Displaying publications 21 - 40 of 831 in total

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  1. Al-Samarrai G, Singh H, Syarhabil M
    Ann Agric Environ Med, 2012;19(4):673-6.
    PMID: 23311787
    Fungicides are widely used in conventional agriculture to control plant diseases. Prolonged usage often poses health problems as modern society is becoming more health-conscious. Penicillium digitatum, the cause of citrus green mould, is an important postharvest pathogen which causes serious losses annually. The disease is currently managed with synthetic fungicides. There is, however, a growing concern globally about the continuous use of synthetic chemicals on food crops because of their potential effects on human health and the environment.
    Matched MeSH terms: Dose-Response Relationship, Drug
  2. Gan GG, Phipps ME, Lee MM, Lu LS, Subramaniam RY, Bee PC, et al.
    Ann Hematol, 2011 Jun;90(6):635-41.
    PMID: 21110192 DOI: 10.1007/s00277-010-1119-6
    Within the Asian populations, Indian patients had been reported to require higher warfarin dose compared with the Chinese and Malay patients, and this could not entirely be explained by cytochrome P450 (CYP)2C9 gene variants. Genetic variants of vitamin K epoxide oxidase reductase complex subunit 1 (VKORC1) has been well established as one of key determinants in the different responses of warfarin amongst patients. Adult patients who attended an anticoagulation clinic with stable INR were recruited. VKORC1 and CYP2C9 genotype were sequenced, and clinical characteristics were assessed. A total of 91 Malays, 96 Chinese, and 46 Indian patients were recruited. The mean age was 55 years and 51.5% were males. The mean dose of warfarin for all patients was 3.7 mg, and the mean daily dose of warfarin was significantly higher in Indians compared with the Chinese and Malay patients, 4.9 versus 3.5 and 3.3 mg, respectively (p dose in patients with GG genotype required a significant higher warfarin dose compared with those with AG and AA genotype (4.9 vs. 3.7 vs. 3.1 mg, respectively; p dose, 2.9 versus 3.7 mg in CYP2C9*1; p dose. In conclusion, VKORC1 and CYP2C9 polymorphism contribute to the difference dose requirement amongst the patients but other additional possible factors may play a role in the Indian race.
    Study site: Anticoagulation clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
    Matched MeSH terms: Dose-Response Relationship, Drug
  3. Lim CP, Md-Redzuan A, Lai YK, Borhanuddin B, Cheah FC
    Ann Acad Med Singap, 2017 10;46(10):395-398.
    PMID: 29177368
    Matched MeSH terms: Dose-Response Relationship, Drug*
  4. Sizaret P, Tuyns A, Martel N, Jouvenceaux A, Levin A, Ong YW, et al.
    Ann N Y Acad Sci, 1975 Aug 22;259:136-55.
    PMID: 54017
    Alpha-Fetoprotein (AFP) levels of 1,335 males (15 years and older) of seven ethnic groups (Chinese, Indians, and Malays from Singapore, Caucasians from Lyon, and Blacks from Nairobi, forest, and the savanna region of the Ivory Coast) were determined by radioimmunoassay. A few elevated levels (up to 30 nanounits/ml) were detected in some normal individuals, especially in the older age-groups. In addition, there was a systematic age-dependency of AFP levels particularly evident in the groups from Singapore-Lyon, in which there was a 50% AFP increase between the ages of 20 and 40. Comparison between Africans on the one hand and people from Singapore-Lyon on the other hand revealed highly significant differences (p less than 0.001), especially in the younger groups, whereas Chinese, Malays, and Indians from Singapore had very similar AFP pattern; this suggests an important role for environmental factors in the regulation of AFP levels. The age dependency of the presumed effect of environmental factors is in keeping with experimental data showing that young animals respond more vigorously to AFP-stimulating factors. Although the incidence of hepatocellular carcinoma (HCC) differs in the three Singapore groups (the highest in Chinese and the lowest in Indians), no relationship was observed in this study between mean AFP level and HCC incidence in Singapore.
    Matched MeSH terms: Dose-Response Relationship, Drug
  5. Arulnathan SB, Leong KH, Ariffin A, Kareem HS, Cheah KKH
    Anticancer Agents Med Chem, 2020;20(9):1072-1086.
    PMID: 32188392 DOI: 10.2174/1871520620666200318100051
    BACKGROUND: Oxadiazoles, triazoles, and their respective precursors have been shown to exhibit various pharmacological properties, namely antitumour activities. Cytotoxic activity was reported for these compounds in various cancer cell lines.

