Protective effect of sarsasapogenin in TNBS induced ulcerative colitis in rats associated with downregulation of pro-inflammatory mediators and oxidative stress.

BACKGROUND: Ulcerative colitis (UC) is a chronic inflammatory bowel condition considered by oxido-nitrosative stress and the release of pro-inflammatory cytokines that affects the mucosal lining of the colon. Sarsasapogenin (SG), as an active component, has been found in many plants, and it exhibits potential protective effects, such as anti-inflammatory, antioxidant, anti-psoriasis, anti-arthritis, anti-asthma, anti-depressant and anti-cancer. However, the effects of SG on UC remain unknown. OBJECTIVE: The purpose of this study was to investigate the effects of SG on 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced UC in rats. METHOD: Thirty Wistar rats were randomized into five groups: (i) Normal control, (ii) Disease control (TNBS), (iii) Sarsasapogenin (SG) (50 µg/rat), (iv) Fluticasone (FC) (50 µg/rat), (v) Sarsasapogenin + Fluticasone (SG + FC) (25 µg/rat). UC was induced in rats by trans-rectal instillation of TNBS (10 mg/kg). SG, FC and SG + FC were administered for 11 days and on the 8th day colitis was induced. Several molecular, biochemical and histological alterations were evaluated in the colon tissue. All treatment group results were compared to the TNBS group results. RESULT: The study results revealed that treatment of rats with SG and SG + FC combination significantly decreased the colon weight/length ratio, macroscopic inflammation score, lesions score, diarrhea score and adhesion score. Combination treatment in rats significantly reduced the production of biochemical parameters, proinflammatory cytokines, haematological parameters, serum IgE levels and restored the oxidative stress markers. SG and SG + FC treatment also considerably restored the histopathological changes induced by TNBS. CONCLUSION: Thus, SG and SG + FC combination could alter the disease progression and could be a hopeful therapeutic target for the management of UC by reducing its dose in combination with FC to elude the long term adverse effects of FC.

The nephroprotective effects and mechanisms of rehmapicrogenin include ROS inhibition via an oestrogen-like pathway both in vivo and in vitro.

BACKGROUND: The root of Rehmannia glutinosa (R. glutinosa) is commonly used in various traditional Chinese herbal formulae to ameliorate nephropathy; however, little is known about its active component(s) and mechanisms. AIM: In the present study, we examined the protective effect and potential mechanism of rehmapicrogenin, a monomeric compound extracted from R. glutinosa, against Adriamycin (ADR)-induced nephropathy (AN) in vivo and in vitro. METHODS: In this study, an ADR-induced kidney injury model was employed to investigate the nephroprotective effects of rehmapicrogenin in mice. In vivo, ELISA kits, flow cytometry, haematoxylin-eosin staining, immunofluorescence techniques, and western blotting were used to evaluate the effect of rehmapicrogenin on kidney injury in mice. In vitro, the effects of rehmapicrogenin on NRK-52E cellular damage induced by ADR were determined using the 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The mechanism was investigated using ELISA kits, flow cytometry and In-Cell Western™ blotting. RESULTS: In vivo, rehmapicrogenin treatment significantly attenuated the pathological changes in the kidney induced by ADR; rescued weight, serum creatinine (Scr), blood urea nitrogen (BUN) and urine albumin (U-ALB) levels; reduced reactive oxygen species (ROS) accumulation; and decreased oxidative stress, the apoptosis rate, and cell survival in ADR-treated mice. Importantly, both in vivo and in vitro experimental results demonstrated that rehmapicrogenin regulates the Nrf2/ARE signalling pathway, the most important pathway for oxidative stress. Rehmapicrogenin attenuated ADR-induced kidney damage by reducing oxidative stress through the oestrogen receptor pathway. Moreover, after treatment with ICI 182780 (the oestrogen receptor-nonspecific antagonist Faslodex), the improvement induced by rehmapicrogenin was significantly reversed. CONCLUSIONS: In conclusion, rehmapicrogenin attenuates kidney damage by reducing inflammatory factor release through the oestrogen signalling pathway.

Protective effects of syringin against oxidative stress and inflammation in diabetic pregnant rats via TLR4/MyD88/NF-κB signaling pathway.

