Effect of Aloe vera gel extract on antioxidant enzymes and azoxymethane-induced oxidative stress in rats.

The present work was undertaken with a view to study the effect of oral feeding of 2% Aloe vera gel extract (AGE) for 30 days on azoxymethane (AOM)-induced oxidative stress in rats. It was observed that AOM administration resulted in a significant increase in malondialdehyde and conjugated dienes, with reduction in hepatic glutathione (GSH), vitamin A and uric acid contents. AOM-induced reduction in hepatic GSH and uric acid was brought back to normal by AGE. There was a significant raise in hepatic catalase, superoxide dismutase and glucose-6-phosphate dehydrogenase (G-6-PD) activities as a result of feeding of the extract. Ingestion of the extract effected reduction in AOM-induced colonic GSH-peroxidase, G-6-PD and glutathione S-transferase and femur bone marrow micronuclei formation. Hence, it is suggested that Aloe vera gel extract possess the ability to reduce AOM- induced oxidative stress and toxicity in liver.

Cytoprotective propensity of green tea polyphenols against citrinin-induced skeletal-myotube damage in C2C12 cells.

The mycotoxin citrinin, is produced by several species of Penicillium, Aspergillus and Monascus, and is capable of inducing cytotoxicity, oxidative stress and apoptosis. The aim of the present study was to investigate the effect of citrinin in mouse skeletal muscle cells (C2C12) and to overcome the cellular adverse effects by supplementing green tea extract (GTE) rich in polyphenols. C2C12 myoblasts were differentiated to myotubes and were exposed to citrinin in a dose dependent manner (0-100 µM) for 24 h and IC50 value was found to be 100 µM that resulted in decreased cell viability, increased LDH leakage and compromised membrane integrity. Mitochondrial membrane potential loss, increased accumulation of intracellular ROS and sub G1 phase of cell cycle was observed. To ameliorate the cytotoxic effects of CTN, C2C12 cells were pretreated with GTE (20, 40, 80 µg/ml) for 2 h followed by citrinin (100 µM) treatment for 24 h. GTE pretreatment combated citrinin-induced cytotoxicity and oxidative stress. GTE at 40 and 80 µg/ml significantly promoted cell survival and upregulated antioxidant enzyme activities (CAT, SOD, GPx) and endogenous antioxidant GSH, while the gene and protein expression levels were significantly restored through its effective antioxidant mechanism. Present study results suggested the antioxidant properties of GTE as a herbal source in ameliorating the citrinin-induced oxidative stress.

Pelargonidin Modulates Keap1/Nrf2 Pathway Gene Expression and Ameliorates Citrinin-Induced Oxidative Stress in HepG2 Cells.

Pelargonidin chloride (PC) is one of the major anthocyanin found in berries, radish and other natural foods. Many natural chemopreventive compounds have been shown to be potent inducers of phase II detoxification genes and its up-regulation is important for oxidative stress related disorders. In the present study, we investigated the effect of PC in ameliorating citrinin (CTN) induced cytotoxicity and oxidative stress. The cytotoxicity of CTN was evaluated by treating HepG2 (Human hepatocellular carcinoma) cells with CTN (0-150 µM) in a dose dependent manner for 24 h, and the IC50 was determined to be 96.16 µM. CTN increased lactate dehydrogenase leakage (59%), elevated reactive oxygen species (2.5-fold), depolarized mitochondrial membrane potential as confirmed by JC-1 monomers and arrested cell cycle at G2/M phase. Further, apoptotic and necrotic analysis revealed significant changes followed by DNA damage. To overcome these toxicological effects, PC was pretreated for 2 h followed by CTN exposure for 24 h. Pretreatment with PC resulted in significant increase in cell viability (84.5%), restored membrane integrity, reactive oxygen species level were maintained and cell cycle phases were normal. PC significantly up-regulated the activity of detoxification enzymes: heme oxygenase 1 (HO-1), glutathione transferase, glutathione peroxidase, superoxide dismutase and quinone reductase. Nrf2 translocation into the nucleus was also observed by immunocytochemistry analysis. These data demonstrate the protective effect of PC against CTN-induced oxidative stress in HepG2 cells and up-regulated the activity of detoxification enzyme levels through Keap1/Nrf2 signaling pathway.

Optimisation of extraction of bioactive compounds from Feronia limonia (wood apple) fruit using response surface methodology (RSM).

In this study, the extraction conditions for the maximum recovery of polyphenols with high antioxidant activity were optimised by response surface methodology (RSM) in Feronia limonia fruit. The independent variables were viz. concentration of ethanol (X1: 30-70%), incubation temperature (X2: 37-60%) and solvent-to-solid ratio (X3: 20-40%). ANOVA results showed that concentration of ethanol and temperature affected the total polyphenol content (TPC, Y1), DPPH (Y2) and ABTS (Y3) radical scavenging activities significantly (p<0.05) whereas solvent-to-solid ratio was found to be insignificant. A second-order polynomial model satisfactorily fitted the experimental data with the R(2) values of 0.966, 0.946 and 0.955, respectively for the responses Y1, Y2 and Y3 (p<0.0001), implying a good agreement between the predicted and experimental values. The optimal conditions for the highest yield of TPC (7.21±1.4 g GAE/g) with >80% radical scavenging activities were derived at X1=62.7%, X1=49.7 °C and X3=39.4 mL/g.

Amelioration of alcohol-induced hepatotoxicity and oxidative stress in rats by Acorus calamus.

The protective effect of a methanolic extract (ME) of Acorus calamus against alcohol-induced hepatotoxicity and oxidative stress was studied in rats. The in vitro assays using DPPH and ABTS showed a strong antioxidant activity of the extract with the total polyphenolic content of 156 mg/g. Chronic ethanol administration causes an increase in oxidative stress and tissue injury with decreased antioxidant status. In this study, continuous administration of ethanol (7.9 g/kg body weight/day) for a period of 6 weeks resulted in a significant (p < .001) increase in the levels of serum aspartate aminotransferase, serum alanine aminotransferase, alkaline phospahatase, and bilirubin with the decreased level of total antioxidant status. Moreover, the levels of lipid peroxidation markers (malondialdehyde and hydroperoxides) as well as protein carbonyl content were also increased (p < .001), whereas the levels of non-enzymic antioxidants (glutathione, vitamin C, and vitamin E) decreased significantly in the liver tissues of ethanol-administered control rats. Pretreatment of rats with ME at doses of 300 and 600 g/kg body weight before alcohol administration significantly reduced the hepatic marker enzymes, level of lipid peroxidation, and protein oxidation, and increased the enzymatic and non-enzymatic antioxidant levels in liver. These observations were supplemented by histopathological examination of liver sections. Overall, the present study shows that the administration of ME ameliorates the antioxidant status as well as protects against the toxic effects of ethanol in rats, thereby suggesting its use as an effective botanical supplement for hepatoprotection.