    AIM AND OBJECTIVES: In this study, we aim at investigating the mechanism of apoptosis by N-(4-chlorophenyl)-2-(4- (3,4,5-trimethoxybenzyloxy)benzoyl)-hydrazinecarbothioamide, a triazole precursor, henceforth termed compound P7a, in breast cancer cell line, MCF-7. We first screen a series of analogues containing (3,4,5-trimethoxybenzyloxy) phenyl moiety in breast cancer cell lines (MCF-7 and MDA-MB-231) to select the most cytotoxic compound and demonstrate a dose- and time-dependent cytotoxicity. Then, we unravel the mechanism of apoptosis of P7a in MCF-7 as well as its ability to cause cell cycle arrest.

    METHODS: Synthesis was performed as previously described by Kareem and co-workers. Cytotoxicity of analogues containing (3,4,5-trimethoxybenzyloxy)phenyl moiety against MCF-7 and MDA-MB-231 cell lines was evaluated using the MTS assay. Flow cytometric analyses was done using Annexin V/PI staining, JC-1 staining and ROS assay. The activity of caspases using a chemoluminescence assay and western blot analysis was conducted to study the apoptotic pathway induced by the compound in MCF-7 cells. Lastly, cell cycle analysis was conducted using flow cytometry.

    RESULTS: Upon 48 hours of treatment, compound P7a inhibited the proliferation of human breast cancer cells with IC50 values of 178.92 ± 12.51μM and 33.75 ± 1.20μM for MDA-MB-231 and MCF-7, respectively. Additionally, compound P7a showed selectivity towards the cancer cell line, MCF-7 compared to the normal breast cell line, hTERT-HME1, an advantage against current anticancer drugs (tamoxifen and vinblastine). Flow cytometric analyses using different assays indicated that compound P7a significantly increased the proportion of apoptotic cells, increased mitochondria membrane permeabilisation and caused generation of ROS in MCF-7. In addition, cell cycle analysis showed that cell proliferation was arrested at the G1 phase in the MCF-7 cell line. Furthermore, upon treatment, the MCF-7 cell line showed increased activity of caspase-3/7, and caspase-9. Lastly, the western blot analysis showed the up-regulation of pro-apoptotic proteins along with up-regulation of caspase-7 and caspase-9, indicating that an intrinsic pathway of apoptosis was induced.

    CONCLUSION: The results suggest that compound P7a could be a potential chemotherapeutic agent for breast cancer.

    Matched MeSH terms: Dose-Response Relationship, Drug
  6. Jeyamogan S, Khan NA, Sagathevan K, Siddiqui R
    Anticancer Agents Med Chem, 2020;20(13):1558-1570.
    PMID: 32364082 DOI: 10.2174/1871520620666200504103056
    BACKGROUND: Cancer contributes to significant morbidity and mortality despite advances in treatment and supportive care. There is a need for the identification of effective anticancer agents. Reptiles such as tortoise, python, and water monitor lizards are exposed to heavy metals, tolerate high levels of radiation, feed on rotten/germ-infested feed, thrive in unsanitary habitat and yet have prolonged lifespans. Such species are rarely reported to develop cancer, suggesting the presence of anticancer molecules/mechanisms.

    METHODS: Here, we tested effects from sera of Asian water monitor lizard (Varanus salvator), python (Malayopython reticulatus) and tortoise (Cuora kamaroma amboinensis) against cancer cells. Sera were collected and cytotoxicity assays were performed using prostate cancer cells (PC3), Henrietta Lacks cervical adenocarcinoma cells (HeLa) and human breast adenocarcinoma cells (MCF7), as well as human keratinized skin cells (Hacat), by measuring lactate dehydrogenase release as an indicator for cell death. Growth inhibition assays were performed to determine the effects on cancer cell proliferation. Liquid chromatography mass spectrometry was performed for molecular identification.

