Targeting STATs in neuroinflammation: The road less traveled!

JAK/STAT transduction pathway is a highly conserved pathway implicated in regulating cellular proliferation, differentiation, survival and apoptosis. Dysregulation of this pathway is involved in the onset of autoimmune, haematological, oncological, metabolic and neurological diseases. Over the last few years, the research of anti-neuroinflammatory agents has gained considerable attention. The ability to diminish the STAT-induced transcription of inflammatory genes is documented for both natural compounds (such as polyphenols) and chemical drugs. Among polyphenols, quercetin and curcumin directly inhibit STAT, while Berberis vulgaris L. and Sophora alopecuroides L extracts act indirectly. Also, the Food and Drug Administration has approved several JAK/STAT inhibitors (direct or indirect) for treating inflammatory diseases, indicating STAT can be considered as a therapeutic target for neuroinflammatory pathologies. Considering the encouraging data obtained so far, clinical trials are warranted to demonstrate the effectiveness and potential use in the clinical practice of STAT inhibitors to treat inflammation-associated neurodegenerative pathologies.

Gelidiella acerosa Exhibits Neuroprotective Effect Against Amyloid Beta 25-35 Peptide-Induced Toxicity in PC12 Cells.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with multiple pathological consequences such as oxidative stress, inflammation, apoptosis, cholinergic deficit, amyloid plaques, and tangles formation. Hence, development of drugs with multiple targets will be effective in the treatment of AD. The present study aims at evaluation of the neuroprotective effect of Gelidiella acerosa against amyloid beta 25-35 (Aß 25-35) induced toxicity in PC12 cells. The antioxidative effect was evaluated by monitoring levels of antioxidant enzymes. Protection against ROS-induced damage was assessed by the measurement of lipid peroxidation, protein carbonyl content (PCC), 2',7'-dichlorofluorescein diacetate (DCFH-DA) fluorescence, and nitric oxide (NO) production. The cholinesterase (ChE) inhibitory activity was also evaluated. The antiapoptotic activity was verified by caspase-3 activity. The results of antioxidant assays suggest that G. acerosa significantly (P < .05) restores the levels of antioxidant enzymes. Moreover, the seaweed extract was found to prevent the formation of intracellular ROS induced by Aß 25-35 and thereby protects PC12 cells from macromolecular damage. The study demonstrated that G. acerosa inhibits ChE activity significantly (P < .05) in PC12 cells. The significant decrease (P < .05) in the level of caspase-3 activity indicates that the seaweed has anti-apoptotic activity. Hence, the outcome of this study signifies the neuroprotective effect of G. acerosa targeting multiple pathological consequences of AD.

Grewia tiliaefolia and its active compound vitexin regulate the expression of glutamate transporters and protect Neuro-2a cells from glutamate toxicity.

AIM: Glutamate is a major neurotransmitter involved in several brain functions and glutamate excitotoxicity is involved in Alzheimer's disease (AD). In the current study, the neuroprotective effect of the Indian medicinal plant Grewia tiliaefolia (GT) and its active component vitexin was evaluated in Neuro-2a cells against glutamate toxicity. MATERIALS AND METHODS: Neuro-2a cells were exposed to glutamate to cause excitotoxicity and the neuroprotective effect of GT and vitexin were evaluated using biochemical studies (estimation of reactive oxygen species, reactive nitrogen species, protein carbonyl content, lipid peroxidation level, mitochondrial membrane potential and caspase-3 activity), molecular docking studies, gene expression and western blot analysis. KEY FINDINGS: Glutamate exposure to Neuro-2a cells induced oxidative stress, loss of membrane potential, suppressed the expression of antioxidant response genes (Nrf-2, HO-1, NQO-1), glutamate transporters (GLAST-1, GLT-1) and induced the expression of NMDAR, Calpain. However, pre-treatment of cells with GT/vitexin inhibited oxidative stress mediated damage by augmenting the expression of Nrf-2/HO-1 pathway, inducing the expression of glutamate transporters and downregulating Calpain, NMDAR. Molecular docking showed that vitexin effectively binds to NMDAR and GSK-3ß and thereby can inhibit their activation. GT/vitexin also inhibited glutamate induced Bax expression. SIGNIFICANCE: Methanol extract of G. tiliaefolia and its active component vitexin can act in an antioxidant dependent mechanism as well as by regulating glutamate transporters in mitigating the toxicity exerted by glutamate in Neuro-2a cells. Our results conclude that GT/vitexin can act as potential drug leads for the therapeutic intervention of AD.

