Radioprotective potential of Lagenaria siceraria extract against radiation-induced gastrointestinal injury.

The cucurbits (prebiotics) were investigated as novel agents for radio-modification against gastrointestinal injury. The cell-cycle fractions and DNA damage were monitored in HCT-15 cells. A cucurbit extract was added to culture medium 2 h before irradiation (6 Gy) and was substituted by fresh medium at 4 h post-irradiation. The whole extract of the fruits of Lagenaria siceraria, Luffa cylindrica, or Cucurbita pepo extract enhanced G2 fractions (42%, 34%, and 37%, respectively) as compared with control (20%) and irradiated control (31%). With cucurbits, the comet tail length remained shorter (L. siceraria, 28 µm; L. cylindrica, 34.2 µm; C. pepo, 36.75 µm) than irradiated control (41.75 µm). For in vivo studies, L. siceraria extract (2 mg/kg body weight) was administered orally to mice at 2 h before and 4 and 24 h after whole-body irradiation (10 Gy). L. siceraria treatment restored the glutathione contents to 48.8 µmol/gm as compared with control (27.6 µmol/gm) and irradiated control (19.6 µmol/gm). Irradiation reduced the villi height from 379 to 350 µm and width from 54 to 27 µm. L. siceraria administration countered the radiation effects (length, 366 µm; width, 30 µm, respectively) and improved the villi morphology and tight junction integrity. This study reveals the therapeutic potential of cucurbits against radiation-induced gastrointestinal injury.

Effect of Tinospora cordifolia on gamma ray-induced perturbations in macrophages and splenocytes.

Tinospora cordifolia (RTc) has already been reported to protect whole-body lethally irradiated mice. This study has focussed on certain aspects of immuno-competence, which are adversely affected by irradiation. This study included estimation of spleen size, cell count, DNA fragmentation and apoptosis in splenocytes. The adherence, spreading and phagocytic activities of macrophages were also assessed. Cytokines in serum and anti-oxidants in plasma were also estimated. Administration of RTc (200 mg/kg.b.wt.) one hour before irradiation showed recovery of spleen weight from 49% of control in irradiated group to 93%; apoptosis from 19% to 2.8%; DNA fragmentation from 43% to 20.4%; macrophage adherence form 75% of control to 120% and macrophage spread size from 8 microm to 15 microm. RTc also stimulated proliferation in splenocytes in a dose-dependent manner. RTc administration before irradiation also increased levels of IL-1beta and GM-CSF levels, from 56 pg/ml and 53 pg/ml respectively in irradiated group to 59 pg/ml and 63 pg/ml. Similarly, radiation-induced decrease of anti-oxidant potential of plasma (32 Fe(2+) equiv.) as compared to control (132 Fe(2+) equiv.) was countered by administration of RTc before irradiation (74.2 Fe(2+) equiv.) RTc treatment thus reveals several radio-protective mechanisms.

Anti-inflammatory effects of Podophyllum hexandrum (RP-1) against lipopolysaccharides induced inflammation in mice.

PURPOSE: Down-regulation of lipopolysaccharide (LPS) induced hyper-inflammatory response by non-toxic pharmacological agents acquires paramount importance for countering bacterial sepsis. Anti-inflammatory potential of aqueous extract of Podophyllum hexandrum, a plant well documented in Ayurvedic literature for various therapeutic purposes, was investigated. METHODS: In vivo studies were performed on Balb/c mice pre-treated with supra-lethal dose of LPS endotoxin (E.coli 055:B5) with or without treatment with P. hexandrum extract (RP-1). Mouse peritoneal macrophage cultures were used to understand ex vivo effects of RP-1 on LPS generated nitric oxide (NO), secretion of IFN-gamma, IL-6 and TNF-alpha. Griess assay and sandwich ELISA method were used to quantify inducible NO and cytokines respectively. RESULTS: Minimal dose of LPS that rendered 100% mortality to mice was found to be 450 microg/kg b.w. Administration of RP-1 (200 mg/kg b.w., i.p.) one hour before lethal LPS treatment (0.5 mg/kg b.w.) rendered maximum (78%) survival. Ex vivo study revealed that RP-1 (50 microg/ml) treatment to peritoneal macrophages inhibited LPS (5 microg/ml) induced nitrite generation to 37%, IFN-gamma secretion to 5%, IL-6 secretion to 50% and TNF-alpha secretion to 50 % of LPS treated control values. CONCLUSION: This study has demonstrated anti-inflammatory potential of aqueous extract of P. hexandrum.

