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16. Antioxidant and hepatoprotective activity of some dimethoxy flavones
N. Jayshree,N. Narayanan
International Journal of Pharmaceutical and Biomedical Research (IJPBR) , 2011,
Abstract: Liver is one of the most important organs of the body. Any untreated injury to the liver leads to progression to liver fibrosis and cirrhosis of the liver. Paracetamol in high doses is known to be hepatotoxic and this is mainly due to the release of free radicals. Hence compounds with antioxidant properties are considered to be potential hepatoprotective agents. Naturally occurring flavonoids are known to be potent antioxidants and by virtue of this activity are also known to possess hepatoprotective ability. The present study was undertaken to determine the antioxidant and hepatoprotective activity of 3 synthetic flavones namely 3,6-dimethoxy flavone (3,6-DMF), 6,2'-dimethoxy flavone (6,2'-DMF) and 6,3'-dimethoxy flavone (6,3'-DMF).The antioxidant activity was determined by testing their ability to scavenge DPPH and hydroxyl radicals. The acute toxicity studies were carried out to determine the safety of the compounds. For evaluating the hepatoprotective ability, Paracetamol induced hepatotoxic model was used. All the three compounds exhibited good antioxidant activity which was comparable to the standard compound Vitamin E. Of the three compounds, 6,3'-DMF showed the best activity. The acute toxicity studies revealed that all the 3 compounds were safe even at the dose level of 2000mg/kg. The compounds were tested for hepatoprotective ability at 2 dose levels of 50 and 100mg/kg s.c. and the activity was compared with the standard drug Silymarin at the dose of 50mg/kg p.o. All the three compounds showed hepatoprotection at both the dose levels tested but the activity was more significant at the higher dose level. Thus it can be concluded that the synthetic dimethoxy flavones 3,6-DMF, 6,2'-DMF and 6,3'-DMFare potential hepatoprotectants and this activity could be mediated by their antioxidant property.
Overexpression of Hydroxynitrile Lyase in Cassava Roots Elevates Protein and Free Amino Acids while Reducing Residual Cyanogen Levels
Narayanan N. Narayanan,Uzoma Ihemere,Claire Ellery,Richard T. Sayre
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0021996
Abstract: Cassava is the major source of calories for more than 250 million Sub-Saharan Africans, however, it has the lowest protein-to-energy ratio of any major staple food crop in the world. A cassava-based diet provides less than 30% of the minimum daily requirement for protein. Moreover, both leaves and roots contain potentially toxic levels of cyanogenic glucosides. The major cyanogen in cassava is linamarin which is stored in the vacuole. Upon tissue disruption linamarin is deglycosylated by the apolplastic enzyme, linamarase, producing acetone cyanohydrin. Acetone cyanohydrin can spontaneously decompose at pHs >5.0 or temperatures >35°C, or is enzymatically broken down by hydroxynitrile lyase (HNL) to produce acetone and free cyanide which is then volatilized. Unlike leaves, cassava roots have little HNL activity. The lack of HNL activity in roots is associated with the accumulation of potentially toxic levels of acetone cyanohydrin in poorly processed roots. We hypothesized that the over-expression of HNL in cassava roots under the control of a root-specific, patatin promoter would not only accelerate cyanogenesis during food processing, resulting in a safer food product, but lead to increased root protein levels since HNL is sequestered in the cell wall. Transgenic lines expressing a patatin-driven HNL gene construct exhibited a 2–20 fold increase in relative HNL mRNA levels in roots when compared with wild type resulting in a threefold increase in total root protein in 7 month old plants. After food processing, HNL overexpressing lines had substantially reduced acetone cyanohydrin and cyanide levels in roots relative to wild-type roots. Furthermore, steady state linamarin levels in intact tissues were reduced by 80% in transgenic cassava roots. These results suggest that enhanced linamarin metabolism contributed to the elevated root protein levels.
