Raj Kumar

Evaluation of radioprotective activities of Rhodiola imbricata Edgew – A high altitude plant

The present study reports the radioprotective properties of a hydro-alcoholic rhizome extract of Rhodiola imbricata (code named REC-7004), a plant native to the high-altitude Himalayas. The radioprotective effect, along with its relevant superoxide ion scavenging, metal chelation, antioxidant, anti-lipid peroxidation and anti-hemolytic activities was evaluated under both in vitro and in vivo conditions. Chemical analysis showed the presence of high content of polyphenolics (0.971 ± 0.01 mg% of quercetin). Absorption spectra analysis revealed constituents that absorb in the range of 220–290 nm, while high-performance liquid chromatography (HPLC) analysis confirmed the presence of four major peaks with retention times of 4.780, 5.767, 6.397 and 7.577 min. REC-7004 was found to lower lipid oxidation significantly (p < 0.05) at concentrations viz., 8 and 80 μg/ml respectively as compared to reduced glutathione, although the optimally protective dose was 80 μg/ml, which showed 59.5% inhibition of induction of linoleic acid degradation within first 24 h. The metal chelation activity of REC-7004 was found to increase concomitantly from 1 to 50 μg/ml. REC-7004 (10–50 μg/ml) exhibited significant metal chelation activity (p < 0.05), as compared to control, and maximum percentage inhibition (30%) of formation of iron-2,2′-bi-pyridyl complex was observed at 50 μg/ml, which correlated well with quercetin (34.9%), taken as standard. The reducing power of REC-7004 increased in a dose-dependent manner. The absorption unit value of REC-7004 was significantly lower (0.0183± 0.0033) as compared to butylated hydroxy toluene, a standard antioxidant (0.230± 0.091), confirming its high reducing ability. Superoxide ion scavenging ability of REC-7004 exhibited a dose-dependent increase (1–100 μg/ml) and was significantly higher (p < 0.05) than that of quercetin at lower concentrations (1–10 μg/ml), while at 100 μg/ml, both quercetin and REC-7004 scavenged over 90% superoxide anions. MTT assay in U87 cell line revealed an increase in percent survival of cells at doses between 25 and 125 μg/ml in case of drug + radiation group. In vivo evaluation of radio-protective efficacy in mice revealed that intraperitoneal administration of REC-7004 (maximally effective dose: 400 mg/kg b.w.) 30 min prior to lethal (10 Gy) total-body γ-irradiation rendered 83.3% survival. The ability of REC-7004 to inhibit lipid peroxidation induced by iron/ascorbate, radiation (250 Gy) and their combination [i.e., iron/ascorbate and radiation (250 Gy)], was also investigated and was found to decrease in a dose-dependent manner (0.05–2 mg/ml). The maximum percent inhibition of formation of MDA-TBA complex at 2 mg/ml in case of iron/ascorbate, radiation (250 Gy) and both i.e., iron/ascorbate with radiation (250 Gy) was 53.78, 63.07, and 51.76% respectively and were found to be comparable to that of quercetin. REC-7004 (1 μg/ml) also exhibited significant anti-hemolytic capacity by preventing radiation-induced membrane degeneration of human erythrocytes. In conclusion, Rhodiola renders in vitro and in vivo radioprotection via multifarious mechanisms that act in a synergistic manner.

Design of Slotted Ground Hexagonal Microstrip Patch Antenna and Gain Improvement with FSS Screen

Three hexagonal patch antennas are designed for circular polarization and experimentally validated. These antennas are labeled; simple hexagonal patch, hexagonal patch with slotted ground and hexagonal patch with parasitic element. The measured impedance bandwidths of the three antennas are 2% for the simple patch, 5.2% for the patch with slotted ground and 6.35% for the antenna with parasitic element. The axial ratio (measured) obtained is 4.73% for the patch with slotted ground and 3.33% for the hexagonal patch antenna with parasitic element. The measured radiation patterns of these antennas are found to be in good agreement with the simulated radiation patterns. The average gain of all the three antennas is also evaluated. A frequency selective surface (FSS) is proposed with dimensions smaller than that of a conventional FSS structure. The measured gain improvement with the proposed FSS is around 3dB in the operating band.