    RESULTS: The findings revealed that reptilian sera, but not bovine serum, abolished viability of Hela, PC3 and MCF7 cells. Samples were subjected to liquid chromatography mass spectrometry, which detected 57 molecules from V. salvator, 81 molecules from Malayopython reticulatus and 33 molecules from C. kamaroma amboinensis and putatively identified 9 molecules from V. salvator, 20 molecules from Malayopython reticulatus and 9 molecules from C. kamaroma amboinensis when matched against METLIN database. Based on peptide amino acid composition, binary profile, dipeptide composition and pseudo-amino acid composition, 123 potential Anticancer Peptides (ACPs) were identified from 883 peptides from V. salvator, 306 potential ACPs from 1074 peptides from Malayopython reticulatus and 235 potential ACPs from 885 peptides from C. kamaroma amboinensis.

    CONCLUSION: To our knowledge, for the first time, we reported comprehensive analyses of selected reptiles' sera using liquid chromatography mass spectrometry, leading to the identification of potentially novel anticancer agents. We hope that the discovery of molecules from these animals will pave the way for the rational development of new anticancer agents.

    Matched MeSH terms: Dose-Response Relationship, Drug
  7. Abuelizz HA, Anouar EH, Marzouk M, Hasan MH, Saleh SR, Ahudhaif A, et al.
    Anticancer Agents Med Chem, 2020;20(14):1714-1721.
    PMID: 32593283 DOI: 10.2174/1871520620666200627212128
    BACKGROUND: The use of tyrosinase has confirmed to be the best means of recognizing safe, effective, and potent tyrosinase inhibitors for whitening skin. Twenty-four 2-phenoxy(thiomethyl)pyridotriazolopyrimidines were synthesized and characterized in our previous studies.

    OBJECTIVE: The present work aimed to evaluate their cytotoxicity against HepG2 (hepatocellular carcinoma), A549 (pulmonary adenocarcinoma), MCF-7 (breast adenocarcinoma) and WRL 68 (embryonic liver) cell lines.

    METHODS: MTT assay was employed to investigate the cytotoxicity, and a tyrosinase inhibitor screening kit was used to evaluate the Tyrosinase (TYR) inhibitory activity of the targets.

    RESULTS: The tested compounds exhibited no considerable cytotoxicity, and nine of them were selected for a tyrosinase inhibitory test. Compounds 2b, 2m, and 5a showed good inhibitory percentages against TYR compared to that of kojic acid (reference substance). Molecular docking was performed to rationalize the Structure-Activity Relationship (SAR) of the target pyridotriazolopyrimidines and analyze the binding between the docked-selected compounds and the amino acid residues in the active site of tyrosinase.

    CONCLUSION: The target pyridotriazolopyrimidines were identified as a new class of tyrosinase inhibitors.

    Matched MeSH terms: Dose-Response Relationship, Drug
  8. Sinniah SK, Tan KW, Ng SW, Sim KS
    Anticancer Agents Med Chem, 2017;17(5):741-753.
    PMID: 27671302 DOI: 10.2174/1871520616666160926110929
    BACKGROUND: Thiosemicarbazone (TSC) is a Schiff base that has been receiving considerable attention owing to its promising biological implication and remarkable pharmacological properties. The most promising drug candidate of this class would be Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone) which has entered phase II clinical trials as a potent anti-cancer chemotherapeutic agent.

    OBJECTIVE: The current research aimed to synthesize several Schiff base ligands from (3-formyl-4-hydroxyphenyl) methyltriphenylphosphonium (T). Additionally, the current research aimed to study the growth inhibitory effect of triphenylphosphonium containing thiosemicarbazone derivatives on PC-3 cells by deciphering the mechanisms involved in cell death.

    METHOD: The compounds were characterized by various spectroscopic methods (infrared spectra, 1H NMR, 13C NMR, HRESIMS and X-ray crystallography) and the results were in conformity with the structure of the targeted compounds. Growth inhibitory effect of the compounds were performed against six human cell lines.

    RESULTS: DM(tsc)T displayed most potent activity against PC-3 cells with IC50 value of 2.64 ± 0.33 μM, surpassing that of the positive control cisplatin (5.47 ± 0.06 μM). There were marked morphological changes observed in DM(tsc)T treated cells stained with acridine orange and ethidium bromide which were indicative of cell apoptosis. Treatment with DM(tsc)T showed that the cell cycle is arrested in the G0/G1 phase after 72 hours. Mitochondrial membrane potential loss was observed in cells treated with DM(tsc)T, indicating the apoptosis could be due to mitochondria mediated pathway.

