The Essential Oil of Eucalyptus tereticornis and its Constituents, α - and β -Pinene, Show...
3
The Essential Oil of Eucalyptus tereticornis and its Constituents, α- and β-Pinene, Show Accelerative Properties on Rat Gastrointestinal Transit Davi Matthews Jucá 1 , Moisés Tolentino Bento da Silva 1 , Raimundo Campos Palheta Junior 2 , Francisco José Batista de Lima 1 , Willy Okoba 1 , Saad Lahlou 3 , Ricardo Brandt de Oliveira 4 , Armênio Aguiar dos Santos 1 , Pedro Jorge Caldas Magalhães 1 1 Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil 2 Curso de Medicina Veterinária, Universidade Federal do Vale do São Francisco, Petrolina, PE, Brasil 3 Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza, CE, Brasil 4 Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil Abstract ! The essential oil of Eucalyptus tereticornis (EOET) has pharmaco- logical activities but their effects on the gastrointestinal tract are yet unknown. It possesses α- and β-pinene as minor constituents, isomers largely used as food or drink additives. In this work, we studied their actions on gut motility. After feeding with a liquid test meal, conscious rats received perorally EOET, α-, or β-pinene, and the fractional dye retention was determined. EOET and its constituents decreased the gastric retention. In anesthetized rats, pinenes increased gastric tonus, while enhancing the meal pro- gression in the small intestine of conscious rats. Both α- and β- pinene contracted gastric strips in vitro but relaxed the duode- num. Conversely, EOET relaxed both the gastric and duodenal strips. In conclusion, EOET accelerates the gastric emptying of liq- uid, and part of its action is attributed to the contrasting effects induced by α- and β-pinene on the gut. Key words Eucalyptus tereticornis · Myrtaceae · gastric emptying · mono- terpenes · prokinetics Supporting information available online at http://www.thieme-connect.de/ejournals/toc/plantamedica Eucalyptus tereticornis Sm. (Myrtaceae) is an aromatic species of eucalyptus, and its essential oil (EOET), which has antioxidant properties [1], is largely used as insect repellent [2] as well as in the treatment of airway dysfunctions [3–6]. EOET contains α- (7.8% v/v) and β-pinene (7.4%), isomers found in many essential oils such as those of pine and cedar [7]. Since they are used as an additive in foods and drinks as well as in tobacco products, their estimated daily per capita intake varies from 0.1 to 8.3 mg [8], which implies a frequent human exposure to such substances. The effects of EOET on gut motility are unknown, but pinenes, alone or in essential oils, relax the small intestine [9–12]. Given that their effects on the gut hitherto have not been reported in vivo, this is the major aim of this study. In gastric motility assay (l " Fig. 1 a), EOET (10 or 100 mg/kg; p. o.) decreased (p < 0.05) at 10 min postprandial the gastric retention (53.5 ± 2.5 % in vehicle-treated rats vs. 34.1 ± 3.3 % and 39.1 ± 2.8 %, respectively, for the two concentrations). Gastric dye retention by EOET was similar to that induced by the positive control 5-hy- droxytryptamine (5-HT, 3 mg/kg, p. o.; 33.4 ± 2.0 %), although on- ly 5-HT increased (p < 0.05) retention at the proximal segment of the intestine. Alpha- and β-pinene (100 mg/kg) also enhanced the gastric emptying rate and gastrointestinal transit. At 10 min postprandial (l " Fig. 1 b), they decreased (p < 0.05) the gastric re- tention (43.9 ± 2.2% and 42.2 ± 2.8%, respectively, for α- and β- pinene), whilst increasing (p < 0.05) retention at the distal intes- tine (6.9 ± 0.9 % in vehicle-treated rats vs. 15.8 ± 3.3 % and 10.1 ± 1.0%, respectively). At 20 min postprandial, both monoter- penes decreased (p < 0.05) the retention values at the proximal intestine (l " Fig. 1 c). At 30 min postprandial, no significant changes were observed in the gastric or intestinal dye retention values between control and pinene-treated groups (data not shown). Our data show that EOET has prokinetic