Showing papers by "Central Drug Research Institute published in 2003"

Adaptogenic effect of Bacopa monniera (Brahmi)

Abstract: As stress is linked to many diseases, research on an effective antistress agent (adaptogen) from plants has gained importance. We report the investigations on the adaptogenic property of a standardized extract of Bacopa monniera against acute (AS) and chronic stress (CS) models in rats. Panax root powder (Panax quinquefolium) was taken as a standard. Male SD rats, weighing 180-200 g, exposed to immobilization stress for 150 min once only for AS and for seven consecutive days in CS, were fed with B. monniera or Panax root powder daily for 3 days in AS and for 7 days in CS, 45 min prior to each exposure of stress. Rats were sacrificed immediately after stress, the blood was collected, and the plasma was separated out for biochemical estimation. Adrenals, spleen, and thymus were dissected for organ weight and stomach for ulcer score. AS exposure significantly increased the ulcer index, adrenal gland weight, plasma glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatine kinase (CK) but significantly decreased the spleen weight. Pretreatment with B. monniera at 40 mg/kg po significantly reduced the AS-induced increase in the ulcer index, adrenal gland weight, plasma glucose, AST, and CK. A dose of 80 mg/kg po significantly reversed the AS-induced changes in adrenal gland weight, spleen weight, plasma glucose, ALT, and AST. Panax root powder, 100 mg/kg po, significantly reversed the AS-induced changes in spleen weight, plasma ALT, AST, and CK. CS exposure resulted in a significant increase in the ulcer index, adrenal gland weight, plasma AST, and CK with a significant decrease in the thymus and spleen weight, plasma triglyceride, and cholesterol. Pretreatment with low dose of B. monniera extract at 40 mg/kg significantly reversed changes in ulcer index and plasma AST only, whereas the pretreatment with higher dose significantly reversed CS-induced changes in ulcer index, adrenal gland weight, CK, and AST. Panax root powder significantly reversed CS-induced increase in ulcer index, adrenal gland weight, CK, and AST. On the basis of our result, it is concluded that the standardized extract of B. monniera possesses a potent adaptogenic activity.

Modulation of inflammatory mediators by ibuprofen and curcumin treatment during chronic inflammation in rat.

Abstract: Inflammation is a protective tissue response occurring in three distinct phases, acute, subacute and a chronic proliferative phase. We undertook the present study to understand the overall immune response of the body during adjuvant induced chronic inflammation in rat and the effect of ibuprofen and curcumin on this response. Inflammatory mediators were estimated on day 21 and day 35 after adjuvant injection. The level of C-reactive protein increased to 200% on day 21 and then reduced to 50% on day 35 compared to control. Curcumin and ibuprofen further reduced the increased levels at both the time intervals. Haptoglobin level decreased to 42% on day 21 but increased to 5 times of control on day 35. Curcumin and ibuprofen reduced the increased levels at day 35. No significant change was observed in Prostaglandin-E2 and Leukotriene-B4 levels and in Lymphocyte proliferation. The level of Tumor Necrosis Factor-alpha increased by three folds on day 21, but came down to 88% on day 35. Ibuprofen treatment decreased the raised level on day 21 and increased the reduced level on day 35. Interleukin-1beta increased to 2 folds on day 21 and 10 folds on day 35 which were significantly brought down by curcumin and ibuprofen. Nitric oxide level was reduced at both the time intervals, which were increased by drug treatment.

Comparison of MLR, PLS and GA-MLR in QSAR analysis*

Abstract: The use of the internet has evolved in quantitative structure-activity relationship (QSAR) over the past decade with the development of web based activities like the availability of numerous public domain software tools for descriptor calculation and chemometric toolboxes. The importance of chemometrics in QSAR has accelerated in recent years for processing the enormous amount of information in form of predictive mathematical models for large datasets of molecules. With the availability of huge numbers of physicochemical and structural parameters, variable selection became crucial in deriving interpretable and predictive QSAR models. Among several approaches to address this problem, the principle component regression (PCR) and partial least squares (PLS) analyses provide highly predictive QSAR models but being more abstract, they are difficult to understand and interpret. Genetic algorithm (GA) is a stochastic method well suited to the problem of variable selection and to solve optimization problems. Consequently the hybrid approach (GA-MLR) combining GA with multiple linear regression (MLR) may be useful in derivation of highly predictive and interpretable QSAR models. In view of the above, a comparative study of stepwise-MLR, PLS and GA-MLR in deriving QSAR models for datasets of alpha1-adrenoreceptor antagonists and beta3-adrenoreceptor agonists has been carried out using the public domain software Dragon for computing descriptors and free Matlab codes for data modeling.

