Lactam -Kaurane Diterpene: A New Class of Diterpenoids Present in Roasted Beans of .

Seven new lactam -kaurane diterpenoids, cafemides A-G (-), were isolated from roasted beans of . Their structures were elucidated by extensive spectroscopic analysis including 1D, 2D NMR (heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC), H-H correlation spectroscopy (COSY), and rotating frame Overhauser effect spectroscopy (ROESY)), high-resolution electrospray ionization mass spectrometry (HRESIMS), and IR spectra. They were divided into subtype I-III according to the structure. Further, with the aid of liquid chromatography-tandem mass spectrometry (LC-MS/MS) based molecular network, seven (-) subtype II diterpenoids were successfully identified. In addition, a variety of other subtypes of N-containing diterpenoids have been proven in roasted coffee. Compounds , , , , and showed a moderate inhibitory effect on α-glucosidase with an IC value of 8.28 ± 0.62 μM, 38.23 ± 8.87 μM, 28.94 ± 1.42 μM, 12.44 ± 1.37 μM, and 22.2 ± 5.34 μM, respectively. To the best of our knowledge, this is the first time that N-containing diterpenoids have been reported in coffee.