The repertoire of G protein-coupled receptors in the sea squirt Ciona intestinalis
N Kamesh, Gopala K Aradhyam, Narayanan Manoj
BMC Evolutionary Biology , 2008, DOI: 10.1186/1471-2148-8-129
Abstract: We have identified 169 gene products in the Ciona genome that code for putative GPCRs. Phylogenetic analyses reveal that Ciona GPCRs have homologous representatives from the five major GRAFS (Glutamate, Rhodopsin, Adhesion, Frizzled and Secretin) families concomitant with other vertebrate GPCR repertoires. Nearly 39% of Ciona GPCRs have unambiguous orthologs of vertebrate GPCR families, as defined for the human, mouse, puffer fish and chicken genomes. The Rhodopsin family accounts for ~68% of the Ciona GPCR repertoire wherein the LGR-like subfamily exhibits a lineage specific gene expansion of a group of receptors that possess a novel domain organisation hitherto unobserved in metazoan genomes.Comparison of GPCRs in Ciona to that in human reveals a high level of orthology of a protochordate repertoire with that of vertebrate GPCRs. Our studies suggest that the ascidians contain the basic ancestral complement of vertebrate GPCR genes. This is evident at the subfamily level comparisons since Ciona GPCR sequences are significantly analogous to vertebrate GPCR subfamilies even while exhibiting Ciona specific genes. Our analysis provides a framework to perform future experimental and comparative studies to understand the roles of the ancestral chordate versions of GPCRs that predated the divergence of the urochordates and the vertebrates.On a taxonomic and phylogenetic scale, Ciona intestinalis is a protochordate belonging to the ascidian class of urochordates that diverged from a lineage leading to the vertebrates approximately 520 million years ago [1]. This extant ascidian occupies a crucial place in the "Tree of life" as an out-group to the vertebrates and hence studies addressing evolutionary aspects of Ciona have the potential to offer insight into some of the most intriguing questions about the origin of the vertebrates from a chordate lineage. Recent genomic analysis has shown that the urochordates, and not cephalochordates, are the closest extant relatives of ve
Multi Resolution Analysis for Consonant Classification in Noisy Environments
T M Thasleema,N K Narayanan
International Journal of Image, Graphics and Signal Processing , 2012,
Abstract: This paper investigates on the use of Wavelet Transform (WT) to model and recognize the utterances of Consonant – Vowel (CV) speech units in noisy environments. The peculiarity of the proposed method lies in the fact that using WT, non stationary nature of the speech signal can be accurately considered. A hybrid feature extraction namely Normalized Wavelet Hybrid Feature (NWHF) using the combination of Classical Wavelet Decomposition (CWD) and Wavelet Packet Decomposition (WPD) along with z-score normalization technique are studied here. CV speech unit recognition tasks performed for both noisy and clean speech units using Artificial Neural Network (ANN) and k – Nearest Neighborhood (k – NN) are also presented. The result indicates the robustness of the proposed technique based on WT in additive noisy condition.
Management of obstructive sleep apnea: A dental perspective
Padma Ariga,Ramakrishnan N,Narayanan Vinod
Indian Journal of Dental Research , 2007,
Abstract: Sleep disordered breathing is a term which includes simple snoring, upper airway resistance syndrome, and obstructive sleep apnea (OSA). Simple snoring is a common complaint affecting 45% of adults occasionally and 25% of adults habitually and is a sign of upper airway obstruction. Snoring has also been identified as a possible risk factor for hypertension, ischemic heart disease, and stroke. The role of dentistry in sleep disorders is becoming more significant, especially in co-managing patients with simple snoring and mild to moderate OSA. The practicing dental professional has the opportunity to assist patients at a variety of levels, starting with the recognition of a sleep-related disorder, referring patients to a physician for evaluation, and assisting in the management of sleep disorders. Obesity is the main predisposing factor for OSA. In nonobese patients, craniofacial anomalies like micrognathia and retrognathia may also predispose to OSA. Diagnosis of OSA is made on the basis of the history and physical examination and investigations such as polysomnography, limited channel testing, split-night testing, and oximetry. Nocturnal attended polysomnography, which requires an overnight stay in a sleep facility, is the standard diagnostic modality in determining if a patient has OSA. As far as treatment is concerned, the less invasive procedures are to be preferred to the more invasive options. The first and simplest option would be behavior modification, followed by insertion of oral devices suited to the patient, especially in those with mild to moderate OSA. Continuous positive airway pressure (CPAP) and surgical options are chosen for patients with moderate to severe OSA. The American Academy of Sleep Medicine (AAOSM) has recommended oral appliances for use in patients with primary snoring and mild to moderate OSA. It can also be used in patients with a lesser degree of oxygen saturation, relatively less day time sleepiness, lower frequency of apnea, those who are intolerant to CPAP, or those who refuse surgery. Oral appliances improve the blood oxygen saturation levels as they relieve apnea in 20-75% of patients. They reduce the apnea-hypopnea index (AHI) by 50% or to < 10 events per h. Oral appliances also reduce the AHI to normal in 50-60% patients.
