Planta Med 2010; 76(3): 303-308
DOI: 10.1055/s-0029-1186085
Biological Screening
Original Papers
© Georg Thieme Verlag KG Stuttgart · New York

Screening of Five Essential Oils for Identification of Potential Inhibitors of IL-1-induced Nf-κB Activation and NO Production in Human Chondrocytes: Characterization of the Inhibitory Activity of α-Pinene

Ângela Neves1 [*] , Susana Rosa2 , 3 [*] , Juliana Gonçalves2 , Ana Rufino2 , 3 , Fernando Judas4 , 5 , Lígia Salgueiro1 , Maria Celeste Lopes2 , 3 , Carlos Cavaleiro1 , Alexandrina Ferreira Mendes2 , 3
  • 1Laboratory of Pharmacognosy, Faculty of Pharmacy/CEF, University of Coimbra, Coimbra, Portugal
  • 2Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
  • 3Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
  • 4Orthopedics Department and Bone Bank, University Hospital of Coimbra, Coimbra, Portugal
  • 5Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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Publikationsverlauf

received June 3, 2009 revised July 24, 2009

accepted August 3, 2009

Publikationsdatum:
11. September 2009 (online)

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Abstract

Nuclear factor-κB is a key transcription factor activated by pro-inflammatory signals, like interleukin-1β (IL-1), being required for the expression of many inflammatory and catabolic mediators, such as nitric oxide (NO), that play an important role in arthritic diseases. This work aimed at screening and identifying natural inhibitors of IL-induced NF-κB activation and NO production in human articular chondrocytes. Five essential oils obtained from four plants of the Iberian flora, Mentha x piperita L. (Lamiaceae), Origanum virens L. (Lamiaceae), Lavandula luiseri L. (Lamiaceae), and Juniperus oxycedrus L. subsp. oxycedrus (Cupressaceae), were screened for their ability to prevent IL-1-induced NO production. The oil showing higher inhibitory activity was fractionated, concentrated, analyzed for composition elucidation and prepared for further assays. For this purpose, the human chondrocytic cell line C-28/I2 was used to evaluate NF-κB activation by determining the cytoplasmic levels of the total and phosphorylated forms of the inhibitory protein, IκB-α, and the NF-κB‐DNA binding activity. The essential oil from the leaves of J. oxycedrus in a concentration of 0.02 % (v/v) achieved the greatest inhibition (80 ± 8 %) of IL-1-induced NO production. Chemical analysis showed that this essential oil is predominantly composed of monoterpene hydrocabons, being α-pinene [2,6,6-trimethyl-bicyclo(3.1.1)hept-3-ene] the major constituent (76 %). Similarly to the effect of the whole oil, a fraction containing 93 % α-pinene reduced significantly IL-1-induced IκB-α degradation. Moreover, α-pinene also decreased IκB-α phosphorylation, NF-κB‐DNA binding activity, and NO production. Another fraction containing oxygenated mono- and sesquiterpenes was nearly as effective as α-pinene. The ability of the α-pinene-containing fraction to reduce IL-1-induced NF-κB activation and NO production warrants further studies to demonstrate the usefulness of α-pinene in the treatment of arthritic diseases and other conditions in which NF-κB and NO play pathological roles.

References

1 These authors contributed equally to this work.

Alexandrina Ferreira Mendes

Faculty of Pharmacy and Center for Neurosciences and Cell Biology
University of Coimbra

Rua do Norte

3000–295 Coimbra

Portugal

Telefon: + 35 12 39 48 02 03

Fax: + 35 12 39 48 02 08

eMail: afmendes@ff.uc.pt