Antioxidant activity of gallic acid from rose flowers in senescence accelerated mice

Effect of Colla corii asini (E'jiao) on D-galactose induced aging mice

Colla corii asini (E'jiao), donkey-hide gelatin prepared by stewing and concentrating from Equus asinus L. donkey hide, is a traditional Chinese medicine preparation widely used in clinical hematic antanemic therapy in China. The aim of the present study was to investigate potential anti-aging effect of Colla corii asini and explore related mechanisms in D-galactose (gal) induced aging model mice. The mice were artificially induced aging by subcutaneously injection with D-gal at the dose of 100 mg/kg·d for 8 weeks. Colla corii asini was simultaneously treated to them once daily by intragastric gavage. Appetite, mental condition, body weight, and organ index were observed. Activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), as well as levels of malondialdehyde (MDA) in serum, brain, and liver were determined by according assay kits. Western blotting analysis was used to detect p16 and p21 expression. Results indicated that Colla corii asini could improve appetite, mental condition, body weight, and organ condition of model mice, improve SOD, CAT, and GSH-Px activities, reduce MDA levels, and modulate age-related genes expression in D-gal induced mice. Therefore, Colla corii asini may have effect to suppress the aging process through enhancing antioxidant activity, scavenging free radicals, and modulating aging-related gene expression.

Antiaging effect of dietary chitosan supplementation on glutathione-dependent antioxidant system in young and aged rats

Aging has been defined as the changes that occur in living organisms with the passage of time that lead to functional impairment and ultimately to death. Free radical-induced oxidative damage has long been thought to be the most important consequence of the aging process. In the present study, an attempt has been made to study the salubrious effects of dietary supplementation of chitosan on glutathione-dependent antioxidant defense system in young and aged rats. The dietary supplementation of chitosan significantly reduced the age-associated dyslipidemic abnormalities noted in the levels of total cholesterol, HDL-cholesterol, and LDL-cholesterol in plasma and heart tissue. Its administration significantly (P < 0.05) attenuated the oxidative stress in the heart tissue of aged rats through the counteraction of free radical formation by maintaining the enzymatic [glutathione peroxidase (GPx) and glutathione reductase (GR)] and non-enzymatic [reduced glutathione (GSH)] status at levels comparable to that of normal young rats. Our results conclude that dietary intake of chitosan restores the depleted myocardial antioxidant status and suggest that it could be an effective therapeutic agent in treatment of age-associated disorders where hypercholesterolemia and oxidative stress are the major causative factors.

The protective effect of resveratrol on islet insulin secretion and morphology in mice on a high-fat diet

The aim of this study was to investigate the effect of resveratrol on beta cells in male C57BL/6J mice fed a high-fat diet and the possible mechanisms. Male C57BL/6J mice were randomly divided into three groups: normal control (NC) group, high-fat diet (HF) group and high-fat diet and resveratrol treatment (HFR) group (15 in each group). HFR group was fed with high fat diet for 8 weeks and then orally administered resveratrol at 400mg/kg daily. Twenty-four weeks later, the function of insulin secretion in vivo and in vitro was improved robustly in HFR group compared with HF group. The levels of glucose and lipid metabolism, beta cell mass, lipid content, and oxidative stress were lower in HFR group than in HF group. Simultaneously, resveratrol administration promoted the expression of SIRT1 in islets, while the expression of uncoupling protein 2 (UCP2) was restrained. Resveratrol, as well, also had a beneficial effect on the ratios of expressions of Bcl-2/Bax and levels of malondialdehyde/glutathione peroxidase. Resveratrol can protect islets from abnormal insulin secretion and morphological changes induced by a high-fat diet. The effect might be partly related to activated SIRT1 signal pathway, improved oxidative stress induced damage and incidence of apoptosis.

