Farnesol quells oxidative stress, reactive gliosis and inflammation during acrylamide-induced neurotoxicity: Behavioral and biochemical evidence

Acrylamide (ACR) is an industrial pollutant, to which humans are exposed through chemicals associated with day to day human life and contributes to neurological disorders. The role of reactive gliosis upon toxic insults remains paradoxical, and the immunomodulatory events during ACR intoxication remain obscure. In view of this, the present study investigated ACR-induced (20mg/kgb.wt for 4weeks) neurodegeneration in the context of oxidative stress and associated inflammatory events and the ability of farnesol, a sesquiterpene, to mitigate reactive gliosis in the brain of Swiss albino mice. Farnesol supplementation (100mg/kgb.wt.) showed a marked improvement in gait performance, neuromuscular function and fine motor coordination and attenuated ACR-induced diminution in glutathione (GSH) with parallel reduction in lipid peroxidation (LPO), protein carbonyls, hydroxide, hydroperoxide and nitrite levels. Farnesol treatment significantly ameliorated ACR-mediated histological aberrations and reactive gliosis by downregulating Glial fibrillary acidic protein (GFAP) and Ionizsed calcium-binding adapter molecule-1 ​(Iba-1) in the cortex, hippocampus and striatum. Further, ACR stimulated increase in levels of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β) and inducible form of nitric oxide synthase (iNOS) were considerably decreased by farnesol. In conclusion, our findings indicate that farnesol exerts neuroprotective efficacy during ACR-induced neuropathology by suppressing reactive gliosis and associated inflammatory events.

XIAP inhibitor and antiestrogen embelin abrogates metastasis and augments apoptosis in estrogen receptor positive human breast adenocarcinoma cell line MCF-7

Tamoxifen therapy for the treatment of hormone responsive breast cancer has limitations due to acquired resistance in the case of recurrences. Embelin, a known inhibitor of X-linked inhibitor of apoptosis protein (XIAP) was also reported to exhibit strong antiestrogenic effects in animal models. Dual role of embelin as a proapoptotic and antiestrogenic agent may have potential benefits in the therapy of breast cancer. In this study, the effects of embelin treatment on estrogen receptor positive Human breast adenocarcinoma (MCF-7) cells was investigated to primarily understand if embelin being an antiestrogen and XIAP inhibitor could be a potential alternative to tamoxifen therapy. Results revealed that, embelin at a concentration of 65 μg/ml attenuated proliferation, inhibited metastatic migration, modulated the expression of Bcl2, Caspases and induced apoptosis in MCF-7 cells which was found to be p53 mediated. Hence, chemotherapy with embelin could be a promising strategy to be experimented in hormone responsive breast cancers.

Naringin modulates oxidative stress and inflammation in 3-nitropropionic acid-induced neurodegeneration through the activation of nuclear factor-erythroid 2-related factor-2 signalling pathway

Nuclear factor-erythroid 2-related factor-2 (Nrf2) mediated regulation of cellular antioxidant production and the anti-inflammatory mechanism play an important role in neuroprotection against neurodegenerative diseases. Naringin a citrus flavonone, has been reported to possess neuroprotective effect against Huntington's disease, and other neurodegenerative disorders, however the mechanisms underlying its beneficial effects on 3-nitropropionic acid (3-NP)-induced neurodegeneration are poorly defined. The objective of the present study was to investigate the neuroprotective role of naringin and delineate the mechanism of action on 3-NP-induced neurodegeneration. Rats were injected with 3-NP (10mg/kg body weight/day, i.p.) for 2 weeks to develop neurodegeneration, while naringin (80 mg/kg body weight/day, orally) was administered throughout the experimental period, 1h prior to 3-NP exposure. Thereafter rats were euthanized for biochemical, histological, and molecular studies. Treatment with naringin ameliorated the reduced glutathione/oxidized glutathione ratio with concomitant decrease in the levels of hydroxyl radical, hydroperoxide and nitrite in 3-NP-induced rats. Nissl staining and transmission electron microscopic studies showed that naringin modulated 3-NP-induced histological changes. Naringin induces NAD(P)H:quinone oxidoreductase-1, heme oxygenase-1, glutathione S-transferase P1 and gamma-glutamylcysteine ligase mRNA expressions through the activation of Nrf2 and decreased the expressions of pro-inflammatory mediators like tumour necrosis factor-alpha, cyclooxygenase-2 and inducible nitric oxide synthase. These results indicate that naringin might be beneficial in mitigating 3-NP-induced neurodegeneration through the enhancement of phase II and antioxidant gene expressions via Nrf2 activation; thereby modulating the oxidative stress and inflammatory responses.

Effect of curcumin on selenite-induced cataractogenesis in Wistar rat pups

PURPOSE

The present study was aimed at investigating the possible antioxidant potential of curcumin at a dose of 75 mg/kg body weight on selenite-induced cataract in experimental rat pups.

