Neuroprotective effect of tea polyphenols on oxyhemoglobin induced subarachnoid hemorrhage in mice

Therapeutic Potential of Natural Compounds in Subarachnoid Haemorrhage

Subarachnoid hemorrhage (SAH) is a common and fatal cerebrovascular disease with high morbidity, mortality and very poor prognosis worldwide. SAH can induce a complex series of pathophysiological processes, and the main factors affecting its prognosis are early brain injury (EBI) and delayed cerebral ischemia (DCI). The pathophysiological features of EBI mainly include intense neuroinflammation, oxidative stress, neuronal cell death, mitochondrial dysfunction and brain edema, while DCI is characterized by delayed onset ischemic neurological deficits and cerebral vasospasm (CVS). Despite much exploration in people to improve the prognostic outcome of SAH, effective treatment strategies are still lacking. In recent years, numerous studies have shown that natural compounds of plant origin have unique neuro- and vascular protective effects in EBI and DCI after SAH and long-term neurological deficits, which mainly include inhibition of inflammatory response, reduction of oxidative stress, anti-apoptosis, and improvement of blood-brain barrier and cerebral vasospasm. The aim of this paper is to systematically explore the processes of neuroinflammation, oxidative stress, and apoptosis in SAH, and to summarize natural compounds as potential targets for improving the prognosis of SAH and their related mechanisms of action for future therapies.

Plant-based dietary patterns and their association with mood in healthy individuals

Background: Healthy, plant-based dietary patterns, particularly the Mediterranean diet (MD), have been associated with positive effect on mood symptoms and have been proposed to help prevent age-related cognitive decline. However, to date no study has investigated which existing plant-based dietary pattern might be most likely to be associated with better mood in the general population. The aim of this study was to evaluate the relationship between different plant-rich dietary patterns and current mood in healthy individuals across a broad age range. Methods: We evaluated 333 healthy participants aged 8-79, who previously participated in dietary intervention studies. Current mood was assessed with the Positive and Negative Affect Schedule (PANAS) questionnaire, standardised by Z scores. Dietary patterns were estimated using food consumption data obtained from the European Prospective Investigation into Cancer (EPIC) Food Frequency Questionnaires (FFQ), and included the Plant-based Diet Index (PDI), Dietary Approaches to Stop Hypertension Diet (DASH), Mediterranean-DASH Diet Intervention for Neurodegenerative Delay (MIND), Original Mediterranean Diet (oMED) and Alternate Mediterranean Diet (aMED). Results: PDI, DASH, oMED and aMED diet scores were all significantly associated with positive mood (rs = 0.12-0.16), but not with negative mood. Linear regression models suggested that after adjusting for potential confounders (sex and age), only the oMED and aMED diet scores were still significantly associated with positive mood (β = 0.119, p = 0.031 and β = 0.111, p = 0.048, respectively). Furthermore, the relationship between PDI diet scores and positive mood was only significant in children (β = 0.663, p = 0.003), pointing to a potential moderating effect of age in the relationship between PDI and positive mood. Conclusion: Adherence to oMED and aMED diets is associated with better mood in healthy adults, while the PDI diet might be more specifically associated with positive mood in children.

New Mechanisms and Targets of Subarachnoid Hemorrhage: A Focus on Mitochondria

Spontaneous subarachnoid hemorrhage (SAH) accounts for 5-10% of all strokes and is a subtype of hemorrhagic stroke that places a heavy burden on health care. Despite great progress in surgical clipping and endovascular treatment for ruptured aneurysms, cerebral vasospasm (CVS) and delayed cerebral ischemia (DCI) threaten the long-term outcomes of patients with SAH. Moreover, there are limited drugs available to reduce the risk of DCI and adverse outcomes in SAH patients. New insight suggests that early brain injury (EBI), which occurs within 72 h after the onset of SAH, may lay the foundation for further DCI development and poor outcomes. The mechanisms of EBI mainly include excitotoxicity, oxidative stress, neuroinflammation, blood-brain barrier (BBB) destruction, and cellular death. Mitochondria are a double-membrane organelle, and they play an important role in energy production, cell growth, differentiation, apoptosis, and survival. Mitochondrial dysfunction, which can lead to mitochondrial membrane potential (Δψm) collapse, overproduction of reactive oxygen species (ROS), release of apoptogenic proteins, disorders of mitochondrial dynamics, and activation of mitochondria-related inflammation, is considered a novel mechanism of EBI related to DCI as well as post-SAH outcomes. In addition, mitophagy is activated after SAH. In this review, we discuss the latest perspectives on the role of mitochondria in EBI and DCI after SAH. We emphasize the potential of mitochondria as therapeutic targets and summarize the promising therapeutic strategies targeting mitochondria for SAH.