Gestational diabetes (GDM) is common in pregnancies due to the inflammation and oxidative stress-mediated insulin resistance. In the present study, GDM was induced in the Wistar rats by administering the streptozotocin to elucidate whether the administration of syringin (50 mg/kg/day) during pregnancy could improve maternal glycemia and protect against the complications of GDM. The animals were assessed for their morphological changes in the ß-islets of Langerhans and their insulin-producing ability, inflammatory cytokine markers, and the involvement of TLR4/MyD88/NF-κB signaling pathway using RT-PCR. The results demonstrated that the onset of GDM demonstrated pancreatic tissue degeneration in the islets of Langerhans with a significant increase in oxidative stress and reduced antioxidant enzymes. Besides, the mRNA expression levels of TLR4, MyD88, NF-Kß p65; NLRP3 mRNA were profoundly increased in GDM rats compared to normal pregnant rats. On the other hand, syringin administered GDM rats abrogated the oxidative stress and attenuated the level of the inflammatory cytokines. Intriguingly, the decrease in TLR4 expression and the downstream molecules of MyD88, NF-κB, and NLRP3 were also observed in syringin administered GDM rats that indicate the insulin secretion stimulatory actions of syringin through the suppression of TLR4 signaling. These novel findings of the study provide evidence that syringin could be a probable candidate to be used in the treatment of gestational diabetes in the future.

Therapeutic potential of prenylated stilbenoid macasiamenene F through its anti-inflammatory and cytoprotective effects on LPS-challenged monocytes and microglia.

ETHNOPHARMACOLOGICAL RELEVANCE: Macaranga Thou. (Euphorbiaceae) is a large genus that comprises over 300 species distributed between Western Africa and the islands of the South Pacific. Plants of this genus have a long-standing history of use in traditional medicine for different purposes, including the treatment of inflammation. Fresh and dried leaves of certain Macaranga species (e.g. M. tanarius (L.) Müll.Arg.), have been used to treat cuts, bruises, boils, swellings, sores and covering of wounds in general. Several reports described Macaranga spp. being a rich source of polyphenols, such as prenylated stilbenoids and flavonoids, mostly responsible for its biological activity. Similarly, an abundant content of prenylated stilbenes was also described in M. siamensis S.J.Davies, species recently identified (2001) in Thailand. While the respective biological activity of the prenylated stilbenes from M. siamensis was poorly investigated to date, our recent study pointed out the interest as the natural source of several novel anti-inflammatory stilbenoids isolated from this species. AIM OF THE STUDY: This work investigated the potential anti-inflammatory effects of the stilbenoid macasiamenene F (MF) isolated from M. siamensis S.J.Davies (Euphorbiaceae) on the lipopolysaccharide (LPS)-induced inflammation-like response of monocytes and microglia, major cells involved in the peripheral and central inflammatory response, respectively. MATERIALS AND METHODS: LPS-induced stimulation of TLR4 signaling led to the activation of inflammatory pathways in in vitro models of THP-1 and THP-1-XBlue™-MD2-CD14 human monocytes, BV-2 mouse microglia, and an ex vivo model of brain-sorted mouse microglia. The ability of the stilbenoid MF to intervene in the IкB/NF-кB and MAPKs/AP-1 inflammatory cascade was investigated. The gene and protein expressions of the pro-inflammatory cytokines IL-1ß and TNF-α were evaluated at the transcription and translation levels. The protective effect of MF against LPS-triggered microglial loss was assessed by cell counting and the LDH assay. RESULTS: MF demonstrated beneficial effects, reducing both monocyte and microglial inflammation as assessed in vitro. It efficiently inhibited the degradation of IкBα, thereby reducing the NF-кB activity and TNF-α expression in human monocytes. Furthermore, the LPS-induced expression of IL-1ß and TNF-α in microglia was dampened by pre-, co-, or post-treatment with MF. In addition to its anti-inflammatory effect, MF demonstrated a cytoprotective effect against the LPS-induced death of BV-2 microglia. CONCLUSION: Our research into anti-inflammatory and protective effects of MF has shown that it is a promising candidate for further in vitro and in vivo investigations of MF interventions with respect to acute and chronic inflammation, including potentially beneficial effects on the inflammatory component of brain diseases such as stroke and Alzheimer's disease.