Gallic acid induces the apoptosis of human osteosarcoma cells in vitro and in vivo via the regulation of mitogen-activated protein kinase pathways

To examine the antitumor effects of gallic acid (GA) on osteosarcoma, two human osteosarcoma cell lines U-2OS and MNNG/HOS were treated by GA and subjected to cell proliferation and apoptosis assays. In addition, MNNG/HOS xenograft tumors were established in nude BALB/c mice to evaluate the anticancer capacity of GA in vivo. The results showed that GA inhibited the proliferation and induced the apoptosis of osteosarcoma cells, accompanied by the upregulation of p-38 activation and the downregulation of c-Jun N-terminal kinase (JNK) and extracellular signal regulated kinase (ERK1/2) activation. Additionally, p38 MAPK inhibitor abrogated GA-induced growth inhibition of osteosarcoma cells, whereas JNK or ERK1/2 inhibitors sensitized osteosarcoma cells to GA-induced growth inhibition. In vivo studies further showed that GA administration decreased xenograft tumor growth in a dose-dependent manner. Immunohistochemistry analysis demonstrated the downregulation of PCNA and CD31 expression and upregulation of apoptosis in MNNG/HOS tumor tissues following GA treatment. This study demonstrates the antitumor efficacy of GA for osteosarcoma that is mediated by the modulation of cell proliferation, apoptosis, and angiogenesis. Our findings suggest that GA could be a potent agent for osteosarcoma intervention.

Protective role of gallic acid on sodium fluoride induced oxidative stress in rat brain

Gallic acid is known as a potent antioxidant active compound of the edible and medicinal plant Peltiphyllum peltatum. The main objective of this study was to evaluate the neuroprotective effects of gallic acid against sodium fluoride induced oxidative stress in rat brain. Gallic acid (10 and 20 mg/kg) and vitamin C (10 mg/kg) were intraperitoneally administrated for 1 week prior to sodium fluoride intoxication. After the treatment period, brain tissues were collected and homogenized, and antioxidant parameters were measured in the homogenates. The level of thiobarbituric acid reactive substances in sodium fluoride intoxicated rats (42.04 ± 2.14 nmol MDA eq/g tissue, p < 0.01 vs. normal) increased compared to the normal rats (35.99 ± 1.08 nmol MDA eq/g tissue). Pretreatment with gallic acid at 20 mg/kg was exhibited significant reduction in the thiobarbituric acid reactive substances level (37.06 ± 1.4 nmol MDA eq/g tissue, p > 0.05 vs. normal). This increasing in thiobarbituric acid reactive substances level was accompanied with a decrease in the level of reduced glutathione (6.74 ± 0.28 μg/mg of protein, p < 0.001 vs. normal), superoxide dismutase (53.24 ± 1.62 U/mg of protein, p < 0.001 vs. normal) and catalase (70.73 ± 2.94 μmol/min/mg of protein p < 0.001 vs. normal) activities in sodium fluoride intoxicated rat. Gallic acid at 20 mg/kg was significantly modified the level of reduced glutathione (11.02 ± 0.53 μg/mg of protein, p < 0.05 vs normal) and catalase activity (89.22 ± 3.67 μmol/min/mg of protein, p > 0.05 vs. normal) in rat brain. However, gallic acid at 20 mg/kg was significantly more effective in retrieving superoxide dismutase (124.78 ± 5.7 U/mg of protein) activity than vitamin C (115.5 ± 4.97 U/mg of protein).

Motor disorders and impaired electrical power of pallidal EEG improved by gallic acid in animal model of Parkinson's disease

The aim of this study was evaluation the effect of Gallic acid on movement disorders and pallidal electrical power in animal model of Parkinson's Disease (PD). PD is clinically characterized by development of motor disturbances, such as bradykinesia, resting tremors, rigidity and a later loss ofpostural reflexes. Oxidative stress is a hallmark factor where the oxidation of dopamine generates Reactive Oxygen Species (ROS) and an unbalanced production ROS induces neuronal damage, therefor leading the neuronal death. Gallic Acid (GA) and its derivatives are present in the plant kingdom and acts as a potent antioxidant. Wistar male rats divided into seven groups randomly with 8 in each. Animals in all groups except control received 8 microg/2 microL 6-hydroxydopamine dissolved in normal saline contains 0.01% ascorbate or vehicle in right Medial Forbrain Bundle (MFB) and a bipolar wire electrode was implanted in the left globus pallidus nucleus of all animals under stereotaxic surgery. Two weeks later PD was approved by contralateral rotation signs induced by apomorphine and then movements and electrical power of pallidal were evaluated. Motor functions and pallidal electrical power were impaired and GA could improve motor dysfunctions and gamma wave power in parkinsonian rats' significantly with higher dose of GA (200 mg kg(-1)). Present result showed that GA may act as a potent antioxidant and free radical scavenger to reverse motor disorders and pallidal gamma wave power after 6-OHDA neurotoxicity in brain.

