Analgesic Potential of Monoterpenes from Citrus Essential Oils

Abstract

Chronic pain is a noteworthy health issue with immense impact on global healthcare systems. Although this issue has not come into the limelight as other noncommunicable diseases, it should be highlighted that modern medicine still has no efficient treatment to curb chronic pain. In this aspect, essential oils have been used for the prevention of several disease conditions including pain management. These odorous products, obtained from botanically defined raw material, have a variable and complex composition. Their composition largely depends on the extraction technique used, from simple hydro-distillation, to supercritical or microwave-assisted extraction. Monoterpenoids are some of the most biologically active and highly researched compounds when it comes to antinociceptive effects. They are volatile oils, primarily composed of two isoprene units with highly distinctive aromas and flavors. More than 90% of the essential oils of medicinal plants consist of monoterpenoids like limonene, myrcene, α-terpineol, linalool, pinene, p-cymene, and nerol. Besides strong anti-inflammatory effect, all essential oils with high D-limonene content pose a significant free radical scavenging effect, predominantly disabling the production of reactive oxygen species. Further studies in humans are encouraged to determine the real long-term potential in treating chronic pain.