An insight on 7- ketocholesterol mediated inflammation in atherosclerosis and potential therapeutics.

7-ketocholesterol, a toxic oxidative product of oxysterol is a causative agent of several diseases and disabilities concomitant to aging including cardiovascular diseases like atherosclerosis. Auto-oxidation of cholesterol esters present in low-density lipoprotein (LDL) deposits lead to the formation of oxidized LDL (Ox-LDL) along with its byproducts, namely 7KCh. It is predominantly found in atherosclerotic plaque and also found to be more atherogenic than cholesterol by being cytotoxic, interfering with cellular homeostasis. This makes it a serious threat by being the foremost cause of morbidity and mortality worldwide and is likely to become more serious during forth coming years. It involves in mediating inflammatory mechanisms characterized by the advancement of fibroatheroma plaques. The atherosclerotic lesion is composed of Ox-LDL along with fibrotic mass consisting of immune cells and molecules. Macrophages being the specialized phagocytic cells, contribute to removal of detrimental contents of the lesion along with accumulated lipids leading to alteration of its biology and functionality due to its plasticity. Here, we have explored the known as well as proposed mechanisms involved with 7KCh associated atherogenesis along with potential therapeutic strategies for targeting 7KCh as a diagnostic and target in medicine.

A focus on resveratrol and ocular problems, especially cataract: From chemistry to medical uses and clinical relevance.

Low vision and blindness are important health problems that affect millions of people throughout the world. The most common and important pathologies are diabetic retinopathy, age-related macular degeneration, glaucoma as well as cataracts. The latter consists of an opacification of the lens of the eye which impedes the passage of light and represents one of the most important causes of vision loss. Among the risk factors for cataract development, there are life-style factors such as the use of tobacco, abuse of alcohol and unhealthy diet. In light of this, dietary components that possess anti-oxidant activity, such as polyphenols for instance, can be considered good candidates for human studies in the prevention and or treatment of such diseases. Among dietary components, the antioxidant capacity of certain polyphenols is well known, and these could be good candidates. In this review we focus our attention on the current scientific literature regarding to the effects of resveratrol on cataracts and other ocular diseases, along with its potential mechanism/s of action. A large number of preclinical studies support the involvement of resveratrol in clinical trials for the prevention and treatment of eye diseases induced by oxidative stress and inflammation, such as age-related cataract.

Cytoprotective mechanism of action of curcumin against cataract.

This review discusses the relationship between oxidative stress and cataract formation, molecular mechanism of curcumin action and potential benefits of treatment with the antioxidant curcumin. The first section deals with curcumin and endogenous antioxidants. The second section focuses on the action of curcumin on lipid peroxidation. Calcium homeostasis and curcumin will be discussed in the third section. The fourth section discusses the role of crystallin proteins that are responsible for maintaining lens transparency and the role of curcumin in regulating crystallin expression. The interaction of curcumin with transcription factors will be dealt in the fifth section. The final section will focus on the effect of curcumin on aldose reductase, which is associated with hyperglycemia and cataract. One of the strongest antioxidants is curcumin which has been shown to be very effective against cataract. This compound is better than other antioxidants in preventing cataract but its limited bioavailability can be addressed by employing nanotechnology.

Zeaxanthin and ocular health, from bench to bedside.

Cataracts, glaucoma, and age-related macular degeneration are known as major ocular problems which cause blindness among the elderly population worldwide. Oxidative stress plays an important role in both the initiation and progression of ocular problems and with respect to this; dietary antioxidants can serve as a therapeutic strategy for the improvement of ocular health. Zeaxanthin is known as one of the most important and common xanthophyll carotenoids, possessing multiple therapeutic effects such as strong antioxidant and pro-oxidant behaviour as well as anti-inflammatory effects. A growing body of literature shows that zeaxanthin mitigates ocular problems and suppresses oxidative stress in the retinal tissues. This paper aims to critically review the available literature regarding the beneficial effects of zeaxanthin on ocular problems with emphasis on its chemistry, bioavailability, and sources.

