Sixteen new 2-(2-phenylethyl)chromone dimers, including four pairs of enantiomers (1a/1b, 3a/3b, 6a/6b, and 8a/8b), along with eight optically pure analogues (2, 4, 5, 7, and 9–12) were isolated from the resinous wood of Aquilaria sinensis. Their structures were determined by extensive spectroscopic analysis (1D and 2D NMR, UV, IR, and HRMS) and experimental and computed ECD data. Compounds 1–10 feature an unusual 3,4-dihydro-2H-pyran ring linkage connecting two 2-(2-phenylethyl)chromone monomeric units, while compounds 11 and 12 possess an unprecedented 6,7-dihydro-5H-1,4-dioxepine moiety in their structures. A putative biosynthetic pathway of the representative structures via a diepoxy derivative of a chromone with a nonoxygenated A-ring is also proposed. Compounds 1a/1b, 2, 3a/3b, 5, 7, 8a/8b, and 10–12 exhibited significant inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells with IC₅₀ values in the range 7.0–12.0 μM.

中文翻译：

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中华沉香树脂木材的抗炎性二聚2-（2-苯乙基）色酮

十六新的2-（2-苯乙基）色酮二聚体，其中四对对映体（的1A / 1B，3A / 3B，6A / 6B，和图8a / 8B），与八个光学纯类似物（沿2，4，5，7和9 - 12）获自的树脂木材中分离白木香。通过广泛的光谱分析（1D和2D NMR，UV，IR和HRMS）以及实验和计算的ECD数据确定了它们的结构。化合物1 – 10具有一个异常的3,4-二氢-2 H-吡喃环键，连接两个2-（2-苯基乙基）色酮单体单元，而化合物11和12具有空前的6,7-二氢-5 H -1,4-二氧杂环庚烷结构中的部分。还提出了经由色酮的二环氧衍生物与未氧化的A环的代表性结构的假定生物合成途径。化合物1A / 1B，2，图3a / 3b中，5，7，图8A / 8B，和10 - 12在脂多糖刺激的RAW264.7细胞中表现出对一氧化氮产生的显着抑制作用，IC ₅₀值在7.0-12.0μM范围内。