Protection of mitochondrial system by Hippophae rhamnoides L. against radiation-induced oxidative damage in mice.

The whole extract of the fresh berries of Hippophae rhamnoides L. (RH-3), which has been reported to provide protection to whole mice, various tissues, cells and cell organelles against lethal irradiation, was further investigated for its effects on mitochondria isolated from mouse liver. Superoxide anion, reduced (GSH) and oxidized glutathione (GSSG) levels, NADH-ubiquinone oxidoreductase (complex I), NADH-cytochrome c oxidoreductase (complex I/II), succinate-cytochrome c oxidoreductase (complex II/III), mitochondrial membrane potential (MMP), lipid peroxidation (LPx) and protein oxidation (PO) were determined for RH-3-mediated radioprotective manifestation. Pre-irradiation treatment of mice with RH-3 (30 mg kg(-1,) i. p.; single dose; -30 min) significantly inhibited the radiation-induced increase in superoxide anions, GSSG, thiobarbituric acid reactive substances (TBARS), complex I, complex I/III activity and MMP maximally at 4 h (P < 0.05). This treatment inhibited the oxidation of proteins (P < 0.05) at all the time periods studied here. This study suggests that pre-irradiation treatment of mice with RH-3 protects the functional integrity of mitochondria from radiation-induced oxidative stress.

Radioprotective potential of an herbal extract of Tinospora cordifolia.

A preparation of Tinospora cordifolia (RTc) administered i.p. (200 mg/kg b.w.) to strain "A" male mice 1 h before whole body gamma-irradiation was evaluated for its radioprotective efficacy in terms of whole body survival, spleen colony forming units (CFU), hematological parameters, cell cycle progression, and micronuclei induction. Preirradiation treatment with RTc rendered 76.3% survival (30 days), compared to 100% mortality in irradiated control and prevented radiation induced weight loss. On 10th postirradiation day, the endogenous CFU counts in spleen were decreased with increasing radiation doses 12.0 (5 Gy), 2.16 (7.5 Gy) and 0.33 (10 Gy) but pre-irradiation administration of 200 mg/kg b.w. of RTc increased CFU counts to 31.16, 21.83 and 3.00 respectively. Pre-irradiation RTc treatment could restore total lymphocyte counts (TLC) by the 15th day to normal. It also increased the S-phase cell population that was reduced following 2 Gy irradiation in a time dependent manner. 2 Gy irradiation-induced micronuclei were also decreased by a pre-irradiation administration of RTc from 2.9 to 0.52%. Because the radioprotective manifestation of RTc observed in several systems in experimental animals can be exploited for human applications.

Induction of apoptosis in thymocytes by Hippophae rhamnoides: implications in radioprotection.

