Peganum harmala L.: Essential Oil Composition, Extraction Technologies, Biological Activities and Emerging Applications

Peganum harmala L. is a xerophytic medicinal and aromatic plant of considerable ethnopharmacological importance, characterized by a rich diversity of β-carboline alkaloids, phenolic compounds, and essential oil constituents. Despite increasing scientific interest, current knowledge remains fragmented across phytochemistry, essential oils, extraction technologies, biological activities, and safety assessments. This review provides an integrated overview of the essential oil composition, extraction methods, analytical characterization, biological properties, toxicological considerations, and emerging applications of P. harmala. Particular emphasis is given to organ-specific chemical variability, geographical and environmental influences on volatile profiles, and the importance of standardized chemical characterization for reliable bioactivity evaluation. Conventional extraction methods, including hydrodistillation and steam distillation, are critically compared with emerging green technologies such as ultrasound-assisted, microwave-assisted, and supercritical CO2 extraction. Advanced analytical tools, including GC-MS, LC-MS/MS, NMR, and chemometric approaches, are highlighted for comprehensive phytochemical profiling. Reported biological activities include antimicrobial, antifungal, antioxidant, anti-inflammatory, antidiabetic, anticancer, and agricultural effects, although their translation requires rigorous chemical standardization, mechanistic validation, and safety evaluation. Overall, this review emphasizes that the sustainable development of P. harmala should rely on quality-by-design strategies integrating botanical authentication, chemotyping, green extraction, and regulatory-oriented toxicological assessment.