Raman Chawla
Defence Research and Development Organisation
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Publication
Featured researches published by Raman Chawla.
Journal of diabetes and metabolic disorders | 2013
Raman Chawla; Pallavi Thakur; Ayush Chowdhry; Sarita Jaiswal; A. K. Sharma; Rajeev Goel; Jyoti Sharma; Smruti Sagar Priyadarshi; Vinod Kumar; Rakesh Kumar Sharma; Rajesh Arora
Plants by virtue of its composition of containing multiple constituents developed during its growth under various environmental stresses providing a plethora of chemical families with medicinal utility. Researchers are exploring this wealth and trying to decode its utility for enhancing health standards of human beings. Diabetes is dreadful lifestyle disorder of 21st century caused due to lack of insulin production or insulin physiological unresponsiveness. The chronic impact of untreated diabetes significantly affects vital organs. The allopathic medicines have five classes of drugs, or otherwise insulin in Type I diabetes, targeting insulin secretion, decreasing effect of glucagon, sensitization of receptors for enhanced glucose uptake etc. In addition, diet management, increased food fiber intake, Resistant Starch intake and routine exercise aid in managing such dangerous metabolic disorder. One of the key factors that limit commercial utility of herbal drugs is standardization. Standardization poses numerous challenges related to marker identification, active principle(s), lack of defined regulations, non-availability of universally acceptable technical standards for testing and implementation of quality control/safety standard (toxicological testing). The present study proposed an integrated herbal drug development & standardization model which is an amalgamation of Classical Approach of Ayurvedic Therapeutics, Reverse Pharmacological Approach based on Observational Therapeutics, Technical Standards for complete product cycle, Chemi-informatics, Herbal Qualitative Structure Activity Relationship and Pharmacophore modeling and, Post-Launch Market Analysis. Further studies are warranted to ensure that an effective herbal drug standardization methodology will be developed, backed by a regulatory standard guide the future research endeavors in more focused manner.
Pharmacology, Biochemistry and Behavior | 2006
Anupum Haksar; Ashok Sharma; Raman Chawla; Raj Kumar; Rajesh Arora; Surender Singh; Jagdish Prasad; Mukul Kumar Gupta; R. P. Tripathi; Meenakshi Arora; Fakhrul Islam; Rupam Sharma
At the organismic level, exposure to radiation can produce taste aversion (CTA) learning and emesis, which have been proposed as behavioral endpoints that are mediated by harmful effects of radiations on peripheral systems, primarily the gastrointestinal system. Thus, the aim of the present investigation was to study the gastroprotective action of hydroalcoholic extract of zingiber rhizome (Zingiber officinale Rosc.) against radiation-induced conditioned taste aversion (CTA) in both male and female species of animals, for testing its potential as a behavioral radioprotector. Administration of zingiber extract 1 h before 2-Gy gamma-radiation was significantly effective in blocking the saccharin avoidance response, with 200 and 250 mg/kg b.wt. i.p., being the most effective doses for male and female rats, respectively. A comparison of the efficacy of zingiber extract with two antiemetic drugs, ondansteron and dexamethasone, revealed that the extract rendered comparable protection against radiation-induced CTA. Our experiments also confirmed the existence of sex dichotomy (i.e., the sex of animal greatly influenced response towards radiation exposure) in relation to behavioral responses (CTA) or differential metabolism. The observed gender variations were hypothesized to be a result of hormonal fluctuations and differences in pharmacological parameters in male and female rats. To correlate the mechanism of action, the free-radical-scavenging potential of zingiber extract to scavenge hydroxyl ion and nitric oxide was also tested, in cell-free system and a concentration of 1000 microg/ml, was found to be the most potent, which has been proposed as one the many activities assisting in its overall ability to modulate radiation-induced taste aversion. The results demonstrate that Z. officinale possesses antioxidant, radioprotective and neuromodulatory properties that can be effectively utilized for behavioral radioprotection and for efficiently mitigating radiation-induced CTA in both males and females species.
