Pharmacology of R ( + ) - Limonene and Some Citrus Peel Essences

Transcription

1 Essential Oils and Cancer. Proceedings of the 4th Aromatherapy Conference on the Therapeutic Uses of Essential Oils. San Francisco, November Kurt Schnaubelt Institute of Aromatherapy 2000 Pharmacology of R ( + ) - Limonene and Some Citrus Peel Essences Pierre Franchomme Introduction The pharmacological in vitro studies of this molecule show very low to moderate cytotoxic properties on healthy cells and conversely high cytotoxicity on tumoral cells, inducing apoptosis; anti-oxidant and free radicals scavenger properties to be quasi non-existant, as well as the anti-inflammatory properties; but the antiviral properties to be pronounced. Citrus essences also contain other compounds which are able to modulate these properties. Pharmacological actions 1. Anticancerous properties 1.1. Specific cyto and genotoxic activities Ex vivo, in vitro, and in vivo 1.2. Anti-neo-angiogenesic activity Chemoprotective activity Antioxidant and free radical scavenger properties Anti-inflammatory properties 3.1. Moderating NPs activities 3.2. Enzymatic inhibitive activities 4. Temporizing properties of the action of citrals 5. Antiviral properties 6. Antiseptic properties 7. Anticatarrhal properties Limonene-rich plants (+) - limonene and (-) - limonene rich taxons 167

2 Revision of properties and indication of any Citrus Extension to valuable antitumoral mono- and sesquiterpenic- rich EO Pharmacological Actions The biological properties of ( + ) - limonene are compared with the levo isomere and also other important monoterpenic hydrocarbons, and with the essences of different citrus species. 1. Anticancerous properties Arise from a twofold mechanism: -curative, by inducation of apoptosis; -preventative, by detoxification of cancerogenic compounds 1.1. Specific cytotoxic and genotoxic activities The cytotoxicity of ( +) - limonene is exerted specifically on the cancerous cells, the healthy cells being affected only to a much lesser degree by this molecule. Ex vivo tests Studies of the NPs viability (MIT method). Absence of cytotoxicity to a concentration up to 25%0 (>75% of viability) Cone. % ( + ) - linomene Citrus limon (arg.) C. sinensis C. reticulata (Z) (-) - linamene 5 95 > In vitro tests Studies of the plasmidic DNA integrity (3D method). Absence of direct genotoxic effects, the ratio of genotoxicity being equal or under

3 Cone. % (+) - limonene (-) -limonene C. retie. (Z) MMS* mM mM Standard of toxicity Studies of twnoral cells sensitivity Inhibition of the post-translational isoprenylation of cell growth-regulating factors and/or induction of tumoral cells apoptosis.1) In vivo tests Studies of the activity on induced mouse skin twnor Absence of bad reaction with the purified ( + ) - limonene; but the topically applied orange peel oil acts as a very weak promoter of both skin papillomas and carcinomas, activity coming from other compounds, probably the furocoumarins; however, neither the ( + ) limonene nor the orange peel oil have an orally promoting action.2) 1.2. Anti-neo-angiogenic activity Studies in progress.3. Chemoprotective activity Strong competitive inhibition of the liver microsomal isoenzymes involved in the activation of genotoxic or promutagenic substances, particularly the P450, 2B1 cytochrome monooxygenase.3) C;oHC (-) - a-pinene (+) - a-pinene myrcene (-) - limonene ICso (fjm) e Pacific Institute of Aromatherapy. PO Box 6723 San Rafael. CA