Beta sitosterol and Daucosterol (phytosterols identified in Grewia tiliaefolia) perturbs cell cycle and induces apoptotic cell death in A549 cells.

Lung cancer is the leading cause of cancer related deaths both in developed and developing countries. Since majority of the existing therapeutic methods harms both normal and malignant cells, a viable alternative is to switch into safe and beneficial traditional medicinal plants. Hence the present study was framed to identify selective anti-lung cancer agents from the medicinal plant Grewia tiliaefolia (GT). Cell viability experiments showed that benzene extract of GT (BGT) leaf effectively inhibited the growth of A549 cells, while being non-toxic to normal human lung L132 and PBMC cells. Ames and comet assays demonstrated that BGT is of non-mutagenic and non-genotoxic nature in untransformed cells. The hematological and histopathological profiles of the in vivo acute and sub-acute toxicity studies demonstrated that BGT is safe and tolerable. Importantly, western blot analysis and Annexin V-FITC staining confirmed that BGT promotes mitochondrial dependent apoptotic cell death in A549 cells by arresting cell cycle at G2/M phase. Bio-assay guided fractionation revealed the presence of phytosteols (ß-sitosterol and daucosterol) which significantly inhibited the growth of A549 cells both alone and in combination. This study warrants that these phytosterols in alone or in combination can be considered as safe and potential drug candidates for lung cancer treatment.

A Mini Review on the Chemistry and Neuroprotective Effects of Silymarin.

BACKGROUND: The plant milk thistle and silymarin has been traditionally used as a natural remedy for the treatment of various ailments including neurological disorders such as Alzheimer's and Parkinson's disease and cerebral ischemia for over 2000 years. OBJECTIVE: In this article we review the neuroprotective effects of silymarin against various neurological dysfunctions. RESULTS: The neuroprotective effects conferred by silymarin include modulation of various antioxidant mechanisms, and several kinases involved in cell signaling pathways, inhibition of the inflammatory response generated during neurodegeneration, neurotropic effects, regulation of neurotransmitters and inhibition of apoptosis. The ease of availability, comparative low cost and safety profile provide additional advantages for the use of this compound as a potent drug with immense clinical benefit. However, there is a growing need for improvements in the bioavailability of silymarin and related products, and more consistent and reliable human trials are required to accurately validate the neuroprotective efficacy of this natural compound. CONCLUSION: The promising outcomes of the studies mentioned in this review provide renewed insight into the clinical relevance of silymarin in a variety of neurodegenerative disorders where neuroinflammation and oxidative stress are pathologically relevant to disease progression.

Rhizophora mucronata attenuates beta-amyloid induced cognitive dysfunction, oxidative stress and cholinergic deficit in Alzheimer's disease animal model.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, characterized by accumulation and deposition of Aß peptide in human brain. The present study aimed to determine the protective effect of catechin rich extract of MERM (methanolic extract of Rhizophora mucronata) on Aß (25-35) induced cognitive impairment and neuronal toxicity in mice. In the present study AD characteristics were induced by intracerberoventricular administration of aggregated Aß (25-35) in the Swiss albino mice. Learning and memory deficits were assessed using behavioral assays such as Morris water maze, Y-maze and step down avoidance tasks. Oxidative stress mediated impairment were assessed by measuring the activities of enzymatic and non-enzymatic antioxidants, level of apoptotic protein and oxidative markers in the hippocampus and frontal cortex region. Histolopathological analysis of brain was also carried out. Results illustrated that oral treatment of MERM (200 and 400 mg/kg bw) significantly attenuated Aß (25-35) induced memory impairment as evaluated by behavioral tests. In addition treatment with MERM attenuated the elevation of ß-secretase activity accompanying the reduced level of Aß (25-35) in the cortex and hippocampus of brain. MERM also enhanced the cognitive function by significantly inhibiting AChE, BuChE and MAO-B. Furthermore, MERM attenuated lipid peroxidation, protein oxidation, restored the antioxidant status and inhibited neuronal apoptosis by down-regulating the level of caspase 3 and Bax protein. These data suggest that MERM rich in catechin can act as promising drug for AD treatment because of its antioxidant, anti-apoptotic and reducing Aß oligomer activities.

Gracilaria edulis exhibit antiproliferative activity against human lung adenocarcinoma cell line A549 without causing adverse toxic effect in vitro and in vivo.