Terminalia chebula extract acts as a potential NF-κB inhibitor in human lymphoblastic T cells

Terminalia chebula (TC) is native to southern Asia to southwestern China and is used in traditional medicine for the treatment of human ailments including malignant tumors and diabetes. This plant also has antibacterial and immunomodulatory properties. Nuclear factor kappa-light chain-enhancer of activated B cells (NF-κB) is responsible for the expression of numerous genes involved in cell survival, proliferation, angiogenesis, inflammation, invasion and metastasis, among other processes. This study aims to assess the NF-κB inhibitory effect of TC extract in human lymphoblastic T (Jurkat) cells. The effects of TC extract were investigated using the FRET-based Gene Blazer technique in transfected Jurkat-NF-κB-RE-bla cells. The concentration of TC extract required for NF-κB inhibition was determined by a cell proliferation assay. Treatment with TC extract (50 μg/mL) inhibited NF-κB activity and protected against IκBα degradation and strongly suppressed IκBα phosphorylation in Jurkat-NF-κB-RE-bla cells. This treatment might be crucial for inhibiting NF-κB translocation and activation. In addition, the TC extract downregulated certain NF-κB regulated genes, including IL-8 and MCP-1, in Jurkat-NF-κB-RE-bla cells. Moreover, gallic acid was identified from the TC extract demonstrating its ability to inhibit NF-κB activity in Jurkat-NF-κB-RE-bla cells. Further studies to identify the role of gallic acid in NF-κB inhibition may uncover the crucial antiinflammatory and antitumor properties of the TC extract.

Potent protection of gallic acid against DNA oxidation: results of human and animal experiments

Gallic acid (3,4,5-trihydroxybenzoic acid, GA) is a constituent of plant derived foods, beverages and herbal remedies. We investigated its DNA protective properties in a placebo controlled human intervention trial in single cell gel electrophoresis experiments. Supplementation of drinking water with GA (12.8 mg/person/d) for three days led to a significant reduction of DNA migration attributable to oxidised pyrimidines (endonuclease III sensitive sites) and oxidised purines (formamidopyrimidine glycosylase sensitive sites) in lymphocytes of healthy individuals by 75% and 64% respectively. Also DNA damage caused by treatment of the cells with reactive oxygen species (ROS) was reduced after GA consumption (by 41%). These effects were paralleled by an increase of the activities of antioxidant enzymes (superoxide dismutase, glutathione peroxidase and glutathion-S-transferase-π) and a decrease of intracellular ROS concentrations in lymphocytes, while no alterations of the total antioxidant capacity (TAC), of malondialdehyde levels in serum and of the urinary excretion of isoprostanes were found. Experiments with rats showed that GA reduces oxidatively damaged DNA in lymphocytes, liver, colon and lungs and protects these organs against γ-irradiation-induced strand breaks and formation of oxidatively damaged DNA-bases. Furthermore, the number of radiation-induced preneoplastic hepatic foci was decreased by 43% after oral administration of the phenolic. Since we did not find alterations of the TAC in plasma and lipid peroxidation of cell membranes but intracellular effects it is likely that the antioxidant properties of GA seen in vivo are not due to direct scavenging of radicals but rather to indirect mechanisms (e.g. protection against ROS via activation of transcription factors). As the amount of GA used in the intervention trial is similar to the daily intake in Middle Europe (18 mg/person/day), our findings indicate that it may contribute to prevention of formation of oxidatively damaged DNA in humans.

