Displaying publications 1 - 20 of 289 in total

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  1. Shy TW, Gaurav A
    Cent Nerv Syst Agents Med Chem, 2021;21(3):195-204.
    PMID: 34970959 DOI: 10.2174/1871524922666211231115638
    AIM: The aim of the present study was to apply pharmacophore based virtual screening to a natural product database to identify potential PDE1B inhibitor lead compounds for neurodegenerative and neuropsychiatric disorders.

    BACKGROUND: Neurodegenerative and neuropsychiatric disorders are a major health burden globally. The existing therapies do not provide optimal relief and are associated with substantial adverse effects. This has resulted in a huge unmet medical need for newer and more effective therapies for these disorders. Phosphodiesterase (PDEs) enzymes have been identified as potential targets of drugs for neurodegenerative and neuropsychiatric disorders, and one of the subtypes, i.e., PDE1B, accounts for more than 90 % of total brain PDE activity associated with learning and memory process, making it an interesting drug target for the treatment of neurodegenerative disorders.

    OBJECTIVES: The present study has been conducted to identify potential PDE1B inhibitor lead compounds from the natural product database.

    METHODS: Ligand-based pharmacophore models were generated and validated; they were then employed for virtual screening of Universal Natural Products Database (UNPD) followed by docking with PDE1B to identify the best hit compound.

    RESULTS: Virtual screening led to the identification of 85 compounds which were then docked into the active site of PDE1B. Out of the 85 compounds, six showed a higher affinity for PDE1B than the standard PDE1B inhibitors. The top scoring compound was identified as Cedreprenone.

    CONCLUSION: Virtual screening of UNPD using Ligand based pharmacophore led to the identification of Cedreprenone, a potential new natural PDE1B inhibitor lead compound.

  2. Gaurav A, Gautam V
    Iran J Pharm Res, 2017;16(3):910-923.
    PMID: 29201082
    Phosphodiesterase 4 (PDE4) has been established as a promising target in asthma and chronic obstructive pulmonary disease. PDE4B subtype selective inhibitors are known to reduce the dose limiting adverse effect associated with non-selective PDE4B inhibitors. This makes the development of PDE4B subtype selective inhibitors a desirable research goal. To achieve this goal, ligand based pharmacophore modeling approach is employed. Separate pharmacophore hypotheses for PDE4B and PDE4D inhibitors were generated using HypoGen algorithm and 106 PDE4 inhibitors from literature having thiopyrano [3,2-d] Pyrimidines, 2-arylpyrimidines, and triazines skeleton. Suitable training and test sets were created using the molecules as per the guidelines available for HypoGen program. Training set was used for hypothesis development while test set was used for validation purpose. Fisher validation was also used to test the significance of the developed hypothesis. The validated pharmacophore hypotheses for PDE4B and PDE4D inhibitors were used in sequential virtual screening of zinc database of drug like molecules to identify selective PDE4B inhibitors. The hits were screened for their estimated activity and fit value. The top hit was subjected to docking into the active sites of PDE4B and PDE4D to confirm its selectivity for PDE4B. The hits are proposed to be evaluated further using in-vitro assays.
  3. Al-Nema MY, Gaurav A
    Curr Top Med Chem, 2019;19(7):555-564.
    PMID: 30931862 DOI: 10.2174/1568026619666190401113803
    BACKGROUND: Phosphodiesterases (PDEs) are enzymes that play a key role in terminating cyclic nucleotides signalling by catalysing the hydrolysis of 3', 5'- cyclic adenosine monophosphate (cAMP) and/or 3', 5' cyclic guanosine monophosphate (cGMP), the second messengers within the cell that transport the signals produced by extracellular signalling molecules which are unable to get into the cells. However, PDEs are proteins which do not operate alone but in complexes that made up of a many proteins.

    OBJECTIVE: This review highlights some of the general characteristics of PDEs and focuses mainly on the Protein-Protein Interactions (PPIs) of selected PDE enzymes. The objective is to review the role of PPIs in the specific mechanism for activation and thereby regulation of certain biological functions of PDEs.