In the present study, the antiproliferative potential of various solvent extracts of Gracilaria edulis (GE) was tested against various cancer cell lines. In the A549 lung cancer cell line model, GE ethyl acetate extract (GEEA) (100 µg mL(-1)) treated group showed the maximum and significant (P < 0.05) growth inhibition at 48 h. The IC50 value was found to be 24.5 ± 19.1 µg mL(-1) at 48 h. Moreover, a low level of LDH release was observed at 48 h at various concentrations of (40, 60, 80 and 100 µg mL(-1)) GEEA extract-treated group compared to a control group. Changes in the cell morphology and echinoid spikes formation were observed at 48 h. Safety evaluation of GEEA in a non-cancerous liver cell line, PBMC and in Wistar rats positively revealed that the extract did not show any adverse toxic effects. The GEEA extract was partially purified by column chromatography and the active fraction was characterized through LC-MS analysis. Furthermore, HPLC and FT-IR analysis of the active fractions confirmed the presence of phytol, a diterpene compound with potent antiproliferative activity, which positively suggests that the red alga G. edulis contains a potent anticancer active principle.

Omega-3 polyunsaturated fatty acids and cancer: lessons learned from clinical trials.

Over the past decades, extensive studies have addressed the therapeutic effects of omega-3 polyunsaturated fatty acids (omega-3 FAs) against different human diseases such as cardiovascular and neurodegenerative diseases, cancer, etc. A growing body of scientific research shows the pharmacokinetic information and safety of these natural occurring substances. Moreover, during recent years, a plethora of studies has demonstrated that omega-3 FAs possess therapeutic role against certain types of cancer. It is also known that omega-3 FAs can improve efficacy and tolerability of chemotherapy. Previous reports showed that suppression of nuclear factor-κB, activation of AMPK/SIRT1, modulation of cyclooxygenase (COX) activity, and up-regulation of novel anti-inflammatory lipid mediators such as protectins, maresins, and resolvins, are the main mechanisms of antineoplastic effect of omega-3 FAs. In this review, we have collected the available clinical data on the therapeutic role of omega-3 FAs against breast cancer, colorectal cancer, leukemia, gastric cancer, pancreatic cancer, esophageal cancer, prostate cancer, lung cancer, head and neck cancer, as well as cancer cachexia. We also discussed the chemistry, dietary source, and bioavailability of omega-3 FAs, and the potential molecular mechanisms of anticancer and adverse effects.

Ferulic acid and Alzheimer's disease: promises and pitfalls.

Oxidative stress plays an important role in both initiation and progression of neurodegenerative diseases, such as Alzheimer and Parkinson. Therefore, much attention has been paid to antioxidants for developing therapeutic strategies for the neurodegenerative diseases. However, as serious adverse effects are related to synthetic antioxidants, recent research has been focused on natural products especially phenolic antioxidants. In the present article, we critically review the available literature related to the beneficial role of ferulic acid on Alzheimer's disease, since it is a natural antioxidant which is widely found in different fruits and vegetables. We also provide some informations about sources, chemical structure, bioavailability and clinical impacts of ferulic acid.

Assessment of anti-amyloidogenic activity of marine red alga G. acerosa against Alzheimer's beta-amyloid peptide 25-35.

OBJECTIVE: The amyloid hypothesis stimulates the discovery of compounds, which promotes beta-amyloid peptide (Aß) clearance, thereby altering the underlying pathophysiology of Alzheimer's disease (AD). Hence, the present study aims at the evaluation of anti-amyloidogenic potential of Gelidiella acerosa. METHODS: Prevention of Aß 25-35 aggregate formation and disaggregation of pre-formed fibrils by G. acerosa was evaluated in three phases by thioflavin T spectrophotometric assay. The results were further validated by confocal microscopic analysis. The conformational changes in the aggregated and non-aggregated Aß in the presence of G. acerosa were analyzed by Fourier transform infrared (FTIR) spectroscopic analysis. RESULTS: Phase-I study shows that G. acerosa reverts (4.56 ± 0.35 AU at 96 hours) the increase in fluorescence intensity of aggregated Aß (18.76 ± 0.99 AU) significantly (P < 0.05) as that of non-aggregated peptides, which suggests that G. acerosa prevents the formation of oligomers from monomers. The seaweed also prevents the fibril formation even after the aggregation process was initiated at 20 hours, which was verified by the significant (P < 0.05) decrease in the fluorescence intensity (2.94 ± 0.0721 AU) at 36 hours (Phase II). In addition, G. acerosa promotes fibrillar destabilization (Phase III), which was further substantiated by confocal microscopic analysis. Fourier transform infrared spectroscopy reveals that alteration in amide I and amide II band spectrum, which occurs due to Aß 25-35 aggregation was restored upon co-treatment with G. acerosa benzene extract. CONCLUSION: Overall, the results suggest that G. acerosa might have direct interaction with the aggregated peptide, thereby preventing oligomerization and fibrillation of Aß 25-35.

