Estudos biológicos dos extratos e composição química dos óleos essenciais de espécies da família Lauraceae

Abstract

The family Lauraceae is one of the most important families in the Amazon rainforest featuring an significant number of species with different uses due to the quality of products natural.The species this family are Chemically characterized by the presence of alkaloids, neolignans, flavonoids, terpenes and phenylpropanoids. This study contributes to the analysis of the chemical profile of the three genera Endlicheria, Ocotea and Rhodostemonodaphne about directing the investigations on the chemical composition of extracts and essential oils, contributing to the screening of promising genera and species. This work was carried out prospecting phytochemical , alkaloid profile analysis by thin layer chromatography (TLC) and mass spectrometry of the ethanol extracts, identification of the essential oil and analysis of activities: anticholinesterase, antioxidant and cytotoxic of ethanolic extracts of E. citriodora, E. sericea, O. minor, O. ceanothifolia, O. leucoxylon, R. recurva and R. crenaticupula. The species were collected in Reserva Ducke, in Manaus. The material was separated to obtain essential oils and ethanolic extracts. These were analyzed for chemical / biological activities and subjected to acid-base partition to obtain enriched fractions of alkaloids. The alkaloid profile was analyzed by mass spectrometry and TLC with revealing specific. The essential oils were analyzed by GC-FID and GC-MS. It was confirmed the high presence of alkaloids in the genus Ocotea and low in species Endlicheria and Rhodostemonodaphne. In mass spectrometry the peaks m/z 300 and 330 were present in most fractions and may correspond to the type alkaloids Benzylisoquinolines and Aporphines. The yields of essential oils obtained by hydrodistillation in Clevenger modified ranged from 0.02% to 4.29%. The specie Endlicheria citriodora was the highest yield, 2.5% in the branches and 4.3% in the leaves. The Methyl geranate was the major constituent, (above 93%), elucidated by GC-FID, GC-MS RMN1H and RMN 13C. The essential oils from other species showed less than 1% yield and caryophyllene and its oxide were the major constituents. The antioxidant activity was assessed by sequestering ability of the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH ), using quercetin as external standard, expressed as effective concentration values (EC50). The extracts of Ocotea minor presented the best antioxidant potential (EC50 = 7.31 ± 0.32 μg / mL). Qualitative analysis of anticholinesterase activity was performed according to the method of Ellman (modified), with negative results for inhibiting the enzyme acetylcholinesterase. The branches of the three species of Ocotea were positive. The antitumor activity was evaluated against four cell lines (leukemia, breast, colon and glioblastoma) by the method of Mossman. None of the extracts tested showed pronounced cytotoxic activity.