Gallic acid induces G2/M phase arrest of breast cancer cell MCF-7 through stabilization of p27(Kip1) attributed to disruption of p27(Kip1)/Skp2 complex

Gallic acid (GA), 3,4,5-trihydroxybenzoic acid, is a natural polyphenolic acid and widely found in gallnuts, tea leaves and various fruits. Previous studies have shown that GA possesses anti-inflammatory, antiallergic and anticarcinogenic activity. In the present study, we aim to investigate the antitumor effects of GA on breast cancer cell. Our results revealed that GA treatment significantly reduced the cell growth of human breast cancer cell MCF-7 in a dose-dependent manner. Further flow cytometric analysis showed that GA induced significant G2/M phase arrest but slightly affected the population of sub-G1MCF-7 cells. Therefore, levels of cyclins, cyclin-dependent kinases (CDKs), and their regulatory proteins involved in S-G2/M transition were investigated. Our findings revealed that levels of cyclin A, CDK2, cyclin B1 and cdc2/CDK1 were diminished; in contrast, levels of the negative regulators p27(Kip1) and p21(Cip1) were increased by GA treatment. Additionally, Skp2, a specific ubiquitin E3 ligase for polyubiquitination of p27(Kip1) was reduced by GA treatment. Further investigation showed that GA attenuated Skp2-p27(Kip1) association and diminished polyubiquitination of p27(Kip1) in MCF-7 cells. Moreover, knockdown of p27(Kip1) but not p21(Cip1) significantly alleviated GA-induced accumulation of G2/M phase. These findings indicate that GA may upregulate p27(Kip1) level via disruption of p27(Kip1)/Skp2 association and the consequent degradation of p27(Kip1) by proteosome, leading to G2/M phase arrest of MCF-7 cell. It is suggested that GA should be beneficial to treatment of breast cancer and p27(Kip1)-deficient carcinomas.

Protective effect of gallic acid against lindane induced toxicity in experimental rats

Lindane is an organochlorine pesticide that persists in the environment, bioaccumulate through food chain and has a risk of causing adverse effects to human health and the environment. It induces cell damage by producing free radicals and reactive oxygen species. The aim of the present study is to investigate the protective effect of gallic acid (a plant derived polyphenol) against lindane induced hepatic and renal toxicity in rats. Liver damage was assessed by hepatic serum marker enzymes like SGOT, SGPT and ALP and histopathological observation. Renal damage was observed by histopathological examination and serum markers like creatinine and urea. Treatment with lindane increased the levels of lipid peroxidation, serum marker enzyme activity with a concomitant decrease in GSH, CAT, SOD, GPx and GST. Histological alterations were also observed in kidney and liver tissue with lindane treatment. Co-treatment of gallic acid significantly prevented the lindane induced alterations in kidney and liver tissues with a decrease in LPO, serum marker enzyme activity and a significant increase in antioxidant levels. These results suggest that gallic acid has protective effect over lindane induced oxidative damage in rat liver and kidney.

Antioxidant potential and phenolic acid content of certain cucurbitaceous plants cultivated in Egypt

Many species belonging to Cucurbitaceae family have long been regarded as food, medicinal plants, or both. Preliminary phytochemical screening of Citrullus colocynthis L., Cucumis sativus L. and Momordica charantia L. herbs showed the presence of phenolic compounds. Quantitative analysis of total phenolic compounds using Folin-Ciocalteu reagent revealed the presence of 50.87 mg GAE g(-1), 56.58 mg GAE g(-1) and 42.36 mg GAE g(-1) in C. colocynthis L., C. sativus L. and M. charantia L. herbs, respectively. HPLC analysis of phenolic content showed the presence of chlorogenic acid (16.3 mg per 100g dry sample and 27.7 mg per 100 g(-1) dry samples in C. colocynthis L. and C. sativus L., respectively) and gallic acid (26.7 mg per 100 g dry sample) as a major phenolic acids in M. charantia L. herb. The antioxidant activity of the herb of plants under investigation was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and total antioxidant capacity was determined in terms of GAE. This study showed that C. sativus L. is the most active antioxidant, followed by C. colocynthis L., while M. charantia L. has the least antioxidant activity.

