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.

Lemon Oil Enhances the Anti-Rheumatic Activity of Woody Essential Oils in Formaldehyde-Induced Arthritis in Wistar Rats

“…This could be attributed to the presence of D-Limonene as shown in studies of different models of nociception without opioid receptor stimulation (42). In addition, a study has revealed that monoterpenes are the key holders of analgesic potential in Citrus essential oils, especially D-limonene and linalool (43). This explains why there was no significant reduction in inflammation with lemon oil.…”

“…There is a possibility that the synergistic effects observed with the ginger/lemon and turmeric/lemon oil blends as against lemon alone, are due to the combined reaction mechanisms against rheumatoid arthritis, attributable to an abundance of monoterpenes in lemon oil (17,43), and an abundance of sesquiterpenes in ginger and turmeric oils (9,35).…”