4.1. Plant Extraction and EOCz Analysis and Composition Determination

The extraction method and the composition analysis of the sample of EOCz employed in the present study has been previously published [56]. Briefly, Croton zehntneri were collected near the city of Viçosa (lat. 3°33′48″ S.; long. 41°5′41″ W.), CE, Brazil, in the period from June to August 2010. Plant identification was confirmed by botanicals from the State University of Ceará (UECE) and the exsiccate was deposited in the Prisco Bezerra herbarium at the Federal University of Ceará (UFC) and received the protocol number 277477. The leaves were separated from the stems and kept on a surface to dry. Subsequently, the leaves were put in a semi-industrial essential oil extractor (model MA 480, Marconi equipment, Piracicaba, São Paulo, Brazil) that uses a water steam distillation method. The mixture of water and essential oil vapor was collected in a condenser connected to the extractor, the essential oil was separated from aqueous phases, and it was stored in a freezer (approximately −20 °C) in amber glasses until use [56].

The constituents of EOCz were determined by gas-liquid chromatography coupled to mass spectroscopy (model 5971, Hewlett-Packard, Palo Alto, CA, USA) at Parque de Desenvolvimento Tecnológico (PADETEC) of UFC and received the protocol number 002/19.18.2010. The EOCz showed the main following constituents: anethole, estragol (9.53%), bicyclogermacrene (3.98%) and myrcene (1.95%). The other constituents showed individual values inferior to 1.0%, as previously described [56]. The experiments were done between 2011 and 2012.