Estudo fitoquímico e citotóxico de Oleorresinas de Burseraceae

Abstract

PHYTOCHEMICAL AND CITOTOXIC STUDY OF BURSERACEAE OLEORESINS. The Burseraceae family includes approximately 700 specimens distributed in 19 genres, and many of these specimens do not present phytochemical studies. Interested on describing the chemical composition, evaluate the cytotoxic activity and isolate substances of chemical and cytotoxic interest, this work has been divided in three parts: Determination of the extraction in hexane chemical profiles; cytotoxicity evaluation of oleoresins against HCT-8 (collon), MDA/MB-435 (breast) and SF-295 (glioblastom); and isolation of substances present in the oleoresins. The isolated substances were identified by mass spectrometry techniques (GC-MS and ESI-IT-MS) and nuclear magnetic resonance (NMR). In the volatile compounds profile it was possible to observe that among the monoterpenes, the p-cymene was detected more times, in 11 out 23 specimens evaluated. The highest concentration of this compound was observed in Protium apiculatum (2.4%), however the compound mostly found in this specimen is αpinene (5.1%). Among the sesquiterpenes, the compound that presented highest concentration was the junenol, in P. cf. rubrum (23.9%) and P. cf. ferrugineum (11.3%) being isolated and elucidated. The samples with the most complex sesquiterpenic profile were P. tenuifolum and Tetragastris panamensis, with common detection of sesquiterpenes of bisabolane, cadinane, cubebane, eudesmane, guaiane and muurulane series. The total ion chromatograms evaluations showed the presence of α- and β-amyrin in all the samples, confirming the presence of these triterpenes as family markers. In P. cf. ferrugineum, it has been observed the absence of α- and β-amyrone, and it was the differential of this specimen among other samples. About the triterpenes, glutinol (first description in the genres studied) and the multiflorenol (first description in the family) were detected. The chemometric analysis resulted in five distinct cluster (C-1 to C-5), where C-1 presented high concentration of α- and β-amyrone and absence of brein and maniladiol; C-2, having potentially producers of new triterpene and volatile compound specimens; C-3 with medium concentration among the variables analyzed; C-4 with high concentration of brein and maniladiol; and C-5, having α- and β-amyrin high concentration specimens. Te cititoxicity assays showed that two extracts in hexane (P. cf. rubrum e Trattinnickia peruviana - HrTPE) showed inhibition against HCT-8 (93.08 % for both specimens) and SF-295 (93.46 e 86.34%, respectively) tumor cells lines. In the extracts in acetate and acetyl, inhibition for P. giganteum var giganteum and Trattinnickia glaziovii against HCT-8 (88.7 e 92.9%, respectively) and MDAM B-435 (97.8 e 96.2%, respectively) lines were observed. HrTPE was submitted to fractioning, being identified the β-amyradienol. From the extract in ethyl acetate of P. paniculatum var. modestum, breine and maniladiol triterpenes in binary mixture, 3-hydroxy-tirucalla-8,24-diene-21-oic acid, pure and in binary mixture with 3-hydroxy-tirucalla-7,24-dieno-21-oic acid were isolated. In the P. bahianum ethyl acetate extract, the ursolic and oleanolic acids were isolated. From the Tetragastris panamensis ethyl acetate extract, an unpublished triterpene (3-oxo-triptocallic B acid) and two triterpenes decribed for the first time in the Burseraceae family (triptocallic B and 3-oxo-katononic acids) were isolated. A 2,3-seco-isobriononico acid biosynthesis from multiflorenol proposal was presented. The family chemosystematics has been discussed.