Abstract:
Two unprecedented rearranged fusicoccane diterpenoids, hyperperins A (
1) and B (
2), and twenty-two new fusicoccane diterpenoids, hyperperins C–X (
3–24), were isolated from the aerial parts of
Hypoestes purpurea, as well as one known analog (
25). The structures and absolute configurations of all newly isolated compounds were determined through comprehensive analyses, including NMR spectroscopy, HR-ESI-MS, electronic circular dichroism calculations, and single-crystal X-ray diffraction analysis. Structurally, compounds
1 and
2 were characterized by a previously unreported carbon skeleton featuring a 5/7/5/3 tetracyclic ring system. Compounds
19 and
20 represent the first examples of fusicoccane diterpenoids with epoxy groups at C-2/C-6 and C-6/C-7, respectively. A plausible biosynthesis pathway for compounds
1 and
2 was proposed. Additionally, compounds
1,
2,
3,
7, and
25 exhibited potent inhibitory activity against the Ca
v3.1 calcium channel with IC
50 values of 15.06 ± 1.19, 9.00 ± 1.04, 6.04 ± 0.67, 14.00 ± 1.20, and 6.26 ± 0.82 μmol·L
−1, respectively. These findings enrich the structural diversity of fusicoccane diterpenoids and provide promising lead compounds for the development of Ca
v3.1 calcium channel inhibitors.