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Stronger Activity (stronger + activity)
Selected AbstractsSynthesis, Antibacterial and Antifungal Activities of Novel 1,2,4-Triazolium DerivativesARCHIV DER PHARMAZIE, Issue 7 2009Yan Luo Abstract A series of novel 1,2,4-triazolium derivatives was synthesized starting from commercially available 1H -1,2,4-triazole, 2,4-dichlorobenzyl chloride, or 2,4-difluorobenzyl bromide. Their antibacterial and antifungal activities were evaluated against Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, Bacillus proteus, Bacillus subtilis, Pseudomonas aeruginosa, Candida albicans ATCC 76615, and Aspergillus fumigatus. All structures of the new compounds were confirmed by NMR, IR, and MS spectra, and elemental analyses. The antimicrobial tests showed that most of synthesized triazolium derivatives exhibit significant antibacterial and antifungal activities in vitro. 1-(2,4-Difluorobenzyl)-4-dodecyl-1H -1,2,4-triazol-4-ium bromide and 1-(2,4-Dichlorobenzyl)-4-dodecyl-1H -1,2,4- triazol-4-ium bromide were the most potent compounds against all tested strains with the MIC values ranging from 1.05 to 8.38 ,M. They exhibited much stronger activities than the standard drugs chloramphenicol and fluconazole which are in clinical use. The results also showed that the antimicrobial activities of triazolium derivatives depend upon the type of substituent, the length of the alkyl chain, and the number of triazolium rings. [source] EVALUATION OF EXTRACTS FROM BAMBOO FOR BIOLOGICAL ACTIVITY AGAINST CULEX PIPIENS PALLENSINSECT SCIENCE, Issue 4 2004Hai-qun Cao Abstract The extracts from 7 species of bamboo were tested for larvicidal activity against Culex pipiens pallens. At the tested concentration, the extracts of selected bamboo had different degree of toxic effects on the fourth instar larvae of Culex pipiens pallens. Among them, the extracts of Pleioblastus juxianensis, Brachystachyum albostriatum, Phyllostachys platyglossa and Pleioblastus amarus were found to be effective with LC50values at 24 h of 30.65 mg/L, 53.94 mg/L, 41.21 mg/L and 54.49 mg/L respectively, against Culex pipiens pallens larvae. The extract of Pleioblastus juxianensis by Soxhlet method showed stronger activity than the extract obtained by interval-shaking, the LC50 of which were 30.65 mg/L and 48.34 mg/L, respectively. The diethyl ether extract of Pleioblastus juxianensis exhibited better larvicidal activity than the methanol extract and the petroleum ether extract. The results would help to provide the basis for the study of environment acceptable pesticide for mosquito control, and also help to comprehensively utilize the source of bamboo. [source] Novel bromomelatonin derivatives suppress osteoclastic activity and increase osteoblastic activity: implications for the treatment of bone diseasesJOURNAL OF PINEAL RESEARCH, Issue 3 2008Nobuo Suzuki Abstract:, The teleost scale is a calcified tissue that contains osteoclasts, osteoblasts, and bone matrix, all of which are similar to those found in mammalian membrane bone. Using the goldfish scale, we recently developed a new in vitro assay system and previously demonstrated that melatonin suppressed both osteoclastic and osteoblastic activities in this assay system. In mammals, 2-bromomelatonin possesses a higher affinity for the melatonin receptor than does melatonin. Using a newly developed synthetic method, we synthesized 2-bromomelatonin, 2,4,6-tribromomelatonin and novel bromomelatonin derivatives (1-allyl-2,4,6-tribromomelatonin, 1-propargyl-2,4,6-tribromomelatonin, 1-benzyl-2,4,6-tribromomelatonin, and 2,4,6,7-tetrabromomelatonin) and then examined the effects of these chemicals on osteoclasts and osteoblasts. All bromomelatonin derivatives, as well as melatonin, had an inhibitory action on osteoclasts. In particular, 1-benzyl-2,4,6-tribromomelatonin (benzyl-tribromomelatonin) possessed a stronger activity than melatonin. At an in vitro concentration of 10,10 m, benzyl-tribromomelatonin still suppressed osteoclastic activity after 6 hr of incubation. In reference to osteoblasts, all bromomelatonin derivatives had a stimulatory action, although melatonin inhibited osteoblastic activity. In addition, estrogen receptor mRNA expression (an osteoblastic marker) was increased in benzyl-tribromomelatonin (10,7 m)-treated scales. Taken together, the present results strongly suggest that these novel melatonin derivatives have significant potential for use as beneficial drug for bone diseases such as osteoporosis. [source] Antimicrobial activity of essential oil and methanol extracts of Achillea sintenisii Hub.PHYTOTHERAPY RESEARCH, Issue 9 2003Mor. (Asteraceae) Abstract The essential oil, obtained by Clevenger distillation, and water-soluble and water-insoluble parts of the methanol extracts of Achillea sintenisii Hub. Mor. were individually assayed for their antimicrobial activities against 12 bacteria and two yeasts, Candida albicans and C. krusei. No