Molecular and Cellular Biochemistry | 2005
Rajesh Arora; Raman Chawla; Ravinder Sagar; Jagdish Prasad; S.P. Singh; Raj Kumar; Ashok Sharma; Rakesh Kumar Sharma
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.
Molecular and Cellular Biochemistry | 2005
Raman Chawla; Rajesh Arora; Raj Kumar; Ashok Sharma; Jagdish Prasad; S.P. Singh; Ravinder Sagar; Pankaj Chaudhary; Sandeep Kumar Shukla; Gurpreet Kaur; Rakesh Kumar Sharma; Satish Chander Puri; K.L. Dhar; G. Handa; Vinay Gupta; Ghulam Nabi Qazi
Whole extract of rhizomes of Podophyllum hexandrum has been reported earlier by our group to render whole-body radioprotection. High-altitude P. hexandrum (HAPH) was therefore fractionated using solvents of varying polarity (non-polar to polar) and the different fractions were designated as, n-hexane (HE), chloroform (CE), alcohol (AE), hydro-alcohol (HA) and water (WE). The total polyphenolic content (mg% of quercetin) was determined spectrophotometrically, while. The major constituents present in each fraction were identified and characterized using LC-APCI/MS/MS. In vitro screening of the individual fractions, rich in polyphenols and lignans, revealed several bioactivities of direct relevance to radioprotection e.g. metal-chelation activity, antioxidant activity, DNA protection, inhibition of radiation (250 Gy) and iron/ascorbate-induced lipid peroxidation (LPO). CE exhibited maximum protection to plasmid (pBR322) DNA in the plasmid relaxation assay (68.09% of SC form retention). It also showed maximal metal chelation activity (41.59%), evaluated using 2,2′-bipyridyl assay, followed by AE (31.25%), which exhibited maximum antioxidant potential (lowest absorption unit value: 0.0389± 0.00717) in the reducing power assay. AE also maximally inhibited iron/ascorbate-induced and radiation-induced LPO (99.76 and 92.249%, respectively, at 2000 μg/ml) in mouse liver homogenate. Under conditions of combined stress (radiation (250 Gy) + iron/ascorbate), at a concentration of 2000 μg/ml, HA exhibited higher percentage of inhibition (93.05%) of LPO activity. HA was found to be effective in significantly (p < 0.05) lowering LPO activity over a wide range of concentrations as compared to AE. The present comparative study indicated that alcoholic (AE) and hydro-alcoholic (HA) fractions are the most promising fractions, which can effectively tackle radiation-induced oxidative stress.
Evidence-based Complementary and Alternative Medicine | 2006
Raman Chawla; Rajesh Arora; Ravinder Sagar; Rakesh Kumar Sharma; Rinesh Kumar; Avdhesh Sharma; R. P. Tripathi; S. C. Puri; Haider A. Khan; A. S. Shawl; P. Sultan; Tej Krishan; Ghulam Nabi Qazi
We have evaluated the effect of variation in aryl-tetralin lignans on the radioprotective properties of Podophyllum hexandrum. Two fractionated fractions of P. hexandrum [methanolic (S1) and chloroform fractions (S2)], with varying aryl-tetralin lignan content were utilized for the present study. The peroxyl ion scavenging potentials of S1 and S2 were found to be comparable [i.e. 45.88% (S1) and 41% (S2)] after a 48 h interval in a time-dependent study, whereas in a 2 h study, S2 exhibited significant (P < 0.05) antioxidant activity in different metal ion + flux states. In the aqueous phase, S2 exhibited non-site-specific reactive oxygen species scavenging activity, i.e. 73.12% inhibition at 500 μg ml−1. S1 exhibited 58.40 ± 0.8% inhibition (at 0.025 μg ml−1) of the formation of reactive nitrite radicals, comparable to S2 (52.45 ± 0.825%), and also showed 45.01% site-specific activity (1000 μg ml−1), along with significant (P < 0.05) electron donation potential (50–2000 μg ml−1) compared to S2. Such activities of S1 could be attributed to the significantly (P < 0.05) higher levels of podophyllotoxin β-d-glucopyranoside (16.5 times) and demethyl podophyllotoxin glucoside (2.9 times) compared with S2. Together, these findings clearly prove that aryl-tetralin lignan content influences the radiation protective potential of the Podophyllum fractions to a great extent.
