Anti-inflammatory Effects Of Essential Oils From Three Citrus Aromatic Plants

Essential oils from aromatic plants has the characteristics of wide source,low toxicity and high biological activity,citrus essential oil has anti-inflammatory,antibacterial,antioxidant and other biological activities,they can be studied as potential natural anti-inflammatory drugs.Based on the anti-inflammatory active components of essential oils,this paper explores the anti-inflammatory effects of essential oils from Citrus aurantium L.subspecies bergamia（bergamot）,Citrus limon（L.）Burm.f.（lemon）and leaves of Citrus aurantium L.subspecies amara L.（bitter orange）.The anti-inflammatory effect and anti-inflammatory mechanism of several essential oils were comprehensively evaluated through the analyse of free radicals relative enzymes,inflammatory mediators and inflammatory cytokines in vitro and in vivo.1.Gas chromatography-mass spectrometry（GC-MS）results showed that linalyl acetate and linalool were the main constituents of essential oil from leaves of bitter orange.Limonene,linalyl acetate and linalool were the main constituents of essential oil from bergamot,and limonene was the main constituents of essential oil from lemon.Essential oil from leaves of bitter orange at concentration of 25μg/mL and 12.5μg/mL bergamot essential oils significantly inhibited the lipopolysaccharide（LPS）-induced inflammatory mediator nitric oxide（NO）and inflammatory cytokine tumor necrosis factor alpha（TNF-α）production in RAW 264.7 cells measured with Griess method and Elisa method.Meanwhile,lemon essential oil shows no significant effect.2.Through the croton oil induced mouse ear edema model and the fresh egg white induced mouse paw edema model,detected myeloperoxidase（MPO）,superoxide dismutase（SOD）,malondialdehyde（MDA）,NO,prostaglandin E₂（PGE₂）and TNF-αcontent.It was found that the two essential oils in these inflammatory animal models reflect a certain anti-inflammatory effect.The middle concentration of essential oil from leaves of bitter orange and low concentration bergamot essential oil had the best anti-inflammatory effect.And the anti-inflammatory effect of these two essential oils may be through reducing the MPO activity,reducing the infiltration of inflammatory cell cells and tissue inflammatory damage,while improving SOD activity to remove free radicals in the body,increasing antioxidant defenses,and reducing the production of multiple inflammatory and damaged substances when inflammatory cells invade,inhibiting the production of inflammatory media NO,PGE₂,reducing macrophages and other inflammatory cells to produce TNF-αand other cytokines,inhibiting inflammatory cascade reaction to play an anti-inflammatory role.The above experiments show that the essential oil from leaves of bitter orange and bergamot essential oil have certain anti-inflammatory effects in vitro and vivo,that provides a theoretical basis for further exploration of their corresponding anti-inflammatory mechanism and development of natural anti-inflammatory drugs in a rational and effective way.