title: Composition and cytotoxic and antioxidant activities of the oil of Piper aequale Vahl.
abstract: BACKGROUND
  Piper aequale Vahl is a small shrub that grows in the shadow of large trees in the Carajás National Forest, Municipality of Parauapebas, Para state, Brazil. The local people have used the plant against rheumatism and inflammation.
  
  
  METHODS
  The essential oil of the aerial parts was extracted and analyzed by GC and GC-MS. The MTT colorimetric assay was used to measuring the cytotoxic activity of the oil against human cancer lines. The determination of antioxidant activity of the oil was conducted by DPPH radical scavenging assay.
  
  
  RESULTS
  The main constituents were δ-elemene (18.92 %), β-pinene (15.56 %), α-pinene (12.57 %), cubebol (7.20 %), β-atlantol (5.87 %), and bicyclogermacrene (5.51 %), totalizing 65.63 % of the oil. The oil displayed a strong in vitro cytotoxic activity against the human cancer cell lines HCT-116 (colon) and ACP03 (gastric) with IC50values of 8.69 μg/ml and 1.54 μg/ml, respectively. The oil has induced the apoptosis in a gastric cancer cells in all tested concentration (0.75-3.0 μg/ml), after 72 h of treatment, when compared to negative control (p < 0.001). Also, the oil showed a significant antioxidant activity (280.9 ± 22.2 mg TE/ml), when analyzed as Trolox equivalent, and a weak acetylcholinesterase inhibition, with a detection limit of 100 ng, when compared to the physostigmine standard (1.0 ng).
  
  
  CONCLUSIONS
  The higher cell growth inhibition induced by the oil of P. aequale is probably due to its primary terpene compounds, which were previously reported in the proliferation inhibition, in stimulation of apoptosis and induction of cell cycle arrest in malignant cells.
authors.affiliation: Programa de Pós-Graduação em Biotecnologia, Universidade Federal do Pará, 66075-900, Belém, PA, Brazil. joycekellys@ufpa.br.
authors.forename: Joyce Kelly R
authors.initials: JK
authors.lastname: da Silva
authors.affiliation: Laboratório de Citogenética Humana, Universidade Federal do Pará, 66075-900, Belém, PA, Brazil.
authors.forename: Laine C
authors.initials: LC
authors.lastname: Pinto
authors.affiliation: Laboratório de Citogenética Humana, Universidade Federal do Pará, 66075-900, Belém, PA, Brazil.
authors.forename: Rommel M R
authors.initials: RM
authors.lastname: Burbano
authors.affiliation: Programa de Pós-Graduação em Biotecnologia, Universidade Federal do Pará, 66075-900, Belém, PA, Brazil.|Laboratório de Citogenética Humana, Universidade Federal do Pará, 66075-900, Belém, PA, Brazil.
authors.forename: Raquel C
authors.initials: RC
authors.lastname: Montenegro
authors.affiliation: Programa de Pós-Graduação em Química, Universidade Federal do Pará, 66075-900, Belém, PA, Brazil.
authors.forename: Eloísa Helena A
authors.initials: EH
authors.lastname: Andrade
authors.affiliation: Programa de Pós-Graduação em Química, Universidade Federal do Pará, 66075-900, Belém, PA, Brazil.|Programa de Pós-Graduação em Recursos Naturais da Amazônia, Universidade Federal do Oeste do Pará, 68035-110, Santarém, PA, Brazil.
authors.forename: José Guilherme S
authors.initials: JG
authors.lastname: Maia
mesh_terms: D000975:Antioxidants / Q000008:administration & dosage* / Q000737:chemistry; D017209:Apoptosis / Q000187:drug effects; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045325:HCT116 Cells; D006801:Humans; D009822:Oils, Volatile / Q000008:administration & dosage* / Q000737:chemistry; D031701:Piper / Q000737:chemistry; D010938:Plant Oils / Q000008:administration & dosage* / Q000737:chemistry; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000473:pathology
chemical_list: D000975:Antioxidants; D009822:Oils, Volatile; D010938:Plant Oils
keywords: Apoptosis; Cytotoxic and antioxidant activities; Essential oil composition; Terpene compounds