Oxidant and genotoxic-mediated strong antifungal activity of the essential oils from Cupressus arizonica var. arizonica and var. glabra

• Autor(a) principal: Khouadja, W.
• Data de Publicação: 2015
• Outros Autores: Oliveira, Rui Pedro Soares de, Raies, A., Dias, Alberto Carlos Pires
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/50763
• topic: Cupressus arizonica; Essential oil; Yeasts; Genotoxicity; Oxidative stress; Ciências Naturais::Ciências Biológicas; Science & Technology

The composition and the evaluation of the antifungal activity and the mechanisms of action of the essential oils (EO) of Cupressus arizonica leaves of two varieties, glabra and arizonica, were studied. EOs were extracted by hydrodistillation and the chemical composition was determined by gas chromatog- raphy/mass spectrometry (GC–MS). Both var. arizonica and var. glabra EOs, displayed high contents of -pinene (29.76% and 26.53%, respectively) and umbellulone (11.86% and 15.05%, respectively). The anti- fungal activity of the EOs of both varieties against pathogenic yeasts of the genus Candida was investigated and showed that very low concentrations of var. glabra EO, such as 5.10−2 l/ml, were sufficient to inhibit growth of most of the species, while, all species, except Candida albicans (MIC = 5 × 10−2 l/ml), were inhibited for growth with only 10−2 l/ml when the EO of var. arizonica was used. The cytotoxicity of the EOs was assessed in Saccharomyces cerevisiae (used as a yeast experimental model) wild type and mutants affected in oxidative stress response and DNA repair pathways. Oxidative stress imposed by the EOs was determined by flow cytometry and the genotoxicity was assessed by yeast comet assay. A higher loss of yeast viability was observed with incubation of the EO from var. arizonica (5 × 10−2 l/ml, 60% viability loss) compared to var. glabra (5 × 10−2 l/ml, 30% viability loss). DNA damage was observed as long comet tails when cells were exposed to the EO of var. arizonica and of var. glabra, (17 and 13 m, respectively), compared to the negative control (5 m). Intracellular oxidation increased in cells treated with the EOs, the var. arizonica being more active in the oxidant activity. The results obtained with the wild type yeast strain suggest that the EOs cause toxicity via an oxidative mechanism. To investigate the mechanism of oxidation, mutants affected in the oxidative stress response (yap1) and base excision repair DNA pathway (apn1) were investigated. The results show that the yap1 and apn1 yeast mutant strains are more sensitive to EOs than the wild type. For mutants affected in nucleotide excision repair (rad4), a pathway not involved in the repair of oxidative DNA damage, the results were similar to those obtained with the wild type.