New bioactive monoterpene indole alkaloid from Rinorea yaundensis Engl.

Abstract

Extraction of the aerial part of Rinorea yaundensis has led to the isolation of a new monoterpene indole alkaloid (1) along with 10 known compounds (2–11) for the first time from this plant. Their structures were determined by HRMS and NMR spectroscopic analyses as yaundentine hydrochloride (1), N_b-oxide of iso-reserpiline (2), iso-reserpiline (3), iso-carapanaubine (4), lichenxanthone (5), stigmastane-3,6-dione (6), methyl β-orcinol carboxylate (7), β−sitosterol-3-O-β-D-glucoside (8), betulinic acid (9), ursolic acid (10) and benzoic acid (11) while the stereochemistry and absolute configuration of 1 was confirmed by single crystal x-ray crystallography and circular dichroism CD spectrum. Yaundentine hydrochloride (1) exhibited pronounced antioxidant, urease and lipoxygenase inhibitory activities with IC₅₀ values of 35.6 ± 0.23, 20.3 ± 0.58 and 29.6 ± 0.77 µM, respectively. Compound 1 also showed good antimicrobial activity against some Gram positive and negative bacteria.

Graphical Abstract

Keywords:

• Yaundentine
• Rinorea yaundensis
• indole alkaloid
• NMR

Disclosure statement

No potential conflict of interest was reported by the authors.