Protecting HaCaT cells from ionizing radiation using persimmon tannin-Aloe gel composite.

Context: Persimmon tannin (extract of Diospyros kaki L.f [Ebenaceae]) and Aloe gel (extract of Aloe vera (L.) Burm.f. [Asphodelaceae]) are known as anti-radiation agents. However, radiation resistance of the persimmon tannin-Aloe gel composite remains inconclusive.Objective: To investigate the capacity of the persimmon tannin-Aloe gel composite to protect against ionising radiation at the cellular level.Materials and methods: HaCaT (human epidermal keratinocytes) cells were pre-treated with PT-A-1 (the mass ratio of persimmon tannin and Aloe gel was 2:1) or the single component (persimmon tannin or Aloe gel) at various concentrations (0, 50, 100, 200, 400, 800 µg/mL. Control group: medium with no HaCaT cells), and then radiated with X-rays (radiation dose: 4, 8, 12, 16, and 20 Gy). Cell viability, cell apoptosis, and radiation-induced intracellular reactive oxygen species (ROS) generation were analysed by CCK-8, Hoechst 33258 staining/flow cytometry, and 2',7'-dichlorfluorescein diacetate (DCFH-DA) assay, respectively, for 12 or 24 h incubation after radiation.Results: The optimal radiation dose and post-radiation incubation period were determined to be 8 Gy and 12 h. CCK-8 activity detection showed that the cell activity was 77.85% (p < 0.05, IC50 = 55.67 µg/mL). The apoptotic rate was the lowest (4.32%) at 200 µg/mL of PT-A-1 towards HaCaT cells. ROS production was the most effectively suppressed by 200 µg/mL PT-A-1 towards HaCaT cells.Discussion and conclusions: The persimmon tannin-Aloe gel composite has good radioprotective effect, and which will facilitate its clinic application as a potential natural anti-radiation agent in future.

Protection of the Retinal Ganglion Cells: Intravitreal Injection of Resveratrol in Mouse Model of Ocular Hypertension.

Purpose: To investigate the efficacy of intravitreal administration of resveratrol (RSV) in a microbead-induced high intraocular pressure (IOP) murine model for glaucoma. Methods: Experiments were performed using adult C57BL/6JJcl mice. Polystyrene microbeads were injected into the anterior chamber to induce IOP elevation. Retinal flat-mounts and sections were assessed by immunohistochemistry to detect the expression of reactive oxygen species and acetyl-p53 in retinal ganglion cells (RGCs), brain-derived neurotrophic factor (BDNF) in Müller glial cells (MGCs), and the receptor tropomyosin receptor kinase B (TrkB) in RGCs. Light cycler real-time PCR was also used for confirming gene expression of BDNF in primary cultured MGCs exposed to RSV. Results: Microbeads induced high IOP followed by RGC death and axon loss. Administration of RSV rescued RGCs via decreased reactive oxygen species generation and acetyl-p53 expression in RGCs and upregulated BDNF in MGCs and TrkB expression in RGCs, which exhibited a strong cytoprotective action against cell death through multiple pathways under high IOP. Conclusions: Our data suggest that administration of RSV may delay the progress of visual dysfunction during glaucoma and may therefore have therapeutic potential.

Renoprotective effect and mechanism of polysaccharide from Polyporus umbellatus sclerotia on renal fibrosis.

As a fungal polysaccharide, polysaccharide (PPUS) from Polyporus umbellatus sclerotia have showed remarkable anti-inflammatory activities. In view of the closely relationship between inflammation and renal fibrosis, and considering the significant role of other fungal polysaccharides on treatment of renal fibrosis, we speculated that PPUS may have therapeutic effects on renal fibrosis. However, there was not any reports about PPUS treatment this disease. The purpose of this paper is to investigate renoprotective effect and mechanism of PPUS on renal fibrosis. The results indicated that PPUS can improve renal function and ameliorate the degree of renal collagen deposition and further fibrosis. Its mechanism was found to be related with decreased inflammation, suppressive epithelial-mesenchymal transition, reconstructed the balance of matrix metalloproteinases and tissue inhibitor of metalloproteinases, and pro-fibrotic and anti-fibrotic factors. The data implied that PPUS can serve as a clinical candidate on treatment of renal interstitial fibrosis.

