Isolation, spectral characterization, molecular docking, and cytotoxic activity of alkaloids from Erythroxylum pungens O. E. Shulz

Abstract

Stem bark, root bark, and leaf extracts of Erythroxylum pungens were subjected to phytochemical analysis. N,N-dimethyltryptamine (DMT) was isolated and characterized from E. pungens roots. This unprecedented result is remarkable since no indole alkaloid has been previously reported from Erythroxylaceae so far. Eleven known tropane alkaloids were identified by their mass spectra and 3-(2-methylbutyryloxy)tropan-6,7-diol as well as 3-(2-methylbutyryloxy)nortropan-6,7-diol were isolated and characterized based on mass spectrometry, ¹H, ¹³C, COSY, and NOESY NMR analysis. The complete NMR data are reported for the first time. Inverse Structure-based and Ligand-Based virtual screening were carried out to identify possible targets for 3-(2-methylbutyryloxy)tropan-6,7-diol. The level of cytotoxicity of this tropane alkaloid aliphatic ester was discrete with potencies on the order of 0.3-1.0 mg/mL and better results against HeLa (50% cell viability reduction). Otherwise, atropine (0.3 mg/mL), a Solanaceae tropane alkaloid, and DMT (0.5 mg/mL) from E. pungens roots impaired at 50% the cell viability against HeLa, SiHa, PC3, and 786-0. This study stimulates scientific investigation of the impact of edaphoclimatic features in a semi-arid environment on tropane alkaloid biosynthesis.

Keywords: Cytotoxicity; Erythroxylaceae; Erythroxylum pungens; N,N-dimethyltryptamine; Tropane alkaloids.