    METHODS: The article discusses some of the PPIs of selected PDEs as reported in recent scientific literature. These interactions are critical for understanding the biological role of the target PDE.

    RESULTS: The PPIs have shown that each PDE has a specific mechanism for activation and thereby regulation a certain biological function.

    CONCLUSION: Targeting of PDEs to specific regions of the cell is based on the interaction with other proteins where each PDE enzyme binds with specific protein(s) via PPIs.

  4. Al-Nema MY, Gaurav A
    Curr Top Med Chem, 2020;20(26):2404-2421.
    PMID: 32533817 DOI: 10.2174/1568026620666200613202641
    Schizophrenia is a severe mental disorder that affects more than 1% of the population worldwide. Dopamine system dysfunction and alterations in glutamatergic neurotransmission are strongly implicated in the aetiology of schizophrenia. To date, antipsychotic drugs are the only available treatment for the symptoms of schizophrenia. These medications, which act as D2-receptor antagonist, adequately address the positive symptoms of the disease, but they fail to improve the negative symptoms and cognitive impairment. In schizophrenia, cognitive impairment is a core feature of the disorder. Therefore, the treatment of cognitive impairment and the other symptoms related to schizophrenia remains a significant unmet medical need. Currently, phosphodiesterases (PDEs) are considered the best drug target for the treatment of schizophrenia since many PDE subfamilies are abundant in the brain regions that are relevant to cognition. Thus, this review aims to illustrate the mechanism of PDEs in treating the symptoms of schizophrenia and summarises the encouraging results of PDE inhibitors as anti-schizophrenic drugs in preclinical and clinical studies.
  5. Ha CH, Fatima A, Gaurav A
    Adv Bioinformatics, 2015;2015:826047.
    PMID: 26640486 DOI: 10.1155/2015/826047
    Human African Trypanosomiasis is endemic to 37 countries of sub-Saharan Africa. It is caused by two related species of Trypanosoma brucei. Current therapies suffer from resistance and public accessibility of expensive medicines. Finding safer and effective therapies of natural origin is being extensively explored worldwide. Pentamidine is the only available therapy for inhibiting the P2 adenosine transporter involved in the purine salvage pathway of the trypanosomatids. The objective of the present study is to use computational studies for the investigation of the probable trypanocidal mechanism of flavonoids. Docking experiments were carried out on eight flavonoids of varying level of hydroxylation, namely, flavone, 5-hydroxyflavone, 7-hydroxyflavone, chrysin, apigenin, kaempferol, fisetin, and quercetin. Using AutoDock 4.2, these compounds were tested for their affinity towards inosine-adenosine-guanosine nucleoside hydrolase and the inosine-guanosine nucleoside hydrolase, the major enzymes of the purine salvage pathway. Our results showed that all of the eight tested flavonoids showed high affinities for both hydrolases (lowest free binding energy ranging from -10.23 to -7.14 kcal/mol). These compounds, especially the hydroxylated derivatives, could be further studied as potential inhibitors of the nucleoside hydrolases.
  6. Al-Nema M, Gaurav A, Lee VS
    Heliyon, 2020 Sep;6(9):e04856.
    PMID: 32984588 DOI: 10.1016/j.heliyon.2020.e04856
    Inhibition of phosphodiesterase 4 (PDE4) is a promising therapeutic approach for the treatment of inflammatory pulmonary disorders, i.e. asthma and chronic obstructive pulmonary disease. However, the treatment with non-selective PDE4 inhibitors is associated with side effects such as nausea and vomiting. Among the subtypes of PDE4 inhibited by these inhibitors, PDE4B is expressed in immune, inflammatory and airway smooth muscle cells, whereas, PDE4D is expressed in the area postrema and nucleus of the solitary tract. Thus, PDE4D inhibition is responsible for the emetic response. In this regard, a selective PDE4B inhibitor is expected to be a potential drug candidate for the treatment of inflammatory pulmonary disorders. Therefore, a shared feature pharmacophore model was developed and used as a query for the virtual screening of Maybridge and SPECS databases. A number of filters were applied to ensure only compounds with drug-like properties were selected. Accordingly, nine compounds have been identified as final hits, where HTS04529 showed the highest affinity and selectivity for PDE4B over PDE4D in molecular docking. The docked complexes of HTS04529 with PDE4B and PDE4D were subjected to molecular dynamics simulations for 100ns to assess their binding stability. The results showed that HTS04529 was bound tightly to PDE4B and formed a more stable complex with it than with PDE4D.
  7. Yi YX, Gaurav A, Akowuah GA
    Curr Drug Discov Technol, 2020;17(2):248-260.
    PMID: 30332967 DOI: 10.2174/1570163815666181017091655
    INTRODUCTION: The primary aim of this study is to understand the binding of curcumin and its analogues to different PDE4 subtypes and identify the role of PDE4 subtype inhibition in the anti-inflammatory property of curcumin. Docking analysis has been used to acquire the above mentioned structural information and this has been further used for designing of curcumin derivatives with better anti-inflammatory activity.

