Fusicoccane Diterpenes from Hypoestes forsskaolii as Heat Shock Protein 90 (Hsp90) Modulators

Ten new (1–10) and six known (11–16) fusicoccane diterpenes were isolated from the roots of Hypoestes forsskaolii. The structural characterization of 1–10 was performed by spectroscopic analysis, including 1D and 2D NMR, ECD, and HRESIMS experiments. From a perspective of obtaining potential Hsp90α inhibitors, the isolates were screened by surface plasmon resonance measurements and their cytotoxic activity was assayed using Jurkat and HeLa cancer cells. Compound 6, 18-hydroxyhypoestenone, was shown to be the most active compound against Hsp90, and its interactions were studied also by biochemical and cellular assays and by molecular docking.