Citrus Essential Oils: A Review of Chemical Composition, Bioactivity, Safe Use, and Potential Applications

The genus Citrus (Rutaceae) produces essential oils (EOs) widely utilized in food, pharmaceutical, cosmetic, and biomaterial industries due to their distinct organoleptic properties. These EOs are primarily composed of monoterpenes (e.g., limonene), sesquiterpene hydrocarbons, and oxygenated derivatives, which exhibit anti-inflammatory, antioxidant, antibacterial, antineoplastic, and insecticidal activities. Principal extraction methods include cold pressing (CP), solvent extraction, distillation, ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and supercritical fluid extraction (SFE). Due to the increasing prevalence of adulteration and pesticide residues, robust analytical methods for their detection are required. This review addresses the major chemical components, common extraction techniques, and biological activities of Citrus EOs. Analytical approaches for identifying adulterants and pesticide residues are also examined. Particular attention is given to furocoumarin-induced photosensitivity, a critical safety concern. Addressing these issues is essential to provide a scientific basis for the rational and expanded application of Citrus EOs in food science, material engineering, and related fields.