Astragaloside IV Protects Primary Cerebral Cortical Neurons from Oxygen and Glucose Deprivation/Reoxygenation by Activating the PKA/CREB Pathway.

Stroke is one of the major leading causes of death and disability worldwide, and post-stroke cognitive impairment is a major contributor to this disability. Astragaloside IV (AST-IV) is a primary bioactive compound of Radix Astragali, which is widely used in traditional Chinese medicine to treat stroke. AST-IV was found to possess cognition-enhancing properties against ischemic stroke; however, the mechanisms underlying this effect remain largely elusive. Mitochondrial health is critical to cell viability after ischemic injury. Cyclic AMP response element-binding protein (CREB) is a transcription factor that can be activated by protein kinase A (PKA) to preserve mitochondria, regulate memory and cognitive functions. We used an in vitro model of ischemic injury via oxygen and glucose deprivation (OGD) of cultured neurons, which led to PKA inactivation and decreased CREB phosphorylation, reduced cell viability, and increased neuronal apoptosis. We hypothesized that AST-IV could protect OGD-exposed cerebral cortical neurons by modulating the PKA/CREB signaling pathway and preserving mitochondrial function. We found that the mitochondrial and cellular injuries induced by OGD were reversed following treatment with AST-IV. The activity of neuronal mitochondria was evaluated by measuring the mitochondrial potential and the levels of reactive oxygen species (ROS) and adenosine triphosphate (ATP). AST-IV significantly enhanced PKA and CREB phosphorylation and prevented OGD-induced mitochondrial dysfunction, thereby protecting neurons exposed to OGD from injury and death. Furthermore, the effects of AST-IV were partially blocked by a PKA inhibitor. Collectively, these data elucidated the molecular mechanisms underlying the protective effects of AST-IV against ischemic injury in cortical neurons.

Protective Effects of Alpha-Lipoic Acid on Glutamate-Induced Cytotoxicity in C6 Glioma Cells.

Glutamate-mediated cytotoxicity has been implicated in the pathogenesis of neurological diseases, including Parkinson's disease, Alzheimer's disease, and stroke. In this study, we investigated the protective effects of alpha-lipoic acid (ALA), a naturally occurring thiol antioxidant, on glutamate-induced cytotoxicity in cultured C6 astroglial cells. Exposure to high-dose glutamate (10 mM) caused oxidative stress and mitochondrial dysfunction through the elevation of reactive oxygen species, depletion of glutathione, and loss of the mitochondrial membrane potential (ΔΨm). Pretreatment with ALA (200 µM), however, significantly inhibited the glutamate-induced oxidative stress and mitochondrial dysfunction. ALA pretreatment dose-dependently suppressed glutamate-induced apoptotic events including altered nuclear morphology and activation of caspase-3. In addition, ALA significantly attenuated glutamate-induced endoplasmic reticulum (ER) stress markers; namely, glucose-regulated protein 78 (GRP78), activating transcription factor 6 (ATF6), protein kinase regulated by RNA (PKR)-like ER-associated kinase (PERK), eukaryotic translation initiation factor 2 alpha (eIF2α), inositol-requiring enzyme 1 (IRE1), CCAAT/enhancer binding protein homologous protein (CHOP), and caspase-12. We confirmed that CHOP and caspase-12 are key mediators of glutamate-induced ER stress. Furthermore, exposure of the cells to a caspase-12-specific inhibitor and CHOP small interfering RNAs (siRNAs) led to restoration of the ΔΨm that was damaged by glutamate treatment. These results suggest that ALA can effectively suppress oxidative stress, mitochondrial dysfunction, and ER stress in astroglial cells.

Protective effect of Juglans regia L., against ultraviolet-B induced photoaging in human epidermal keratinocytes.