Influence of beneficial microorganisms during in vivo acclimatization of in vitro-derived tea (Camellia sinensis) plants

The effects of native isolates of Pseudomonas fluorescens, Azospirillum brasilense, and Trichoderma harzianum on rooting and acclimatization of in vitro-grown shoots and plantlets of tea were evaluated. In vitro bacterization of P. fluorescens failed to establish, while both T. harzianum and A. brasilense retarded shoot growth, eventually overtaking shoot cultures in in vitro rooting. Acclimatization of rooted plantlets in soil amended with bioinoculants, either individually or in various combinations, promoted plantlet survival. Moreover, efficiency of nutrient uptake of plantlets was higher in the presence of microorganisms. Root rot or wilting of tissue culture-derived plants was not observed in bioinoculant-treated plants, as they possessed relatively higher activities of defense enzymes, including peroxidase and phenylalanine ammonia lyase.

Cross-Species Induction and Enhancement of Antimicrobial Properties in Response to Gamma Irradiation in Exiguobacterium sp. HKG 126.

A gram positive, extreme haloalkaliphilic, radioresistant bacterium was isolated from mangrove region of Kerala (India) which was characterized as Exiguobacterium sp. HKG-126 using morphological, physiological, biochemical and molecular characterization. Present investigation was undertaken to examine Exiguobacterium sp. as a potential source of broad-spectrum antimicrobial activity and enhancement in this activity was observed due to cross-species/cross-genera induction and also in response to high dose of gamma (γ) irradiation. Individual studies on the antimicrobial activity of all the co-cultivated bacterial strains before and after mixed culture fermentation, showed excellent enhancement in antimicrobial activity of Exiguobacterium sp. against a variety of clinical pathogens. To the best of our knowledge, this is the first report showing existence of an extremely high radioresistant strain of (up to 15xa0kGy) Exiguobacterium sp.

Evaluation of anti-oxidant activities and total phenol and flavonoid content of the hydro- alcoholic extracts of Rhodiola sp.

Abstract Rhodiola sp. ( R. heterodanta and R. imbricata ), belonging to the stone crop family Crassulaceae , is an important medicinal plant and food crop in Trans-Himalayan cold desert. It is a well known medicinal plant in the Amchi system of medicine (Tibetan system of medicine) being used in various ailments like anti-stress, radio-protective, anticancer, anti-inflammatory agent, adaptogen etc. Hydro- alcoholic extracts of Rhodiola sp. root and shoot were investigated in the present study to quantify total Phenolic as well as anti-oxidant activity. Total phenolic contents were determined as total flavonoids (TF), and total polyphenols (TPP). Rhodiola heterodanta root extract had highest amount of total phenol and flavonoids are found to be 79.21±.26 mg GAE/g and 269.3±.82mg Qc/g respectively. In vitro antioxidant activity was investigated by DPPH radical scavenging activity, reducing power assay. R. imbricata hydro-alcoholic root extract showed the highest reducing power and DPPH. radical scavenging. A significant correlation existed between concentrations of the extract and percentage inhibition of free radicals and reducing power. These results clearly indicate that Rhodiola sp. are effective against free radical mediated diseases and also helpful to draw special attention for further studies.

Acute and sub acute toxicity and efficacy studies of Hippophae rhamnoides based herbal antioxidant supplement

