Anti-inflammatory effects of compounds alpha-humulene and (−)-trans-caryophyllene isolated from the essential oil of Cordia verbenacea

This study evaluated the anti-inflammatory properties of two sesquiterpenes isolated from Cordia verbenacea's essential oil, α-humulene and (−)-trans-caryophyllene. Our results revealed that oral treatment with both compounds displayed marked inhibitory effects in different inflammatory experimental models in mice and rats. α-humulene and (−)-trans-caryophyllene were effective in reducing platelet activating factor-, bradykinin- and ovoalbumin-induced mouse paw oedema, while only α-humulene was able to diminish the oedema formation caused by histamine injection. Also, both compounds had important inhibitory effects on the mouse and rat carrageenan-induced paw oedema. Systemic treatment with α-humulene largely prevented both tumor necrosis factor-α (TNFα) and interleukin-1β (IL-1β) generation in carrageenan-injected rats, whereas (−)-trans-caryophyllene diminished only TNFα release. Furthermore, both compounds reduced the production of prostaglandin E2 (PGE2), as well as inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) expression, induced by the intraplantar injection of carrageenan in rats. The anti-inflammatory effects of α-humulene and (−)-trans-caryophyllene were comparable to those observed in dexamethasone-treated animals, used as positive control drug. All these findings indicate that α-humulene and (−)-trans-caryophyllene, derived from the essential oil of C. verbenacea, might represent important tools for the management and/or treatment of inflammatory diseases.