    CONCLUSION: This study indicates that DM(tsc)T would serve as a lead scaffold for rational anticancer agent development.

    Matched MeSH terms: Dose-Response Relationship, Drug
  9. Hassan LEA, Iqbal MA, Dahham SS, Tabana YM, Ahamed MBK, Majid AMSA
    Anticancer Agents Med Chem, 2017;17(4):590-598.
    PMID: 27671298 DOI: 10.2174/1871520616666160926113711
    BACKGROUND: Cancer is characterized by uncontrolled cell division caused by dysregulation of cell proliferation. Therefore, agents that impair cancer cell proliferation could have potential therapeutic value. Higher plants are considered to be a good source of anticancer agents, and several clinically tested chemotherapeutic agents have been isolated from plants or derived from constituents of plant origin.

    METHODS: In the present study, a prenylated flavone (isoglabratephrin) was isolated from aerial parts of Tephrosia apollinea using a bioassay-guided technique. Chemical structure of the isolated compound was elucidated using spectroscopic techniques (NMR, IR, and LC-MC), elemental analysis and confirmed by using single crystal X-ray analysis. The antiproliferative effect of isoglabratephrin was tested using three human cancer cell lines (prostate (PC3), pancreatic (PANC-1), and colon (HCT-116) and one normal cell line (human fibroblast).

    RESULTS: Isoglabratephrin displayed selective inhibitory activity against proliferation of PC3 and PANC-1 cells with median inhibitory concentration values of 20.4 and 26.6 μg/ml, respectively. Isoglabratephrin demonstrated proapoptotic features, as it induced chromatin dissolution, nuclear condensation, and fragmentation. It also disrupted the mitochondrial membrane potential in the treated cancer cells.

    CONCLUSION: Isoglabratephrin could be a new lead to treat human prostate (PC3) and pancreatic (PANC-1) malignancies.

    Matched MeSH terms: Dose-Response Relationship, Drug
  10. Khairul WM, Hashim F, Mohammed M, Shah NSMN, Johari SATT, Rahamathullah R, et al.
    Anticancer Agents Med Chem, 2021;21(13):1738-1750.
    PMID: 33176667 DOI: 10.2174/1871520620999201110190709
    INTRODUCTION: In this contribution, a series of alkoxy substituted chalcones were successfully designed, synthesized, spectroscopically characterized and evaluated for their cytotoxicity potential in inhibiting the growth of MCF-7 cells.

    OBJECTIVE: In order to investigate the influence between electron density in conjugated π-systems and biological activities, different withdrawing substituents, namely Nitro (NO2), Cyano (C≡N) and trifluoromethyl (CF3) were introduced in the chalcone-based molecular system.

    METHODS: All the derivatives were then tested on MCF-7 cell line using the fluorescence microscopy-based cytotoxicity analyses.

    RESULTS: The preliminary findings showed that both -NO2 and -CF3 substituents revealed their potential to inhibit the growth of MCF-7 with IC;50 values of 14.75 and 13.75 μg/ml, respectively. In addition, the morphological changes of MCF-7 cells were observed in response to alkoxy substituted chalcone treatment through an induction of apoptosis pathway with cell blebbing, phosphatidylserine exposure and autophagic activity with acidification of lysosomal structure. Intermolecular interaction based on in silico investigation on nitro, trifluoromethyl and cyano based chalcones exhibited several types of interactions with tumor necrosis factor receptor (PDB: 1EXT) protein and high hydrogen bond in the molecule-receptor interaction have given significant impact towards their toxicity on MCF-7 cells.

    CONCLUSION: Significantly, these types of chalcones exhibited ideal and high potential to be further developed as anti-cancer agents.