Antioxidant activity of oligosaccharide ester extracted from Polygala tenuifolia roots in senescence-accelerated mice

The constituents of the ethanol extract from the root of Polygala tenuifolia Willd. (Polygalaceae) were investigated for antioxidant activity in senescence-accelerated mice. Consequently, two relevant samples were obtained, a fraction separated by macroporous resin (YZ-OE), and a major pure crystal of 3,6'-disinapoyl sucrose (DISS). Based on HPLC-ESI-MS analysis, the most constituents in the YZ-OE fraction from the extract of P. tenuifolia were oligosaccharide esters. The antioxidant activities of these two samples were evaluated using the accelerated senescence-prone, short-lived mice (SAMP) in vivo. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were increased significantly in SAMP mice fed oligosaccharide esters (YZ-OE 50 mg/kg) and its constituents (DISS 50 mg/kg). However, the content of malondialdehyde (MDA) was increased in the blood and liver of SAMP mice. But when given YZ-OE, it could be decreased, by 44.3% and 47.5%, respectively, compared with the SAMP model. Results from the analyses indicated that the oligosaccharide esters (YZ-OE) from roots of P. tenuifolia had a high in vivo antioxidant activity.

Gallic acid inhibits the growth of HeLa cervical cancer cells via apoptosis and/or necrosis

Gallic acid (GA) is widely distributed in various plants and foods, and its various biological effects have been reported. Here, we evaluated the effects of GA on HeLa cells in relation to cell growth inhibition and death. HeLa cell growth was diminished with an IC(50) of approximately 80 microM GA at 24h whereas an IC(50) of GA in human umbilical vein endothelial cells (HUVEC) was approximately 400 microM. GA-induced apoptosis and/or necrosis in HeLa cells and HUVEC, which was accompanied by the loss of mitochondrial membrane potential (MMP; DeltaPsi(m)). The percentages of MMP (DeltaPsi(m)) loss cells and death cells were lower in HUVEC than HeLa cells. All the tested caspase inhibitors (pan-caspase, caspase-3, -8 or -9 inhibitor) significantly rescued HeLa cells from GA-induced cell death. GA increased reactive oxygen species (ROS) level and GSH (glutathione) depleted cell number in HeLa cells. Caspase inhibitors reduced GSH depleted cell number but not ROS level in GA-treated HeLa cells. In conclusion, GA inhibited the growth of HeLa cells and HUVEC via apoptosis and/or necrosis. The susceptibility of HeLa cells to GA was higher than that of HUVEC. GA-induced HeLa cell death was accompanied by ROS increase and GSH depletion.

A polysaccharopeptide complex and a condensed tannin with antioxidant activity from dried rose (Rosa rugosa) flowers

In this study, the fraction (P) from an aqueous extract of dried rose (Rosa rugosa) flowers was obtained by ethanol precipitation. P was chromatographed on DEAE-cellulose. The components retained on DEAE-cellulose were eluted with a linear gradient of 0–2 m NaCl solution. Two fractions, eluted at concentrations of 0.5 m NaCl and 1 m NaCl, respectively, were obtained. These two components were designated as P1 and P2, respectively. P1 was further purified using gel filtration on Sephadex G-200. P1 yielded two peaks, and the two components were designated as P1-a and P1-b, respectively. P1-a was a polysaccharide-peptide complex, and P1-b exhibited chemical properties of a condensed tannin as revealed by FTIR and NMR assay of carbohydrate and protein contents and HPLC-ESI-MS. The molecular masses of P1-a and P1-b were 150kDa and 8kDa, respectively. Both P1-a and P1-b possessed antioxidant activity, with the activity of P1-b higher than that of P1-a. This study demonstrated that different components from rose flowers exhibited antioxidant activity.

