Showing papers by "Central Drug Research Institute published in 1999"

Curcumin enhances wound healing in streptozotocin induced diabetic rats and genetically diabetic mice

Abstract: Tissue repair and wound healing are complex processes that involve inflammation, granulation and tissue remodeling. Interactions of different cells, extracellular matrix proteins and their receptors are involved in wound healing, and are mediated by cytokines and growth factors. Previous studies from our laboratory have shown that curcumin (diferuloylmethane), a natural product obtained from the rhizomes of Curcuma longa, enhanced cutaneous wound healing in rats and guinea pigs. In this study, we have evaluated the efficacy of curcumin treatment by oral and topical applications on impaired wound healing in diabetic rats and genetically diabetic mice using a full thickness cutaneous punch wound model. Wounds of animals treated with curcumin showed earlier re-epithelialization, improved neovascularization, increased migration of various cells including dermal myofibroblasts, fibroblasts, and macrophages into the wound bed, and a higher collagen content. Immunohistochemical localization showed an increase in transforming growth factor-β1 in curcumin-treated wounds compared to controls. Enhanced transforming growth factor-β1 mRNA expression in treated wounds was confirmed by in situ hybridization, and laser scan cytometry. A delay in the apoptosis patterns was seen in diabetic wounds compared to curcumin treated wounds as shown by terminal deoxynucleotidyl transferase–mediated deoxyuridyl triphosphate nick end labeling analysis. Curcumin was effective both orally and topically. These results show that curcumin enhanced wound repair in diabetic impaired healing, and could be developed as a pharmacological agent in such clinical settings.

Asiaticoside‐induced elevation of antioxidant levels in healing wounds

Abstract: Asiaticoside derived from the plant Centella asiatica is known to possess good wound healing activity. Enhanced healing activity has been attributed to increased collagen formation and angiogenesis. Since antioxidants have been reported to play a significant role in the wound healing process we studied the effect of asiaticoside on the levels of certain antioxidants in the wound so as to explore the possible involvement of such a mechanism in the asiaticoside induced wound healing. Asiaticoside application (0.2%, topical) twice daily for 7 days to excision-type cutaneous wounds in rats led to increased enzymatic and non-enzymatic antioxidants, namely superoxide dismutase (35%), catalase (67%), glutathione peroxidase (49%), vitamin E (77%) and ascorbic acid (36%) in newly formed tissues. It also resulted in a several fold decrease in lipid peroxide levels (69%) as measured in terms of thiobarbituric acid reactive substance. However, continued application for 14 days showed no significant difference in these antioxidants compared with their values in vehicle treated wound tissue. It appears from the present study that asiaticosides enhanced induction of antioxidant levels at an initial stage of healing which may be an important contributory factor in the healing properties of this substance.

Efficacy of Curcumin in the Management of Chronic Anterior Uveitis

Abstract: Curcumin, obtained from rhizomes of Curcuma longa, was administered orally to patients suffering from chronic anterior uveitis (CAU) at a dose of 375 mg three times a day for 12 weeks. Of 53 patients enrolled, 32 completed the 12-week study. They were divided into two groups: one group of 18 patients received curcumin alone, whereas the other group of 14 patients, who had a strong PPD reaction, in addition received antitubercular treatment. The patients in both the groups started improving after 2 weeks of treatment. All the patients who received curcumin alone improved, whereas the group receiving antitubercular therapy along with curcumin had a response rate of 86%. Follow up of all the patients for the next 3 years indicated a recurrence rate of 55% in the first group and of 36% in the second group. Four of 18 (22%) patients in the first group and 3 of 14 patients (21%) in the second group lost their vision in the follow up period due to various complications in the eyes, e.g. vitritis, macular oedema, central venous block, cataract formation, glaucomatous optic nerve damage etc. None of the patients reported any side effect of the drug. The efficacy of curcumin and recurrences following treatment are comparable to corticosteroid therapy which is presently the only available standard treatment for this disease. The lack of side effects with curcumin is its greatest advantage compared with corticosteroids. A double blind multi-centric clinical trial with this drug in CAU is highly desirable to further validate the results of the present study.