Evidence-based Complementary and Alternative Medicine | 2011
Rajesh Arora; Raman Chawla; Rohit Marwah; Preeti Arora; Rupam Sharma; Vinod Kaushik; Rajeev Goel; A. Kaur; M. Silambarasan; R. P. Tripathi; Janak Raj Bhardwaj
The emergence of novel H1N1 has posed a situation that warrants urgent global attention. Though antiviral drugs are available in mainstream medicine for treating symptoms of swine flu, currently there is no preventive medicine available. Even when available, they would be in short supply and ineffective in a pandemic situation, for treating the masses worldwide. Besides the development of drug resistance, emergence of mutant strains of the virus, emergence of a more virulent strain, prohibitive costs of available drugs, time lag between vaccine developments, and mass casualties would pose difficult problems. In view of this, complementary and alternative medicine (CAM) offers a plethora of interesting preventive possibilities in patients. Herbs exhibit a diverse array of biological activities and can be effectively harnessed for managing pandemic flu. Potentially active herbs can serve as effective anti influenza agents. The role of CAM for managing novel H1N1 flu and the mode of action of these botanicals is presented here in an evidence-based approach that can be followed to establish their potential use in the management of influenza pandemics. The complementary and alternative medicine approach deliberated in the paper should also be useful in treating the patients with serious influenza in non pandemic situations.
Journal of Pharmacy and Bioallied Sciences | 2010
Vinod Kumar; Rajeev Goel; Raman Chawla; M Silambarasan; Rakesh Kumar Sharma
Chemical, biological, radiological, and nuclear (CBRN) decontamination is the removal of CBRN material from equipment or humans. The objective of the decontamination is to reduce radiation burden, salvage equipment, and materials, remove loose CBRN contaminants, and fix the remaining in place in preparation for protective storage or permanent disposal work activities. Decontamination may be carried out using chemical, electrochemical, and mechanical means. Like materials, humans may also be contaminated with CBRN contamination. Changes in cellular function can occur at lower radiation doses and exposure to chemicals. At high dose, cell death may take place. Therefore, decontamination of humans at the time of emergency while generating bare minimum waste is an enormous task requiring dedication of large number of personnel and large amount of time. General principles of CBRN decontamination are discussed in this review with emphasis on radiodecontamination.
Pharmacology, Biochemistry and Behavior | 2005
Ashok Sharma; Anupum Haksar; Raman Chawla; Raj Kumar; Rajesh Arora; Surender Singh; Jagdish Prasad; Fakhrul Islam; Meenakshi Arora; Rakesh Kumar Sharma
The aim of the present study was to investigate the neurobehavioral protective efficacy of a hydroalcoholic extract of ginger (Zingiber officinale Rosc.) in mitigating gamma radiation-induced conditioned taste aversion in Sprague-Dawley rats. Administration of Zingiber extract 1 h before 2-Gy gamma irradiation was effective in blocking the saccharin avoidance response for 5 post-treatment observational days, both in a dose- and time-dependent manner, with 200 mg/kg b.w. i.p. being the most effective dose. Highest saccharin intake in all the groups was observed on the fifth post-treatment day. The potential of ginger extract to inhibit lipid peroxidation induced by radiation (2 Gy) and ascorbate-ion stress in brain homogenate and its ability to scavenge highly reactive superoxide anions were evaluated. The 1000-microg/ml and 2000-microg/ml concentration of ginger extract showed the highest efficiency in scavenging free radicals and in inhibiting lipid peroxidation. The lipid peroxidation and superoxide-anion scavenging ability of the extract further supports its radioprotective properties. The results clearly establish the neurobehavioral efficacy of ginger extract and the antioxidant properties appear to be a contributing factor in its overall ability to modulate radiation-induced conditioned taste aversion. Ginger extract has tremendous potential for clinical applications in mitigation of radiation-induced emesis in humans.