Solar ultraviolet-B radiation (UVB) has severe adverse effects on the structure and functions of the skin. Although, UVB (290-320 nm) represents only 5-10% of UV light reaching earth's surface, its contribution towards photoaging is tremendous. In this present study was investigate the photoprotective effect of methanolic extract of the male flower of J. regia L. (MEJR) against UVB induced photoaging in human epidermal keratinocytes (HaCaT). Cells were exposed to UVB-irradiation at a dose of 20 mJ/cm2, induces the activation of several signaling pathways which are associated with oxidative stress and photoaging. A single dose of UVB irradiation increased the protein and mRNA expression of MAPKs, AP-1, MMPs, Smad7 and decreased expression of TIMP-1/2, TGF-ß1, Smad3, procollagen type-1 in HaCaT cells. In contrast, pretreatment of MEJR (80 µg/ml) prior to UVB-irradiation significantly prevented the overexpression of MAPKs, AP-1, MMPs, Smad7 and decreased expression of TIMP-1/2, TGF-ß1, Smad3 and procollagen type-1 in HaCaT cells. Moreover, pretreatment of MEJR (80 µg/ml) prior to UVB-irradiation significantly prevents apoptosis in sub Go-phase. Thus, MEJR protects UVB-mediated photoaging in human skin cells, by modulating the expression of photoaging markers. The protection might be because of the presence of the good amount of bioactive compounds in MEJR.

BPA and Nutraceuticals, Simultaneous Effects on Endocrine Functions.

BACKGROUND: Bisphenol A (BPA) is worldwide diffused as a monomer of epoxy resins and polycarbonate plastics and has recognized activity as Endocrine Disruptor (ED). It is capable to interfere or compete with endogenous hormones in many physiological activities thus having adverse outcomes on health. Diet highly affects health status and in addition to macronutrients, provides a large number of substances with recognized pro-heath activity, and thus called nutraceuticals. OBJECTIVE: This mini-review aims at summarizing the possible opposite and simultaneous effects of BPA and nutraceuticals on endocrine functions. The possibility that diet may represent the first instrument to preserve health status against BPA damages has been discussed. METHODS: The screening of recent literature in the field has been carried out. RESULTS: The therapeutic and anti-oxidant properties of many nutraceuticals may reverse the adverse health effects of BPA. CONCLUSION: In vitro and in vivo studies provided evidence that nutraceuticals can preserve the health. Thus, the use of nutraceuticals can be considered a support for clinical treatment. In conclusion, dietary remediation may represent a successful therapeutic approach to maintain and preserve health against BPA damage.

Protective effects of Cinnamomum zeylanicum L. (Darchini) in acetaminophen-induced oxidative stress, hepatotoxicity and nephrotoxicity in mouse model.

Cinnamomum zeylanicum, a widely used spice and flavor, is used in the treatment and prevention of many diseases. In the current study, Balb/c mice were pretreated with cinnamon bark aqueous extract (200 mg/kg/day i.g.) 14 days prior to intragastrically administer single toxic dose of acetaminophen (200 mg/kg). Blood samples were collected for analysis of biochemical and oxidative stress parameters and liver and kidney samples were collected for histopathological analysis. The results indicate that cinnamon aqueous extract exhibit a highly significant preventive potential by ameliorating APAP-induced elevated levels of serum alanine aminotransferase, aspartate aminotransferase, creatinine, urea and macroscopic and histological alterations in liver and kidney. Moreover, significant increase in total oxidant status and decrease in total antioxidant capacity accompanied by APAP exposure, were restored by cinnamon pretreatment. We found that prior administration of cinnamon prevented the toxic changes induced by acetaminophen as confirmed by histopathological examination, more possibly owing to its antioxidant potential. In conclusion, the pretreatment with cinnamon provide potential therapeutic applications in acute liver and kidney injury induced by APAP in experimental animal model and it could have therapeutic potential in oxidative stress associated diseases.

Protective effects of radish (Raphanus sativus L.) leaves extract against hydrogen peroxide-induced oxidative damage in human fetal lung fibroblast (MRC-5) cells.