    Matched MeSH terms: Dose-Response Relationship, Drug
  11. Hazalin NA, Lim SM, Cole AL, Majeed AB, Ramasamy K
    Anticancer Drugs, 2013 Sep;24(8):852-61.
    PMID: 23764760 DOI: 10.1097/CAD.0b013e3283635a47
    There is growing interest in the discovery of bioactive metabolites from endophytes as an alternative source of therapeutics. Identification of their therapeutic targets is essential in understanding the underlying mechanisms and enhancing the resultant therapeutic effects. As such, bioactive compounds produced by endophytic fungi from plants at the National Park, Pahang, Malaysia, were investigated. Five known compounds were identified using LC-UV-MS-NMR and they include trichodermol, 7-epi-brefeldin A, (3R,4S)-4-hydroxymellein, desmethyl-lasiodiplodin and cytochalasin D. The present study went on to investigate the potential anticancer effects of these compounds and the corresponding molecular mechanisms of the lead compound against human breast adenocarcinoma, MCF-7. For the preliminary screening, the cytotoxicity and apoptotic effects of these compounds against MCF-7 were examined. The compounds were also tested against noncarcinogenic hepatocytes (WRL68). The differential cytotoxicity was then determined using the MTT assay. Desmethyl-lasiodiplodin was found to suppress the growth of MCF-7, yielding an inhibitory concentration (IC50) that was seven-fold lower than that of the normal cells. The cytotoxic effect of desmethyl-lasiodiplodin was accompanied by apoptosis. Subsequent analysis demonstrated increased expression levels of caspase 3, c-myc and p53. Further, desmethyl-lasiodiplodin resulted in inhibition of monocyte chemotactic protein (MCP)-3, a cytokine involved in cell survival and metastasis. Hence, this study proposed that desmethyl-lasiodiplodin inhibited growth and survival of MCF-7 through the induction of apoptosis. This anticancer effect is mediated, in part, by upregulation of apoptotic genes and downregulation of MCP-3. As desmethyl-lasiodiplodin elicited minimal impact against normal hepatocytes, our findings also imply its potential use as a specific apoptotic agent in breast cancer treatment.
    Matched MeSH terms: Dose-Response Relationship, Drug
  12. Dua K, Sheshala R, Ling TY, Hui Ling S, Gorajana A
    PMID: 23286236
    At present, approximately 25%of drugs in modern pharmacopoeia are derived from plant sources (phytomedicines) that can be developed for the treatment of diseases and disorders. Many other drugs are synthetic analogues built on the prototype compounds isolated from plants. Cocos nucifera Linn. (Arecaceae), which is commonly known as coconut, is a plant possessing a lot of potential as an ingredient in traditional medicines for the treatment of metabolic disorders and particularly as an anti-inflammatory, antimicrobial and analgesic agent. This review emphasizes on the recent literature and research findings that highlight the significant biological activities of C. nucifera Linn. such as its anti-inflammatory, antimicrobial and analgesic properties. This review can help researchers keen on exploiting the therapeutic potential of C. nucifera Linn. which may motivate them to further explore their commercial viability.
    Matched MeSH terms: Dose-Response Relationship, Drug
  13. Cheah YH, Nordin FJ, Tee TT, Azimahtol HL, Abdullah NR, Ismail Z
    Anticancer Res, 2008 Nov-Dec;28(6A):3677-89.
    PMID: 19189649
    Xanthorrhizol is a natural sesquiterpenoid compound isolated from the rhizome of Curcuma xanthorrhizza Roxb (Zingerberaceae). Recent studies of xanthorrhizol in cell cultures strongly support the role of xanthorrhizol as an antiproliferative agent. In our study, we tested the antiproliferative effect of xanthorrhizol using different breast cancer cell lines. The invasive breast cancer cell line, MDA-MB-231, was then selected for further investigations. Treatment with xanthorrhizol caused 50% growth inhibition on MDA-MB-231 cells at 8.67 +/- 0.79 microg/ml as determined by sulforhodamine B (SRB) assay. Hoechst 33258 nuclear staining assay showed the rate of apoptosis of MDA-MB-231 cells to increase in response to xanthorrhizol treatment. Immunofluorescence staining using antibody MitoCapture and fluorescein isothiocyanate (FITC)-labeled cytochrome c revealed the possibility of altered mitochondrial transmembrane potential and the release of