    MATERIALS AND METHODS: Curcumin and its analogues were subjected to docking using PDE4A, PDE4B, PDE4C and PDE4D as the targets. A data set comprising 18 analogues of curcumin, was used as ligands for docking of PDE4 subtypes. Curcumin was used as the standard for comparison. Docking was performed using AutoDock Vina 1.1.2 software integrated in LigandScout 4.1. During this process water molecules were removed from proteins, charges were added and receptor structures were minimised by applying suitable force fields. The docking scores were compared, and the selectivity of compounds for PDE4B over PDE4D was calculated as well.

    RESULTS: All curcumin analogues used in the study showed good binding affinity with all PDE4 subtypes, with evident selectivity towards PDE4B subtype. Analogue A11 provides the highest binding affinity among all ligands.

    CONCLUSION: Curcumin and analogues have moderate to strong affinity towards all PDE4 subtypes and have evident selectivity towards PDE4B. The Oxygen atom of the methoxy group plays a key role in PDE4B binding and any alterations could interfere with the binding. Tetrahydropyran side chain and heterocyclic rings are also suggested to be helpful in PDE4B binding.

  8. Al-Nema M, Gaurav A, Akowuah G
    Comput Biol Chem, 2018 Dec;77:52-63.
    PMID: 30240986 DOI: 10.1016/j.compbiolchem.2018.09.001
    The major complaint that most of the schizophrenic patients' face is the cognitive impairment which affects the patient's quality of life. The current antipsychotic drugs treat only the positive symptoms without alleviating the negative or cognitive symptoms of the disease. In addition, the existing therapies are known to produce extrapyramidal side effects that affect the patient adherence to the treatment. PDE10A inhibitor is the new therapeutic approach which has been proven to be effective in alleviating the negative and cognitive symptoms of the disease. A number of PDE10A inhibitors have been developed, but no inhibitor has made it beyond the clinical trials so far. Thus, the present study has been conducted to identify a PDE10A inhibitor from natural sources to be used as a lead compound for the designing of novel selective PDE10A inhibitors. Ligand and structure-based pharmacophore models for PDE10A inhibitors were generated and employed for virtual screening of universal natural products database. From the virtual screening results, 37 compounds were docked into the active site of the PDE10A. Out of 37 compounds, three inhibitors showed the highest affinity for PDE10A where UNPD216549 showed the lowest binding energy and has been chosen as starting point for designing of novel PDE10A inhibitors. The structure-activity-relationship studies assisted in designing of selective PDE10A inhibitors. The optimization of the substituents on the phenyl ring resulted in 26 derivatives with lower binding energy with PDE10A as compared to the lead compound. Among these, MA 8 and MA 98 exhibited the highest affinity for PDE10A with binding energy (-10.90 Kcal/mol).
  9. Al-Nema M, Gaurav A, Lee VS
    Comput Biol Med, 2023 Apr 03;159:106869.
    PMID: 37071939 DOI: 10.1016/j.compbiomed.2023.106869
    In recent years, the PDE1B enzyme has become a desirable drug target for the treatment of psychological and neurological disorders, particularly schizophrenia disorder, due to the expression of PDE1B in brain regions involved in volitional behaviour, learning and memory. Although several inhibitors of PDE1 have been identified using different methods, none of these inhibitors has reached the market yet. Thus, searching for novel PDE1B inhibitors is considered a major scientific challenge. In this study, pharmacophore-based screening, ensemble docking and molecular dynamics simulations have been performed to identify a lead inhibitor of PDE1B with a new chemical scaffold. Five PDE1B crystal structures have been utilised in the docking study to improve the possibility of identifying an active compound compared to the use of a single crystal structure. Finally, the structure-activity- relationship was studied, and the structure of the lead molecule was modified to design novel inhibitors with a high affinity for PDE1B. As a result, two novel compounds have been designed that exhibited a higher affinity to PDE1B compared to the lead compound and the other designed compounds.
  10. Patil VM, Gaurav A, Garg P, Masand N
    J Egypt Natl Canc Inst, 2021 Nov 08;33(1):33.
    PMID: 34746987 DOI: 10.1186/s43046-021-00091-3
    BACKGROUND: The expression of hERG K+ channels is observed in various cancer cells including epithelial, neuronal, leukemic, and connective tissue. The role of hERG potassium channels in regulating the growth and death of cancer cells include cell proliferation, survival, secretion of proangiogenic factors, invasiveness, and metastasis.

