2.2. Preparation of Peganum harmala Alkaloid-Rich Fraction (L)

Dried mature seeds of P. harmala L. were provided from the local Egyptian market. The alkaloid-rich fraction of P. harmala seeds was extracted as described previously. Briefly, P. harmala ground seeds (2.4 kg) were soaked in 70% ethanol three successive times until exhaustion. The extracts were collected, filtered, and evaporated using rotavap to yield 520 g residue. Part of this residue was subjected to acid/base extraction to yield a rich fraction of harmala alkaloids (L). Then, the extracted L fraction was characterized using ultraperformance liquid chromatography–electrospray ionization–tandem mass spectrometry (UPLC/ESI-MS) following our formerly reported protocol [24,27].