從黃梔子萃取之Crocin抑制鳥胺酸去羧基酶作用

Inhibition of Ornithine Decarboxylase by Digentiobiosyl Crocetin (Crocin) Isolated from Gardenia Jasminoids Ellis

黃梔子(Gardenia Jasminoids Ellis)為常作為治療肝病或發炎的中藥。利用液相層析法可分離出三種成份，其中一種成份經鑑定為digentiobiosyl crocetin (crocin)。crocin包括三種類似物，digentiobiosyl crocetin，gentiobiosyl glucosyl crocetin和diglucosyl crocetin。Digentiobiosyl crocetin在濃度50μg/ml可抑制14%由黃嘌呤及黃嘌呤氧化酶所產生之超氧陰離子攻擊花生四烯酸而產生的丙二醯雙醛(malondialdehyde)。更進一步，將digentiobiosyl crocetin局部塗抹在敘利亞黃金鼠之口腔囊中，其可抑制由12-O-tetradecanoylphorbol 13-acetate(TPA)誘發之鳥胺酸去羧基酶(ornithine decarboxylase, ODC)活性達58%。同時和β-carotene比較，β-carotene只能抑制41%由TPA誘發的ODC活性。這些研究結果顯示digentiobiosyl crocetin可以作為癌症的化學阻斷劑。

Gardenia Jasminoids Ellis (Huang-jee-chee in Chinese) is used in Chinese medicine for the treatment of various inflammatory diseases and liver disorders. Three major fractions were obtained from this Chinese herbal medicine by liquid chromatography; and the first peak was identified as digentiobiosyl crocetin which is one of crocins. Digentiobiosyl crocetin inhibited 14% of the formation of malon-dialdehyde (MDA) in an artificial xanthine and xanthine oxidase system using arachidonic acid as substrate. Furthermore, digentiobiosyl crocetin was applied topically to the buccal pouch of Syrian golden hamsters, and inhibited the 12-O-tetradecanoylphorhol-13-acetate-induced ornithine decarboxylase activity (ODC) by 58%, while 13-carotene inhibited 41% of this enzyme activity under similar conditions. However, digentiobiosyl crocetin has less activity in inhibition of MDA production than β-carotene. These results indicate that digentiobiosyl crocetin may act as an effective chemopreventing agent via inhibition of ODC activity.