Neuroprotection of Tropical Fruit Juice Mixture via the Reduction of iNOS Expression and CRH Level in β-Amyloid-Induced Rats Model of Alzheimer's Disease

This study aimed to determine the effects of tropical fruit juice mixture (pomegranate, white guava, and Roselle) on biochemical, behavioral, and histopathological changes of β-amyloid- (Aβ-) induced rats. Formulation 8 (F8) of tropical fruit juice mixture was chosen for this present study due to its high phenolic content and antioxidant capacity. Forty Wistar male rats were divided into five groups: dPBS (sham-operated control), dAβ (Aβ control), JPBS (F8 and PBS), JAβ (F8 and Aβ), and IBFAβ (ibuprofen and Aβ). F8 (5 ml/kg BW), and ibuprofen (10 ml/kg BW) was given orally daily for four weeks before the intracerebroventricular infusion of Aβ for two weeks. Histological analysis and neuronal count of hippocampus tissue in the Cornu Ammonis (CA1) region showed that supplementation with F8 was able to prevent Aβ-induced tissue damage and neuronal shrinkage. However, no significant difference in locomotor activity and novel object recognition (NOR) percentage was detected among different groups at day 7 and day 14 following Aβ infusion. Only effect of time differences (main effect of day) was observed at day 7 as compared to day 14, where reduction in locomotor activity and NOR percentage was observed in all groups, with F (1, 7) = 6.940, p < 0.05 and F (1, 7) = 7.152, p < 0.05, respectively. Besides, the MDA level of the JAβ group was significantly lower (p < 0.01) than that of the dPBS group. However, no significant changes in SOD activity were detected among different groups. Significant reduction in plasma CRH level (p < 0.05) and iNOS expression (p < 0.01) in the brain was detected in the JAβ group as compared to the dAβ group. Hence, our current findings suggest that the tropical fruit juice mixture (F8) has the potential to protect the rats from Aβ-induced neurotoxicity in brain hippocampus tissue possibly via its antioxidant properties and the suppression of iNOS expression and CRH production.

Plant Resources, Chemical Constituents, and Bioactivities of Tea Plants from the Genus Camellia Section Thea

Tea, as one of the most popular beverages with various bioactivities, is commonly produced from the fresh leaves of two widely cultivated tea plants, Camellia sinensis and C. sinensis var. assamica. Both plants belong to the genus Camellia section Thea, which was considered to have 12 species and 6 varieties according to Min's taxonomic system. Most species, except the cultivated species, are known as wild tea plants and have been exploited and utilized to produce tea by the local people of its growing areas. Thus far, six species and varieties have been phytochemically studied, leading to the identification of 398 compounds, including hydrolyzable tannins, flavan-3-ols, flavonoids, terpenoids, alkaloids, and other phenolic and related compounds. Various beneficial health effects were reported for tea and its components, involving antioxidant, antitumor, antimutagenic, antidiabetic, hypolipidemic, anti-inflammatory, antimicrobial, antiviral, antifungal, neuroprotective, hepatoprotective, etc. In this review, the geographical distribution of tea plants and the chemical constituents (1-398) reported from the genus Camellia section Thea and some tea products (green, black, oolong, and pu-erh tea) that have ever been studied between 1970 and 2018 have been summarized, taking species as the main hint, and the main biological activities are also discussed.

Evaluation of the neuroprotective effect of EGCG: a potential mechanism of mitochondrial dysfunction and mitochondrial dynamics after subarachnoid hemorrhage