    METHODS: In the reported study, an attempt has been made to investigate some non-cancer hERG blockers as potential cancer therapeutics using a computational drug repurposing strategy. Preliminary investigation for hERG blockers/non-blockers has identified 26 potential clinically approved compounds for further studies using molecular modeling.

    RESULTS: The interactions at the binding pockets have been investigated along with the prioritization based on the binding score. Some of the identified potential hERG inhibitors, i.e., Bromocriptine, Darglitazone, and Troglitazone, have been investigated to derive the mechanism of cancer inhibition.

    CONCLUSIONS: The proposed mechanism for anti-cancer properties via hERG blocking for some of the potential compounds is required to be explored using other experimental methodologies. The drug repurposing approach applied to investigate anti-cancer therapeutics may direct to provide a therapeutic solution to late-stage cancer and benefit a significant population of patients.

  11. Gaurav A, Agrawal N, Al-Nema M, Gautam V
    Curr Top Med Chem, 2022;22(26):2190-2206.
    PMID: 36278463 DOI: 10.2174/1568026623666221019110334
    Over the last two decades, computational technologies have played a crucial role in antiviral drug development. Whenever a virus spreads and becomes a threat to global health, it brings along the challenge of developing new therapeutics and prophylactics. Computational drug and vaccine discovery has evolved quickly over the years. Some interesting examples of computational drug discovery are anti-AIDS drugs, where HIV protease and reverse transcriptase have been targeted by agents developed using computational methods. Various computational methods that have been applied to anti-viral research include ligand-based methods that rely on known active compounds, i.e., pharmacophore modeling, machine learning or classical QSAR; structure-based methods that rely on an experimentally determined 3D structure of the targets, i.e., molecular docking and molecular dynamics and methods for the development of vaccines such as reverse vaccinology; structural vaccinology and vaccine epitope prediction. This review summarizes these approaches to battle viral diseases and underscores their importance for anti-viral research. We discuss the role of computational methods in developing small molecules and vaccines against human immunodeficiency virus, yellow fever, human papilloma virus, SARS-CoV-2, and other viruses. Various computational tools available for the abovementioned purposes have been listed and described. A discussion on applying artificial intelligence-based methods for antiviral drug discovery has also been included.
  12. Xing M, Akowuah GA, Gautam V, Gaurav A
    J Biomol Struct Dyn, 2017 Oct;35(13):2910-2924.
    PMID: 27608741 DOI: 10.1080/07391102.2016.1234417
    Phosphodiesterase 4 (PDE4) has been established as a drug target for inflammatory diseases of respiratory tract like asthma and chronic obstructive pulmonary disease. The selective inhibitors of PDE4B, a subtype of PDE4, are devoid of adverse effects like nausea and vomiting commonly associated with non-selective PDE4B inhibitors. This makes the development of PDE4B subtype selective inhibitors a desirable research goal. Thus, in the present study, molecular docking, molecular dynamic simulations and binding free energy were performed to explore potential selective PDE4B inhibitors based on ginger phenolic compounds. The results of docking studies indicate that some of the ginger phenolic compounds demonstrate higher selective PDE4B inhibition than existing selective PDE4B inhibitors. Additionally, 6-gingerol showed the highest PDE4B inhibitory activity as well as selectivity. The comparison of binding mode of PDE4B/6-gingerol and PDE4D/6-gingerol complexes revealed that 6-gingerol formed additional hydrogen bond and hydrophobic interactions with active site and control