properties, which may be attributable to α- and β-pinene. Pinenes adminis- tered orally appear be active for at least 20 min postprandial. We also evaluated the effects of α- and β-pinene on small intestine transit of a liquid test meal, which was distributed significantly more distally after α- and β-pinene treatments (l " Fig. 2 a; 2.7 ± 0.1 and 2.9 ± 0.1, respectively, vs. 2.2 ± 0.1, in the vehicle group). Pinene values were smaller than those observed to 5-HT (3 mg/kg, p. o.; 3.6 ± 0.1). The gastric emptying rate is regulated via a complex interplay of mechanisms involving neurotransmit- ters, paracrine substances, hormones, and smooth muscle excit- ability [13, 14], and these monoterpenes probably act on the bal- ance existing between the stomach and duodenum, accelerating Fig. 1 Comparison of fractional dye retention (%) values in the stom- ach and in the proximal, medial, and distal small intestine of conscious rats 10 (panels a and b) or 20 (panel c) min after they were gavage fed with the test meal. Ani- mals were treated with vehicle (Tween 80), EOET (10 or 100 mg/kg, p. o., panel a), α-(α- pin), or β-pinene (β-pin) (both at 100 mg/kg -1 , p. o., panels b and c). 5-Hydroxytriptamine (5-HT, 3 mg/kg, p. o.) was used as a positive control at 10 min post- prandial (a). Results were expressed as mean ± SEM of 8 rats per group. * P < 0.05 compared to the ve- hicle group, ANOVA and Holm-Sidak test. 57 Matthews Jucá D et al. The Essential Oil … Planta Med 2011; 77: 57–59 Letters
Transcript of The Essential Oil of Eucalyptus tereticornis and its Constituents, α - and β -Pinene, Show...
Fig. 1 Comparison offractional dye retention(%) values in the stom-ach and in the proximal,medial, and distal smallintestine of consciousrats 10 (panels a and b)or 20 (panel c) min afterthey were gavage fedwith the test meal. Ani-mals were treated withvehicle (Tween 80),EOET (10 or 100mg/kg,p.o., panel a), α- (α-pin), or β-pinene (β-pin)(both at 100mg/kg−1,p.o., panels b and c).5-Hydroxytriptamine(5-HT, 3mg/kg, p.o.)was used as a positivecontrol at 10min post-prandial (a). Resultswere expressed asmean ± SEM of 8 ratsper group. * P < 0.05compared to the ve-hicle group, ANOVAand Holm-Sidak test.
57Letters
The Essential Oil of Eucalyptustereticornis and its Constituents,α- and β-Pinene, Show AccelerativeProperties on Rat GastrointestinalTransit
Davi Matthews Jucá1, Moisés Tolentino Bento da Silva1,Raimundo Campos Palheta Junior2,Francisco José Batista de Lima1, Willy Okoba1,Saad Lahlou3, Ricardo Brandt de Oliveira4,Armênio Aguiar dos Santos1, Pedro Jorge Caldas Magalhães11 Departamento de Fisiologia e Farmacologia,Faculdade de Medicina, Universidade Federal do Ceará,Fortaleza, CE, Brasil
2 Curso de Medicina Veterinária, Universidade Federaldo Vale do São Francisco, Petrolina, PE, Brasil
3 Instituto Superior de Ciências Biomédicas,Universidade Estadual do Ceará, Fortaleza, CE, Brasil
4 Departamento de Clínica Médica, Faculdade de Medicinade Ribeirão Preto, Universidade de São Paulo,Ribeirão Preto, SP, Brasil
Abstract!
The essential oil of Eucalyptus tereticornis (EOET) has pharmaco-logical activities but their effects on the gastrointestinal tract areyet unknown. It possesses α- and β-pinene as minor constituents,isomers largely used as food or drink additives. In this work, westudied their actions on gut motility. After feeding with a liquidtest meal, conscious rats received perorally EOET, α-, or β-pinene,and the fractional dye retention was determined. EOET and itsconstituents decreased the gastric retention. In anesthetized rats,pinenes increased gastric tonus, while enhancing the meal pro-gression in the small intestine of conscious rats. Both α- and β-pinene contracted gastric strips in vitro but relaxed the duode-num. Conversely, EOET relaxed both the gastric and duodenalstrips. In conclusion, EOET accelerates the gastric emptying of liq-uid, and part of its action is attributed to the contrasting effectsinduced by α- and β-pinene on the gut.