Hydroxytyrosol, the phenolic compound of olive oil protects human PBMC against oxidative stress and DNA damage mediated by 2,3,7,8-TCDD.

The protective effect of hydroxytyrosol (HT), a strong antioxidant compound from extra virgin olive oil, against TCDD induced toxicity was investigated in human peripheral blood mononuclear cells (PBMC). PBMC (1 × 10(6)cellsmL(-1)) were divided into four groups and were incubated in a CO(2) incubator (5% CO(2)) for 12h with vehicle, TCDD (10 nM), TCDD+HT (10 nM+100 µM) and HT alone (100 µM) respectively. To clarify the role of HT against TCDD induced cytotoxicity, oxidative stress and the levels of antioxidant enzymes were assessed. Incubation of PBMC with TCDD significantly decreased cell viability, catalase (CAT) and glutathione peroxidase (GPx) and increased the levels of superoxide dismutase (SOD), glutathione reductase (GR) and oxidative stress markers such as lipid peroxidation products (LPO), protein carbonyl content (PCC) and reactive oxygen species (ROS). Whereas, HT had an effective antioxidant property as observed by the increased cell viability, normalization of antioxidant enzymes and decreased levels of LPO, PCC and ROS in PBMC co-treated with HT and TCDD. Apoptosis detection and comet assay results shows that HT, by acting as an antioxidant, prevents the damage to DNA induced by TCDD. In addition light microscopic and histopathological observations revealed that the cells are apoptotic and degenerated during TCDD treatment, whereas cells showed intact morphology during co-treatment with HT. On the whole, the results reveal that HT exerts a promising antioxidant potential in protecting the PBMC against TCDD induced oxidative stress, which might be due to the presence of catechol moiety in its structure.

Cholinesterase inhibitory effects of Rhizophora lamarckii, Avicennia officinalis, Sesuvium portulacastrum and Suaeda monica: Mangroves inhabiting an Indian coastal area (Vellar Estuary).

Alzheimer's disease is a progressive neurodegenerative illness accounting for approximately 50% of all types of dementia in elderly people. The only symptomatic treatment proven effective to date is the use of cholinesterase inhibitors to augment surviving cholinergic activity. The purpose of this study is to investigate cholinesterase inhibitory activity of mangroves as an alternative medicine for the treatment of Alzheimer's disease. About nine mangrove plants, which were used as folk medicine in tropical countries, were collected from Parangipettai, Vellar estuary, Tamilnadu, India. Nile Tilapia muscle homogenate was used as source of enzyme. Inhibitory effect of methanolic leaf extract was assessed under in vitro condition by incubating various concentration of the extract with total cholinesterase and butyryl cholinesterase and assessing their residual activities by Ellman's colorimetric method. The results showed that of the nine plants screened Rhizophora lamarckii, Suaeda monica, Avicennia officinalis and Sesuvium portulacastrum showed 50% inhibitory activity to both TChE and BChE at concentrations less than 2 mg/mL when compared to other plant extracts, which was comparable to the standard drug Donepezil. Phytochemical analysis showed the presence of alkaloids in high concentration which might be correlated to its cholinesterase inhibitory activity.

Bioprotective properties of seaweeds: in vitro evaluation of antioxidant activity and antimicrobial activity against food borne bacteria in relation to polyphenolic content.

BACKGROUND: For many years chemical preservatives have been used in food, to act as either antimicrobials or antioxidants or both. In general, consumers regard additive-free foods as safer since preservatives can cause health hazards like asthma and cancer and are suspected to be mutagenic and neurotoxic. The present study was carried out to evaluate the antimicrobial and antioxidant activity of methanolic extracts of seaweeds, with a view to developing safer food preservatives. METHODS: Ten edible seaweeds, which have wide pharmaceutical application, were collected from Central Marine Fisheries Research Institute, Tamil Nadu, India and evaluated for antioxidant and antimicrobial activity against food borne pathogens. RESULTS: The results indicate that Gelidiella acerosa has the highest antioxidant activity while Haligra sps exhibited antibacterial activity against Staphylococcus aureus (MTCC 96). CONCLUSION: Quantitative analysis of the total phenolic content of the seaweeds indicated that Gelidella acerosa and Haligra sps have high phenolic contents, which correlated to their respective antioxidant and antimicrobial activity.