Perspective in antimalarial chemotherapy.

Abstract: Antimalarial chemotherapy has become more complex and challenging because of multidrug resistant strains of Plasmodium falciparum. Due to resistance of malarial parasite against well known drugs, the chemotherapy of malaria has become complicated. In this review we have discussed brief introduction followed by life cycle of malaria parasite. The list of commercially available antimalarial drugs along with there action on different stages of parasite have been discussed. A brief description of their mechanism of action and advantages and disadvantages were reported. The natural products as antimalarial have been discussed in the review. On the basis of chemical classes the natural products were divided in the following categories; Quinoline alkaloids, Iso-quinoline alkaloids, Indoloquinoline alkaloids, Carbolines, Bis-isoquinoline, 4-Quinazole derivatives, Trioxanes, Terpenes, Naphthoquinone, Anthraquinones, Chalcones, Hydroxy flavanones, Coumarins and phenolic glycoside. The combination chemotherapy has been highlighted in the review. The Biochemical and Immunological changes in malarial infection are discussed along with complications of malarial chemotherapy due to resistance. In the conclusion section, the future strategies for the chemotherapy of malaria have been discussed.

Synthesis of aminonicotinonitriles and diaminopyridines through base-catalyzed ring transformation of 2H-pyran-2-ones.

Abstract: An efficient and convenient synthesis of 2-amino-6-aryl-4-methylsulfanylnicotinonitriles (2), 2-amino-6-aryl-4-substituted-aminonicotinonitriles (4), and 2-amino-6-aryl-4-substituted-aminopyridines (6) has been delineated and illustrated through base-catalyzed ring transformation of 6-aryl-3-cyano-4-methylsulfanyl/substituted-amino-2H-pyran-2-ones (1, 3, and 5) with cyanamide and ammonium carbonate separately.

Novel Mechanism of Drug Resistance in Kala Azar Field Isolates

Abstract: Clinical resistance to pentavalent antimonial drugs in the form of sodium antimony gluconate (SAG) has become a major problem in the treatment of kala azar (visceral leishmaniasis) in India. The mechanism of resistance is unclear in these clinical isolates, although work has been conducted with Leishmania species mutants selected in vitro by stepwise increase of drug concentration, using antimony-related metal arsenic and, more recently, SAG. In the present study, we investigated the molecular aspect of drug resistance in clinically confirmed SAG-resistant field isolates. Our results show that the mechanisms of resistance postulated for laboratory mutants of Leishmania species are not operating in field isolates of Leishmania donovani. Instead, we identified a novel gene amplified in these drug-resistant parasites whose locus is on chromosome 9. The significant finding was that this isolated fragment confers antimony resistance to wild-type Leishmania species after transfection. We speculate that protein phosphorylation may play a role in signal transduction pathway in the parasite after exposure to drug-conferring resistance.

A Combinatorial Approach to the Variable Selection in Multiple Linear Regression: Analysis of Selwood et al. Data Set – A Case Study

Abstract: A combinatorial protocol (CP) is introduced here to interface it with the multiple linear regression (MLR) for variable selection. The efficiency of CP-MLR is primarily based on the restriction of entry of correlated variables to the model development stage. It has been used for the analysis of Selwood et al data set [16], and the obtained models are compared with those reported from GFA [8] and MUSEUM [9] approaches. For this data set CP-MLR could identify three highly independent models (27, 28 and 31) with Q 2 value in the range of 0.632 -0.518. Also, these models are divergent and unique. Even though, the present study does not share any models with GFA [8], and MUSEUM [9] results, there are several descriptors common to all these studies, including the present one. Also a simulation is carried out on the same data set to explain the model formation in CP-MLR. The results demonstrate that the proposed method should be able to offer solutions to data sets with 50 to 60 descriptors in reasonable time frame. By carefully selecting the interparameter correlation cutoff values in CP-MLR one can identify divergent models and handle data sets larger than the present one without involving excessive computer time.