(-)-Epigallocatechin-3-gallate (EGCG), the main bioactive component of tea catechins, exhibits broad-spectrum health efficacy against mitochondrial damage after subarachnoid hemorrhage (SAH). The mechanisms, however, are largely unknown. Here, the ability of EGCG to rescue mitochondrial dysfunction and mitochondrial dynamics following the inhibition of cell death was investigated by using in vitro and in vivo SAH models. EGCG blocked the cytosolic channel ([Ca2+])i influx via voltage-gated calcium channels (VGCCs), which induced mitochondrial dysfunction, including mitochondrial membrane potential depolarization and reactive oxygen species (ROS) release. As expected, EGCG ameliorated oxyhemoglobin (OxyHb)-induced impairment of mitochondrial dynamics by regulating the expression of Drp1, Fis1, OPA1, Mfn1, and Mfn2. As a result, EGCG restored the increases in fragmented mitochondria and the mtDNA copy number in the OxyHb group to almost the normal level after SAH. In addition, the normal autophagic flux induced by EGCG at both the initiation and formation stages regulated Atg5 and Beclin-1 after SAH for the timely elimination of damaged mitochondria. In the end, EGCG increased the neurological score by decreasing cell death through the cyt c-mediated intrinsic apoptotic pathway. The results revealed the mechanisms behind the neuroprotective effects of EGCG via inhibition of the overloaded [Ca2+]i-induced mitochondrial dysfunction and the imbalanced mitochondrial fusion and fission cycle. Therefore, the simultaneous inhibition and timely elimination of damaged mitochondria could determine the therapeutic effect of EGCG.

Oxidative stress-induced diseases and tea polyphenols

Reactive oxide species are the middle products of normal metabolism, and play a crucial role in cell signaling transduction. On the contrary, accumulation of excess reactive oxide species results in oxidative stress that often brings multifarious impairment to cells, including decrease of ATP level in cells, elevation of cytosolic Ca2+, DNA damage, dysfunction of biological function in lipid bilayer and so on. These effects will finally lead to all kinds of diseases. Tea polyphenols are widely considered as a kind of excellent antioxidant agents. It can be antioxidants by directly scavenging reactive oxide species or chelating transition metals, and indirectly upregulating the activity of antioxidant enzymes. In addition, tea polyphenols have also been observed a potent pro-oxidant capacity, which directly leads to the generation of reactive oxide species, and indirectly induces apoptosis and death of cancer cells. The underlying characters of its pro-oxidant activity in some diseases is not well understood. The present review we will discuss the dual character of tea polyphenols, both antioxidant and pro-oxidant properties, in some human diseases induced by oxidative stress.

Differential expression of microRNAs contributed to the health efficacy of EGCG inin vitrosubarachnoid hemorrhage model

(1) EGCG prevented miRNA dysregulation after SAH; (2) multi-target mechanisms of EGCG might rely on its regulatory roles on miRNAs expression, such as those miRNAs targeting p38, Ca²⁺, and autophagic activation; (3) the differential expression of miRNAs might determine the therapeutic efficacy of different concentration of EGCG.

Reduction in Autophagy by (-)-Epigallocatechin-3-Gallate (EGCG): a Potential Mechanism of Prevention of Mitochondrial Dysfunction After Subarachnoid Hemorrhage

Mitochondrial dysfunction and subsequent autophagy, which are common features in central nervous system (CNS) disorders, were found to contribute to neuronal cell injury after subarachnoid hemorrhage (SAH). (-)-Epigallocatechin-3-gallate (EGCG), the main biological active of tea catechin, is well known for its beneficial effects in the treatment of CNS diseases. Here, the ability of EGCG to rescue cellular injury and mitochondrial function following the improvement of autophagic flux after SAH was investigated. As expected, EGCG-protected mitochondrial function depended on the inhibition of cytosolic Ca²⁺ concentration ([Ca²⁺]_i) influx via voltage-gated calcium channels (VGCCs) and, consequently, mitochondrial Ca²⁺ concentration ([Ca²⁺]_m) overload via mitochondrial Ca²⁺ uniporter (MCU). The attenuated [Ca²⁺]_i and [Ca²⁺]_m levels observed in the EGCG-treated group likely lessened oxyhemoglobin (OxyHb)-induced mitochondrial dysfunction, including mitochondrial membrane potential depolarization, mitochondrial membrane permeability transition pore (mPTP) opening, reactive oxygen species (ROS), and cytochrosome c (cyt c) releasing. Subsequently, EGCG can restore the disrupted autophagy flux after SAH both at the initiation and formation stages by regulating Atg5, LC3B, and Becn-1 (Beclin-1) mRNA expressions. Thus, precondition EGCG resulted in autophagosomes and more autolysosomes compared with SAH group. As a result, EGCG pre-treatment increased the neurological score and decreased cell death. This study suggested that the mitochondrial dysfunction and abnormal autophagy flux synergistically contribute to SAH pathogenesis. Thus, EGCG can be regarded as a new pharmacological agent that targets both mitochondria and altered autophagy in SAH therapy.