Epigallocatechin gallate attenuates fibroblast proliferation and excessive collagen production by effectively intervening TGF-ß1 signalling.

Pulmonary fibrosis (PF) poses a huge burden to the patients and society due to lack of an effective treatment drug. Activation of fibrocyte, fibroblast and myofibroblasts are important steps in the development of PF. Targeting this common pathway with natural chemicals may lead to the development of new drug regimens for PF treatment. In this study, PF was induced in male Wistar rats by intratracheal administration of Bleomycin (BLM). Epigallocatechin gallate (EGCG) was administered to one of the groups of rats to test its efficacy against the development of PF. Bleomycin-induction resulted in significant elevation of matrix metalloproteinase (MMP)-2 and -9 expression, increased RNA and protein expression of transforming growth factor (TGF)-ß1, Smads and alpha-smooth muscle actin (α-SMA). EGCG treatment normalized the BLM induced aberrations in these rats. The protective role of EGCG was also validated in vitro using the WI-38 fibroblast cell line. TGF-ß1 incubated cells exhibited increased fibroblast proliferation and hydroxyproline levels with a concomitant decrease in the expression of MMPs 2 and 9. An increase in protein expression levels of p-Smad, α-SMA and type I collagen (COL1A) was also exhibited by fibroblasts upon TGF-ß1 incubation. Simultaneous treatment of EGCG to WI-38 cells significantly decreased these protein expressions alongside normalizing the MMPs expression. The study revealed that EGCG inhibited fibroblast activation and collagen accumulation by inhibiting TGF-ß1 signalling and thus can be considered as an effective drug against PF.

Analysis on the arcelin expression in bruchid pest resistant wild pulses using real time RT-qPCR.

Arcelin, the antimetabolic protein from wild pulses is a known natural insecticidal molecule. Wild pulses with high arcelin content could serve as potential source to. increase the levels of insect resistance in cultivated pulse crops. In this study, arcelin (Arl) gene expression was screened in seven stored product insect pest resistant wild pulse varieties using real time RT-qPCR. Arcelin gene specific real time PCR primers were synthesized from arcelin mRNA sequence of the wild pulse variety, Lablab purpureus. The results revealed different levels of arcelin gene expression in the tested varieties. Canavalia virosa registered significantly high content indicating its suitability for utilization of arcelin gene in developing stored product insect pest resistance with other cultivated pulses.

Immuno-suppressive effects of aqueous extract of soapnut Sapindus emarginatus on the larvae and pupae of vector mosquito, Aedes aegypti.

We recently reported the presence of potent anti-mosquito activity in aqueous kernel extract of the soapnut, Sapindus emarginatus, and demonstrated its impact on marker enzymes in larvae and pupae of the vector mosquito, Aedes aegypti. As a sequel to these findings, the present study elucidates immunotoxicity of this extract with respect to hemocyte-mediated cellular immune responses in fourth instar larvae and pupae as well as cuticular melanization reaction in the larvae of A. aegypti. The exposure of these two developmental stages of the mosquito to the soapnut extract at a lethal threshold concentration neither affected hemocyte viability tested up to 3h in vitro nor did it influence the hemocyte count. By contrast, exposure of the mosquito larvae and pupae to this extract significantly reduced the ability of their hemocytes to bind yeast cells, an important early event in the process of non-self recognition by immune cells. Consequently, the phagocytic activity of these hemocytes against yeast cells was also found to be adversely affected upon exposure of larvae and pupae to the extract. Besides, a perceptible initial delay in melanization reaction at the injured site of the cuticle in the extract-exposed larvae was observed. All these findings demonstrate, for the first time, the immuno-suppressive potential of a botanical biocide in the vector mosquito.

Ameliorative effects of curcumin against renal injuries mediated by inducible nitric oxide synthase and nuclear factor kappa B during gentamicin-induced toxicity in Wistar rats.

