A new flavanone, 7-hydroxy-5,6-dimethoxyflavanone (1), together with three other flavonoids, didymocarpin (2), 2Ј,4Ј-dihydroxy-5Ј,6Ј-dimethoxychalcone (3), and isodidymocarpin (4), had been isolated from the methanol extract of the tree bark of Cryptocarya costata. The structures of these compounds were determined based on spectral evidence, including UV, IR, 1-D and 2-D NMR, and mass spectra. Cytotoxic properties of compounds 1Ð4 were evaluated against murine leukemia P-388 cells. The chalcones 3 and 4 were found to have substantial cytotoxicity with IC 50 of 5.7 and 11.1 µm, respectively.
Key indicatorsSingle-crystal X-ray study T = 298 K Mean (C-C) = 0.003 Å R factor = 0.053 wR factor = 0.130 Data-to-parameter ratio = 13.8For details of how these key indicators were automatically derived from the article, see
An investigation on purification and characterization of lipase enzyme production Aspergillus oryzae from copra by fermentation of olive oil has been carried out. This enzyme can be produced by fermenting olive oil in a medium containing Aspergillus oryzae. Crude enzyme is obtained by centrifuging the medium cultures containing Aspergillus oryzae at 3500 rpm for 30 minutes and than adding 0.2 M borat buffer (pH 8.2). Enzyme activity was determined from paranitrophenol as product of lipase catalysis of paranitrophenylbutirat (0.2 M) as substrate measured by the Vorderwulbecke method. Prepurification process was by ammonium sulphate fractionation. Precipitation 60-80% ammonium sulphate produced maximum activity of enzyme. Purification by Q sepharosa FF and sephadex G-75 collum chromatography produced four and three fractions with purifity of 12.85 and 20.25 times than crude enzyme respectively. Characterization of this enzyme showed optimum condition at pH 8.2, temperature at 35 0 C, the K m value at 0.046 M, and V maks is 1.926 µmol/menit and the molecular weight at 40.7 kDa.
Enzyme immobilization is a recovery technique that has been studied in several years, using support as a media to help enzyme dissolutions to the reaction substrate. Immobilization method used in this study was adsorption method, using specific lipase fromAspergillus oryzae. Lipase was partially purified from the culture supernatant ofAspergillus oryzae. Enzyme was immobilized by adsorbed on silica gel. Studies on free and immobilized lipase systems for determination of optimum pH, optimum temperature, thermal stability and reusability were carried out. The results showed that free lipase had optimum pH 8,2 and optimum temperature 35 °C while the immobilized lipase had optimum 8,2 and optimum temperature 45 °C. The thermal stability of the immobilized lipase, relative to that of the free lipase, was markedly increased. The immobilized lipase can be reused for at least six times.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.