The Anti-inflammatory effects of the Jamaican species of Cymbopogon citratus (lemon grass) and Croton linearis (wild rosemary) plant extracts on carrageenaninduced inflammation

Author(s): Audrey Jacob, L.A.D Williams. Anthony Webly and Michael Heron E.A Thomas.

Inflammation occurs in response to injury and if left untreated can lead to several diseases including arthritis. In Jamaican folklore practice plant extracts have been traditionally used to treat inflammatory conditions including rheumatoid arthritis and asthma. This is the first preliminary scientific investigation of the anti-inflammatory effects of extracts from the Jamaican species of Croton linearis (wild rosemary) and Cymbopogan citratus (lemon grass) leaves on carrageenan-induced rat paw edema. The methods used involved testing of plant extracts on inflammation induced by carrageenan lambda on the rat paw model. 0.1ml of 1% Carrageenan lambda in saline solution (0.9%) was injected into the plantar region of the right hind paw of all groups to induce inflammation. Hexane extract (50mg/kg) of Croton linearis screened by BSA assay represents a sample inhibiting denaturation greater than 0%. Findings show that Croton linearis extract and aspirin (NSAID) shows comparable efficacy in reducing rat paw oedema (p< 0.05)(n=18 Sprague Dawley rats). This extract might be blocking the COX enzymes, with emphasis on COX-2 actions inflammation. Lemon grass extract 400 mg/kg showed reduction in paw volume (p < 0.001), 200 mg/kg extract (p <0.01), saline group showed no significance compared to aceclofenac group (p<0.05), n=24. In concluding extracts of both Wild rosemary and lemon grass showed comparable efficacy to aspirin and aceclofenac in reducing the inflammatory response induced by carrageenan lambda. This data indicates that the extracts of Jamaican species of our samples contain components with anti-inflammatory potential. We are hoping to assess if the extracts are arresting inflammation at the early stage where there is release of histamine, 5-hydroxytrptamine and bradykinin or in in the late phase where prostaglandins are detectable (Prakash et al., 2011). Further work needs to be done to assess for toxicity and to purify the extracts to ensure safety.