Evaluation of metronidazole toxicity: a prospective study.

Abstract: Metronidazole is an antimicrobial, antiprotozoal agent that has been widely used in the treatment of a variety of infections. Some therapeutic indications necessitate prolonged treatment with metronidazole. Peripheral neuropathy is a potential metronidazole-induced toxicity, which has been reported in only a few isolated retrospective studies. This prospective study was designed to determine the toxic profile of metronidazole in patients undergoing long-term treatment with this drug. In the present study, 17 patients of both sexes, aged between 20 and 50 years, with body weights ranging from 46 to 62 kg and who were suffering from various medical ailments were recruited. The patients received 400 mg t.i.d. oral metronidazole in a total dose of 16.8-39.6 g for 2-4 weeks. It was found that patients usually suffered from some of the toxic symptoms of metallic taste, headache and dry mouth and to a lesser extent nausea, glossitis, urticaria, pruritus, urethral burning and dark colored urine. Symptoms were irrespective of sex and directly proportional to duration of therapy. Deep tendon ankle jerks were maximally reduced in four patients and sense of vibration at the level of olecranon and patella was affected in two patients. Distal latency and velocity of the sural and posterior tibial nerves were significantly affected (p < 0.01) compared with control values. These results indicate possible motor-sensory neurotoxicity involving the lower limbs due to long-term metronidazole therapy.

8-anilino-1-naphthalene sulfonic acid (ANS) induces folding of acid unfolded cytochrome c to molten globule state as a result of electrostatic interactions.

Abstract: Hydrophobic interaction of 8-anilino-1-naphthalene sulfonic acid (ANS) with proteins is one of the widely used methods for characterizing/detecting partially folded states of proteins. We have carried out a systematic investigation on the effect of ANS, a charged hydrophobic fluorescent dye, on structural properties of acid-unfolded horse heart cytochrome c at pH 2.0 by a combination of optical methods and electrospray ionization mass spectroscopy (ESI MS). ANS was found to induce, a secondary structure similar to native protein and quenching of fluorescence of tryptophan residue, in the acid-unfolded protein. However, the tertiary structure was found to be disrupted thus indicating that ANS stabilizes a molten globule state in acid-unfolded protein. To understand the mechanism of ANS-induced folding of acid-unfolded cytochrome c, comparative ESI MS, soret absorption, and tryptophan fluorescence studies using nile red, a neutral hydrophobic dye, and ANS were carried out. These studies suggested that, at low pH, electrostatic interactions between negatively charged ANS molecules and positively charged amino acid residues present in acid-unfolded cytochrome c are probably responsible for ANS-induced folding of acid-unfolded protein to partially folded compact state or molten globule state. This is the first experimental demonstration of ANS induced folding of unfolded protein and puts to question the usefulness of ANS for characterization/determination of partially folded intermediates of proteins observed under low pH conditions.

Nitric oxide inhibits wound collagen synthesis

Abstract: Nitric oxide (NO) is a messenger molecule which regulates many physiological functions like immunity, vascular tone and serves as a neurotransmitter. Although it is known to participate in healing process, its role in collagen synthesis is not clear. Therefore, the present investigation was done to study the role of NO in wound collagen synthesis. Rats received full thickness, circular (8 mm), transdermal wounds which were treated with NO releaser, sodium nitroprusside (SNP, 0.001 100 μM) topically for 5 days. Wound collagen content estimated in terms of hydroxyproline (HP) and confirmed histochemically was decreased significantly by all SNP doses. L-Arginine, a substrate for nitric oxide synthase (NOS) when applied topically decreased collagen content of the wounded tissues. N-Nitro-L-arginine methyl ester (L-NAME), a competitive inhibitor of NOS, increased wound collagen content significantly as compared to untreated and SNP treated animal wounds when administered intraperitoneally at the doses 3, 10 and 30 mg/kg. Furthermore, histological findings also demonstrated laying down of thick collagen bundles and proliferation of fibroblasts together with prominent angiogenesis in L-NAME treated wound tissues as compared to untreated and SNP treated tissues. N-nitro-D-arginine methyl ester, an inactive isomer, was found to have no effect on wound collagen levels. When L-arginine was administered in L-NAME pretreated rats, it significantly elevated wound HP content. The results indicate that NO plays an important role in regulating the collagen biosynthesis in skin model of a healing wound.