Hippophae rhamnoides (RH-3), which has been recently reported to elicit dose-dependent pro- and antioxidant properties in vitro, induced apoptosis in murine thymocytes. In a concentration-dependent manner, RH-3 induced apoptosis in thymocytes in ex vivo conditions. The maximum effect was observed with 100 microg/mL of RH-3. Beyond this dose, the induction of apoptosis was inhibited, as seen on the ladder formation. However, apoptotic body formation, another indicator of apoptosis, was not manifested when various doses of RH-3 (20-200 microg/mL) were administered. RH-3 (>100 microg/mL) compacted chromatin in the form of densely stained masses, and subsequent treatment with proteinase-K loosened them and developed a halo around each mass. RH-3 treatment of cells that had already undergone apoptosis induced chromatin compaction, which made the ladder invisible. During in vivo experiments in mice, the radioprotective dose of RH-3 (30 mg/kg b.w.) induced significant DNA fragmentation in thymocytes studied spectrofluorimetrically. RH-3 treatment before irradiation in vivo enhanced radiation-induced apoptosis. These results were confirmed by hypodiploid population studied flow-cytometrically and also by ladder formation. RH-3 treatment was prooxidative in nature because it depleted thiols and enhanced lipids peroxidation after 8 hours of treatment. The paradox between the prooxidant and the antioxidant effects of RH-3 in the context of its overall radioprotective efficacy has been explained.

Radioprotective effect of podophyllotoxin in Saccharomyces cerevisiae.

Recent reports showed that whole extract of Podophyllum hexandrum was radioprotective in mice. Podophyllotoxin is one of the major constituents of the whole extract of Podophyllum. In this study we report on the radioprotective action of podophyllotoxin in Saccharomyces cerevisiae yeast. Proliferating yeast cells pretreated with podophyllotoxin (2.5-5.0 microg/mL) for > or =3 hours showed a higher surviving fraction after (60)Co-gamma-irradiation (200-600 Gy) than did the irradiated cells not pretreated with podophyllotoxin. The maximum increase (2.0 times) in surviving fraction was observed in cells treated with 2.5 microg/mL podophyllotoxin, 5 hours before (60)Co-gamma-irradiation (400 Gy). Podophyllotoxin was not mutagenic or recombinogenic at radioprotective doses (2.5 microg/mL). A post-irradiation decrease in revertants and gene convertants was observed in cells treated with podophyllotoxin (2.5 microg/mL podophyllotoxin, -5 hours, 400 Gy). This study indicates that podophyllotoxin is radioprotective in yeast, and its radioprotective effects in higher eukaryotes would be worth investigating.

Modification of radiation damage to mitochondrial system in vivo by Podophyllum hexandrum: mechanistic aspects.

The present study was undertaken to investigate whether RP-1 treatment protected mitochondrial system against radiation damage and also to unravel the mechanism associated with this process. Radioprotection of mitochondrial system by Podophyllum hexandrum (RP-1) was investigated to understand its mechanism of action. Levels of superoxide anion (O2-), reduced or oxidized glutathione (GSH or GSSG), thiobarbituric acid reactive substance (TBARS), protein carbonyl (PC), ATP, NADH-ubiquinone oxidoreductase (complex-I), NADH-cytochrome c oxidoreductase (complex I/II), succinate-cytochrome c oxidoreductase (complex II/III) and mitochondrial membrane potential (MMP) were studied in mitochondria isolated from liver of mice belonging to various treatment groups. Whole body y-irradiation (10 Gy) significantly (p < 0.01) increased the formation of O2-, PC, and TBARS, upto 24 h as compared to untreated control. RP-1 treatment (200 mg/kg b.w.) to mice 2 h before irradiation reduced the radiation-induced O2- generation within 4 h and formation of TBARS and PC upto 24 h significantly (p < 0.01). Singularly irradiation or RP-1 treatment significantly (p < 0.01) increased the levels of glutathione within an hour, as compared to untreated control. Pre-irradiation administration of RP-1 enhanced levels of GSH induced increase in complex I (upto 16 h), complex I/III (4 h) complex II/III activity (upto 24 h; p < 0.01) and inhibited the radiation-induced decrease in MMP significantly (24 h; p < 0.01). The present study indicates that RP-1 itself modulates several mitichondrial perameters due to its influence on the biochemical milieu within and outside the cells. However, RP-1 treatment before irradiation modulates radiation induced perturbations such as the increase in electron transport chain enzyme activity, formation of O2-, TBARS and PC to offer radioprotection.