4 2. Anti-oxidant and free radical scavenger properties The cyto- and genoprotective activity of a molecule is in direct relation with this anti-oxidant power; in the case of ( + ) - limonene, those are few, as is the case with the majority of C10 Hydrocarbon Lipoperoxidation studies - Method of ascorbic acid induction on brain phospholipids Low pro-oxidant activity of ( +) - and (-) -limonenes and citrus peel oils, except two organic ones and C. sinensis. Cone. % ( +) - limonene (-) - limonene C. limon (Z) C. limon (org.) C. paradisii (Z) C. reticulata (Z) C. reticul.(org) C. sinensis Method of ABTS induction on egg yolk Very low activity in comparison with thymol for example C10 Hydrocarbon (1000 ppm) ( + ) - sabinene ~ - ocimene a - terpinene a - pinene P - cymene a - phellandrene ~ - pinene (:t ) - limonene g-terpinene terpinolene!! Carene Myrcene Thymol Trolox equivalent (j.tmoi/l)4) :t :t :t :t :t :to :t :t :to :t :t :t :t

5 Studies of plasmidic DNA lesions (3D method) Very low protective activity of the DNA against the genotoxic effects of the oxygen active fontis, particularly the singulet oxygen and the hydroxyl radical. Cone. (%) 'positive control % of Specific Protection Besides 102 & HO (+) - limonene (-) -limonene c. retic. (Z) % 2/0 1/4 5/0 5/0 3/0 % % % 20/10 1/23 % Silymarine" 10/9 11/18 61/56 76/80 Anti-inflammatory properties Research is not able to demonstrate an activity in this field, except for those citrus peel oils, in which other components playa role. On the other hand, the (-) -limonene develops a relatively good activity, inhibiting chemotaxis and oxidative bursts NPs - moderating activities Studies of adhesion inhibition (see the method in "L'aromatherapie, therapeutique de pointe en medecine naturelle") Cone. % 5 (+) - limonene 10 Citrus limon (Z) 65 C. sinensis 7.5 C. reticulata 15 (-) - limonene 10 Studies of chemotaxis inhibition (idem) Cone. % 5 10 (+) -limonene 0.0 (-) - limonene Studies of oxidative bursts inhibition (idem)

6 3.2. Enzyme Inhibiting Activity Low to zero activity on 2 metalloproteinase (Hyaluronidase and elastase) 4. Suppressing the Action of Citrals ( +) - limonene reduces the irritant action of citrals and other aldehydes on skin; a non-deterpenated lemon peel oil acts four times less aggressive that a deterpeneted one, which is causing the appearance of a thick erythemateous layer. 5. Antiviral Properties Effective inhibition of Herpes Simplex (viral suspension at 105/0.1mL) on cell culture of kidney "vero" at the concentration of 0.1 % 5) CMf in mglml g - terpinene (+) -limonene sebinene The numerals represent the number of formed viral plaques 6. Antiseptic properties Equivalent to a- and ~-pinenes 7. Anticatarrhal properties No studies Limonene-Rich Plants Distribution ( +) - limonene and (-) - limonene rich taxons Revision of Properties and Indication of Any Citrus Peel Oils Properties and indications mentioned in "L'aromatherapie exactement" are true. However, the above anticancerous activities have not become the subject of clinical research; so the only one suggested indication today is prevention by dietary intake. 172 (Q Pacific Institute of Aromatherapy. PO Box 6723 San Rafael, CA 94903

7 Extension to Valuable Antitumoral Mono-and Sesquiterpenic-Rich EO Tetraclinis articulata (Cupressaceae) Zingiber officinalis (Zingiberaceae) Canella Winteriana (Canellaceae) References 1. Crowell P.L. - Prevention and therapy of cancer by dietary monoterpenes - J. Nutr., 129(3), S (1999). 2. Ref. Elegbede S.A. et. ai. (1987). 3. De Oliveira A.C. et. ai. - Inh. of CYP 2Bl by ~-myrcene and others ClO oides compo - Toxicol- Lett., 92(1), 35-65(1997). 4. Droman H. J. D. et. ai. - In vitro antioxidant activity of nb of pi. e. o. and phytoconstituants J. Essent. Oil Res., IL, (2000). 5. Lembke A. et Deninger R. - Wirkung von Bestandteilen etherischer Ole auf Bakterien, Pilze und Viren, in Phytotherepie, Grundlage, Klinik, Praxis, ed. Hippokrates, Stuttgart (1988). (g Pacific Institute of Aromatherapy. PO Box 6723 San Rafael, CA