cytochrome c respectively. This was further confirmed by Western-blotting, where cytochrome c was showed to migrate from mitochondrial fraction to the cytosol fraction of treated MDA-MB-231 cells. Caspase activity assay showed the involvement of caspase-3 and caspase-9, but not caspase-6 or caspase-8 in MDA-MB-231 apoptotic cell death. Subsequently, cleavage of PARP-1 protein is suggested. These data suggest treatment with xanthorrhizol modulates MDA-MB-231 cell apoptosis through the mitochondria-mediated pathway subsequent to the disruption of mitochondrial transmembrane potential, release of cytochrome c, activation of caspase-3 and caspase-9, and the modulation of PARP-1 protein.
    Matched MeSH terms: Dose-Response Relationship, Drug
  14. Pihie AH, Stanslas J, Din LB
    Anticancer Res, 1998 May-Jun;18(3A):1739-43.
    PMID: 9673398
    The antiproliferative activity of a styrylpyrone derivative (SPD) plant extract, was studied in three different human breast cancer cell lines in culture, and was compared with tamoxifen. The number of living cells was evaluated by Methylene Blue staining technique. SPD showed strong antiproliferative activity in estrogen receptor (ER) and progestin receptor (PgR) positive MCF-7 cells (EC50 = 6.30 x 10(-7) M) and receptor-negative MDA-MB-231 (EC50 = 5.62 x 10(-7) M), but it partially inhibited the high progestin receptor positive T47D cells (EC50 = 1.58 x 10(-6) M). Whereas tamoxifen, a nonsteroidal antiestrogen exhibited strong inhibition on MCF-7 cells (EC50 = 1.41 x 10(-6) M) and partial inhibition on T47D cells (EC50 = 2.5 x 10(-6) M), but did not affect the MDA-MB-231 cells in the concentration range 0.1 nM-1 microM (EC50 = 5.01 microM). At the same concentration range SPD and tamoxifen did not inhibit the proliferation of normal human liver cell line CCL 13 and normal bovine kidney MDBK; whereas adriamycin, a common chemotherapy drug for the treatment of advance cancer, caused 95% inhibition at 10(-6) M. Competitive binding studies showed SPD had no ability to inhibit the binding of [3H]estradiol and [3H]progesterone to ER and PgR, respectively but, tamoxifen exhibited affinity for ER. Therefore, it can be concluded that the antiproliferative activity of SPD was selective towards breast cancer cell lines and not mediated by ER or PgR.
    Matched MeSH terms: Dose-Response Relationship, Drug
  15. Dhabaan GN, AbuBakar S, Cerqueira GM, Al-Haroni M, Pang SP, Hassan H
    Antimicrob Agents Chemother, 2015 Dec 14;60(3):1370-6.
    PMID: 26666943 DOI: 10.1128/AAC.01696-15
    Acinetobacter baumannii has emerged as a notorious multidrug-resistant pathogen, and development of novel control measures is of the utmost importance. Understanding the factors that play a role in drug resistance may contribute to the identification of novel therapeutic targets. Pili are essential for A. baumannii adherence to and biofilm formation on abiotic surfaces as well as virulence. In the present study, we found that biofilm formation was significantly induced in an imipenem-resistant (Imp(r)) strain treated with a subinhibitory concentration of antibiotic compared to that in an untreated control and an imipenem-susceptible (Imp(s)) isolate. Using microarray and quantitative PCR analyses, we observed that several genes responsible for the synthesis of type IV pili were significantly upregulated in the Imp(r) but not in the Imp(s) isolate. Notably, this finding is corroborated by an increase in the motility of the Imp(r) strain. Our results suggest that the ability to overproduce colonization factors in response to imipenem treatment confers biological advantage to A. baumannii and may contribute to clinical success.
    Matched MeSH terms: Dose-Response Relationship, Drug
  16. A Abdullah A, Abdullah R, A Nazariah Z, N Balakrishnan K, Firdaus J Abdullah F, A Bala J, et al.
    Antivir Chem Chemother, 2018;26:2040206618811413.
    PMID: 30449131 DOI: 10.1177/2040206618811413
    BACKGROUND: Viruses are obligate parasites that depend on the cellular machinery of the host to regenerate and manufacture their proteins. Most antiviral drugs on the market today target viral proteins. However, the more recent strategies involve targeting the host cell proteins or pathways that mediate viral replication. This new approach would be effective for most viruses while minimizing drug resistance and toxicity.