METHODS

Group I: Control rat pups receiving physiological saline; Group II: Selenite-induced group (15 microM/kg body wt); Group III: Selenite-induced group co-treated with curcumin (single dose of curcumin orally 75 mg/kg body wt); Group IV: Selenite-induced animals post-treated (after 24 hrs) with curcumin at a dose mentioned for group III; Group V: Rat pups were pretreated with curcumin (dose as mentioned in Group III), 24 hrs before the administration of selenite. Encapsulated lenses liver, kidney, and serum were analyzed for antioxidant enzymes and malondialdehyde, a marker of lipid peroxidation.

RESULTS

Intraperitoneal injection of sodium selenite (15 microM/kg body wt) to 8-10-day-old rat pups led to severe oxidative stress in eye lens as evidenced by enhanced LPO levels that led to cataract formation. Sodium selenite also led to decrease in activities of SOD, GST, GPx, CAT with simultaneous decrease in the levels of GSH, vitamin C, and vitamin E. Treatment with curcumin (75 mg/kg body wt) led to a significant decrease in the levels of LPO, enzymic antioxidants, and nonenzymic antioxidants, which were similar to that of control.

CONCLUSIONS

Curcumin suppressed selenite-induced oxidative stress and cataract formation in rat pups. The presence of oxidative stress in selenite cataract development and its prevention by curcumin support the possibility that the natural consumption of curcumin in food can help prevent the onset of senile cataract.

Anti-cataractogenic effect of curcumin and aminoguanidine against selenium-induced oxidative stress in the eye lens of Wistar rat pups: An in vitro study using isolated lens

The aim of this study was to investigate whether curcumin and aminoguanidine (AG) prevent selenium-induced cataractogenesis in vitro. On postpartum day 8, transparent isolated lens were incubated in 24 well plates containing Dulbecco's Modified Eagle Medium (DMEM). Isolated lens of group I were incubated with DMEM medium alone. Group II: lenses incubated in DMEM containing 100microM sodium selenite; group III: lenses incubated in DMEM containing 100microM sodium selenite and 100microM curcumin; group IV: lenses incubated in DMEM containing 100microM sodium selenite and 200microM curcumin; group V: lenses incubated in DMEM containing 100microM sodium selenite and 100microM AG; group V: lenses incubated in DMEM containing 100microM sodium selenite and 200microM AG. On day 12, cataract development was graded using an inverted microscope and the lenses were analyzed for enzymic as well as non-enzymic antioxidants, lipid peroxidation (LPO), nitric oxide (NO), superoxide anion (O(2)(-)) and hydroxyl radical generation (OH) and inducible nitric oxide synthase (iNOS) activity by Western blotting and RT-PCR. All control lenses in group I were clear (0). In groups II and III, all isolated lenses developed cataract with variation in levels (+++ or ++), whereas isolated lenses from groups IV, V and VI were clear (0). In agreement to this, a decrease in antioxidants and increased free radical generation and also iNOS expression were observed in selenium exposed lenses when compared to other groups. AG (100microM) was found to be more effective in anti-cataractogenic effect than curcumin (200microM). Curcumin and AG suppressed selenium-induced oxidative stress and cataract formation in isolated lens from Wistar rat pups, possibly by inhibiting depletion of enzymic as well as non-enzymic antioxidants, and preventing uncontrolled generation of free radicals and also by inhibiting iNOS expression. Our results implicate a major role for curcumin and AG in preventing cataractogenesis in selenite-exposed lenses, wherein AG was found to be more potent.

Antimonial-induced increase in intracellular Ca2+ through non-selective cation channels in the host and the parasite is responsible for apoptosis of intracellular Leishmania donovani amastigotes

The capability of the obligate intracellular parasites like Leishmania donovani to survive within the host cell parasitophorous vacuoles as nonmotile amastigotes determines disease pathogenesis, but the mechanism of elimination of the parasites from these vacuoles are not well understood. By using the anti-leishmanial drug potassium antimony tartrate, we demonstrate that, upon drug exposure, intracellular L. donovani amastigotes undergo apoptotic death characterized by nuclear DNA fragmentation and externalization of phosphatidylserine. Changes upstream of DNA fragmentation included generation of reactive oxygen species like superoxide, nitric oxide, and hydrogen peroxide that were primarily concentrated in the parasitophorous vacuoles. In the presence of antioxidants like N-acetylcysteine or Mn(III) tetrakis(4-benzoic acid)porphyrin chloride, an inhibitor of inducible nitric-oxide synthase, a diminution of reactive oxygen species generation and improvement of amastigote survival were observed, suggesting a close link between drug-induced oxidative stress and amastigote death. Changes downstream to reactive oxygen species increase involved elevation of intracellular Ca2+ concentrations in both the parasite and the host that was preventable by antioxidants. Flufenamic acid, a non-selective cation channel blocker, decreased the elevation of Ca2+ in both the cell types and reduced amastigote death, thus establishing a central role of Ca2+ in intracellular parasite clearance. This influx of Ca2+ was preceded by a fall in the amastigote mitochondrial membrane potential. Therefore, this study projects the importance of flufenamic acid-sensitive non-selective cation channels as important modulators of antimonial efficacy and lends credence to the suggestion that, within the host cell, apoptosis is the preferred mode of death for the parasites.