Hepatoprotective activity of ellagic acid against carbon tetrachloride induced hepatotoxicity in rats.

Abstract: Administration of CCl4 to normal rats and consequent oral feeding with ellagic acid (50 mg/kg) provided a significant protection against the biochemical alterations in serum and liver produced by CCl4. In vitro experiments showed that liver microsomes from animals treated with ellagic acid and CCl4, decreased lipid peroxidation compared to microsome prepared from rats exposed to CCl4 alone.

Asymmetric distribution of phosphatidylethanolamine in C. albicans: possible mediation by CDR1, a multidrug transporter belonging to ATP binding cassette (ABC) superfamily.

Abstract: By using two molecular probes, we demonstrate that only 4% of total phosphatidylethanolamine (PtdEtn) in the plasma membrane (PM) of a human pathogenic yeast, Candida albicans, is present in its external half Evidence is presented to show that the availability of PtdEtn could be related to the expression of a multidrug transporter CDR1 of C albicans, and the process is energy-dependent A homozygous CDR1 disruptant strain of C albicans shows almost 23% reduction in the external labelling of PtdEtn This report shows that, similar to human MDRs, yeast multidrug transporter could also be involved in aminophospholipid translocation

Glutathione-S-transferase activity in malarial parasites.

Abstract: Summary Glutathione-S-transferase (GST) activity has been detected in rodent (Plasmodium berghei, P. yoelii), simian (P. knowlesi) and human (P. falciparum) malarial parasites, and in different intraerythrocytic stages of P. knowlesi (schizont > ring > trophozoite). In chloroquine-resistant strains of rodent and human malarial parasites GST activity significantly increases compared to sensitive strains. Further, the increase in enzyme activity is directly related to drug pressure of resistant P. berghei. Complete inhibition of chloroquine-sensitive and resistant P. berghei glutathione-S-transferase activities was observed at 2.5 and 5.0 μm concentration of hemin, respectively. An inverse relationship was found between the heme level and enzyme activity of chloroquine-resistant and sensitive P. berghei. Chloroquine, artemisinin, and primaquine noticeably inhibited GST activity in P. knowlesi.

Potent 1,3-disubstituted-9H-pyrido[3,4-b]indoles as new lead compounds in antifilarial chemotherapy.

Abstract: Substituted 9H-pyrido[3,4-b]indoles (beta-carbolines), identified in our laboratory as potential pharmacophores for designing macrofilaricidal agents, have been explored further for identifying the pharmacophore responsible for the high order of adulticidal activity. This has led to syntheses and macrofilaricidal evaluations of a number of 1-aryl-9H-pyrido[3,4-b]indole-3-carboxylate derivatives (3-7). The macrofilaricidal activity was initially evaluated in vivo against Acanthoeilonema viteae. Among all the synthesized compounds, only 12 compounds, namely 3a, 3c, 3d, 3f, 4c, 4d, 4f, 5a, 6f, 6h, 6i, and 7h, have exhibited either >90% micro- or macrofilaricidal activity or sterlization of female worms. These compounds have also been screened against Litomosoides carinii, and of these only 3f and 5a have also been found to be active. Finally these two compounds have been evaluated against Brugia malayi. The structure-activity relationship (SAR) associated with position 1 and 3 substituents in beta-carbolines has been discussed. It has been observed that the presence of a carbomethoxy at position 3 and an aryl substituent at position 1 in beta-carbolines effectively enhances antifilarial activity particularly against A. viteae. Among the various compounds screened, methyl 1-(4-methylphenyl)-9H-pyrido[3,4-b]indole-3-carboxylate (4c) has shown the highest adulticidal activity and methyl 1-(4-chlorophenyl)-1,2,3,4-tetrahydro-9H-pyrido[3, 4-b]indole-3-carboxylate (3a) has shown the highest microfilaricidal action against A. viteae at 50 mg/kg x 5 days (ip). Another derivative of this compound, namely 1-(4-chlorophenyl)-3-(hydroxymethyl)-9H-pyrido[3,4-b]indole (5a), exhibited the highest activity against L. carinii at 30 mg/kg x 5 days (ip) and against B. malayiat 50 mg/kg x 5 days (ip) or at 200 mg/kg x 5 days (po).