The ameliorative role of curcumin in attenuating gentamicin-induced nephrotoxicity has been reported earlier however, the mechanism of action remains unclear. Gentamicin was injected intraperitoneally (100 mg/kg body weight) once daily for 6 days. Curcumin was administered orally (200 mg/kg body weight) once daily for 7, 15 and 30 days. Gentamicin-induced rats showed significant increase in the levels of kidney markers and the activities of urinary marker enzymes, which was reversed upon curcumin treatment. A significant increase in kidney lipid peroxidation (LPO) and decrease in activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and reduced glutathione (GSH) were observed in gentamicin-induced rats. Immunohistochemical, Western blot and RT-PCR studies in gentamicin-induced rats also demonstrated an increase in the levels of inducible nitric oxide synthase (iNOS) and nuclear factor-κB (NF-κB). All these effects induced by gentamicin were reduced upon treatment with curcumin in a time dependent manner. To conclude, curcumin enhances antioxidants, and decreases iNOS and NF-κB, thereby protecting the cells against oxidative stress induced by gentamicin.

Effects of extract of soapnut Sapindus emarginatus on esterases and phosphatases of the vector mosquito, Aedes aegypti (Diptera: Culicidae).

Our earlier investigations with kernels from the soapnut Sapindus emarginatus revealed it as a new source of botanical biocide with potent antimosquito activity, as evident from the proven unique ability of the aqueous kernel extract to kill all the developmental stages of three important vector mosquito species, Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. This extract was also found to be safe for two non-target aquatic insects. As a sequel to these findings, we have further examined quantitative and qualitative changes in total proteins, esterases, and phosphatases in whole body homogenates of fourth instar larvae and pupae of A. aegypti exposed to this extract at an appropriate threshold time for its lethal effect to gain insights into the impact of the botanical biocide on biochemical characteristics of the target vector mosquito at two distinct developmental stages. The profiles of proteins, esterases (acetylcholinesterse, α- and ß-carboxylesterases), and phosphatases (acid and alkaline) exhibited distinct patterns of variation during normal development of fourth instar larvae and pupae, indicating intrinsic difference in biochemical features between these two developmental stages of A. aegypti. Upon exposure of the larvae to the extract, significant reduction in the activities of acetylcholinesterse, ß-carboxylesterase, and acid phosphatases were recorded, whereas the total proteins, α-carboxylesterase and alkaline phosphatase activities were unaffected. By contrast, only alkaline phosphatase activity was significantly affected in pupae exposed to the extract. Analysis of these enzymes in native PAGE revealed that they exist in isoforms in both the larvae and pupae. The alterations in the levels of enzymatic activities observed from the quantitative assays of various enzymes were reflected by the respective zymograms with perceptible differences in the intensity and the number of bands detected especially with ß-carboxylesterase, acid and alkaline phosphatase activity between the control and exposed test organisms. Despite the fact that the soapnut kernel extract causes mortality of both the larvae and pupae of A. aegypti, the findings of this study demonstrate that the impact of this extract is most pronounced in various enzyme profiles of the larvae rather than the pupae. Such discrepancy implicates the presence of unique biochemical mechanisms in the pupae of mosquito for detoxification of botanical biocides.

1, 2 di-substituted idopyranose from Vitex negundo L. protects against streptozotocin-induced diabetes by inhibiting nuclear factor-kappa B and inducible nitric oxide synthase expression.

The aim of this study is to investigate the mechanism of an action of compound isolated from Vitex negundo in streptozotocin-induced diabetic mice. Light microscopic examination of liver, kidney and pancreatic sections of streptozotocin-induced diabetic mice showed changes like coarsening of acinar cells of endoplasmic reticulum, destruction of ß-cells, and alteration in their secretory function were observed in the pancreas. Changes like dilation of vein, unusual concentric arrangement of hepatocytes, and liver fibrosis were observed in the liver. Thickening of tubules and expansion of glomerulus were observed in kidneys. All these altered parameters were reversed close to normal condition upon treatment using idopyranose. The results show the antidiabetic potential of idopyranose. Interestingly, liver, kidney, and pancreatic sections of diabetic mice fed with the isolated 1, 2 di-substituted idopyranose showed regeneration of hepatocytes, nephrocytes, as well as ß-cells and acinar region appeared normal with increased numbers of ß-cells. To understand the probable mechanism of action of 1, 2 di-substituted idopyranose, we analyzed proinflammatory inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-κB) expression by immunohistochemistry and the results showed an increased iNOS and NF-κB levels in streptozotocin-induced diabetic liver, kidney and pancreas. Such high iNOS and NF-κB levels were inhibited in 1, 2 di-substituted idopyranose treated mice. The results suggest that 1, 2 di-substituted idopyranose helps in the protection of hepatocytes, nephrocytes and pancreatic ß-cells probably by its action against NF-κB and iNOS mediated inflammation in streptozotocin-induced diabetes.