    METHODS: Cytomegalovirus replication, latency, and immune response are mediated by the intermediate early protein 2, the main protein that determines the effectiveness of drugs in cytomegalovirus inhibition. This review explains how intermediate early protein 2 can modify the action of cyclosporin A, an immunosuppressive, and antiviral drug. It also links all the pathways mediated by cyclosporin A, cytomegalovirus replication, and its encoded proteins.

    RESULTS: Intermediate early protein 2 can influence the cellular cyclophilin A pathway, affecting cyclosporin A as a mediator of viral replication or anti-cytomegalovirus drug.

    CONCLUSION: Cyclosporin A has a dual function in cytomegalovirus pathogenesis. It has the immunosuppressive effect that establishes virus replication through the inhibition of T-cell function. It also has an anti-cytomegalovirus effect mediated by intermediate early protein 2. Both of these functions involve cyclophilin A pathway.

    Matched MeSH terms: Dose-Response Relationship, Drug
  17. Lani R, Hassandarvish P, Shu MH, Phoon WH, Chu JJ, Higgs S, et al.
    Antiviral Res, 2016 Sep;133:50-61.
    PMID: 27460167 DOI: 10.1016/j.antiviral.2016.07.009
    This study focuses on the antiviral activity of selected flavonoids against the Chikungunya virus (CHIKV), a mosquito-transmitted virus that can cause incapacitating arthritis in infected individuals. Based on the results of screening on Vero cells, the tested compounds were evaluated further with various assays, including cytotoxicity assay, virus yield assay by quantitative reverse transcription polymerase chain reaction (qRT-PCR), virus RNA replication assay with a CHIKV replicon cell line, Western blotting, and quantitative immunofluorescence assay. Baicalein, fisetin, and quercetagetin displayed potent inhibition of CHIKV infection, with 50% inhibitory concentrations [IC50] of 1.891 μg/ml (6.997 μM), 8.444 μg/ml (29.5 μM), and 13.85 μg/ml (43.52 μM), respectively, and with minimal cytotoxicity. The time-of-addition studies and various antiviral assays demonstrated that baicalein and quercetagetin mainly inhibited CHIKV binding to the Vero cells and displayed potent activity against extracellular CHIKV particles. The qRT-PCR, immunofluorescence assay, and Western blot analyses indicated that each of these flavonoids affects CHIKV RNA production and viral protein expression. These data provide the first evidence of the intracellular anti-CHIKV activity of baicalein, fisetin, and quercetagetin.
    Matched MeSH terms: Dose-Response Relationship, Drug
  18. Oo A, Rausalu K, Merits A, Higgs S, Vanlandingham D, Bakar SA, et al.
    Antiviral Res, 2018 02;150:101-111.
    PMID: 29269135 DOI: 10.1016/j.antiviral.2017.12.012
    The past decade has seen the re-emergence of Chikungunya virus (CHIKV) as a major global health threat, affecting millions around the world. Although fatal infections are rare among infected patients, the occurrence of long-lasting polyarthralgia has a significant impact on patients' quality of lives and ability to work. These issues were the stimuli for this study to determine the potential of baicalin, a bioflavonoid, as the novel antiviral compound against CHIKV. It was found that baicalin was well tolerated by Vero, BHK-21 and HEK 293T cells with maximal nontoxic doses >600 μM, ≈ 350 μM and ≈110 μM, respectively. Antiviral assays indicated that baicalin was the most effective inhibitor when tested for its direct virucidal activity with EC50 ≈ 7 μM, followed by inhibition of virus entry into the host cell, attachment of virus particle to cellular receptors and finally intracellular replication of viral RNA genome. In silico analysis using molecular docking demonstrated close interactions between baicalin and CHIKV envelope protein with considerably strong binding affinity of -9.7 kcal/mol. qRT-PCR analysis revealed that baicalin had the greatest effect on the synthesis of viral negative stand RNA with EC50 ≈ 0.4 μM followed by the inhibition of synthesis of positive-strand genomic (EC50 ≈ 13 μM) and subgenomic RNAs (EC50 ≈ 14 μM). These readings indicate that the compound efficiently inhibits replicase complexes formation but is a less potent inhibitor of existing replicase complexes. Coherent with this hypothesis, the use of recombinant CHIKV replicons harboring Renilla luciferase marker showed that replication of corresponding replicon RNAs was only slightly downregulated at higher doses of baicalin, with EC50 > 100 μM. Immunofluorescence and western blotting experiments demonstrated dose-dependent inhibition of expression of different viral proteins. It was also observed that levels of important protein markers for cellular autophagy (LC3) and apoptosis (Bax) were reduced in baicalin treatment groups as compared with untreated virus infected controls. In summary, given its low toxicity and high efficacy against CHIKV, baicalin has great potential to be developed as the novel antiviral compound for CHIKV. In vivo studies to evaluate its activity in a more complexed system represent a necessary step for future analysis.
    Matched MeSH terms: Dose-Response Relationship, Drug
  19. Antony JJ, Keng CL, Mahmood M, Subramaniam S
    Appl Biochem Biotechnol, 2013 Sep;171(2):315-29.
    PMID: 23832189 DOI: 10.1007/s12010-013-0369-x
    Regrowth of the cryopreserved protocorm-like bodies (PLBs) of Dendrobium Bobby Messina was assessed based on the plant vitrification solution 2 (PVS2) optimisation conditions. The optimized protocol obtained based on TTC spectrophotometrical analysis and growth recovery were 3-4 mm of PLBs size precultured in 0.2 M sucrose for 1 day, treated with a mixture of 2 M glycerol and 0.4 M sucrose supplemented with half-strength liquid MS media at 25 °C for 20 min and subsequently dehydrated with PVS2 at 0 °C for 20 min prior to storage in liquid nitrogen. Following rapid warming in a water bath at 40 °C for 90 s, PLBs were treated with unloading solution containing half-strength liquid MS media supplemented with 1.2 M sucrose. Subsequently, the PLBs were cultured on half-strength semi-solid MS media supplemented with 2 % (w/v) sucrose without any growth regulators and resulted in 40 % growth recovery. In addition, ascorbic acid treatment was used to evaluate the regeneration process of cryopreserved PLBs. However, growth recovery rates of non-cryopreserved and cryopreserved PLBs were 30 and 10 % when 0.6 mM ascorbic acid was added. Scanning electron microscopy analysis indicates that there are not much damages observed on both cryopreserved and non-cryopreserved PLBs in comparison to PLBs stock culture.
    Matched MeSH terms: Dose-Response Relationship, Drug
  20. Nazratun Nafizah AH, Budin SB, Zaryantey AH, Mariati AR, Santhana RL, Osman M, et al.
    Arab J Gastroenterol, 2017 Mar;18(1):13-20.
    PMID: 28336227 DOI: 10.1016/j.ajg.2017.02.001
    BACKGROUND AND STUDY AIMS: The complex series of deleterious events among diabetes patients leads to multiple organ failure. Therefore, a holistic approach of treatment is urgently required to prevent worsening of complications. The present investigation was carried out to study the possible protective effects of Roselle or Hibiscus sabdariffa Linn (HSL) calyxes aqueous extract, as an antidiabetic and antioxidant agent against oxidative liver injury in streptozotocin-induced diabetic rats.