region 3 (CR3) residues in PDE4B, which were primarily responsible for its PDE4B selectivity. The results of binding free energy demonstrated that electrostatic energy is the primary factor in elucidating the mechanism of PDE4B inhibition by 6-gingerol. Dynamic cross-correlation studies also supported the results of docking and molecular dynamics simulation. Finally, a small library of molecules were designed based on the identified structural features, majority of designed molecules showed higher PDE4B selectivity than 6-gingerol. These results provide important structural features for designing new selective PDE4B inhibitors as anti-inflammatory drugs and promising candidates for synthesis and pre-clinical pharmacological investigations.
  13. Khurana NA, Khurana G, Uppal N
    Contemp Clin Dent, 2010 Oct;1(4):255-8.
    PMID: 22114433 DOI: 10.4103/0976-237X.76396
    Socket sclerosis is usually asymptomatic and does not require any treatment. The only potential complication arises during orthodontic treatment, wherein sclerosed socket of the premolar teeth may be an obstacle in closing the space by movement of teeth through the extraction space. This article demonstrates the problems encountered during the orthodontic treatment of a 20-year-old Malaysian woman with socket sclerosis and the treatment strategy employed to overcome the same.
  14. Gupta G, Singh Y, Chellappan D, Dua K
    J Cosmet Dermatol, 2020 Sep;19(9):2447-2448.
    PMID: 32365277 DOI: 10.1111/jocd.13466
  15. Dua K, Chakravarthi S, Kumar D, Sheshala R, Gupta G
    Int J Pharm Investig, 2013 Oct;3(4):183-7.
    PMID: 24350037 DOI: 10.4103/2230-973X.121287
    In an attempt for better treatment of bacterial infections and burn wounds, semisolid formulations containing norfloxacin (NF) and natural wound healing agent Curcuma longa were prepared. The rationale behind employing combination of NF and Curcuma longa is to obtain synergistic wound healing effect. The prepared formulations were compared with silver sulfadiazine cream 1%, USP.
  16. Singh RK, Haq S, Kumar G, Dhiman RC
    J Commun Dis, 2013 Mar-Jun;45(1-2):1-16.
    PMID: 25141549
    Anopheles annularis is widely distributed mosquito species all over the country. An. annularis has been incriminated as a malaria vector in India, Sri Lanka, Bangladesh, Myanmar, Indonesia, Malaysia and China. In India, it has been reported to play an important role in malaria transmission as a secondary vector in certain parts of Assam, West Bengal and U.P. In Odisha and some neighbouring countries such as Sri Lanka, Nepal and Myanmar it has been recognised as a primary vector of malaria. This is a species complex of two sibling species A and B but the role of these sibling species in malaria transmission is not clearly known. An. annularis is resistant to DDT and dieldrin/HCH and susceptible to malathion and synthetic pyrethorides in most of the parts of India. In view of rapid change in ecological conditions, further studies are required on the bionomics of An. annularis and its role in malaria transmission in other parts of the country. Considering the importance of An. annularis as a malaria vector, the bionomics and its role in malaria transmission has been reviewed in this paper. In this communication, an attempt has been made to review its bionomics and its role as malaria vector. An. annularis is a competent vector of malaria, thus, due attention should be paid for its control under the vector control programmes specially in border states where it is playing a primary role in malaria transmission.
  17. Kumar M, Mishra G, Vaibhav R, Priyadarshini S, Simran, Turagam N
    J Pharm Bioallied Sci, 2021 Jun;13(Suppl 1):S391-S394.
    PMID: 34447117 DOI: 10.4103/jpbs.JPBS_591_20
    Background: Musculoskeletal disorders (MSDs) are commonly occurring disorders nowadays. The present study was conducted with the aim of determining MSDs in dentists and to assess knowledge about ergonomics.

