Estudo químico e biológico de Cyperus rotundus l. aclimatada no Amazonas

Abstract

This work describes the isolation, identification structural of the chemical constituents of Cyperus rotundus, acclimatized in the Amazon, as well as seasonal variation of the essential oil extracted from the tubers collected at different times of the year, besides the ability to sequester radical DPPH, enzymatic assays as elastase, tyrosinase and α-glucosidase inhibitors, cytotoxic assay against Artemia salina larvae and colorimetric assay against promastigotes of Leishmania amazonensis. From the hexane extract obtained from the tubers was identified mixture of β-sitosterol and stigmasterol steroids, and the ester ethyl hexadecanoate. The ethyl acetate extract was identified a mixture of cyclic oxygenated sesquiterpenes characterized as α-cyperone and cyperotundone and the ferulic acid. Extract in methanol was isolated d-mannitol and ergosterol peroxide. From inflorescence hexane extract was identified mixture of β-sitosterol and stigmasterol steroids and in methanol extract was isolated luteolin. The essential oil composition was analyzed by a combination of GC- MS and GC-FID, the results reveal variation in the content of essential oil in the dry rainy, as well as qualitative variation of the main constituents depending on the time of year when tubers were collected. The major components of the essential oil were identified β-selineno (5.79 to 7.34%), caryophyllene oxide (from 4.68 to 7.47%), cipereno (10.64 to 18.62%), ciperotundona (13.78 to 24.72%) and α-ciperona (20.34 to 23.73%). In the quantitative assay of scavenging free radicals, the methanol extract of the inflorescence and luteolin showed strong antioxidant activity. In enzymatic assays against elastase and tyrosinase, the extracts and isolated compounds showed weak activity. In enzyme assay against α-glucosidase the hexane extracts (tubers and inflorescences) and the essential oil showed strong activity with IC50 = 2,75 ; 12.75 and 15.17 μg/mL , respectively. The result of the LD50 assay with Artemia salina shows low toxicity to the hexane extract and essential oil and moderate toxicity of the extract in ethyl acetate and methanol. In the evaluation of the antimicrobial activity hexane extract (tubers) and the essential oil showed strong inhibition against Gram positive bacteria and against yeast and methanol extract (inflorescence) and d-mannitol showed high activity against Candida albicans. In assessing the activity of inhibiting microbial adhesion and the essential oil d- mannitol reduced by about 50 % the capacity of biofilm formation with Enterococcus faecalis and Candida albicans, respectively. The results of the colorimetric assay performed in vitro directed the leishmanicidal action against promastigotes of Leishmania amazonensis revealed significant activity for hexane extract (IC = 3.65 μg/mL), ethyl acetate (IC = 4.29 μg/mL) and the essential oil (IC = 5.07 μ/mL). From the tubers were isolated and identified six genera of endophytic fungi, with the most frequent Colletotrichum.