Eleven new ent-labdane diterpenoids, cheodontoins A-K (1-11), and thirteen known diterpenoids involving two ent-labdanes (12-13) and eleven ent-kauranes (14-24), were isolated from the active part of Chelonopsis odontochila (Lamiaceae) under the guidance of bioassay. The structures of cheodontoins A-K (1-11) were elucidated by extensive HRESIMS, 1D and 2D NMR, [α]D and ECD experiments, X-ray diffraction and quantum calculation. Interestingly, five nor-ent-labdanes (9-13) were obtained from this genus for the first time. One ent-labdane diterpenoid (12) and four ent-kaurane diterpenoids (16, 19, 23, and 24) showed α-glucosidase inhibitory activity with IC50 values of 326.5 ± 3.5, 599.1 ± 13.8, 620.1 ± 16.1, 185.0 ± 4.2, and 190.7 ± 11.6 μM, respectively. Compounds 12 and 16 were α-glucosidase mixed-type inhibitors with Ki values of 334.1 and 589.2 μM according to the enzyme kinetics using Lineweaver-Burk and Dixon plots. Docking study manifested that compounds 12 and 23 well located in the catalytic pocket of α-glucosidase by hydrophobic effects with Trp1355, Trp1369, Phe1427, Phe1559, and Phe1560 residues. This study provides new insights for the antidiabetic effects of C. odontochila with ent-labdane and ent-kaurane diterpenoids as the active constituents.

中文翻译：

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齿形龙（Chelonopsis odontochila）的对-拉丹烷和对-月桂烷双萜类化合物具有α-葡萄糖苷酶抑制活性。

从猪牙白屈病（Chelonopsis odontochila）的活性部分中分离出了11种新的拉丹烷二萜类化合物，天青蛋白AK（1-11）和13种已知的涉及两对拉丹类化合物（12-13）和11种高伯灵（14-24）的二萜类化合物（唇形科）在生物测定的指导下。通过广泛的HRESIMS，1D和2D NMR，[α] D和ECD实验，X射线衍射和量子计算，阐明了化学牙本质素AK（1-11）的结构。有趣的是，首次从该属中获得了5个nor-ent-labdanes（9-13）。1个拉丹烷二萜类化合物（12）和4个月桂烷双萜类化合物（16、19、23和24）显示出α-葡萄糖苷酶抑制活性，IC50值为326.5±3.5、599.1±13.8、620.1±16.1、185.0±4.2，和190.7±11.6μM。化合物12和16是α-葡萄糖苷酶混合型抑制剂，Ki值为334.1和589。根据酶动力学，使用Lineweaver-Burk和Dixon图绘制2μM。对接研究表明，化合物12和23通过Trp1355，Trp1369，Phe1427，Phe1559和Phe1560残基的疏水作用很好地位于α-葡萄糖苷酶的催化口袋中。这项研究为以恩达巴丹和恩-金刚烷二萜类化合物为有效成分的C. odontochila的抗糖尿病作用提供了新见识。