Division of Applied Life Science (BK21 program), IALS, GyeongSang National University, Jinju 660-701, Republic of Korea.
Phytochemistry. 2011 Dec;72(17):2148-54. doi: 10.1016/j.phytochem.2011.08.007. Epub 2011 Aug 27.
An ethanol extract of the fruit case of Garcinia mangostan, whose most abundant chemical species are xanthones, showed potent α-glucosidase inhibitory activity (IC(50)=3.2 μg/ml). A series of isolated xanthones (1-16) demonstrated modest to high inhibition of α-glucosidase with IC(50) values of 1.5-63.5 μM. In particular, one hitherto unknown xanthone 16 has a very rare 2-oxoethyl group on C-8. Kinetic enzymatic assays with a p-nitrophenyl glucopyranoside indicated that one of them, compound (9) exhibited the highest activity (K(i)=1.4 μM) and mixed inhibition. Using, a physiologically relevant substrate, maltose, as substrate, many compounds (6, 9, 14, and 15) also showed potent inhibition which ranged between 17.5 and 53.5 μM and thus compared favorably with deoxynojirimycin (IC(50)=68.8 μM). Finally, the actual pharmacological potential of the ethanol extract was demonstrated by showing that it could elicit reduction of postprandial blood glucose levels. Furthermore, the most active α-glucosidase inhibitors (6, 9, and 14) were proven to be present in high quantities in the native seedcase by a HPLC chromatogram.
藤黄果皮的乙醇提取物中，最丰富的化学物质是黄烷酮，表现出很强的α-葡萄糖苷酶抑制活性（IC50=3.2μg/ml）。一系列分离得到的黄烷酮（1-16）对α-葡萄糖苷酶表现出适度到高度的抑制作用，IC50 值为 1.5-63.5μM。特别是一种迄今未知的黄烷酮 16 在 C-8 位上具有非常罕见的 2-氧乙基基团。用对硝基苯-α-D-吡喃葡萄糖苷进行酶动力学测定表明，其中一种化合物（9）具有最高的活性（K i=1.4μM）和混合抑制作用。使用生理相关的底物麦芽糖作为底物，许多化合物（6、9、14 和 15）也表现出很强的抑制作用，其范围在 17.5 和 53.5μM 之间，与脱氧野尻霉素（IC50=68.8μM）相比具有优势。最后，通过证明该乙醇提取物可以降低餐后血糖水平，显示了其实际的药理学潜力。此外，通过 HPLC 色谱图证明，最有效的α-葡萄糖苷酶抑制剂（6、9 和 14）在天然种子壳中以高浓度存在。