    MATERIAL AND METHODS: A single dose of streptozotocin (45mg/kg body weight, iv) was used to induced diabetes in male Sprague Dawley rats which were then divided into two groups: Diabetic control (DC) and HSL-treated diabetic (DR) group. Normal rats were divided into normal control (NC), HSL-treated control (NR). Aqueous calyxes extract of HSL (100mg/kg/day, orally) was given for 28 consecutive days in the treated group. Weight, biochemical and histopathological (light and electron microscopic) parameters were compared in all groups.

    RESULTS: Supplementation of HSL significantly lowered the level of fasting blood glucose and increased plasma insulin level in DR group compared to DC group (p<0.05). Alanine aminotransaminases and aspartate aminotransferase enzymes level were found to be significantly reduced in DR compared to DC. Microscopic examination demonstrated destruction of the liver architecture, cytoplasmic vacuolation of the hepatocytes and signs of necrosis in diabetic rats. Moreover, dilatation and congestion of blood vessels with leucocytes adherence were detected. Ultrastructural study using electron microscope showed homogeneous substance accumulation in nuclear chromatin, a decrease of organelles and mitochondrial degeneration in the diabetic rats.

    CONCLUSION: Administration of HSL in diabetic rats causes significant decrease in hepatocyte destruction and prevented the changes associated with the diabetic condition. Thus, our findings provide a scientific rationale for the use of HSL as promising agent in preventing liver injury in diabetes.

    Matched MeSH terms: Dose-Response Relationship, Drug
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