COMPOSIÇÃO QUÍMICA E ATIVIDADES BIOLÓGICAS DOS ÓLEOS ESSENCIAIS DAS CASCAS DE DUAS VARIEDADES DE Citrus sinensis E DAS FLORES DE Psidum guajava.

Abstract

Essential oils (OEs) are a mixture of volatile compounds extracted from plant parts and are responsible by defense and protection mechanisms of plants. They are responsible for several biological activities among them we can mention: antifungal, antimicrobial and antioxidant. They also have great potential in the phytopathogens control, are less aggressive to humans and to environment are biodegradable and with low cost . Considering that the objective of this study was to determine the essencial oil chemical composition of Citrus Limettioides Tanaka , Citrus sinensis L. Osbeck bark and inflorescences Psidum guajava flower also its antiparasitic activities, as well as antifungal, antimicrobial and cytotoxic activity. The essential oils from two varieties of Citrus sinensis and from Psidum guajava. flowers were obtained by hydrodistillation using a clevenger apparatus . The OEs were analyzed using gas chromatography, flame ionization detector (CG-FID) and mass spectrometry-coupled gas chromatography (CG-MS). Antifungal activity was evaluated against Rhizopus stolonifer fungus, activity against trypanocidal was evaluated on trypomastigote forms of Trypanosoma cruzi, and antibacterial activity in vitro on the bacteria X. fastidiosa and P. carotovorum was determined by the broth dilution method. Cytotoxic activity was evaluated on fibroblasts and determined by the MTT method. The limonene was the principal monoterpene identified in OEs from bark of lime orange file (95,2%) and bahia orange (93.2%). The OEs of Citrus Limettioides Tanaka and Citrus sinensis L. Osbeck inhibited 91.95% and 80.05% of the growing mycelium of R. stolonifer growing, respectively, at the doses 100 µl oil doses. The OE of flowers of Psidum guajava . Flowers presented a mixture of sesquiterpenes , having as major compounds α- cadinol (37.8%), β- caryophyllene (12.2%), nerolidol (9.1%), α- selinene (8.8%), β- selinene (7.4% ) and caryophyllene oxide (7.2% ). The results showed that OE-PG showed strong trypanocidal activity against Trypanosoma cruzi trypomastigote forms with (IC 50 = 14.6 μg / mL ), and antibacterial activity against X. fastidiosa and P. carotovorum bacteria with (MIC = 12.5 μg / mL ) and (MIC = 62.5 μg / mL ) respectively, presenting moderate cytotoxicity against LLCMK2 strain fibroblasts at the evaluated concentration (CC50 = 250.5 μg / mL ). In short, the essential oils of Citrus Limettioides Tanaka and Citrus sinensis L. Osbeck bark showed high antifungal activity against Rhizopus stolonifer fungus, while the essential oil of guava flowers showed moderate antibacterial and cytotoxic activity, demonstrating the oils essential potencial as an alternative to synthetic pesticides in agriculture, and the development of new drugs.