M. Sai Ram

Anti-oxidant and immunomodulatory properties of seabuckthorn (Hippophae rhamnoides)—an in vitro study

This study was designed to determine the anti-oxidant and immunomodulatory properties of seabuckthorn (Hippophae rhamnoides) using lymphocytes as a model system. Chromium(VI) as potassium dichromate was used to induce oxidative damage. The production of free radicals by chromium and the ability of alcoholic leaf and fruit extracts of seabuckthorn to inhibit the oxidative damage induced by chromium was investigated. Addition of chromium (10 microg/ml) to the cells resulted in enhanced cytotoxicity, apoptosis, free radical production and decreased glutathione (reduced) levels. Chromium also caused a significant inhibition of lymphocyte proliferation induced by both lipopolysaccharide and concanavalin A. Alcoholic extracts of leaves and fruits of seabuckthorn at a concentration of 500 microg/ml were found to inhibit chromium-induced free radical production, apoptosis, DNA fragmentation and restored the anti-oxidant status to that of control cells. In addition, these extracts also were able to arrest the chromium-induced inhibition of lymphocyte proliferation. These observations suggest that the alcoholic extracts of leaves and fruits of seabuckthorn have marked cytoprotective properties, which could be attributed to the anti-oxidant activity.

Evaluation of antioxidant activity of leaf extract of Seabuckthorn (Hippophae rhamnoides L.) on chromium(VI) induced oxidative stress in albino rats

The present study reports the antioxidant activity of Seabuckthorn (Hippophae rhamnoides), family Elaegnaceae, on chromium induced oxidative stress in male albino rats. Oxidative stress was induced in the rats by force-feeding of potassium dichromate equivalent to a dose of 30mg/kg body weight (BW) of chromium(VI) for 30 days. Administration of chromium decreased the body weight and increased organ to body weight ratio significantly. Chromium treatment significantly decreased reduced glutathione (GSH), and increased malondialdehyde (MDA) and creatine phosphokinase (CPK) levels; further it also enhanced glutamate oxaloacetate transferase (GOT) and glutamate pyruvate transferase (GPT) levels in the serum. Different doses of the alcoholic leaf extract of Seabuckthorn were evaluated for the protection against the chromium induced oxidative stress. The results show that the leaf extract at a concentration of 100 and 250mg/kg BW protected the animals from the chromium induced oxidative injury significantly.

Cytoprotective and antioxidant activity of Rhodiola imbricata against tert-butyl hydroperoxide induced oxidative injury in U-937 human macrophages

The present study reports cytoprotective and antioxidant activity of aqueous and alcoholic extracts of Rhodiolaimbricata rhizome on tert-butyl hydroperoxide (tert-BHP) induced cytotoxicity in U-937 human macrophages. There was an increase in cytotoxicity and apoptosis significantly in the presence of tert-BHP over control cells. The tert-BHP induced cytotoxicity can be attributed to enhanced reactive oxygen species (ROS) production which in turn is responsible for fall in reduced glutathione (GSH) levels; further there was a significant decrease in mitochondrial potential and increase in apoptosis and DNA fragmentation. Both aqueous and alcoholic extracts of Rhodiola rhizome at a concentration of 250 μg/ml were found to inhibit tert-BHP induced free radical production, apoptosis and to restore the anti-oxidant levels to that of the control cells. The alcoholic extract of Rhodiola showed higher cytoprotective activities than aqueous extract. These observations suggest that the alcoholic and aqueous extracts of Rhodiola have marked cytoprotective and antioxidant activities.

Cyto-protective and immunomodulating properties of Amla (Emblica officinalis) on lymphocytes: an in-vitro study

The fruits extracts of Emblica officinalis (Amla) has been reported to have strong anti-oxidant properties. There is a paucity of studies on the immunomodulatory properties of fruit extracts of Amla in immuno-compromised states, with the emphasis on lymphocytes. Therefore, the aim of the study was to determine the anti-oxidant and immunomodulatory properties of Amla using chromium (VI) as an immunosuppressive agent. Chromium (Cr) treatment results in enhanced cytotoxicity, free radical production, lipid peroxidation and decreased glutathione peroxidase (GPx) activity and diminished glutathione (GSH) levels. There was a significant inhibition of both lipopolysaccharide and concanavalin-A-stimulated lymphocyte proliferation. Chromium also inhibited Con A stimulated interleukin-2 and gamma-interferon production significantly. Further, there was enhanced apoptosis and DNA fragmentation in the presence of Cr. Amla significantly inhibited Cr-induced free radical production and restored the anti-oxidant status back to control level. Amla also inhibited apoptosis and DNA fragmentation induced by Cr. Interestingly, Amla relieved the immunosuppressive effects of Cr on lymphocyte proliferation and even restored the IL-2 and gamma-IFN production considerably.

