The goals of the study were to determine: the antimicrobial and antioxidant activities of essential oil and plant extracts aqueous and ethanolic of Psidium cattleianum Sabine; the chemical composition of the essential oil of P. cattleianum; and the phytochemical screening of aqueous and ethanolic extracts of the same plant. Regarding the antimicrobial activity, the ethanolic extract exhibited moderate antimicrobial activity with respect to bacteria K. pneumoniae and S. epidermidis, whereas, regarding other microorganisms, it showed activity considered weak. The aqueous extract and the essential oil showed activity considered weak, although they inhibited the growth of microorganisms. About the antioxidant potential, the ethanolic and aqueous extracts exhibited a scavenging index exceeding 90%, while the essential oil didn´t show significant antioxidant activity. Regarding the phytochemical composition, the largest class of volatile compounds identified in the essential oil of P. cattleianum included the following terpenic hydrocarbons: α-copaene (22%); eucalyptol (15%), δ-cadinene (9.63%) and α-selinene (6.5%). The phytochemical screening of extracts showed the presence of tannins, flavonoids, and triterpenoids for aqueous and ethanolic extracts. The extracts and essential oils inhibit the growth of microrganisms and plant extracts showed significant antioxidant activity. Also, the phytochemical characterization of the essential oil showed the presence of compounds interest commercial, as well as extracts showed the presence of important classes and compounds with biological activities.Keywords: Psidium cattleianum, antimicrobial action, microdilution, GC-MS, antioxidant activity. Atividade antimicrobiana e antioxidante do óleo essencial e diferentes extratos vegetais de Psidium cattleianum Sabine ResumoOs objetivos do trabalho foram determinar: as atividades antimicrobiana e antioxidante do óleo essencial e dos extratos vegetais aquoso e etanólico de Psidium cattleianum Sabine; a composição química do óleo essencial P. cattleianum e a triagem fitoquímica dos extratos vegetais aquoso e etanólico da mesma planta. Quanto à atividade antimicrobiana, o extrato etanólico apresentou atividade antimicrobiana moderada frente as bactérias K. pneumonieae e S. epidermidis, enquanto frente aos demais micro-organismos apresentou atividade considerada fraca. O extrato aquoso e o óleo essencial apresentaram atividade considerada fraca, embora tenham inibido o crescimento dos micro-organismos. Em relação ao potencial antioxidante, os extratos etanólico e aquoso apresentaram índice de sequestro superior a 90%, enquanto o óleo essencial não apresentou atividade antioxidante significativa. Para a composição fitoquímica, a maior classe de compostos voláteis identificados no óleo essencial de P. cattleianum foram os hidrocarbonetos terpênicos, sendo eles: α-copaeno (22%), eucaliptol (15%), δ-cadineno (9,63%) e α-selineno (6,5%). Na triagem fitoquímica dos extratos verificou-se a presença de taninos, flavonóides e triterpenói...

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