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"ABSTRACT

Cytochrome P450 isoform 2C9 (CYP2C9) is a main enzyme which metabolizes phenytoin [I]. The inhibition of this enzyme will increase plasma level of phenytoin. Cimetidine is known as drug that inhibits this enzyme, resulting an increased plasma level of phenytoin [2]. Recently, the three dimentional molecular basis of interaction between phenytoin and cimetidine toward CYP2C9 has not been described well yet. The present findings may represent an important advance for understanding interaction CYP2C9 with drugs to predict its toxicity an also metabolism based on structural interaction from docking results. A computational methodology, molecular docking can be used to analyze interaction which exist between ligand and macromolecule. AutoDock is one of the most commonly used methodology, shows the efficiency of scoring function ligand that bound to its active site [3]. So that, it can be used to understand about interaction between phenytoin and cimetidine in CYP2C9. Crystal structure of CYP2C9 complexed with flurbiprofen (PDB ID: 1R90) has resolution 2.00 A. This structure, used in this experiment, has the closed conformational structure and complexed with S-warfarin. Three dimensional structure of phenytoin and cimetidine were minimized, charge were added for docking preparation. Binding of substrate phenytoin in CYP2C9 is stabilized by hidrogen bonds, interaction with cationic residue Argl08, hydrophobic interaction particularly with Phel 14. On the other side, binding of cimetidine inhibitor in CYP2C9 is stabilized by hydrogen bonds with some amino acid residues, including Glu300 which has role as anionic residue, also the exist of hydrophobic interaction. Cimetidine being competitive inhibitor of CYP2C9 at the substrate recognition site of phenytoin. "

"The objective of the study is to synthesize of 2-(phenylamino)methyl-2-nitro-4(3H)-quinazolinone and their derivatives under microwave irradiation. Solution of 2-bromomethyl-6-nitro-4(3H)-quinazolinone, aniline or subtituted aniline and pyridine was irradiated under modified home microwave completed with reflux condensor. The structure of the synthesized compounds were confirmed on the basis of IR, 1H-NMR and 13C-NMR data. The results showed that the reactions for 7 minutes in power level 30 to give corresponding 2-(phenylamino)methyl-2-nitro-4(3H)-quinazolinones in facile and good yield "

"ABSTRACTXylitol is a five-carbon polyol sugar. It has many healthy benefits and is widely used in food, pharmaceutical, and healthcare. Natural sources with abundant carbon such as lignocellulose can be used for xylitol production. One of the potencial sources with high prevalency in Indonesia is water hyacinth. It is known as weeds and has not been fully utilized by people. The aim of this research was the utilization of water hyacinth which contains hemicellulose as a substrate in the bioconversion of xylose into xylitol by yeast cells Debaryomyces hansenii. Stages of processing include the optimization of water hyacinth hydrolysis using autohydrolysis method and optimization of fermentation conditions. Xylose and xylitol were determined by HPLC with RI detector and LiChrosorb® NH2 (4 mm x 125,00 mm, 5μm) column. Acetonitrile-water (90:10, v/v) was used as a solvent. 20 μL sample volume was injected at flow rate of 1.0 mL/min and room temperature. The results showed that optimum conditions for the acquisition of xylose were obtained through autohydrolysis methods for 75 minutes with 1:15 water hyacinth and water ratio and posthydrolysis for 45 min using 4% sulfuric acid. Xylose concentration in hydrolyzate obtained was 25.55 g/L. The optimum fermentation condition for xylitol production was achieved by four day cultivation, limited aeration condition, and addition of metal ions CaCl2.2H2O 0.01%. The yield of xylitol obtained using those conditions was 77.43 %. "

"ABSTRACTXylitol is five-carbon polyol sugar which widely used as a sweetener in food and pharmaceutical.Xylitol production by chemical procedures using high pressure and temperature also neededextensive purification are less cost-effective in production. Fermentation which has more advantageswith lower cost due tocheaper substrate and the non-necessity of xylose purification. The purposes ofthis research were to find optimum condition for xylitol production with particular variable such assubstrate concentration, aeration, methanol and nitrogen sources addition. Oil palm empty fruitbunch hydrolyzates containing xylose was fermented into xylitol by Debaryomyces hansenii UICC Y-276 at room temperature. Fermentation was carried out at 200 rpm for 72 hours. Then, xylose andxylitol were determined by HPLC with RI detector and LiChrosorb® NH2 (4 mm x 125,00 mm, 5μm)column. Acetonitrile-water was used as a solvent, 20 mL sample volume was injected at flow rate of1,0 mL/min at room temperature. The optimum fermentation conditions was obtained in a state ofsemi-anaerobic condition (1 : 2.5) with 10,0 % (w/v) xylose concentration. Meanwhile with theaddition of various concentration of methanol and nitrogen sources, it was obtained that 1,5 %methanol and 0,5 % ammonium sulfate gave high yield of xylitol production. The best result for yieldxylitol production was 31,83 %."