Effect of Kombucha tea on chromate(VI)-induced oxidative stress in albino rats

The effect of Kombucha tea (KT) on oxidative stress induced changes in rats subjected to chromate treatment are reported. KT feeding alone did not show any significant change in malondialdehyde (MDA) and reduced glutathione (GSH) levels, but did enhance humoral response and delayed type of hypersensitivity (DTH) response appreciably over control animals. Chromate treatment significantly enhanced plasma and tissue MDA levels, decreased DTH response considerably, enhanced glutathione peroxidase and catalase activities; however, no change in GSH, superoxide dismutase and antibody titres was noticed. KT feeding completely reversed the chromate-induced changes. These results show that Kombucha tea has potent anti-oxidant and immunopotentiating activities.

Antioxidant activities of seabuckthorn (Hippophae rhamnoides) during hypoxia induced oxidative stress in glial cells.

The present study reports the cytoprotective and antioxidant properties of alcoholic leaf extract of seabuckthorn (SBT) against hypoxia induced oxidative stress in C-6 glioma cells. Exposure of cells to hypoxia for 12 h resulted in a significant increase in cytotoxicity and decrease in mitochondrial transmembrane potential compared to the controls. Further an appreciable increase in nitric oxide and reactive oxygen species (ROS) production was noted which in turn was responsible for fall in intracellular antioxidant levels and GSH/GSSG ratio. There was a significant increase in DNA damage during hypoxia as revealed by comet assay. Pretreatment of cells with alcoholic leaf extract of SBT at 200 μg/ml significantly inhibited cytotoxicity, ROS production and maintained antioxidant levels similar to that of control cells. Further, the leaf extract restored the mitochondrial integrity and prevented the DNA damage induced by hypoxia. These results indicate that the leaf extract of SBT has strong antioxidant and cytoprotective activity against hypoxia induced oxidative injury. (Mol Cell Biochem 278: 9–14, 2005)

Immunomodulatory effects of seabuckthorn (Hippophae rhamnoides L.) against chromium (VI) induced immunosuppression.

The present study reports the immunomodulatory effects of seabuckthorn (Hippophae rhamnoides L.) leaf extract on cellular and humoral immune response by studying delayed-type hypersensitivity response, IL-2, IL-4 and γ-IFN levels and antibody titres in chromium-induced immunosuppressed animals. Oral feeding of chromium (30 mg/kg bw) significantly inhibited antibody production and S-RBC induced delayed-type hypersensitivity response. Administration of leaf extract (100 mg/kg bw) along with chromium significantly inhibited chromium-induced immunosuppression. To understand the immunomodulatory mechanism of leaf extract, in vitro studies were carried out using rat lymphocytes. Addition of chromium resulted in a significant decrease in lymphocyte size and increased ROS generation. The leaf extract of seabuckthorn significantly inhibited chromium-induced reactive oxygen species (ROS) generation and maintained the cell size identical to that of control cells. Chromium treatment markedly inhibited the mitochondrial transmembrane potential by larger lymphocytes in particular, while the leaf extract restored the same significantly. Chromium also inhibited significantly concanavalin A (ConA) induced IL-2, IL-4 and γ-IFN production in rat lymphocytes. The leaf extract (100 μg/ml) alone stimulated IL-2 and γ-IFN production even in the absence of ConA and also inhibited chromium-induced decline in IL-2 and γ-IFN production but it did not change IL-4 production. These observations suggest that the leaf extract of seabuckthorn has significant immunomodulatory activity and specifically activates the cell-mediated immune response. (Mol Cell Biochem 278: 101–109, 2005)

Cobalt chloride attenuates hypobaric hypoxia induced vascular leakage in rat brain: Molecular mechanisms of action of cobalt chloride☆