activity was exhibited by the water-soluble subfraction, whereas both the water-insoluble subfraction of the methanol extracts and the essential oil were found to be active against some test microorganisms studied. Since the essential oil possessed stronger activity than the other extracts tested, it was further fractionated and the fractions were evaluated for their antimicrobial activity, followed by GC-MS analysis, resulting in the identi,cation of 32 compounds which constituted 90.2% of the total oil. The GC-MS analysis of the oil and its fractions revealed that the main components of the oil, e.g. camphor and eucalyptol, possessed appreciable activity against C. albicans and Clostridium perfringens. The ,ndings presented here also suggest that the other constituents of the oil, e.g. borneol and piperitone can also be taken into account for the activity observed. Copyright © 2003 John Wiley & Sons, Ltd. [source] Potential Tuberculostatic Agent: Micelle-forming Pyrazinamide ProdrugARCHIV DER PHARMAZIE, Issue 6 2006Marcia Silva Abstract Pyrazinamide was condensed with the poly(ethylene glycol)-poly(aspartic acid) copolymer (PEG-PASP), a micelle-forming derivative was obtained that was characterized in terms of its critical micelle concentration (CMC) and micelle diameter. The CMC was found by observing the solubility of Sudan III in Poly(ethylene glycol)-poly(pyrazinamidomethyl aspartate) copolymer (PEG-PASP-PZA) solutions. The mean diameter of PEG-PASP-PZA micelles, obtained by analyzing the dynamic light-scattering data, was 78.2 nm. The PEG-PASP-PZA derivative, when assayed for anti- Mycobacterium activity, exhibited stronger activity than the simple drug. [source] Antitumor activities of synthetic and natural stilbenes through antiangiogenic actionCANCER SCIENCE, Issue 10 2008Yoshiyuki Kimura We reported that the antitumor and antimetastatic actions of resveratrol might be due to the inhibition of tumor-induced angiogenesis. To search for anticancer agents with stronger activity than resveratrol, we examined the antiangiogenic effects of 21 synthetic and/or natural stilbenes. Among these 21 stilbenes, 2,3-, 3,4-, and 4,4,-dihydroxystilbene inhibited the pro-matrix metalloproteinase (pro-MMP),9 production in colon 26 cells at 5,25 µM, vascular endothelial growth factor (VEGF),induced human umbilical vein endothelial cell (HUVEC) migration at 10 and 25 µM, and VEGF-induced angiogenesis at 5,50 µM. Resvertarol inhibited the pro-MMP-9 production and VEGF-induced angiogenesis at 25 or 50 µM. Thus, the inhibition of pro-MMP-9 production in colon 26 cells and VEGF-induced angiogenesis by three dihydroxystilbenes were greater than those of resveratrol. The three dihydroxystilbenes (8 mg/kg, intraperitoneal injection) inhibited the tumor-induced neovascularization in colon 26,packed chamber-bearing mice and the tumor growth in colon 26,bearing mice. Furthermore, the three dihydroxystilbenes inhibited VEGF-induced VEGFR-2 phosphorylation. On the other hand, the three dihydroxystilbenes had no effect on VEGFR-1 and-2 expression, and VEGF-induced VEGFR-1 phosphorylation in HUVECs. These findings suggest that the inhibition of tumor-induced neovascularization by these three dihydroxystilbenes may be due to the inhibition of VEGF-induced endothelial cell migration and VEGF-induced angiogenesis through the inhibition of VEGF-induced VEGFR-2 phosphorylation in endothelial cells and pro-MMP-9 expression in colon 26 cells. (Cancer Sci 2008; 99: 2083,2096) [source] Tunable Bacterial Agglutination and Motility Inhibition by Self-Assembled Glyco-NanoribbonsCHEMISTRY - AN ASIAN JOURNAL, Issue 11 2007Yong-beom Lim Dr. Abstract We explored a method of controlling bacterial motility and agglutination by using self-assembled carbohydrate-coated ,-sheet nanoribbons. To this aim, we synthesized triblock peptides that consist of a carbohydrate, a polyethylene glycol (PEG) spacer, and a ,-sheet-forming peptide. An investigation into the effect of PEG-spacer length on the self-assembly of the triblock peptides showed that the PEG should be of sufficiently length to stabilize the ,-sheet nanoribbon structure. It was found that the stabilization of the nanoribbon led to stronger activity in bacterial motility inhibition and agglutination, thus suggesting that antibacterial activity can be controlled by the stabilization strategy. Furthermore, another level of control over bacterial motility and agglutination was attained by co-assembly of bacteria-specific and -nonspecific supramolecular building blocks. The nanoribbon specifically detected bacteria after the encapsulation of a fluorescent probe. Moreover, the detection sensitivity was enhanced by the formation of bacterial clusters. All these results suggest that the carbohydrate-coated ,-sheet nanoribbons can be developed as promising agents for pathogen capture, inactivation, and detection, and that the activity can be controlled at will. [source] | ||||||||||||||||