Curcumin protects against hepatic and renal injuries mediated by inducible nitric oxide synthase during selenium-induced toxicity in Wistar rats.

The aim of this study is to evaluate the effect of curcumin in protecting against selenium-induced toxicity in liver and kidney of Wistar rats. Light microscopy evaluation of selenium alone administered rats showed liver to be infiltrated with mononuclear cells, vacuolation, necrosis, and pronounced degeneration. Control liver sections showed a regular morphology of parenchymal cells with intact hepatocytes and sinusoids. Kidney from selenium alone administered rats showed vacuolar degeneration changes in the epithelial cells, cellular proliferation with fibrosis, thickening of capillary walls, and glomerular tuft atrophy. Such changes were also observed in rats administered with selenium and curcumin simultaneously and rats administered first with selenium and then curcumin 24 h later. Interestingly, such degenerative changes observed in liver and kidney induced by selenium were not seen in rats that were administered with curcumin first and selenium 24 h later. This clearly suggests the protective nature of curcumin against selenium toxicity. To understand the probable mechanism of action of curcumin, we analyzed inducible nitric oxide synthase (iNOS) expression by immunohistochemistry, and the results showed an increased iNOS expression in selenium-alone induced liver and kidney. Such high iNOS levels were inhibited in liver and kidney of rats pretreated with curcumin and then with selenium 24 h later. Based on the histological results, it can be concluded that curcumin functions as a protective agent against selenium-induced toxicity in liver as well as kidney, and this action is probably by the regulatory role of curcumin on iNOS expression.

Antimosquito activity of aqueous kernel extract of soapnut Sapindus emarginatus: impact on various developmental stages of three vector mosquito species and nontarget aquatic insects.

Aqueous (physiological saline) extracts of seed kernel from seven indigenous plants were initially screened for their antimosquito activity against eggs, larvae of all instars, and pupae of Aedes aegypti. Among various seed kernels tested, the soapnut Sapindus emarginatus (Sapindaceae) extract was found to exhibit, for the first time, a strong antimosquito activity as evident from its ability to inflict 100% mortality of all the developmental stages of A. aegypti. Furthermore, the kernel extract of S. emarginatus also exerted ovicidal, larvicidal, and pupicidal activity against two other important vector mosquitoes, namely, Anopheles stephensi and Culex quinquefasciatus. Differential susceptibility of the various developmental stages of the three mosquito species exposed to soapnut extract was also noticed. The kernel extract was found to be safe for two nontarget aquatic insects tested: the larvae of Chironomus costatus and the nymphs of Diplonychus rusticus. Lethal concentration values of soapnut extract to these nontarget insects were always threefold or fivefold higher than those that produced 100% mortality of the larvae of the three mosquito species examined. The findings of this study clearly demonstrate that the aqueous kernel extract of S. emarginatus has potent antimosquito activity detectable against all the developmental stages of three important vector mosquito species as well as it is safe for nontarget aquatic organisms, and thus this new botanical resource could be used as an eco-friendly alternative biocidal agent in control of mosquitoes.

Effect of black tea on histological and immunohistochemical changes in pancreatic tissues of normal and streptozotocin-induced diabetic mice (Mus musculus).

