by the increase in the Nrf2 nuclear location and up-regulation of mRNA and protein expressions of heme oxygenase-1, NAD(P)H quinone dehydrogenase 1, glutamate-cysteine ligase catalytic subunit, and glutamate-cysteine ligase modifier subunit l. Wheat bran ARs displayed a neuroprotective function, possibly by promoting the endogenous antioxidant defense system. ARs may be regarded as a functional food ingredient for preventing neurodegenerative diseases in the future.

Bioavailability and Pharmaco-therapeutic Potential of Luteolin in Overcoming Alzheimer's Disease

Luteolin is a naturally occurring, yellow crystalline flavonoid found in numerous dietary supplements we frequently have in our meals. Studies in the last 2 decades have revealed its therapeutic potential to reduce the Alzheimer's disease (AD) symptoms in various in vitro and in vivo models. The anti-Alzheimer's potential of luteolin is attributed to its ability to suppress Aβ as well as tau aggregation or promote their disaggregation, down-regulate the expression of COX-2, NOS, MMP-9, TNF-α, interleukins and chemokines, reduce oxidative stress by scavenging ROS, modulate the activities of transcription factors CREB, cJun, Nrf-1, NF-κB, p38, p53, AP-1 and β-catenine and inhibiting the activities of various protein kinases. In several systems, luteolin has been described as a potent antioxidant and anti-inflammatory agent. In addition, we have also discussed about the bio-availability of the luteolin in the plasma. After being metabolized luteolin persists in plasma as glucuronides and sulphate-conjugates. Human clinical trials indicated no dose limiting toxicity when administered at a dose of 100 mg/day. Improvements in the formulations and drug delivery systems may further enhance the bioavailability and potency of luteolin. The current review describes in detail the data supporting these studies.

Inhibitory Effects of AF-343, a Mixture of Cassia tora L., Ulmus pumila L., and Taraxacum officinale, on Compound 48/80-Mediated Allergic Responses in RBL-2H3 Cells

The purpose of this study was to determine the antiallergic effects of AF-343, a mixture of natural plant extracts from Cassia tora L., Ulmus pumila L., and Taraxacum officinale, on rat basophilic leukemia (RBL-2H3) cells. The inhibitory effects on cell degranulation, proinflammatory cytokine secretion, and reactive oxygen species (ROS) production were studied in compound 48/80-treated RBL-2H3 cells. The bioactive compounds in AF-343 were also identified by HPLC–UV. AF-343 was found to effectively suppress compound 48/80-induced β-hexosaminidase release, and interleukin (IL)-4 and tumor necrosis factor-α (TNF-α) production in RBL-2H3 cells. In addition, AF-343 exhibited DPPH free radical scavenging effects in vitro (half-maximal inhibitory concentration (IC₅₀) = 105 μg/mL) and potently inhibited compound 48/80-induced cellular ROS generation in a 2′,7′-dichlorofluorescein diacetate (DCFH-DA) assay. Specifically, treatment with AF-343 exerted stronger antioxidant effects in vitro and antiallergic effects in cells than treatment with three single natural plant extracts. Furthermore, AF-343 was observed to contain bioactive compounds, including catechin, aurantio-obtusin, and chicoric acid, which have been reported to elicit antiallergic responses. This study reveals that AF-343 attenuates allergic responses via suppression of β-hexosaminidase release, IL-4 and TNF-α secretion, and ROS generation, perhaps through mechanisms related to catechin, aurantio-obtusin, and chicoric acid. The results indicate that AF-343 can be considered a treatment for various allergic diseases.

Four pairs of alkaloid enantiomers from Isatis indigotica Fortune Ex Land with neuroprotective effects against H2O2-induced SH-SY5Y cell injury

In the current study, four pairs of new enantiomeric alkaloids (1a/1b-4a/4b) were obtained from the leaves of Isatis indigotica Fortune Ex Land. Their structures were elucidated through spectroscopic methods and quantum mechanical calculations. Biologically, all isolates were evaluated for their neuroprotective effects against H₂O₂-induced SH-SY5Y cell injury. As a result, 1a and 1b exhibited enantioselective neuroprotective effects, further Annexin V-FITC/PI analysis showed that apoptosis ratios of 1a and 1b were reduced to 20.93% and 17.87%, respectively.