Gallic acid suppresses lipopolysaccharide-induced nuclear factor-kappaB signaling by preventing RelA acetylation in A549 lung cancer cells

Although multiple studies have revealed that gallic acid plays an important role in the inhibition of malignant transformation, cancer development, and inflammation, the molecular mechanism of gallic acid in inflammatory diseases is still unclear. In this study, we identified gallic acid from Rosa rugosa as a histone acetyltransferase (HAT) inhibitor with global specificity for the majority of HAT enzymes, but with no activity toward epigenetic enzymes including sirtuin (silent mating type information regulation 2 homologue) 1 (S. cerevisiae), histone deacetylase, and histone methyltransferase. Enzyme kinetic studies indicated that gallic acid uncompetitively inhibits p300/CBP-dependent HAT activities. We found that gallic acid inhibits p300-induced p65 acetylation, both in vitro and in vivo, increases the level of cytosolic IkappaBalpha, prevents lipopolysaccharide (LPS)-induced p65 translocation to the nucleus, and suppresses LPS-induced nuclear factor-kappaB activation in A549 lung cancer cells. We have also shown that gallic acid treatment inhibits the acetylation of p65 and the LPS-induced serum levels of interleukin-6 in vivo. Importantly, gallic acid generally inhibited inflammatory responses caused by other stimuli, including LPS, IFN-gamma, and interleukin-1beta, and further downregulated the expression of nuclear factor-kappaB-regulated antiapoptotic genes. These results show the crucial role of acetylation in the development of inflammatory diseases.

Stimulatory effect of components of rose flowers on catalytic activity and mRNA expression of superoxide dismutase and catalase in erythrocytes

In the present study, two antioxidant components (polysaccharopeptide complex P(1-a) and condensed tannin P(1-b)) from rose (Rosa rugosa) flowers were each incubated with mouse erythrocytes to investigate their effect on erythrocyte superoxide dismutase (SOD), and catalase (CAT) activities. It was found that the activities of Cu, Zn-SOD and CAT were markedly increased after incubation for 3h with rose flower fractions at the concentration of 500μg/ml. Similar changes were also observed in the erythrocyte gene expression of SOD and CAT. These results show that P(1-a) and P(1-b) are effective antioxidants that increase the activity and the gene expression of SOD and CAT in mouse erythrocytes.

Antioxidants from the Leaf Extract of Byrsonima Bucidaefolia

The radical scavenging assay-guided fractionation of the leaf extract of Byrsonima bucidaefolia Standl. yielded two metabolites with antioxidant activity, identified as methyl gallate (1) and methyl m-trigallate (2) on the basis of their spectroscopic data. Both 1 and 2 were identified as artifacts of the extraction and/or the purification process, possibly resulting from transesterification of precursor gallotannins. Evaluation of the antioxidant activity of both the isolated metabolites 1 and 2 and three of their derivatives (3-5), showed that 1 and 2 have a stronger antioxidant activity than vitamin C when tested using the DPPH reduction assay.

Purple sweet potato color attenuates oxidative stress and inflammatory response induced by d-galactose in mouse liver

The hepatoprotective effects of purple sweet potato color (PSPC), which is natural anthocyanin food colors, have been well demonstrated in many studies. Nevertheless, little work has been done to clarify the detailed mechanism of hepatoprotective effects of PSPC. This study was designed to explore whether PSPC protected mouse liver from d-gal-induced injury by attenuating oxidative stress or suppressing inflammation. The histology changes of mouse liver was assessed by hematoxylin and eosin staining. The results showed that PSPC could effectively suppress the d-gal-induced histology changes including structure damage and leucocyte infiltration in mouse liver. Oxidative stress and antioxidant status in mouse liver were also analysed. The results showed that PSPC could largely attenuate the d-gal-induced MDA increasing and could markedly renew the activities of Cu, Zn-SOD, CAT and GPx in the livers of d-gal-treated mice. Furthermore, the results of western blot analysis showed that PSPC could inhibit the upregulation of the expression of NF-kappaB p65, COX-2 and iNOS caused by d-gal. In conclusion, our data suggested that PSPC could protect the mouse liver from d-gal-induced injury by attenuating lipid peroxidation, renewing the activities of antioxidant enzymes and suppressing inflammatory response. This study provided novel insights into the mechanisms of PSPC in the protection of the liver.