Natural antioxidants play a critical role in the promotion of good health for its prevention of oxidative stress. The main purpose of this study is to investigate the protective effects of radish leaves extract on the oxidative damage in human fetal lung fibroblast (MRC-5) cells. F2, a fraction of radish leaves extracts, which was fractionated by different polarity solvents and AB-8 macroporous resins column shows the best free radical scavenging ability, the highest total polyphenol contents (TPC), and the most potent protective effects on H2O2-induced oxidative damage in MRC-5 cells. The results indicated that pretreatment with F2 before the exposure of cells to H2O2 led to a significant increase in cell viability and internal antioxidant enzyme activities, and a decrease in the content of malondialdehyde (MDA). Furthermore, F2 attenuated the increase in intracellular reactive oxygen species (ROS) level and restored the loss of mitochondria membrane potential (MMP) caused by H2O2. In addition, pretreatment of F2 down-regulated the pro-apoptosis protein (Bax) and up-regulated the anti-apoptosis protein (Bcl-2) suggested its preliminary mechanism of protective effect. In summary, F2 from radish leaves might be used as a source of antioxidant for protecting the oxidative damage of lung.

Ghrelin protects against depleted uranium-induced bone damage by increasing osteoprotegerin/RANKL ratio.

Depleted uranium (DU) is widely used in military and civil activities, and bone is the main target organ of chronic DU toxicity. The aim of this study was to evaluate the effects of ghrelin on rats implanted with DU and explore the underlying mechanisms. The results showed that ghrelin could increase the expression of ghrelin receptor in bone tissue, thus alleviate the apoptosis of bone tissue after 3 months of 0.3 g DU embedded in the tibia. Micro-computed tomography examination showed that after DU implantation, the density of cortical bone showed no significant difference, but the trabecular bone decreased in amount, density and connectivity. Ghrelin treatment can significantly reduce the changes caused by DU. Moreover, ghrelin can inhibit the increase of serum tartrate resistant acid phosphatase and the decrease of alkaline phosphatase and osteocalcin. Furthermore, ghrelin can also significantly reduce the receptor activator of nuclear factor κB ligand (RANKL) and phosphorylated p38-MAPK expression, and increase the level of osteoprotegerin (OPG) in tissues after exposure to DU. Based on cell experimental research, p38-MAPK specific agonist can reverse the function of ghrelin, significantly inhibit the level of OPG and increase the level of RANKL. On the contrary, the use of p38-MAPK specific inhibitor or p38-MAPK siRNA can enhance the function of ghrelin. These results suggest that ghrelin may inhibit p38 MAPK activation induced by DU, and increase the OPG/RANKL ratio caused by DU exposure, hence alleviating the bone damage caused by long-term DU exposure.

Cytoprotective effect exerted by geraniin in HepG2 cells is through microRNA mediated regulation of BACH-1 and HO-1.

Geraniin, a hydrolysable tannin, used in traditional medicine in Southeast Asia, is known to exhibit various biological activities. As an antioxidant it is known to up-regulate phase II enzyme Heme oxygenase-1 (HO-1). However its mechanism is not clearly understood. Nuclear factor erythroid-derived 2 related factor 2 (Nrf-2) is transcriptionally up-regulated by Extracellular signal-regulated kinase (ERK) 1/2 and retained in nucleus due to inactivated Glycogen synthase kinase 3 beta (GSK-3ß). Geraniin additionally down-regulates expression of microRNA 217 and 377 (miR-217 and miR-377) which target HO-1 mRNA. Expression of BTB and CNC homolog 1 (BACH-1), another regulator of HO-1, is also down-regulated by up-regulating microRNA 98 (miR-98), a negative regulator of BACH-1. Thus, geraniin up-regulates HO-1 expression both through activating its positive regulator Nrf-2 and by down-regulating its negative regulator BACH-1. Up-regulation of HO-1 also confers protection to HepG2 cells from tertiary butyl hydroperoxide (TBH) induced cytotoxicity. [BMB Reports 2017; 50(11): 560-565].

The cytoprotective effect of Rumex Aquaticus Herba extract against hydrogen peroxide-induced oxidative stress in AGS cells.