Cardioprotective activity of synthetic guggulsterone (E and Z-isomers) in isoproterenol induced myocardial ischemia in rats: A comparative study

Abstract: Guggulsterone, a mixture of cis (E) and trans (Z) isomers (7∶3 w/w) was synthesized from 16-DPA. The isomers were separated by column chromatography and evaluated for cardioprotective and antioxidant activities. Myocardial necrosis induced by isoproterenol in rats caused marked increase in serum creatine phosphokinase and glutamate pyruvate transaminase. Simultaneously in ischemic heart, phospholipase, xanthine oxidase and lipid peroxides were enhanced following depletion of glycogen, phospholipids and cholesterol. Treatment with guggulsterone and its both isomers at the dose of 50 mg/kg po., significantly protected cardiac damage as assessed by the reversal of blood and heart biochemical parameters in ischemic rats. The cardioprotective activity of guggulsterone and of both the isomers were compared with that of gemfibrozil at the same doses. Guggulsterone and both the isomers at tested concentrations (5-20mM) inhibited oxidative degradation of lipids in human low-density lipoprotein and rat liver microsomes induced by metal ionsin vitro. The drug counteracted against the generation of superoxide anions (O(2)) and hydroxyl radicals (OH(-)) in non-enzymic test systems. It is suggested that cardioprotective and antioxidant activities of synthetic guggulsterone and guggulsterone obtained from gum resinCommiphora mukul that contains isomers E & Z in the ratio of 46∶54w/w are the same.

Swertia chirayita Mediated Modulation of Interleukin‐1β Interleukin‐6, Interleukin‐10, Interferon‐γ, and Tumor Necrosis Factor‐α in Arthritic Mice

Abstract: The effect of aqueous extract of Swertia chirayita stem on the pro- and anti-inflammatory cytokines balance in primary joint synovium of adjuvant-induced arthritic mice has been studied. The level of pro-inflammatory cytokines was found elevated in the joint synovium of arthritic mice in comparison to normal joints. Administration of S. chirayita extract in varying doses through the oral route did not modulate the proinflammatory cytokines on day 2. In contrast, by day 12, a dose dependent (0, 11.86 and 23.72 mg/kg body weight) reduction of tumor necrosis factor-alpha (INF-alpha) interleukin-1beta, (IL-beta) and interferon-gamma, (IFN-gamma) and elevation of Interleukin-10 (IL-10) was observed in the joint homogenates of arthritic mice. Interleukin-6 (IL-6) was not down regulated in joint homogenate of arthritic mice at the dose 11.86 mg/kg but at higher doses (23.72 and 35.58 mg/kg) significant reduction was observed. The aqueous extract was found to possess two polar compounds, amerogentin and mangiferin but was devoid of swerchirin, chiratol, methyl swetianin, and swertanone. Mangiferin has been reported to possess potent anti-inflammatory property and we presume its presence in the aqueous extract of S. chirayita is responsible for reducing TNF-alpha, IL-1beta, IL-6, and IFN-gamma and/or elevating IL-10 in the joint homogenates of arthritic mice on day 12. This study will help in our understanding of the mechanism of anti-inflammatory action of S. chirayita in the light of proinflammatory and anti-inflammatory cytokine balance.

Comparative study of perturbations of peripheral markers in different stressors in rats.

Abstract: Stress has been implicated in the etiopathogenesis of several diseases. In the present study, the effects of acute (AS), chronic (CS), and chronic unpredictable stress (CUS) were studied on the ulcer index, adrenal gland mass, and biochemical and hormonal changes in rats. The stress was provided in the form of immobilization-immobilization for 150 min, once only, and for 10 consecutive days in CS and CUS. In CUS, animals received variable unpredictable stressors. Immediately after stress, animals were decapitated, blood was collected, and plasma was separated for the estimation of plasma glucose, triglyceride, cholesterol, creatine kinase (CK), corticosterone, and insulin. The adrenal gland and stomach were also dissected for mass and ulcer scoring, respectively. AS significantly increased the ulcer index, plasma glucose, CK, corticosterone, and insulin. CS and CUS significantly increased the ulcer index, adrenal gland mass, and corticosterone. In CS, a significant decrease in plasma triglyceride and cholesterol levels was found, but in CUS only cholesterol was decreased significantly. High CK activity and hyperglycemia maintain the energy demands of metabolism, and elevated corticosterone desensitizes the insulin receptor in AS. In CS and CUS, prolonged elevation of corticosterone shifts metabolism to utilization of lipids as a secondary substrate by gluconeogenesis. From our experiment, it is clear that AS causes maximum activation of energy metabolism, which becomes specific after habituation in prolonged CS. These biochemical manipulations in the body by using different types of stressors are good markers that can be of great use to understand, target, and manage stress-induced etiologies.