Psychiatric Disorders and Polyphenols: Can They Be Helpful in Therapy?

The prevalence of psychiatric disorders permanently increases. Polyphenolic compounds can be involved in modulation of mental health including brain plasticity, behaviour, mood, depression, and cognition. In addition to their antioxidant ability other biomodulating properties have been observed. In the pathogenesis of depression disturbance in neurotransmitters, increased inflammatory processes, defects in neurogenesis and synaptic plasticity, mitochondrial dysfunction, and redox imbalance are observed. Ginkgo biloba, green tea, and Quercus robur extracts and curcumin can affect neuronal system in depressive patients. ADHD patients treated with antipsychotic drugs, especially stimulants, report significant adverse effects; therefore, an alternative treatment is searched for. An extract from Ginkgo biloba and from Pinus pinaster bark, Pycnogenol, could become promising complementary supplements in ADHD treatment. Schizophrenia is a devastating mental disorder, with oxidative stress involved in its pathophysiology. The direct interference of polyphenols with schizophrenia pathophysiology has not been reported yet. However, increased oxidative stress caused by haloperidol was inhibited ex vivo by different polyphenols. Curcumin, extract from green tea and from Ginkgo biloba, may have benefits on serious side effects associated with administration of neuroleptics to patients suffering from schizophrenia. Polyphenols in the diet have the potential to become medicaments in the field of mental health after a thorough study of their mechanism of action.

Protective effect of curculigo orchioides extract on cyclophosphamide-induced neurotoxicity in murine model

Free radicals are one of the frequent products of normal cellular metabolism. Disparity of metabolism and excessive generation of free radicals predisposes to disorders like Parkinson's disease, Alzheimer's disease, and aging phenomenon. Curculigo orchioides Gaertn. is known for “adaptogen” and “aphrodisiac” activity and has been proved for antiasthmatic, estrogenic, antiosteoporotic activity along with protection from cisplatin-induced cell damage. C. orchioides was powdered and subjected to soxhlet extraction using methanol. Phytochemical studies and estimation of polyphenols and flavonoids was performed. Acute toxicity studies were performed by Organization for Economic Cooperation and Development OECD guidelines. Animals were treated with cyclophosphamide to induce neurotoxicity. Curculigo orchioides was powdered and subjected to soxhlet extraction using methanol. Catalase, superoxide dismutase, glutathione peroxidase, and lipid peroxidation were estimated by reported methods. C. orchioides (400 mg/kg) significantly promoted restoration of catalase (P < 0.005), superoxide dismutase (P < 0.005), and glutathion (P < 0.05) levels. Similarly, a very significant decrease (P < 0.005) in the levels of malondialdehyde was observed. In all cases as mentioned previously, C. orchioides at dose 200 mg/kg promoted significant (P < 0.05) restoration of enzyme levels. C. orchioides (Kali Musli) is rich source of phytochemicals like flavonoids and polyphenols. Flavonoids and polyphenols are reputed to demonstrate neuroprotective effect. These phytochemicals in the present study might be responsible to demonstrate neuroprotective effect.

Neurovascular events after subarachnoid hemorrhage: focusing on subcellular organelles

Subarachnoid hemorrhage (SAH) is a devastating condition with high morbidity and mortality rates due to the lack of effective therapy. Early brain injury (EBI) and cerebral vasospasm (CVS) are the two most important pathophysiological mechanisms for brain injury and poor outcomes for patients with SAH. CVS has traditionally been considered the sole cause of delayed ischemic neurological deficits after SAH. However, the failure of antivasospastic therapy in patients with SAH supported changing the research target from CVS to other mechanisms. Currently, more attention has been focused on global brain injury within 3 days after ictus, designated as EBI. The dysfunction of subcellular organelles, such as endoplasmic reticulum stress, mitochondrial failure, and autophagy-lysosomal system activation, has developed during EBI and delayed brain injury after SAH. To our knowledge, there is a lack of review articles addressing the direction of organelle dysfunction after SAH. In this review, we discuss the roles of organelle dysfunction in the pathogenesis of SAH and present the opportunity to develop novel therapeutic strategies of SAH via modulating the functions of organelles.