Antigiardial and immunostimulatory effect of Piper longum on giardiasis due to Giardia lamblia.

Abstract: Piper longum fruit, used in traditional remedies as well as in the Ayurvedic system of medicine against intestinal disorders, was tested for its efficacy against experimental infection of Giardia lamblia in mice. On in vitro test, an aqueous extract of P. longum fruit powder (PF) at 250 microg/mL and its ethanol extract at 125 microg/mL showed 100% giardicidal activity. A low order activity was found in the n-butanol extract. Further fractionation in hexane and chloroform resulted in a total loss of activity. The survival of-trophozoites in mice at 900 mg/kg body weight was 11.12 in PF, 8. 54 in aqueous extract, 5.81 in ethanol extract. The antigiardial activity of PF in hexane, chloroform and n-butanol soluble fractions was comparable to the drug-untreated control (47.63). Piper longum possessed a demonstrable immunostimulatory activity, both specific and nonspecific, as evident from the standard test parameters such as haemagglutination titre (HA), plaque forming cell (PFC) counts, macrophage migration index (MMI) and phagocytic index (PI). A maximum effect was found at 225 mg/kg body weight in mice. The effect was marginally reduced at higher doses of 450 and 900 mg/kg or the lower dose of 112.5 mg/kg.

Effect of a Carbon Dioxide Laser on Periodontally Involved Root Surfaces

Abstract: Background: The purpose of this in vitro study was to evaluate the effect of CO2 laser on the periodontally involved root surface, and to compare its efficacy with citric acid, EDTA and hydrogen peroxide in removal of root surface smear layer after root planing. Methods: The study was conducted on 50 periodontally involved single rooted human teeth with poor prognosis. Immediately after extraction the teeth were scaled and root planed with Gracey curets; 50 specimens were obtained from the proximal side of each tooth which were assigned randomly to 1 of the 4 groups. Group A (35 specimens) was divided into 7 subgroups of 5 specimens each and irradiated with CO2 laser using a defocused mode at 3-watt power for 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, or 1.4 seconds, respectively. Groups B, C, and D (5 specimens each) were treated with 6% hydrogen peroxide, EDTA solution (pH 7.4), or saturated citric acid solution (pH 1), respectively for 3 minutes. The specimens were then fixed and scanned using SEM. Results: It was ...

Cadmium induced hypertension.

Abstract: The effect of cadmium acetate (0.32, 1.0, 3.2 mg/kg) and (1, 3.2, 10 μg) injected intravenously (i.v.) and intracerebroventricularly (i.c.v.) respectively in urethane anesthetized male Sprague-Dawley (S-D) rats on blood pressure was examined. Cadmium injected (i.v.) produced transient fall in blood pressure followed by persistent rise. Hypertensive response in rats was dose and time dependent on intravenous cadmium administration. Cadmium (i.c.v.) produced statistically significant (p<0.01) hypertensive response at different time intervals as compared to saline treated controls. Repeated administration of cadmium (1 mg/kg i.p. for 5 days) produced increase in blood pressure. In four groups of rats treated with cadmium (1 mg/kg i.p. for 5 days), blood pressure was recorded 2,4,10,15 days after stopping the cadmium treatment. Blood pressure values at 2, 4, 10 days after stopping cadmium treatment were statistically significant (p<0.01). However, in the last group, blood pressure values were not statisticall...

Chromium(III) interactions with nucleosides and nucleotides: a mass spectrometric study.

