文旦柚樹之成分研究—莖皮成分、Imperatorin之生物轉化及果皮中香豆精與氮營養之關係

Abstract

Buntan (Citrus maxima Merr.) is a popular seasonal fruit. The annual planting area is about 6,336 ha and the fruit harvest is about 74,480 tons in Taiwan. Many kinds of secondary product with biological activities from the stem bark and fruit peel of buntan have been studied, but the effects of the cultivation conditions and seasonal variations on the composition and the contents of secondary products in buntan peel tissues need more study. The purposes of this research are to study (1) isolation and identification of the pure compounds from the higher polar fractionation in the stem bark of buntan, and to examine their cytotoxic effects on several types of cancer cell lines; (2) the effect of application rates of nitrogen fertilizer on the growth of fruits of buntan and the concentration of coumarins in the outer fruit peel of buntan; (3) the efficiency of the extraction of coumarins from the fruit peel of buntan by supercritical carbon dioxide fluid (SF-CO2) under various conditions, i.e., difference of temperature, pressure, and accompanied with entrainers; (4) the possibility of biotransformation of imperatorin by fungi, and to assess the biological activities of the transformed metabolites. The results indicated that after the concentrated methanolic extract of the stem bark of buntan being treated with water, a new acridone alkaloid, 5-hydroxynoracronycine alcohol, along with three known limonin-type terpenoids: obacunone, nomilin, and limonin, and six known acridone alkaloids: glycocitrine-I, 5-hydroxynoracronycine, citrusinine-I, grandisine-I, natsucitrine-II, and citracridone-III were identified. All test compounds were found to be cytotoxic on HepG2 and KB tumor cell lines. In coumarins research, the content of coumarins in fruit peels of the highest application rate of nitrogen fertilizer was the higher, however there was no significant difference among treatments. However, there was a seasonal variation in the production of coumarins. This implies that the production of coumarins is development reflected. The efficiency of extraction of coumarins by SF-CO2 under 50