    Materials and Methods: This questionnaire study was conducted among 460 dental professionals of different age groups. Parameters such as posture of dentists, working alone or with an assistant, and number of breaks were recorded. Type of MSDs and the type and effectiveness were recorded.

    Results: BDS students were seventy, interns were 112, general dentists were 186, and specialists were 92. Year of practice was <5 years in 215, 5-10 years in 70, 10-20 years in 35, and >20 years in 140 students. Fourteen percent of students, 18% interns, 45% general practitioners, and 32% of specialists had a prevalence of MSD. Most common MSDs in students were upper back pain seen in 6%, in interns were upper back pain seen in 8%, in general practitioners were shoulder pain seen in 21%, and in specialists were hand/wrist pain seen in 10%. Forty-five percent of students, 67% interns, 72% general dentists, and 80% of specialists had idea about ergonomics. Seventy-four percent of students, 80% of interns, 83% of general dentists, and 87% of specialists think that ergonomics may improve performance. Sitting position was preferred seen in 53% of students, 58% of interns, 65% general dentists, and 60% of specialists. Forty-five percent of students, 47% of interns, 56% of general dentists, and 52% of specialists perform physical activity during work. The difference was found to be statistically significant (P < 0.05). Seventy-nine percent of students, 83% of interns, 86% of general dentists, and 88% of specialists show prolong sitting or standing.

    Conclusion: Authors found that all prefer to apply ergonomic in clinical practice. There is a lack of knowledge among BDS students and interns about ergonomics.

  18. Satija S, Mehta M, Gupta G, Chellappan DK, Dua K
    Future Med Chem, 2020 10;12(20):1805-1807.
    PMID: 33016120 DOI: 10.4155/fmc-2020-0190
  19. Chellappan DK, Yenese Y, Wei CC, Gupta G
    Endocr Metab Immune Disord Drug Targets, 2017 09 11;17(2):87 - 95.
    PMID: 28427246 DOI: 10.2174/1871530317666170421121202
    Background and Objective: The incidence of diabetes has been on the rise and the rate of rise since the turn of this century has been phenomenal. One of the various battling issues faced by diabetics all over the globe is the management of diabetic wounds. Currently, there are several management strategies to deal with the treatment of diabetic wounds. The conventional methods have several limitations. One of the major limitations is the rate and progression of healing of a diabetic wound when adopting a conventional diabetic wound management therapy. Lately, several nano techniques and nano products have emerged in the market that offer promising results for such patients. The treatment outcomes are achieved more efficiently with such nanomedical products.
    Methods: This review attempts to consider the currently available nanotechnological applications in the management of diabetic wounds. We take a deeper look into the available nanotherapeutic agents and the different nanocarriers that could be used in the management of diabetic wound healing. Lately, researchers around the globe have started providing evidences on the effective use of such nanoparticles in various fields of Medicine extending from genetics to various other branches of medicine. This also includes the management of diabetic wounds.
    Conclusion: This paper discusses the challenges faced with these nanotherapies and nanoparticles with regard to the treatment of diabetic wounds.
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