Abstract: Interactions of [Cr(salprn)(H2O)2]ClO4 with nucleosides and dinucleotides were studied using electrospray ionization mass spectrometry. The nucleosides 2′-deoxycytidine, thymidine, 2′-deoxyadenosine, 2′-deoxyguanosine, cytidine, adenosine and guanosine form 1 : 1 and 2 : 1 adducts with [Cr(salprn)]+, whereas the dinucleotides CpG, GpC, ApT, TpA and TpC form only the 1 : 1 adducts. Collisional activation (CA) spectra of these adducts reveal that Cr+ attaches to the bases in nucleosides and to both the phosphate and base, especially cytosine and guanine moieties, in the nucleotides. The sugar residues appear to offer no binding sites as elimination of sugar residues is fairly abundant in the CA spectra of the adducts of many of the nucleosides. Copyright © 1999 John Wiley & Sons, Ltd.

Comparative antimutagenic effects of D- and L-centchroman and their comparison with tamoxifen in Salmonella assay.

Abstract: Centchroman (CC)--a contraceptive and a candidate drug for breast cancer has been developed by the Central Drug Research Institute. It has been successfully marketed as a contraceptive for last several years. CC has also been reported to exhibit partial to complete remission of lesions in 40.5% breast cancer patients. Recently, we have reported the antimutagenic effects of CC in Ames Salmonella assay and in vivo and in vitro mammalian cells in multiple mutational assay. The potent antimutagenic activity of CC and its anti-breast cancer activity prompted us to evaluate the antimutagenic effects of its enantiomers, i.e., D-centchroman (DC) and L-centchroman (LC) in the Ames Salmonella strains TA97a, TA98, TA100 and TA102 against known bacterial mutagens. Attempts have also been made to compare the results of antimutagenicity assays of CC and its enantiomers with the known breast cancer drug tamoxifen (TM). The main objective was to identify the best suitable form of CC having antimutagenic effects with anticancer profile similar to TM, would replace the latter for toxicity reasons. When mutagenicity assays were carried out with these compounds as expected like CC, none of these enantiomers or TM showed any mutagenic effects in these Salmonella strains. In the antimutagenicity assay a significantly reduced number of bacterial histidine revertant colonies were observed when positive compounds were co-incubated with certain concentrations of LC compared with bacterial plates treated with respective positive compound. This was observed in some concentrations in all the four strains in both plate incorporation and preincubation tests. The protective effects of LC in preincubation tests were slightly more than in plate incorporation tests. Both the DC and TM showed protective effects only in certain concentrations in some strains in either plate or preincubation tests. Thus the above results indicate that LC showed more protective effects in Salmonella strains TA97a, TA98, TA100 and TA102 than either DC or TM.

Protective effect of ellagic acid on t-butyl hydroperoxide induced lipid peroxidation in isolated rat hepatocytes.

Abstract: Lipid peroxidation results in severe damage to cellular membranes, and organelles in biochemical systems'. Ellagic acid (EA) is a naturally occurring polyphenol which is present in certain food items and is known to bring about effective protection against oxidative stress 2 . In the present study inhibitory effect of EA has been evaluated on generation of superoxide anions (0-2) and hydroxyl radical s (OR) and consequent formation of lipid peroxide induced by tert-butyl hydroperoxide (t-butyl-OOH) with isolated rat hepatocytes as in vitro mode!. Male adult rats of Charles Foster strain (200-250g) were used for isolation of hepatocytes by collagenase as described by Seglen 3 with some modifications 4 . These hepatocytes were suspended in buffer containing NaCI 0.83 %, KCI 0.05 %, HEPES 0.24%; pH 7.4 and viable cells identified using try pan blue solution (0.02% w/v) in methanol. A portion of cell snspensIOn was precipitated with 10% TCA and precipitate assayed for protein . Remaining hepatocytes suspension was then diluted with same buffer to a final concentration of 10 mg protein/m!. The reaction mixture containing 0.1 rnl hepatocytes and 10 III of lOO-fold diluted t-butyl-OOH (70% v/v aqu soln) in absence or presence of EA in a final volume of 1.5 rnl in above HEPES buffer, was incu­ bated at 37°C for 4 hr. The viability of incubated hepatocytes was determined using trypan blue dye_ The reaction mixture was delipidated with CHCh: CH30H (2:1) mixture and the delipidated fraction assayed for lipid peroxideS _ . The effect of EA on generation of 0-2 in both