Diterpenoid alkaloids from the whole herb of Delphinium grandiflorum L

Abstract

Seven previously undescribed diterpenoid alkaloids, eight reaction products and thirteen known compounds were isolated from the whole plant of Delphinium grandiflorum L. (Ranunculaceae). Grandiflonines A and B have an unprecedented C₂₀-diterpenoid alkaloid skeleton, which features inversion of the configuration of C-18. Their structures were determined by comprehensive analyses of spectroscopic data, X-ray diffraction and Mosher's method. The probable biosynthetic pathway of grandiflonine A was discussed. Additionally, the analgesic activity and anti-inflammatory activity by inhibition of NO production were evaluated. Among them, deoxylappaconitine (ED₅₀ = 0.35 mg/kg, TI = 46.22) showed significant analgesic activity that was superior to the reference drug lappaconitine (ED₅₀ = 3.5 mg/kg, TI = 3.34).

Keywords: Analgesic activity; Delphinium grandiflorum; Diterpenoid alkaloids; Grandiflonines A–B; Ranunculaceae.