Olive oil protects rat liver microsomes against benzo(a)pyrene-induced oxidative damages: an in vitro study.

Benzo(a)pyrene (B(a)P), a member of the polycyclic aromatic hydrocarbon family is present ubiquitously in the environment. One of its toxic effects is induction of oxidative stress (mediated by the enzyme B(a)P hydroxylase) which leads to various diseases like cancer. Olive oil (OO) that consists of many antioxidant compounds is reported to have many beneficial properties including protection against cancer. The objective of the present study is to evaluate the effect of OO on B(a)P hydroxylase enzyme and further elucidate the antioxidant capacity of OO against B(a)P-induced toxicity. Rat liver microsomes were divided into three groups: vehicle control, B(a)P treated group, and OO + B(a)P co-incubated group. Antioxidant enzymes which were decreased and protein carbonyl content and lipid peroxidation products which were increased on exposure to B(a)P was attenuated to near normal on OO exposure. B(a)P hydroxylase enzyme was very low in OO incubated group which may be due to inhibition of the enzyme by OO or high utilization for the metabolism of B(a)P. Further, no B(a)P metabolites (3-OH B(a)P and B(a)P 7,8-dihydrodiol) were identified in HPLC during B(a)P + OO exposure. The results prove the protective role of OO against B(a)P-induced oxidative damage.

Immunomodulatory effects of Premna tomentosa (L. Verbenaceae) extract in J 779 macrophage cell cultures under chromate (VI)-induced immunosuppression.

OBJECTIVE: In the present study, the immunomodulatory effects of Premna tomentosa extract against chromate (VI)-induced toxicity was assessed in J 779 macrophage cell line. DESIGN: The cells were analyzed for cytotoxicity, phagocytosis, oxidant burst, antioxidant status, and cell proliferation. RESULT: Chromate treatment resulted in a significant increase in cytotoxicity and free radical production. Furthermore, there is a significant decrease in reduced glutathione (GSH) levels and glutathione peroxidase activity (GPx). There was an appreciable decrease in cell proliferation and phagocytosis by macrophages in the presence of chromate. However, pretreatment of the cells with P. tomentosa extract (500 microg concentration), 30 minutes prior to chromate (VI) treatment resulted in a significant inhibition of chromate-induced cytotoxicity and reactive oxygen species production. The extract also restored the antioxidant status, cell proliferation, and phagocytosis similar to that of control cells. CONCLUSION: The results confirm the cytoprotective and immunomodulatory effects of the leaves of P. tomentosa and its possible usage in immunosuppressed conditions.

Assessment of the protective potential of Premna tomentosa (L. Verbenaceae) extract on lipid profile and lipid-metabolizing enzymes in acetaminophen-intoxicated rats.

OBJECTIVES: The liver is often damaged by environmental toxins, poor eating habits, alcohol and over-the-counter drug use that damage and weaken the liver, leading to important public health problems such as hepatitis, cirrhosis, and alcoholic liver diseases. It is cardinal to treat liver disorders, because it affects the biochemistry of the cell directly. Damage to the liver can be prevented by including a balanced diet that includes nutrients and herbs that support a healthy liver. Premna tomentosa (PT) is one such herbal drug used widely in India for the treatment of liver disorders, and we have already reported the hepatoprotective potential and antioxidant property of methanolic extract of PT leaves. Because injury to the liver can promote a variety of reactions with consequent effect on lipids, the present study was designed to elucidate the hypolipidemic effect of PT extract in acetaminophen (AA)-induced hepatotoxicity in rats. DESIGN AND SUBJECTS: Animals were pretreated with PT extract (750 mg/kg, orally) for 15 days and then induced with hepatotoxicity by AA (640 mg/kg, intraperitoneally). RESULTS: PT extract pretreatment significantly inhibited induced alterations in the levels of cholesterol, triglycerides, free fatty acids, phospholipids, serum lipoproteins, and lipid-metabolizing enzymes. CONCLUSIONS: The results indicate that PT extract improves lipid metabolism and has the potential for use in hepatic disorders.