Objectives: Present study was carried out to evaluate acute and subacute toxicity and efficacy of Seabuckthorn (Hippophae rhamnoides) based herbal antioxidant supplement (HAOS). Materials and Methods: In vivo toxicity studies were performed in male balb ‘C’ mice by oral administration. Acute toxicity study was done at doses ranging from 2000 to 10 000 mg/ kg while in subacute studies, HAOS was given at doses of 2000, 4000, and 8000 mg/kg body weight. Animals were observed for any toxic sign and symptoms periodically. At completion of study animals were sacrificed; their hematological, biochemical parameters were analyzed and histopathology of vital organs was done. In vivo efficacy studies in human volunteers were done and the levels of vitamin A and Vitamin C in blood samples were analyzed in comparison to a similar commercially available formulation. Results: No mortality and any clinical signs of toxicity were found in HAOS administered group of animals. There were no significant alterations in hematological and biochemical parameters. Histopathological analysis of vital organs showed normal architecture in all the HAOS administered groups. Human studies showed an increase of 32% and 172% in Vitamin A and Vitamin C levels respectively in term of bioavailability. Conclusion: The data obtained indicate no toxicity of this antioxidant supplement up to the highest dose studied. Efficacy in terms of increased bioavailability of vitamin A and C in human volunteers indicates the clinical usefulness of the supplement.

Radioprotection to small intestine of the mice against ionizing radiation by semiquinone glucoside derivative (SQGD) isolated from Bacillus sp. INM-1.

Ionizing irradiation induces severe damage to the intestinal crypt cells which are responsible for renovation and maintenance of the intestinal cellular architecture. Therefore, protection of intestinal cells and tissue against lethal irradiation using a semiquinone glucoside derivative (SQGD) isolated from radioresistant bacterium Bacillus sp. INM-1 is the prime focus of the present investigation. BALB/c mice were administered by SQGD (50xa0mg/kg.b.wt. i.p.) 2xa0h before whole body irradiation (10xa0Gy), and histological analysis of the jejunum section was carried out and compared to the irradiated mice. Significant (pxa0<xa00.0001) increase in villus length, number of cells per villus, crypts numbers per villus section, total cells counts and mitotic cell counts per crypt and low goblet cells per villus section, and low apoptotic index per crypt section were observed in the irradiated mice pre-treated by SQGD at 48–168xa0h. Significant induction in NF-kβ at 24xa0h and Bcl-2/Bax ratio was observed in irradiated mice pre-treated by SQGD compared to only irradiated animals. SQGD pre-treatment before irradiation was found instrumental to reverse the radiation-induced degenerative changes by replenishment of the damaged cells by enhancing mitotic, proliferating, pro-survival, and apoptosis inhibitory activities probably through modulation of cell cycle arrest in G1/S phase in the intestinal cellular milieu.

In Vitro Antioxidant Activity Of Methanolic Extract Of Rhodiola Imbricata Edgew.

Abstract Rhodiola imbricata (Roseroot) is a perennial plant distributed in South Asia viz., Pakistan, Nepal, China and India. In India it is endemic to Trans Himalayan cold desert of Ladakh. It is a well known medicinal plant in the Amchi system of medicine (Tibetan system of medicine) being used in various ailments like anti-stress, radio-protective, anticancer, anti-inflammatory agent, adaptogen etc. The aim of this study was to assess the in vitro potential of methanol extract of Rhodiola imbricata roots. The DPPH activity of the extract (0.1–1.2 mg/ml) was increased in a dose dependent manner, which was found in the range of (39.55–70.76%) as compared to ascorbic acid (46.78–81.47%). The IC50 values of methanol extract in DPPH radical, nitric oxide, hydroxyl radical were obtained to be 0.33, 0.47, 0.58 mg/ml, respectively. However, the IC50 values for the standard ascorbic acid were noted to be 0.42, 0.43, 0.51 mg/ml, respectively. Measurement of total phenolic content of the methanol extract of R. imbricata was achieved using Folin-Ciocalteau reagent containing 185.7 mg/g of phenolic content, which was found significantly higher when compared to reference standard gallic acid. The results obtained in this study clearly indicate that R. imbricata has a significant potential to use as a natural anti-oxidant agent.