Troxerutin protects the mouse kidney from d-galactose-caused injury through anti-inflammation and anti-oxidation

This study was carried out to investigate the protective effect of troxerutin against D-galactose (D-gal)-induced renal injury in mice. Hematoxylin and eosin (H&E) stained sections of kidneys revealed D-gal could cause renal injury and troxerutin could significantly attenuate the injury. We further investigated the mechanisms involved in the protective effects of troxerutin on mouse kidney. The following antioxidant defense enzymes were measured: cytosolic Cu/Zn superoxide dismutase (SOD-1), catalase (CAT) and glutathione peroxidase (GPx). The content of the lipid peroxidation product malondialdehyde (MDA) was also analyzed. In D-gal-treated mice, antioxidant enzymes activities were significantly decreased and the level of MDA was significantly higher than those in the vehicle controls. Our results indicated that the protective effect of troxerutin against D-gal induced renal injury might be caused, at least in part, by increasing the activity of antioxidant enzymes with a reduction in lipid peroxidation product. Furthermore, we also examined the inflammatory signal mediators of nuclear factor-kappaB (NF-kappaB), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and prostanoid receptor subtype EP2 by Western blot. After treatment with D-gal, the NF-kappaB p65, iNOS, COX-2 and EP2 were markedly upregulated. Upon co-treatment with the troxerutin, however, the expressions of the NF-kappaB p65, iNOS, COX-2 and EP2 markedly reduced, compared to D-gal treatment alone. These results indicated that troxerutin has significantly inhibitory effects on the NF-kappaB-mediated inflammatory response. These findings suggest troxerutin could attenuate renal injury induced by D-gal probably through its antioxidant and anti-inflammation properties.

Antiproliferative potential of gallic acid against diethylnitrosamine-induced rat hepatocellular carcinoma

One of the focuses in current cancer chemoprevention studies is the search for nontoxic chemopreventive agents that inhibit the initiation of malignant transformation. Cancer biomarkers are quantifiable molecules involved in the physiologic or pathologic events occurring between exposure to carcinogens and the development, progression of cancer. Biomarkers may be the consequence of a continuous process, such as increased cell mass, or a discrete event, such as genetic mutation. Analysis of tumor markers can be used as an indicator of tumor response to therapy. Gallic acid is a naturally available polyphenol, possess strong antioxidant activity with a capacity to inhibit the formation of tumors in several cancer models. In the present study, we investigated the antiproliferative effect of gallic acid during diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC) in male wistar albino rats. DEN treatment resulted in increased levels of aspartate transaminase, alanine transaminase, alkaline phosphatase, acid phosphatase, lactate dehydrogenase, gamma-glutamyltransferase, 5'-nucleotidase, bilirubin, alpha-fetoprotein, carcinoembryonic antigen, argyophillic nucleolar organizing regions, and proliferating cell nuclear antigen. Gallic acid treatment significantly attenuated these alterations and decreased the levels of AgNORs and PCNA. These finding suggests that gallic acid is a potent antiproliferative agent against DEN-induced HCC.

Beneficial effects of nicotinamide on alcohol-induced liver injury in senescence-accelerated mice

The deleterious effects of ethanol in senescence-accelerated prone 8 mice (SAMP8) and the protective role of nicotinamide (NAM) against ethanol-induced liver injury were examined. The mice were orally administered 2 g ethanol/kg BW and 200 mg or 500 mg NAM/kg BW three times/week for 10 weeks. Results showed that ethanol elevated activity of alanine aminotransferase (ALT) significantly. Ethanol also enhanced the formation of malondialdehyde (MDA) and protein carbonyls in the liver, whereas ethanol treatment resulted in significantly lower activity of hepatic glutathione peroxidase (GPx), catalase and superoxide dismutase (SOD). Hematoxylin and eosin staining indicated moderate to severe fatty infiltration but not fibrosis. Administration of high NAM (500 mg/kg BW) led to markedly decreased levels of hepatic MDA, protein carbonyls, fatty infiltration and the activity of ALT, and increased activity of GPx, catalase and SOD in the ethanol-fed group. Thus, using SAMP8 as animal model for ethanol-induced liver injury in the aged mice, this study demonstrates that NAM is effective in protecting such damage.