The aim of the present study is to evaluate the effect of hot water extract of black tea in regenerating beta cells in streptozotocin-induced diabetic mice. Light microscopic examination of pancreatic sections of streptozotocin-induced diabetic mice showed the acinar cells to be small, shrunken, and with deteriorated beta cells. The dose of streptozotocin not only altered the function of beta cells but also damaged the acinar region. The changes in acinar cells were coarsening of endoplasmic reticulation suggesting alteration in their secretory function. The control pancreatic tissue showed well-defined granulated islets and dark beta cells when stained with chrome hematoxylin and phloxine. Interestingly, pancreatic sections of diabetic mice fed with black-tea extract showed regeneration of beta cells and acinar region appeared normal with increased numbers of beta cells. To understand the probable mechanism of action of black-tea extract, we analyzed inducible nitric oxide synthase (iNOS) expression by immunohistochemistry and the results showed an increased iNOS levels in streptozotocin-induced diabetic pancreas, and such high iNOS levels were inhibited in black-tea extract treated mice. According to histological results obtained, it can be concluded that the black-tea extract helps in regeneration of damaged pancreas and protects pancreatic beta cells by its antioxidant action against nitrosative stress in streptozotocin-induced diabetes.

Diallyl sulfide enhances antioxidants and inhibits inflammation through the activation of Nrf2 against gentamicin-induced nephrotoxicity in Wistar rats.

The protective role of diallyl sulfide (DAS) in attenuating gentamicin-induced nephrotoxicity has been reported earlier. However, the mechanism of induction of antioxidants by DAS in nephrotoxicity remains elusive. This study is aimed to elucidate the role of a transcription factor, Nuclear factor E2-related factor 2 (Nrf2) in inducing antioxidants and phase II enzymes during gentamicin toxicity in Wistar rats. DAS was administered intraperitoneally at a dosage of 150 mg/kg body weight once daily for 6 days. Gentamicin was administered intraperitoneally at a dosage of 100 mg/kg body weight, once daily for 6 days. Gentamicin-induced rats showed a significant increase in the levels of kidney markers and the activities of urinary marker enzymes, which was reversed upon treatment with DAS. A significant increase in kidney myeloperoxidase (MPO) and lipid peroxidation (LPO) levels was observed in gentamicin-induced rats, which was reduced upon treatment with DAS. Gentamicin-induced rats also showed a significant decrease in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST) and quinone reductase (QR) in rat kidney, which was increased upon treatment with DAS. Immunohistochemical studies in gentamicin-induced rats demonstrated a marked increase in the immunoreactivity of inducible nitric oxide synthase (iNOS), nuclear transcription factor (NF-kappaB) and tumor necrosis factor alpha (TNF-alpha) that were reduced after treatment with DAS. Further, the involvement of Nrf2 in antioxidant induction was analyzed by Western blot and immunofluorescence. To conclude, DAS enhances antioxidants and suppresses inflammatory cytokines through the activation of Nrf2, thereby protecting the cell against oxidative stress induced by gentamicin.

Agglutinin-mediated phagocytosis-associated generation of superoxide anion and nitric oxide by the hemocytes of the giant freshwater prawn Macrobrachium rosenbergii.

Hemocyte mediated phagocytosis is one of the vital components of innate defence mechanisms in crustaceans and this phagocytic process is aided by serum agglutinins. However, literature on agglutinin mediated opsono-phagocytosis is unclear in the case of Macrobrachium rosenbergii hemocytes. Further, very few studies in the case of superoxide anion generation and none with regard to nitric oxide generation during phagocytosis exist among crustaceans. We investigated the occurrence of agglutinins in the serum and the role of serum agglutinins in mediating phagocytosis by the hemocytes. We show that the prawn serum possesses agglutinins that function as opsonins during phagocytosis of HB RBC by the hemocytes. Hemagglutination-inhibition assays revealed the specificity of serum agglutinins for N-acetylated hexoses, namely GalNAc, GlcNAc and ManNAc, with a higher affinity for ManNAc. In addition, ManNAc was able to inhibit the phagocytic response (by about 60%) of the hemocytes against serum pretreated HB RBC, wherein the serum was previously treated with ManNAc. We next investigated the ability of the hemocytes to generate superoxide anion and nitric oxide during HB RBC phagocytosis and results show generation of both these free radicals. In addition, there was an enhancement in generation (75% increase) of these free radicals during agglutinin mediated opsonophagocytosis, when compared to buffer treated targets and interestingly this enhanced generation was inhibited by ManNAc (27% for superoxide anion and 36% for nitric oxide), an inhibitory sugar for phagocytosis. Inhibition of phagocytosis induced superoxide anion generation by DPI (53%), sodium azide (56%) and tropolone (61%), reveals the possible involvement of NADPH-oxidases, peroxidases and probably phenoloxidases, respectively, in the generation of superoxide anion. Similarly, decrease in nitric oxide generation in the presence of l-NIO (47%) during phagocytosis lends support to the role of nitric oxide generation during cellular immune processes. These findings thus suggest a role for superoxide anion and nitric oxide in the innate defense mechanism, namely phagocytosis, in Macrobrachium rosenbergii.

