Part I:Studies on the Constituents of Prunus phaeosticta (HANCE) MAXIM. Part II:Inhibition of Xanthine Oxidase by the Constituents of Prunus phaeosticta (HANCE) MAXIM. and Benthiazinone Analogues.

• Main Authors: Lin, Chun-Yu, 林君郁
• Other Authors: Sheu Shiow-Yunn
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/33986915272503308403

碩士 === 台北醫學院 === 藥學研究所 === 85 === Part I. The Constituents of Prunus phaeosticta (HANCE) MAXIM. Prunus phaeosticta (HANCE) MAXIM. is a novel Prunus plant of Rosaceae in Taiwan. Prunus plants have been used as nourish the lung, resalve sputum, for treatment of dryness-syndrome, also as diuretic, tonic, astringent and for treatment of benign prostate hyperplasia. In this study, the constituents of the plant were isolated, and compared with the constituents of other Prunus spp. By variaus column chromatography, seven compounds were isolated from the chloroform soluble fraction. Three compounds, beta-amyrin(1), taraxerol(2) and beta-sitosterol-3-O-beta-D- glucoside(3) were characterized by spectroscopic data and chemicalmethods, and four constituents remain to be analyzed. Part II. Inhibition of Xanthine Oxidase by the Constituents of Prunus phaeosticta (HANCE) MAXIM. and Benzothiazinone Analogues. According to the literature, xanthine oxidaseis related to several diseases such as gout, tissue reperusion iniuries, brain tumors, acute pancreatitis and hepatitis. In this study, the constituents of Prunus phaeosticta (HANCE) MAXIM., thiazoles and benzothiazinones have been tested for their inhibitory, effects on xanthine oxidase:determination of percent inhibition, IC50, mode of inhibition and the apparent inhibition constant (Ki). It is expected that xanthine oxidase inhibitors are useful for the treatment or prevention of these diseases mentioned as above. The enzyme, xanthine oxidase catalyses the oxidation of hypoxanthine to xanthine and of xanthine to uric acid which has wavelength of 295 nm. Uric acid was thus forming basis for a spectrophotometric assay of the activity of xanthineoxidase. According to the Lineweaver-Burk plot equation, mode of inhibition andthe apparent inhibition constants (Ki) were estimated. The results showed that the constituents of Prunus phaeosticta (HANCE) MAXIM. showed very weak inhibitory effect on xanthine oxidase. On the other hand, benzothiazinone analogues, 2-amino-4H-1,3-benzothiazin-4-one (IC50-5.54uM, Ki=5.12uM) and 2-guanidino-4H-1,3-benzothiazin-4-one (IC50=5.60uM, Ki=19.47uM) displayed potent activities on xanthine oxidase inhibition. They induced noncompetitive and mixed (non-competi tive-uncompective) type inhibitions respectively, with respect to the substrate xanthine. Rhodanine (IC50=121.40uM, Ki=206.23uM) also showed moderate effects on xanthine oxidase inhibition, and induced mixed (non-compective-uncompetitive) type inhibition of the enzyme with respect to the substrate xanthine.