Anti-ageing effect of a lactococcal strain: analysis using senescence-accelerated mice

The effects of oral administration of a lactococcal strain on physiological changes associated with ageing were investigated using senescence-accelerated mice (SAM). SAM develop normally, but then show an early onset and irreversible advancement of senescence. SAMP6 is a SAM strain that develops osteoporosis with ageing. Oral administration of heat-killedLactococcus lactissubsp.cremorisH61 (strain H61) to aged SAMP6 mice was associated with reduced bone density loss, a suppression of incidence of skin ulcers and reduced hair loss, compared with controls. Spleen cells from mice fed strain H61 produced more interferon-γ and IL-12 than those from control mice, suggesting that administration of strain H61 altered immune responses. The numbers of viable cells ofBifidobacteriumsp.,Bacteroidessp. andEnterococcussp. in faeces were similar for mice fed the strain H61 and control diets, but counts forStaphylococcussp. were significantly lower (P < 0·05) in mice fed strain H61. Mice fed strain H61 had similar serum concentrations of thiobarbituric acid-reactive substances as in controls, indicating a lack of effect on lipid peroxidation status. Administration of living cells of strain H61 or fermented milk containing strain H61 was also associated with a suppression of incidence of skin ulcers and reduced hair loss. These results indicate that oral administration of strain H61 has the potential to suppress some of the manifestations associated with ageing.

A polysaccharide-peptide complex from abalone mushroom (Pleurotus abalonus) fruiting bodies increases activities and gene expression of antioxidant enzymes and reduces lipid peroxidation in senescence-accelerated mice

The antioxidant effects of a polysaccharide-peptide complex (F22) from mushroom (Pleurotus abalonus)-fruiting bodies were studied. The activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in the liver, kidney, and brain of senescence-accelerated mice showed a marked increase after treatment with the polysaccharide-peptide complex. Concurrently, the gene expression levels of SOD, CAT, and GPx, as determined with real-time polymerase chain reaction, were up-regulated in the liver, kidney, and brain, whereas the MDA content in these organs declined. The maximal lifespan of the mice was prolonged.

Quercetin reverses D-galactose induced neurotoxicity in mouse brain

We assessed the neuroprotective effects of quercetin-feeding at doses of 5 and 10 mg/(kg day) on Kunming mice injected daily with D-gal (50 mg/(kg day)) by behavioral tests. Quercetin-fed mice showed higher activity upon induction by new environmental stimuli, lower anxiety and higher novelty-seeking behavior in the open field tasks, and significantly improved learning and memory ability in step-through and Morris water Maze tests compared with D-gal-treated mice. We further investigated the mechanisms involved in the neuroprotective effects of quercetin on mouse brain. Quercetin significantly increased superoxide dismutase (SOD) activity and decreased the malondialdehyde (MDA) level. These results imply that quercetin can reverse oxidant impairment induced by D-gal in mouse brain. Neurotoxicity is also associated with Ca(2+) overload induced by oxidant stress. Quercetin could maintain the Ca(2+) homeostasis in the brain of D-gal-treated mice. Furthermore, we also examined the expression of growth-associated protein GAP43 mRNA in mouse brain by in situ hybridization. We found that quercetin dramatically elevated the GAP43 mRNA expression in the brain of D-gal-treated mice to regenerate normal function of neurons against the cellular injury caused by D-gal.

Gallic acid inhibits ribonucleotide reductase and cyclooxygenases in human HL-60 promyelocytic leukemia cells

Gallic acid (GA) is a naturally occurring polyhydroxyphenolic compound and an excellent free radical scavenger. In this study, we examined its cytotoxic and biochemical effects on the human HL-60 promyelocytic leukemia cell line. GA caused a significant imbalance of deoxynucleosidetriphosphate (dNTP) pool sizes, indicating ribonucleotide reductase inhibition. Moreover, GA induced dose-dependent apoptosis in HL-60 cells (80microM GA led to the induction of apoptosis in 39% of cells) and attenuated progression from G0/G1 to the S phase of the cell cycle (60microM GA doubled the number of cells in G0/G1 phase from 22 to 44% when compared to untreated controls). We further determined IC(50) values of 3.5 and 4.4nM for the inhibition of cyclooxygenases I and II, respectively. When cells were simultaneously treated with GA and trimidox, another inhibitor of RR, highly synergistic growth inhibitory effects could be observed. Taken together, we identified novel biochemical effects of GA which could be the basis for further preclinical and in vivo studies.