No abstract

publicado na web em 18/01/2018 A tea made with the leaves or stem bark of Bauhinia pulchella Benth (Fabaceae) is used in the treatment of diabetes. Ethanol (EEF) and aqueous (EAF) extracts were obtained from the leaves and the antioxidant and citotoxic activities were tested, as well as quantify the content of flavonoids and phenolic compounds (TPC). EEF and EAF showed similar profiles by HPLC, with the presence of three compounds. Column chromatography reverse phase (C18) and Sephadex LH-20, followed by semi preparative HPLC-C18 of EAF resulted in three flavonoids. Their structures were identified by 1 H and 13 C NMR as myricitrin (1), quercitrin (2) and afzelin (3). In assay of determination of reactive substances to thiobarbituric acid (TBARS), with DPPH, ABTS and nitric oxide (NO•) free radicals, EAF showed antioxidant potential higher than the EEF. This is the first report of the occurrence of the flavonoids 1-3, in the species B. pulchella. EEF and EAF were inactive in the cytotoxicity assays. In short, the polar extracts from the leaves of B. pulchella proved to be promising sources of biomolecules phenolic, with antioxidant potential, which may, in the future, be used as chemical markers for species and validation of therapeutic use.

Two steroids (1 and 2), five pentacyclic triperpenoids (3-7) and a new furanosesquiterpene (8) were isolated from the stems of Ximenia americana, family Olacaceae. The structures of the compounds were established by spectral data; two-dimensional NMR spectroscopy has been used to assign all 1 H and 13 C chemical shifts of 8. Compound 8 did not inhibit the growth of HL-60 (human leukemia), HTC-8 (human colon), and MDA-MB-435 (human breast cancer) cell lines.

The new sesquiterpene 1, named ximonicane, and the known stigmastane steroid 2 were isolated from the EtOH extract of the stems of Ximenia americana. Spectroscopic methods, including 2D-NMR techniques, have been used to characterize 1 and assign all the signals of the 1 H-and 13 C-NMR spectra of 1. Ximonicane did not inhibit the growth of HL-60 (human leukemia), HTC-8 (human colon), and MDA-MB-435 (human breast cancer) cell lines.