Key wordsEucalyptus tereticornis · Myrtaceae · gastric emptying · mono-terpenes · prokinetics
Supporting information available online athttp://www.thieme-connect.de/ejournals/toc/plantamedica
Eucalyptus tereticornis Sm. (Myrtaceae) is an aromatic species ofeucalyptus, and its essential oil (EOET), which has antioxidantproperties [1], is largely used as insect repellent [2] as well as inthe treatment of airway dysfunctions [3–6]. EOET contains α-(7.8% v/v) and β-pinene (7.4%), isomers found in many essentialoils such as those of pine and cedar [7]. Since they are used as anadditive in foods and drinks as well as in tobacco products, theirestimated daily per capita intake varies from 0.1 to 8.3mg [8],which implies a frequent human exposure to such substances.The effects of EOET on gut motility are unknown, but pinenes,
alone or in essential oils, relax the small intestine [9–12]. Giventhat their effects on the gut hitherto have not been reported invivo, this is the major aim of this study.In gastric motility assay (l" Fig. 1a), EOET (10 or 100mg/kg; p.o.)decreased (p < 0.05) at 10min postprandial the gastric retention(53.5 ± 2.5% in vehicle-treated rats vs. 34.1 ± 3.3% and 39.1 ± 2.8%,respectively, for the two concentrations). Gastric dye retention byEOET was similar to that induced by the positive control 5-hy-droxytryptamine (5-HT, 3mg/kg, p.o.; 33.4 ± 2.0%), although on-ly 5-HT increased (p < 0.05) retention at the proximal segment ofthe intestine. Alpha- and β-pinene (100mg/kg) also enhancedthe gastric emptying rate and gastrointestinal transit. At 10minpostprandial (l" Fig. 1b), they decreased (p < 0.05) the gastric re-tention (43.9 ± 2.2% and 42.2 ± 2.8%, respectively, for α- and β-pinene), whilst increasing (p < 0.05) retention at the distal intes-tine (6.9 ± 0.9% in vehicle-treated rats vs. 15.8 ± 3.3% and10.1 ± 1.0%, respectively). At 20min postprandial, both monoter-penes decreased (p < 0.05) the retention values at the proximalintestine (l" Fig. 1c). At 30min postprandial, no significantchanges were observed in the gastric or intestinal dye retentionvalues between control and pinene-treated groups (data notshown). Our data show that EOET has prokinetic properties,which may be attributable to α- and β-pinene. Pinenes adminis-tered orally appear be active for at least 20min postprandial. Wealso evaluated the effects of α- and β-pinene on small intestinetransit of a liquid test meal, which was distributed significantlymore distally after α- and β-pinene treatments (l" Fig. 2a;2.7 ± 0.1 and 2.9 ± 0.1, respectively, vs. 2.2 ± 0.1, in the vehiclegroup). Pinene values were smaller than those observed to 5-HT(3mg/kg, p.o.; 3.6 ± 0.1). The gastric emptying rate is regulatedvia a complex interplay of mechanisms involving neurotransmit-ters, paracrine substances, hormones, and smooth muscle excit-ability [13,14], and these monoterpenes probably act on the bal-ance existing between the stomach and duodenum, accelerating
Matthews Jucá D et al. The Essential Oil… Planta Med 2011; 77: 57–59
Fig. 2 Effects of α- and β-pinene on intestinal transit and gastric compli-ance. In a, comparison of intestinal transit indices in conscious rats treatedwith vehicle (□; Tween 80; n = 5; p.o.), α- (○; α-pin; 100mg/kg; n = 7; p.o.),or β-pinene (△; β-pin; 100mg/kg; n = 7; p.o.). 5-Hydroxytriptamine ( △; 5-HT; 3mg/kg; n = 5; p.o.) was used as a positive control. Scatter plots showindividual and median (horizontal line) values for the geometric center ofdye recovery distribution from proximal duodenum (segment number 1) tothe more distal segment of the small intestine (segment number 4).* P < 0.05, ANOVA and Holm-Sidak test compared with control values. In b,comparison of gastric volume values (in mL) recorded by plethysmometryin anesthetized rats submitted to 10min intervals of increasing gastric dis-tension pressure (4, 8, and 12 cmH2O) in absence (□; vehicle treated rats;Tween 80; n = 6) or in presence of 100mg/kg of either α- (○; α-pin; n = 7) orβ-pinene (△; β-pin; n = 8). Data are mean values while vertical lines indicateSEM. * P < 0.05, ANOVA and Holm-Sidak test compared with control valuesat each pressure level.