Future Perspective in Carbonic Anhydrase Inhibitors and its Drugs
S.Petchimuthu,Dr. N. Narayanan
International Journal For Pharmaceutical Research Scholars , 2013,
Abstract: Through this review it is contemplated that carbonic anhydrase inhibitors, were a traditional drugs of choice for the treatment of glaucoma with a myriad of side effects and inadequate topical effectiveness, may be formulated into a topically effective agent by utilizing various newer formulation approaches of ocular drug delivery. Even though the carbonic anhydrase inhibitor, acetazolamide (ACZ) has a poor solubility and penetration power (BCS Class IV), various studies mentioned in the review indicate that it is possible to successfully formulate topically effective ACZ by using:(i) High concentration of the drug, (ii) Surfactant gel preparations of ACZ, (iii) ACZ loaded into liposomes, (iv) Cyclodextrins to increase the solubility and hence bioavailability of ACZ, and Viscolyzers and other polymers either alone or in combination with cyclodextrins. With the advent of newer topical carbonic anhydrase inhibitors (CAIs) like dorzolamide and brinzolamide, a localized effect with fewer side effects is expected.But whenever absorbed systemically, a similar range of adverse effects (attributable to sulphonamides) may occur upon use. Furthermore, oral ACZ is reported to be more physiologically effective than 2% dorzolamide hydrochloridead ministered topically, even though in isolated tissues dorzolamide appears to be the most active as it shows the lowest IC50 values for CA-II and CA-IV. Hence, there exists considerable scope for the development of more/equally effective and inexpensive topically effective formulations of ACZ. The use of various formulation technologies discussed in this review can provide a fresh impetus to research in this area.
ANC System for Noisy Speech
Sivadasan Kottayi,Narayanan N.K
Signal & Image Processing , 2012,
Abstract: The paper explains the effectiveness of Active Noise Control (ANC) System based on adaptive filter forreducing noise from a noisy speech. ANC generally reduces low frequency noise and creates a quiet zone. In this paper a feedforward ANC is used for reducing low frequency noise from a noisy speech signal for improving speech quality. Secondary path transfer function has been compensated using FXNLMS (Filtered-X NLMS) algorithm. The proposed system is analyzed and simulated on a digital computer. Theperformance of the system is evaluated by measuring noise power reduction in the noisy speech by retaining the intelligibility of the speech signal. Simulation results reveal that the method can reduce noise power to a level of -11.6dB.
