Chemical Composition and In Silico Study of the Biological Activities of Alkaloids from Peganum harmala

Peganum harmala is employed extensively in ethnopharmacology but little literature has been done on the bioactive alkaloids of this plant. This paper gives an experimental finding on the chemical composition of P. harmala. It analyzes by quantum-chemical and in silico the biological characteristics of its primary alkaloids, peganine and deoxypyganine. The analysis of the samples by HPLC at various stages of growth showed that the quantity of peganine peaks at the stage when the branching occurs (up to 83% in the sample on May 14, 2023). DFT results indicated that the two alkaloids have good electronic behavior and peganine has high index of electrophilicity and high electron affinity. The active sites were determined by molecular electrostatic potential (MEP) mapping, whereas system-level activity was proved by density of states (DOS) spectra. Molecular docking of human 6s5a protein showed that peganine and deoxypeganine bind with an affinity of -7.59 kcal/mol as well as -8.13 kcal/mol. respectively, which are strong molecular affinities. These findings indicate that the alkaloid of P. harmala especially peganine has promising pharmacological activities that should be further confirmed in the context of in vitro and in vivo experiments.