Fig. 3 Effects of EOET, α-, and β-pinene on isolated strips of gastric fundus(•) and duodenum (▲) of rats. Treatment of the tissues with EOET (1–1000 µg/mL) relaxed basal tonus of both gastric and duodenal strips (panela), whereas treatment with carbachol (CCh, 10−9 – 3.10−6 M) produced justcontractile effects (panel b). Treatment of the tissues with α- or β-pinene(4–408 µg/mL) relaxed basal tonus of isolated rat duodenum while increas-ing basal tonus of fundic strips (panels c and d). Additionally, contractionselicited by acetylcholine at a submaximal concentration (3 µM) were inhib-ited by α- or β-pinene (4–408 µg/mL) pretreatment in duodenal stripsalthough they were not altered in fundic strips (panels e and f). Change inbasal tonus values are expressed as % of an initial 60mM K+-induced controlcontraction (n = 6 per group), whereas values for ACh inhibition are ex-pressed as % of the ACh 3 µM-induced contraction obtained in the absenceof monoterpenes (n = 6 per group). * P < 0.05, ANOVA and Holm-Sidak test,compared to the control values of a given parameter in the absence ofEOET, CCh, α-, or β-pinene as appropriate.
58 Letters
the gastric emptying rate. In anesthetized rats, they decreasedthe gastric compliance, indicating a higher gastric tonus in vivo.For a given gastric distension pressure (4, 8, or 12 cmH20), thegastric volume was always significantly lower in α- as well as inβ-pinene-treated than in vehicle-treated rats (p < 0.05;l" Fig. 2b).Gastric compliance of anesthetized rats was also decreased byeucalyptol, another EOET constituent (~ 75% v/v; [6,15]), indicat-ing that other constituents are also involved in the EOET-inducedeffects.In fundic strips, α- and β-pinene (4–408 µg/mL) increased basaltonus to 50.9 ± 9.3% (n = 6) and 51.2 ± 9.4% (n = 6), respectively(l" Fig. 3c and d; values are % of a reference contraction: KCl60mM; 0.45 ± 0.01 g; n = 12). A nonspecific effect of these sub-stances on the gastric smooth muscle cells appears unlikely be-cause: i) theywere reversible; ii) neither α- nor β-pinene changedthe contractions elicited by ACh in gastric strips (l" Fig. 3e and f);and iii) the effects induced by α- and β-pinene in gastric stripswere clearly opposite to their myorelaxant and antispasmodic ac-tions in duodenal preparations (l" Fig. 3c–f). The effects inducedby EOET (1–600 µg/mL) on basal tonus of gastric and duodenalstrips were inhibitory (l" Fig. 3a), reinforcing the assumptionthat other EOET constituents are important to its pharmacologi-cal actions on the gut. Thus, EOET accelerates gastrointestinaltransit by the contrasting effects induced by α- and β-pinene on
Matthews Jucá D et al. The Essential Oil… Planta Med 2011; 77: 57–59
gastrointestinal smooth muscle. Data of this study may be of in-terest to further investigations regarding potential prokinetic ac-tions of EOET.
Material and Methods!
This study was conducted on male Wistar rats (200–250 g; localanimal ethics committee approval number 13/06). Gastric emp-tying was evaluated after 10, 20, or 30min after administrationof a liquid test meal containing phenol red. After euthanasia bycervical dislocation, the gut was divided into consecutive seg-ments of stomach, proximal (~ 40%), mid (~ 30%), and distal
59Letters
(~ 30%) small intestine. Small intestine transit was evaluated at10min postprandial, and the liquid test meal was administeredby an intraduodenal catheter. After euthanasia by cervical dis-location and gut remotion, the small intestine was divided intofive consecutive segments with similar lengths. Dye retentionwas assayed by spectrophotometry. Gastric compliance was eval-uated by a barostat system used to monitor the gastric volumechanges in anesthetized rats. Longitudinal strips of gastric fundusor duodenum were set up under 1 g of tension in 5-mL tissuebaths with physiological solution (37°C, bubbled with air). Iso-metric contractions were recorded by isometric transducers anda data acquisition system. Data are expressed as mean ± SEM. Thesignificance (p < 0.05) of data was assessed by means of one-wayanalysis of variance (ANOVA), followed by the Holm-Sidak test.
Supporting informationDetailed experimental protocols are available as Supporting In-formation.
Acknowledgements!
This work was supported by the Instituto Nacional de Biomedici-na do Semi-Árido Brasileiro (INCT-IBISAB-CNPq). We thank Mr.Haroldo Pinheiro for technical assistance.
