In this study, four undescribed bibenzyl derivatives (1–4), together with seven known compounds (5–11) were isolated from the aerial parts of Dendrobium officinale. Their chemical structures were determined to be (7’S,8’S) ‐9′′‐acetyldendrocandin U (1), (7’S,8’S) ‐4′‐methoxydendrocandin T (2), (7’R,8’S) ‐dendrocandin B (3), (1S,2R) ‐5′′′‐methoxydendrofindlaphenol C (4) by analyzing of the spectroscopic data including HR‐ESI‐MS, 1D‐, and 2D‐NMR spectra. The absolute configurations of compounds 1‐4 were determined by the electronic circular dichroism (ECD) spectra. Compounds 1–3, 5, 10 and 11 inhibited α‐glucosidase with the IC50 values ranging from 56.3 to 165.3 µM, compounds 1–3, 5, 7–10 inhibited α‐amylase with the IC50 values ranging from 65.2 to 177.6 µM.

中文翻译：

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铁皮石斛地上部分的四种未描述的二苯乙烯衍生物及其 α-葡萄糖苷酶和 α-淀粉酶抑制活性

在这项研究中，从铁皮石斛的地上部分分离出了四种未描述的联苄衍生物 (1-4) 以及七种已知化合物 (5-11)。其化学结构确定为 (7'S,8'S) ‐9''-乙酰树突菌素 U (1)、(7'S,8'S) ‐4'-甲氧基树突菌素 T (2)、(7'R,8'S) ‐树突菌素 B (3) ), (1S,2R) ‐5′′′-甲氧基树芬苯酚 C (4) 通过分析光谱数据（包括 HR-ESI-MS、1D- 和 2D-​​NMR 光谱）。化合物1-4的绝对构型通过电子圆二色性(ECD)光谱测定。化合物1-3、5、10和11抑制α-葡萄糖苷酶，IC50值范围为56.3至165.3μM，化合物1-3、5、7-10抑制α-淀粉酶，IC50值范围为65.2至177.6μM。