This study reports the efficacy of cobalt preconditioning in preventing hypobaric hypoxia induced vascular leakage (an indicator of cerebral edema) using male Sprague-Dawley rats as model system. Exposure of animals to hypobaric hypoxia led to a significant increase in vascular leakage, reactive oxygen species (ROS), nitric oxide (NO), and vascular endothelial growth factor (VEGF) levels. There was a marked increase in Nuclear Factor kappaB (NFkappaB) DNA binding activity and levels of pro-inflammatory cytokines such as Monocyte chemoattractant protein (MCP-1), Interferon-gamma (IFN-gamma), Interleukin-1 (IL-1), and Tumor Necrosis Factor-alpha (TNF-alpha) and cell adhesion molecules such as Vascular Cell Adhesion Molecule-1 (VCAM-1), and P-selectin. Chemical preconditioning by cobalt for 7 days (12.5 mg Co/kg b.w., oral) significantly attenuated cerebral vascular leakage and the expression of inflammatory mediators induced by hypoxia. Administration of NFkappaB inhibitor, curcumin (50 mg/kg b.w.; i.p.) appreciably inhibited hypoxia induced vascular leakage indicating the involvement of NFkappaB in causing vascular leakage. Interestingly, cobalt when administered at 12.5 mg Co/kg b.w. (i.p.), 1 h before hypoxia could not prevent the vascular leakage indicating that cobalt per se did not have an effect on NFkappaB. The lower levels of NFkappaB observed in the brains of cobalt administered animals might be due to higher levels of antioxidant and anti-inflammatory proteins (hemeoxygenase-1 and metallothionein). To conclude cobalt preconditioning inhibited hypobaric hypoxia induced cerebral vascular leakage by lowering NFkappaB DNA binding activity and its regulated pro-inflammatory mediators. This is contemplated to be mediated by cobalt induced reduction in ROS/NO and increase in HO-1 and MT.

Quercetin protects C6 glial cells from oxidative stress induced by tertiary-butylhydroperoxide

The anti-oxidant and cyto-protective activity of quercetin against tertiary-butylhydroperoxide (t-BOOH) induced oxidative stress on C6 glial cells is reported. Exposure of the cells to t-BOOH resulted in a significant increase in cytotoxicity, reactive oxygen species (ROS) generation and lipid peroxidation. There was a significant increase in DNA strand breaks and fall in reduced GSH levels in cells exposed to t-BOOH. A significant increase in calcium ion influx was noticed in cells exposed to t-BOOH. Pre-treatment of cells with quercetin, vitamin C (vit C), Trolox, and deferoxamine (DFO) significantly inhibited t-BOOH induced cytotoxicity and ROS generation. Pretreatment of cells with quercetin, Trolox and DFO inhibited the DNA damage, maintained higher GSH levels and prevented calcium influx significantly. Although vit C protected the cells from cytotoxicity induced by t-BOOH, the intracellular Ca2+ levels were significantly higher than the control cells. However, anti-oxidants like butylated hydroxy toluene (BHT), vitamin E (vit E), N-acetyl cysteine (NAC) did not have significant cytoprotection against t-BOOH induced oxidative injury in C6 glial cells.

Effect of seabuckthorn on sodium nitroprusside-induced cytotoxicity in murine macrophages

The present study reports the anti-oxidant activity of alcoholic extracts of leaf and fruit of seabuckthorn (SBT) on nitric oxide (NO) induced cytotoxicity in J-774 macrophages. Sodium nitroprusside (SNP), which generates NO at the concentration of 500 microg/ml, induced cytotoxicity as revealed by decreased neutral red uptake by macrophages. The cytotoxicity of SNP was attributed to enhanced reactive oxygen species (ROS) production, which in turn resulted in decrease in anti-oxidant levels. Alcoholic leaf and fruit extracts of SBT at the concentration of 500 microg/ml were found to have a significant cytoprotective effect against SNP-induced oxidative stress. These extracts inhibited SNP-induced cytotoxicity, free radical production and maintained the anti-oxidant status identical to that of control cells. The alcoholic fruit extract of SBT was found to have significantly higher anti-oxidant activity than leaf extract against SNP-induced cytotoxicity in murine macrophages.