References1 Singh HP, Mittal S, Kaur S, Batish DR, Kohli RK. Characterization andantioxidant activity of essential oils from fresh and decaying leaves ofEucalyptus tereticornis. J Agric Food Chem 2009; 57: 6962–6966
2 Nerio LS, Olivero-Verbel J, Stashenko E. Repellent activity of essentialoils: a review. Bioresour Technol 2010; 101: 372–378
3 Food & Agriculture Organization of the United Nations (FAO), editors.Eucalyptus oil. In: Flavour and fragrances of plant origin. Rome: Foodand Agriculture Organization of the United Nations; 1995: Chapter 5.Available online at http://www.fao.org/docrep/V5350E/V5350e07.htm. Accessed May 10, 2010
4 Matos FJA. Plantas medicinais: guia de seleção e emprego de plantasusadas em fitoterapia no Nordeste do Brasil. Fortaleza: Edições UFC;2002
5 Silva J, Abebe W, Sousa SM, Duarte VG, Machado MI, Matos FJ. Analgesicand anti-inflammatory effects of essential oils of eucalyptus.J Ethnopharmacol 2003; 89: 277–283
6 Coelho-de-Souza LN, Leal-Cardoso JH, de Abreu Matos FJ, Lahlou S, Mag-alhães PJ. Relaxant effects of the essential oil of Eucalyptus tereticornisand its main constituent 1,8-cineole on guinea-pig tracheal smoothmuscle. Planta Med 2005; 71: 1173–1175
7 Keller M, Lerdau M. Isoprene emission from tropical forest canopyleaves. Global Biochem Cycles 1999; 13: 19–29
8 FAO/WHO. Joint FAO/WHO Expert Committee on Food Additives Evalu-ation of certain food additives: sixty-third report of the Joint FAO/WHOExpert Committee on Food Additives. Geneva, Switzerland; 2004.Available online at http://whqlibdoc.who.int/trs/WHO_TRS_928.pdf.Accessed May 10, 2010
9 Lu M, Battinelli L, Daniele C, Melchioni C, Salvatore G, Mazzanti G.Muscle relaxing activity of Hyssopus officinalis essential oil on isolatedintestinal preparations. Planta Med 2002; 68: 213–216
10 Câmara CC, Nascimento NR, Macêdo-Filho CL, Almeida FB, Fonteles MC.Antispasmodic effect of the essential oil of Plectranthus barbatus andsome major constituents on the guinea-pig ileum. Planta Med 2003;69: 1080–1085
11 Prakash O, Kasana VK, Pant AK, Zafar A, Hore SK, Mathela CS. Phyto-chemical composition of essential oil from seeds of Zingiber roseumRosc. and its antispasmodic activity in rat duodenum. J Ethnophar-macol 2006; 106: 344–347
12 Sadraei H, Asghari GR, Hajhashemi V, Kolagar A, Ebrahimi M. Spasmo-lytic activity of essential oil and various extracts of Ferula gummosaBoiss. on ileum contractions. Phytomedicine 2001; 8: 370–376
13 Smout AJ. Recent developments in gastrointestinal motility. ScandJ Gastroenterol Suppl 2006; 243: 25–31
14 Souza MAN, Sousa MHLP, Palheta Jr RC, Cruz PRM, Rola FH, Magalhães PJ,Troncon LEA, Santos AA. Evaluation of gastrointestinal motility inawake rats: a learning exercise for undergraduate biomedical students.Adv Physiol Educ 2009; 33: 343–348
15 Neves JR, Lira GH, Oliveira Neto RM, Graça JR, Vasconcelos PR, Nobre eSouza MA, Magalhães PJ, Rola FH, Santos AA. 1.8-Cineole decreases gas-tric compliance in anesthetized rats. Acta Cir Bras 2007; 22: 63–67
received February 11, 2009revised May 19, 2010accepted June 14, 2010
BibliographyDOI http://dx.doi.org/10.1055/s-0030-1250116Published online July 20, 2010Planta Med 2011; 77: 57–59© Georg Thieme Verlag KG Stuttgart · New York ·ISSN 0032‑0943
CorrespondenceProf. Pedro MagalhãesDepartamento de Fisiologia e FarmacologiaFaculdade de MedicinaUniversidade Federal do CearáR. Cel. Nunes de Melo 1127, Rodolfo Teófilo60430-270 Fortaleza CEBrasilPhone: + 558533668334Fax: + [email protected]
Matthews Jucá D et al. The Essential Oil… Planta Med 2011; 77: 57–59