The Rumex Aquaticus Herba extract containing quercetin-3-ß-D-glucuronopyranoside (ECQ) has been reported to exhibit various pharmacological activities, including anti-inflammatory and anti-oxidative effects. This plant has been traditionally used for the treatment of diarrhea, disinfestation, edema and jaundice, and as an antipyretic drug. The aim of the present study was to investigate the ability of ECQ to protect against oxidative damage and to determine its signaling mechanism in AGS cells. The protein expressions of heme oxygenase-1 (HO-1) and nuclear factor-erythroid 2 related factor 2 (Nrf2) were measured by Western blots. Cell viability was measured by MTT assay. Intracellular reactive oxygen species (ROS) levels were measured using 2',7'-dichlorofluorescein diacetate. Glutathione peroxidase levels were measured using kits. The protein expressions of HO-1 and its upstream mediator, Nrf2, increased after ECQ treatment. The HO-1 inhibitor, ZnPP, repressed the protective effect of ECQ on H2O2-induced cell damage. We found that LY294002, a specific PI3 K/Akt inhibitor, suppressed ECQ-induced HO-1 expression. ECQ significantly attenuated H2O2-induced cytotoxicity and ROS generation. Also, ECQ enhanced the antioxidant enzyme activities of glutathione peroxidase. These results suggest that ECQ exerts a cytoprotective effect against H2O2-induced oxidative stress by upregulation of Nrf2/HO-1 via the PI3 K/Akt pathway.

Chemical constituents from Phyllanthus emblica and the cytoprotective effects on H2O2-induced PC12 cell injuries.

Two new compounds (1-2), including a bisabolane-type sesquiterpenoid (1), one new diphenyl ether derivative (2), together with 23 known compounds (3-25), were isolated from the fruits of Phyllanthus emblica. Their structures were elucidated by detailed spectroscopic analysis. All the isolated compounds were screened for the DPPH scavenging effects and cytoprotective effects against H2O2 induced PC12 cells injury. Compounds 12-15 showed significant DPPH scavenging effects with the IC50 values in the range of 3.25-4.18 µM. Among these potential antioxidants, compound 14 improved the survival of PC12 cells after H2O2 exposure without showing any cytotoxicity at the tested concentrations.

Isolation of major phenolics from Launaea spinosa and their protective effect on HepG2 cells damaged with t-BHP.

CONTEXT: Some Launaea species (Asteraceae) are used traditionally to treat liver oxidative stress. OBJECTIVE: The present study investigates the protective effects of isolated compounds from Launaea spinosa Sch. Bip. (Asteraceae) against oxidative stress on t-BHP-induced HepG2 cells. MATERIALS AND METHODS: Major phenolic content from flowering aerial parts of L. spinosa was isolated and identified. The protective effects of isolated compounds (10 and 20 µM) against oxidative stress induced by tert-butyl hydroperoxide (t-BHP) in HepG2 cells were investigated through the measurement of aspartate aminotransferase (AST), alanine transaminase (ALT), and superoxide dismutase (SOD) levels. RESULTS: A new phenolic compound identified as 2,3-diferulyl R,R-(+) methyl tartrate (6), in addition to five known metabolites, esculetin (1), esculetin-7-O-d-glucoside (cichoriin) (2), fertaric acid (3), acacetin-7-O-d-glucoside (4), and acacetin-7-O-d-glucuronic acid (5), were isolated. Oxidant-induced damage by 200 µM t-BHP in HepG2 cells was inhibited by compounds 1, 4, and 5 (10 and 20 µM), or quercetin (10 µM; positive control). The protective effects of compounds 1, 4, and 5 were associated with decreasing in AST, ALT, and SOD levels. Compound 4 (20 µM) decreased the AST level from 128.5 ± 13.9 to 7.9 ±1.8 U/mL. Meanwhile, compound 1 (20 µM) decreased ALT activity from 20.3 ± 7.0 to 7.6 ± 2.4 U/mL, while compound 5 decreased SOD levels from 41.6 ± 9.0 to 28.3 ± 3.4 mU/mg. CONCLUSION: The major phenolic compounds isolated from L. spinosa displayed a significant cytoprotective effect against oxidative stress, leading to maintenance of the normal redox status of the cell.

AP39, A Mitochondrially Targeted Hydrogen Sulfide Donor, Exerts Protective Effects in Renal Epithelial Cells Subjected to Oxidative Stress in Vitro and in Acute Renal Injury in Vivo.