Zeitschrift für Naturforschung C | 2005
Raman Chawla; Rajesh Arora; Ravinder Sagar; Satish Chander Puri; Raj Kumara; Surender Singh; Ashok Sharma; Jagdish Prasad; Haider A. Khan; Rakesh Kumar Sharma; K.L. Dhar; Michael Spiteller; Ghulam Nabi Qazi
Abstract The aqueous-ethanolic extract (AEE) of high altitude Podophyllum hexandrum has earlier been reported to render a radioprotective effect against lethal gamma radiation in in vitro model. AEE has also been reported to possess metal chelating and DNA protecting properties. The present study was undertaken to isolate and characterize the bioactive principle present in AEE and investigate its role in radiation protection. A novel molecule was found to be present in AEE and was assigned as 3-O-β-ᴅ-galactoside of quercetin by acid hydrolysis, LC-MS, LC-APCI-MS/MS and 13C NMR spectra. Various biological activities were investigated at in vitro level. The antioxidant potential of AEE in lipid and aqueous phase was determined against numerous stresses. AEE was found to be significantly (p < 0.05) protective, i.e., against Fe2+ and Cu2+-induced linoleic acid degradation, respectively. Radiationinduced lipid oxidation studies revealed that AEE maximally works at a [lignan]/0.25 kGy ratio 400 (ratio of concentration of AEE divided by the radiation dose, i.e., 0.25 kGy) and no drug-induced lipid oxidation at all concentrations tested was found. In a time-dependent study, total antioxidant activity was maximally exhibited at 1 mg/ml. The site-specific and non-site-specific deoxyribose degradation assay exhibited a dose-dependant hydroxyl scavenging potential of AEE (0.05-500 μg/ml). The anti-lipid peroxidation ability of AEE against radiation (0.25 kGy)-induced lipid peroxidation was higher in case of neural tissue homogenate as compared to kidney homogenate [activity ratio: 0.039 (brain) < 0.24 (kidney)]. The protein protection study using bovine serum albumin was also done for two time intervals (2 h and 4 h) and significant (p < 0.05) protection was observed at 500 μg/ml (> 97%). This study implies that 3-O-β-ᴅ-galactoside present in AEE renders radioprotection by protecting lipids, proteins in renal and neural model system against supra-lethal (0.25 kGy) gamma radiation.
Microbial Pathogenesis | 2016
Pallavi Thakur; Raman Chawla; Ankit Tanwar; Ankita Singh Chakotiya; Alka Narula; Rajeev Goel; Rajesh Arora; Rakesh Kumar Sharma
The multi-drug resistance offered by Carbapenem Resistant Escherichia coli (Family: Enterobacteriaceae; Class: Gammaproteobacteria) against third line antibiotics can be attributed towards its ability to develop biofilm. Such process involves adhesion and quorum-sensing induced colonization leading to biomass development. The present study explored the anti-adhesion, anti-quorum sensing and anti-biofilm potential of 05 pre-standardized potent herbals. Berberis aristata (PTRC-2111-A) exhibited maximum potential in all these activities i.e. 91.3% ± 0.05% (Anti-adhesion), 96.06% ± 0.05% (Anti-Quorum sensing) and 51.3% ± 0.07% (Anti-Biofilm formation) respectively. Camellia sinensis (PTRC-31911-A) showed both anti-adhesion (84.1% ± 0.03%) and anti-quorum sensing (90.0%) potential while Holarrhena antidysenterica (PTRC-8111-A) showed only anti-quorum sensing potential as compared to standards/antibiotics. These findings were in line with the molecular docking analysis of phytoligands against Lux S and Pilin receptors. Furthermore, the pairwise correlation analysis of the tested activities with qualitative, quantitative and bioactivity functional descriptors revealed that an increased content of alkaloid, moderate content of flavonoids and decreased content of tannins supported all the three activities. In addition, nitric oxide and superoxide scavenging activity were found to be correlated with anti-quorum sensing activity. The findings indicated clearly that B. aristata (Family: Berberidaceae) and C. sinensis (Family: Theaceae) were potent herbal leads with significant therapeutic potential which further needs to be explored at pre-clinical level in the future.