Cos observations of metal line and broad lyman alpha absorption in the multi-phase o vi and ne viii system toward he 02226-4110
B. Savage,N. Lehner,A. Narayanan
Physics , 2011, DOI: 10.1088/0004-637X/743/2/180
Abstract: Observations of the QSO HE 0226-4110 (zem = 0.495) with the Cosmic Origins Spectrograph (COS) from 1134 to 1796 {\AA} with a resolution of ~17 km s-1 and signal-to- noise (S/N) per resolution element of 20 to 40 are used to study the multi-phase absorption system at z = 0.20701 containing O VI and Ne VIII. The system was previously studied with lower S/N observations with FUSE and STIS. The COS observations provide more reliable measures of the H I and metal lines present in the system and reveal the clear presence of broad Lyman {\alpha} (BLA) absorption with b = 72(+13, -6) km s-1 and logN(H I) = 13.87\pm0.08. Detecting BLAs associated with warm gas absorbers is crucial for determining the temperature, metallicity and total baryonic content of the absorbers. The BLA is probably recording the trace amount of thermally broadened H I in the collisionally ionized plasma with log T ~5.7 that also produces the O VI and Ne VIII absorption. The total hydrogen column in the collisionally ionized gas, logN(H) ~ 20.1, exceeds that in the cooler photoionized gas in the system by a factor of ~22. The oxygen abundance in the collisionally ionized gas is [O/H] = -0.89\pm0.08\pm0.07. The absorber probably occurs in the circumgalactic environment (halo) of a foreground L = 0.25L* disk galaxy with an impact parameter of 109h70-1 kpc identified by Mulchaey & Chen (2009).
Comparative anatomical features of Prosopis cineraria (L.) Druce and Prosopis juliflora (Sw.) DC (Mimosaceae)
Robertson Stellaa,Narayanan N,Deattu N,Ravi Nargis N
International Journal of Green Pharmacy , 2010,
Abstract: A comparative study of the leaflets of two domestic species of Prosopis is reported. Both the species, Prosopis cineraria and Prosopis juliflora, have been reported to possess antibacterial, antifungal, anti-inflammatory and the most concerning anticancer properties. In view of its medicinal importance and taxonomic confusion, the individual morphological and histological characteristics of these two species have been described through certain parameters such as structural profile of the leaflets, stomatal morphology, venation pattern, petiolule and vascular system of the rachis. Evaluation of the fresh and anatomical sections of the leaves of both species was carried out to determine its macro- and microscopical (histological) characters. The studies indicated the presence of bipinnately compound leaf, an entire margin, apiculate apex, obtuse base, reticulate venation, thick and straight anticlinal walled epidermal cells, prismatic type of calcium oxalate crystals in the mesophyll tissue, dense deposition of tannin content and paracytic type stomata in the P. cineraria, whereas P. juliflora has a bipinnately compound leaf with an entire margin, blunt apex, round base, reticulate venation, thick and straight walled epidermal cells, large mucilage cavities in the mesophyll tissue and paracytic type stomata. The above findings provided referential information for identification of the species P. cineraria and P. juliflora.
An Integrative System For Prediction Of Nac Proteins In Rice Using Different Feature Extraction Methods
Hemalatha N,Rajesh M. K.,Narayanan N. K
International Journal on Soft Computing , 2013,
Abstract: TheNAC gene family encodesa large family of plant-specific transcriptionfactorswithdiverseroles invarious developmental processes and stress responsesin plants.Creationof genome wide prediction toolsfor NAC proteinswillhave a significant impacton gene annotationin rice.In the present study,NACSVM,a tool forcomputationalgenome-scale prediction of NACproteins in ricewasdeveloped integratingcompositional and evolutionary information ofNACproteins.Initially, support vector machine (SVM)-based modules weredeveloped usingcombinatorialpresence of diverse protein featuressuch astraditional amino acid, dipeptide (i+1), tripeptide (i+2),four-partscomposition andPSSMand an overallaccuracy of79%, 93%, 93%, 79%and 100% respectively was achieved.Later,twohybrid modules weredeveloped based on amino acid, dipeptideand tripeptidecomposition,through which anoverall accuracyof83% and 79%was achieved.NACSVM wasalso evaluatedusing position-specific iterated–basic localalignment search toolwhich resulted in a loweraccuracy of 50%.In order to benchmark NACSVM,thetool wasevaluated using independent data test and cross validation methods.The different statisticalanalysescarriedout revealed that the proposed algorithm isan useful toolfor annotatingNAC proteinsingenome of rice
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