This study evaluated the effects of AP39 [(10-oxo-10-(4-(3-thioxo-3H-1,2-dithiol-5yl) phenoxy)decyl) triphenyl phosphonium bromide], a mitochondrially targeted donor of hydrogen sulfide (H2S) in an in vitro model of hypoxia/oxidative stress injury in NRK-49F rat kidney epithelial cells (NRK cells) and in a rat model of renal ischemia-reperfusion injury. Renal oxidative stress was induced by the addition of glucose oxidase, which generates hydrogen peroxide in the culture medium at a constant rate. Glucose oxidase (GOx)-induced oxidative stress led to mitochondrial dysfunction, decreased intracellular ATP content, and, at higher concentrations, increased intracellular oxidant formation (estimated by the fluorescent probe 2, 7-dichlorofluorescein, DCF) and promoted necrosis (estimated by the measurement of lactate dehydrogenase release into the medium) of the NRK cells in vitro. Pretreatment with AP39 (30-300 nM) exerted a concentration-dependent protective effect against all of the above effects of GOx. Most of the effects of AP39 followed a bell-shaped concentration-response curve; at the highest concentration of GOx tested, AP39 was no longer able to afford cytoprotective effects. Rats subjected to renal ischemia/reperfusion responded with a marked increase (over four-fold over sham control baseline) blood urea nitrogen and creatinine levels in blood, indicative of significant renal damage. This was associated with increased neutrophil infiltration into the kidneys (assessed by the myeloperoxidase assay in kidney homogenates), increased oxidative stress (assessed by the malondialdehyde assay in kidney homogenates), and an increase in plasma levels of IL-12. Pretreatment with AP39 (0.1, 0.2, and 0.3 mg/kg) provided a dose-dependent protection against these pathophysiological alterations; the most pronounced protective effect was observed at the 0.3 mg/kg dose of the H2S donor; nevertheless, AP39 failed to achieve a complete normalization of any of the injury markers measured. The partial protective effects of AP39 correlated with a partial improvement of kidney histological scores and reduced TUNEL staining (an indicator of DNA damage and apoptosis). In summary, the mitochondria-targeted H2S donor AP39 exerted dose-dependent protective effects against renal epithelial cell injury in vitro and renal ischemia-reperfusion injury in vivo. We hypothesize that the beneficial actions of AP39 are related to the reduction of cellular oxidative stress, and subsequent attenuation of various positive feed-forward cycles of inflammatory and oxidative processes.

Neurorestorative effects of eugenol, a spice bioactive: Evidence in cell model and its efficacy as an intervention molecule to abrogate brain oxidative dysfunctions in the streptozotocin diabetic rat.

Eugenol (EU), an active principle of cloves, is also widely distributed in various other plants (eg. basil, cinnamon, etc). While its antioxidant and anti-inflammatory properties are well established, biochemical insights related to its neuromodulatory potential in diabetic conditions are not clear. In the present study, initially we investigated its potential to modulate specific biochemical responses in SHSY5Y cells under experimentally -induced hyperglycemic condition. Co-exposure of cells with EU (5-10 µM) not only enhanced the cell viability, but significantly offset glucose -associated oxidative stress (as evidenced by diminished levels of reactive oxygen species and hydroperoxides). Further EU enhanced the reduced glutathione (GSH) levels and also ameliorated the levels of 3 - nitrotyrosine and expression of HSP70. We subsequently examined its efficacy to attenuate biochemical aberrations in brain regions of a streptozotocin (STZ) diabetic rat employing an intervention approach. Brain regions of EU treated (10 mg/kg bw/d, post 6 weeks of STZ) diabetic rats showed diminished levels of oxidative markers and protein carbonyls in both cytosolic and mitochondrial fractions. EU treatment caused enhanced activities of enzymic antioxidants and diminished both GSH and total thiols. Further, activities of complex I - III, succinate dehydrogenase and citrate synthase in brain regions were also significantly restored. Interestingly, EU treatment differentially attenuated the elevated activity of acetylcholinesterase and levels of calcium in brain regions. Collectively, based on the data obtained in in vitro and in vivo models, we hypothesize that EU may be employed as an adjuvant therapeutic molecule to alleviate complications under diabetic conditions.