Iduna protects HT22 cells by inhibiting parthanatos: The role of the p53-MDM2 pathway

Traumatic brain injury (TBI) is common and often fatal in current times. The role of poly(adenosine diphosphate-ribose) polymerase (PARP)-induced cell death (parthanatos) in TBI has not been well studied. Our past study showed that oxidative stress-induced cell death includes parthanatos by confirming the occurrence of PARP activation and nuclear translocation of apoptosis-inducing factor (AIF). As oxidative stress plays a key role in pathological progression after TBI, we believe TBI may also be alleviated by the expression of Iduna, which is the only known endogenous regulator of parthanatos. Thus, a transection model in HT-22 cells was established for present study. Downregulation of Iduna aggravated the cell damage caused by mechanical cell injury, whereas upregulation of Iduna reduced mitochondrial dysfunction induced by mechanical cell injury but exerted no effect on apoptosis associated with mitochondrial dysfunction. By contrast, Iduna prevented parthanatos by reducing PARP activation and nuclear translocation of AIF. We also investigated 2 novel p53-MDM2 pathway inhibitors, AMG 232 and Nutlin-3, which substantially reduced the protective effects of Iduna. These findings indicate that Iduna might prevent TBI by specifically inhibiting parthanatos and promoting mitochondrial function, with the p53-MDM2 pathway playing a critical role.

Effect of Illicium verum or Eucommia ulmoides leaf extracts on the anti-stress ability, and mRNA and protein expression of Nrf2 and TNF-α in Duroc × Landrace × Yorkshire and Chinese native Licha-black nursery piglets

Plant extracts are considered to be an effective alternative to antibiotics in response to weaning stress in piglets. This study evaluated the effect of Illicium verum extracts (IVE) or Eucommia ulmoides leaf extracts (ELE) on growth performance, serum and liver antioxidant ability of nursery piglets, as well as the difference of IVE and ELE on Duroc × Landrace × Yorkshire (DLY) and Chinese native Licha-black (LCB) piglets. A total of 96 nursery piglets (48 DLY and 48 LCB piglets) with an average body weight of 11.22 ± 0.32 kg were randomly divided into four treatments in a 2 × 4 factorial design. Each treatment had four replicates with 3 DLY and 3 LCB piglets per replicate respectively. Treatments included: basal diet, basal diet + 500 mg/kg IVE, basal diet + 250 mg/kg ELE and basal diet + 50 mg/kg chlortetracycline (CHL). All piglets were housed individually for the 42 days trial period after 7 days adaptation. Results showed that there were significant interactions (p < .05) between piglets species and dietary treatments in average daily gain (ADG) and feed efficiency, serum and hepatic glutathione peroxidase (GSH-Px) and malondialdehyde (MDA), hepatic integral optical density (IOD) of α-tumour necrosis factor (TNF-α), hepatic relative mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2)/TNF-α and protein expression of TNF-α. Regardless of piglets species, supplementation with IVE and ELE increased (p < .05) ADG and feed efficiency, T-SOD and GSH-Px in serum and liver, hepatic IOD of Nrf2, hepatic mRNA and protein expression of Nrf2/TNF-α. However, CHL treatment resulted in lower (p < .05) serum GSH-Px and hepatic mRNA and protein expression of Nrf2/TNF-α, and higher hepatic MDA and IOD of TNF-α. Compared to LCB, DLY piglets had higher (p < .05) ADG and feed efficiency, serum and hepatic MDA, and protein expression of TNF-α, but lower (p < .05) ADFI, liver index, serum and hepatic GSH-Px, hepatic IOD of TNF-α, mRNA expressions of Nrf2/TNF-α were observed. In conclusion, Illicium verum (500 mg/kg) and Eucommia ulmoides leaf (250 mg/kg) extracts can increase the growth performance and antioxidant ability of DLY and LCB piglets, while chlortetracycline produces undesirable side-effects on the antioxidant ability of DLY and LCB piglets. Illicium verum and Eucommia ulmoides leaf extracts produced different antioxidant effects in DLY and LCB piglets with the Chinese native Licha-black pig responding better than Duroc × Landrace × Yorkshire.