Podophyllum hexandrum as a Potential Botanical Supplement for the Medical Management of Nuclear and Radiological Emergencies (NREs) and Free Radical-Mediated Ailments: Leads From In Vitro/In Vivo Radioprotective Efficacy Evaluation

ABSTRACT. Management of radiation-induced reactive oxygen/nitrogen species requires a holistic approach to mitigate the deleterious effects of free radicals. Flora of the Himalayas, which prevails under extreme climatic conditions, has been explored for its potential utility to develop radioprotective drugs. The Himalayan high altitude medicinal plant, Podophyllum hexandrum Royle, was selected on the basis of its unique properties, and a novel fractionated nonpolar extract (REC-2003) was prepared and evaluated for radioprotective efficacy, in vitro as well as in vivo. The free radical scavenging activity of REC-2003 was found to be > 75% (20 μg/ml) with maximum superoxide scavenging activity (57.56 ± 1.38%) recorded at 1 mg/ml concentration (tetrazolium-based estimation). More than 30% inhibition of nitric oxide radicals was observed at concentrations > 0.5 mg/ml, while hydroxyl radical scavenging activity (deoxy-D-ribose assay) exhibited a dose-dependent (100–600 μg/ml) increase. Significantly high (90%) protection to human erythrocytes was observed at 75 μg/ml, which was found to be the most optimized dose. Similarly, more than 90% inhibition was observed against lipid peroxidation (evaluated by estimating levels of malondialdehyde). The significant antihemolytic potential of REC-2003 could be attributed to its ability to scavenge free radicals, reduce peroxidative stress on lipid membranes, and render protection to DNA (evaluated using plasmid relaxation assay). All these activities holistically contributed toward the radioprotective ability. REC-2003 (8 mg/kg BW; intraperitoneal (i.p.), −30 min) rendered > 80% total-body protection in Swiss Albino Strain ‘A’ mice [against lethal radiation (10 Gy)] in a 30-day survival assay. Phytochemical characterization of the constituents of REC-2003 revealed the presence of polyphenolics (flavonoids). The characterized constituents also included the aryl-tetralin lignans like podophyllotoxin, its glycoside, 4′-demethyl derivative, and epi-podophyllotoxin. The optimized requisite single dose (8 mg/KgBW; i.p., −30 min) for obtaining significant radioprotection is reasonably low and establishes its future utility as a dietary supplement in the medical management of free radical-mediated diseases and specifically for rescue missions during nuclear and radiological emergencies (NREs).

Semiquinone glucoside derivative provides protection against γ‐radiation by modulation of immune response in murine model

Present study was undertaken to evaluate radioprotective and immunomodulatory activities of a novel semiquinone glucoside derivative (SQGD) isolated from Bacillus sp. INM‐1 in C57BL/6 mice. Whole body survival study was performed to evaluate in vivo radioprotective efficacy of SQGD. To observe effect of SQGD on immunostimulation, Circulatory cytokine (i.e., interleukin‐2 (IL‐2), IFN‐γ, IL‐10, granulocyte colony stimulating factor (G‐CSF), granulocyte macrophage colony stimulating factor (GM‐CSF), and macrophage colony stimulating factor (M‐CSF) expression was analyzed in serum of irradiated and SQGD treated mice at different time intervals using ELISA assay. Results of the present investigation indicated that SQGD pre‐treatment (‐2 h) to lethally irradiated mice provide ∼83% whole body survival compared with irradiated mice where no survival was observed at 30th post irradiation day. Significant (p < 0.05) induction in IL‐2 and IFN‐γ expression was observed at all tested time intervals with SQGD pre‐treated irradiated mice as compared with irradiated mice alone. However, sharp increase in IL‐10 expression was observed in irradiated mice which were found to be subsidized in irradiated mice pre‐treated with SQGD. Similarly, significant (p < 0.05%) induction in G‐CSF, M‐CSF and GM‐CSF expression was observed in irradiated mice treated with SQGD as compared with irradiated control mice at tested time intervals. In conclusion, SQGD pre‐treatment to irradiated mice enhanced expression of IL‐12 and IFN‐γ while down‐regulated IL‐10 expression and thus modulates cytoprotective pro‐inflammatory TH1 type immune response in irradiated mice. Further, SQGD pre‐treatment to irradiated mice accelerate G‐CSF, GM‐CSF and M‐CSF expression suggesting improved haematopoiesis and enhanced cellular immune response in immuno‐compromised irradiated mice that may contribute to in vivo radiation protection.