Three new 5,6-dihydro-α-pyrones derivatives, named (S)-rugulactone (1) pulchrinervialactone A (2), and pulchrinervialactone B (4), along with one known pyrone, cryptobrachytone C (3), and three known amide derivatives (5–7) have been isolated from the leaves of Cryptocarya pulchrinervia. The structures of 1–7 were elucidated based on extensive spectroscopic data and comparison with literatures. The configurations of compounds 3 and 4 were established by single crystal X-ray diffraction analysis. This is also the first report in finding (S)-rugulactone (1) as a natural product. In addition, the preliminary cytotoxic activity of the isolated compounds was evaluated against P-388 cells using the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. All the pyrones, except compound 4, were active significantly inhibiting the growth of P-388 cells, while the amides derivatives (5–7) showed moderate to weak activities. Therefore, compounds 1–3 could be potentially examined further for anticancer agents.

中文翻译：

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隐叶番荔枝（金合欢）的叶子中的5，6-二氢-α-吡喃酮。

三种新的5,6-二氢-α-吡喃酮衍生物，分别命名为（S）-丁香内酯（1），pulchrinervialactone A（2）和pulchrinervialactone B（4），以及一种已知的吡喃酮，隐叶酸C（3）和三种已知的吡喃酮从Cryptocarya pulchrinervia的叶子中分离出了酰胺衍生物（5-7）。根据广泛的光谱数据并与文献比较，阐明了1–7的结构。通过单晶X射线衍射分析确定化合物3和4的构型。这也是发现（S）-果内酯（1）作为天然产物。另外，使用[3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四唑溴化物]测定法评估了分离的化合物对P-388细胞的初步细胞毒活性。除化合物4外，所有吡喃酮均具有明显抑制P-388细胞生长的活性，而酰胺衍生物（5-7）则显示中等至弱的活性。因此，可以对化合物1-3进行抗癌剂的进一步检查。