A new racemic xanthone, garmckeanin A (1), and eight known analogs 2–9 were isolated from the ethyl acetate (AcOEt) extract of the Vietnamese Garcinia mckeaniana leaves. Their structures were determined by MS and NMR spectral analyses and compared with the literature. The AcOEt extract showed good cytotoxicity against cancer cell lines KB, Lu, Hep-G2 and MCF7, with IC₅₀ values of 5.40–8.76 μg/mL, and it also possessed α-glucosidase inhibitory activity, with an IC₅₀ value of 9.17 μg/mL. Garmckeanin A (1) exhibited inhibition of all cancer cell lines, with an IC₅₀ value of 7.3–0.9 μM. Allanxanthone C (5) successfully controlled KB growth, with an IC₅₀ value of 0.54 μM, higher than that of the positive control, ellipticine (IC₅₀ 1.22 μM). Norathyriol (8) was a promising α-glucosidase inhibitor, with an IC₅₀ value of 0.07 μM, much higher than that of the positive control, acarbose (IC₅₀ 161.0 μM). The interactions of the potential α-glucosidase inhibitors with the C- and N-terminal domains of human intestinal α-glucosidase were also investigated by molecular docking study. The results indicated that bannaxanthone D (2), garcinone E (4), bannaxanthone E (6), and norathyriol (8) exhibit higher binding affinity to the C-terminal than to the N-terminal domain through essential residues in the active sites. In particular, compound 8 could be assumed to be the most potent mixed inhibitor.

中文翻译：

---

Garcinia mckeaniana 叶子的细胞毒性和 α-葡萄糖苷酶抑制性氧杂蒽酮及分子对接研究

一种新的外消旋的呫吨酮，garmckeanin A（1），和8个已知类似物2 - 9是从乙酸乙酯（AcOEt）纯化越南的提取物中分离藤黄mckeaniana叶子。通过 MS 和 NMR 光谱分析确定了它们的结构，并与文献进行了比较。AcOEt 提取物对癌细胞系 KB、Lu、Hep-G2 和 MCF7 表现出良好的细胞毒性，IC ₅₀值为 5.40-8.76 μg/mL，还具有 α-葡萄糖苷酶抑制活性，IC ₅₀值为 9.17 μg /毫升。Garmckeanin A ( 1 ) 表现出对所有癌细胞系的抑制作用，IC ₅₀值为 7.3–0.9 μM。尿嘧啶 C ( 5) 成功控制了 KB 的生长，其 IC ₅₀值为 0.54 μM，高于阳性对照玫瑰树碱(IC ₅₀ 1.22 μM)。Norathyriol ( 8 ) 是一种很有前途的α-葡萄糖苷酶抑制剂，其IC ₅₀值为0.07 μM，远高于阳性对照阿卡波糖(IC ₅₀ 161.0 μM)。还通过分子对接研究研究了潜在的α-葡萄糖苷酶抑制剂与人肠道α-葡萄糖苷酶的C-和N-末端结构域的相互作用。结果表明，bannaxanthone D ( 2 )、garcinone E ( 4 )、bannaxanthone E ( 6 ) 和norathyriol ( 8) 通过活性位点中的必需残基对 C 端的结合亲和力高于对 N 端结构域的结合亲和力。特别是，可以假设化合物8是最有效的混合抑制剂。