In vitro generation of superoxide anion by the hemocytes of Macrobrachium rosenbergii: possible mechanism and pathways.

The hemocytes from the giant freshwater prawn Macrobrachium rosenbergii were examined for their ability to generate superoxide anion (O(2) (-)) in vitro upon exposure to various components derived from microbial cell wall components. Among the test molecules, laminarin (a polymer of beta-1, 3 glucans), mannan and LPS from five different bacterial species produced a differential response in terms of stimulated O(2) (-) production in prawn hemocytes, suggesting the ability of the hemocytes to differentiate non-self. This response was almost completely inhibited by superoxide dismutase (SOD) suggesting SOD-inhibitable O(2) (-) generation by prawn hemocytes. Phorbol 12-myristate 13-acetate (PMA) and Ca ionophore led to enhanced O(2) (-) generation by the hemocytes and this suggests the possible role of protein kinase C and Ca(2+) ions in such generation. Cytochemical analysis using nitroblue tetrazolium (NBT)-staining revealed the importance of granular hemocytes in O(2) (-) generation in these prawns. Inhibition of O(2) (-) generation by inhibitors of NADPH-oxidase and phenoloxidase pathways clearly reveal the involvement of two different pathways in non-self stimulated O(2) (-) generation by the prawn hemocytes. These findings demonstrate the importance of O(2) (-) generation and role of possible pathways in hemocyte mediated cellular immune response of a crustacean.

Isolation and characterization of an acetyl group-recognizing agglutinin from the serum of the Indian white shrimp Fenneropenaeus indicus.

A natural agglutinin from the serum of the Indian white shrimp Fenneropenaeus (Penaeus) indicus was purified to electrophoretic homogeneity by a single-step affinity chromatography on N-acetylglucosamine-Sepharose 6B. The expression of hemagglutinating (HA) activity of F. indicus agglutinin (FIA) was independent of the presence of divalent cations and insensitive to their chelators. FIA gave a single symmetrical peak in its native form with a molecular mass estimate of 200 kDa on gel filtration in HPLC, and SDS-PAGE under reducing conditions revealed that it is a homo-oligomer of a 27-kDa subunit protein. The pattern of reactivity of FIA against anti-FIA rabbit serum in immunodiffusion and immunoelectrophoretic analysis provided additional evidence for its purity and homogeneity. HA-inhibition studies documented exclusive specificity of FIA for acetyl groups in carbohydrates independently of the presence of these groups at the C-2 or C-5 position and its stereochemical arrangement in the axial or equatorial orientation. The unique ability of FIA to recognize acetyl groups was also explicitly demonstrated with sialo- and asialo-glycoproteins. Strikingly, FIA also interacted equally with amino acids and chemicals containing acetyl groups, thereby unambiguously demonstrating the exquisite specificity of FIA for an acetyl group, irrespective of the presence of this group in carbohydrate or noncarbohydrate ligands. The susceptibility of HA activity of FIA to inhibition by lipopolysaccharides from diverse gram-negative bacteria as well as its ability to selectively agglutinate several bacterial species isolated from infected shrimps implicate a potential role of this humoral agglutinin of F. indicus in the host immunodefense reactions against microbial invaders.