Cinnamic acid and its derivatives show a remarkable variety of biological activities and are often studied in search of the development of new and highly effective drugs. This work aims to synthesize, characterize and evaluate the cytotoxic activity of esters derived from cinnamic acid. Eighteen esters were synthesized through Steglich’s esterification, of which eleven were not reported in the literature. All compounds were fully characterized by Fourier transform infrared epectroscopy (FTIR), nuclear magnetic resonance (1H and 13C NMR) and high-resolution mass spectrometry (HRMS) data. The cytotoxic activity of esters obtained was evaluated using four human tumor cell lines: SNB-19 (astrocytoma), HCT-116 (colon carcinoma, human), PC3 (prostate) and HL60 (promyelocytic leukemia) through the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium (MTT) colorimetric assay. These studies showed that the compound 3-methoxybenzyl (E)-3-(4-methoxyphenyl)acrylate (12) is the most potent against HCT-116, PC3 and SBN-19 cells, with the lowest half maximal inhibitory concentration (IC50) value of 16.2 µM in the HCT-116 strain. The derivatives were obtained in good yields (76.6-95%), except for compounds 5-isopropyl-2-methylphenyl (E)-3-(3-hydroxy-4-methoxyphenyl)acrylate (17) (18.6%) and 2-isopropyl-5-methylphenyl (E)-3-(3-hydroxy-4-methoxyphenyl)acrylate (18) (15.5%).

Analysis of essential oil from fresh leaves of Capraria biflora allowed identification of fourteen essential oil constituents among which thirteen are sesquiterpene compounds, and α-humulene (43.0%) the major constituent. The essential oil was tested for larvicidal activity against Aedes aegypti showing good activity, with LC50 73.39 µg/mL (2.27 g/mL). Chromatographic studies of extracts from roots and stems allowed the isolation of five compounds: naphthoquinone biflorin, sesquiterpene caprariolide B, the steroid β-sitosterol, the carbohydrate D-mannitol and iridoid myopochlorin first reported in the species C. biflora. The structures of compounds were characterized by spectroscopic data, IR, MS, NMR13C, NMR¹H, NOE, HSQC and HMBC.

Lipase-catalysed esterifications of alcohols using immobilized enzyme system from sugar cane (Saccharum officinarum) as biocatalyst afforded the corresponding esters in considerable yields (68-93%). Under optimized conditions, the material was utilized for reactions of acetylation with several advantage. It also investigated the possibility of reuse of immobilized enzymes of S. officinarum as biocatalyst under optimal reaction conditions.

Croton nepetaefolius is an aromatic plant native to the northeast of Brazil where it is extensively used in folk medicine as a sedative, orexigen and antispasmodic agent. The present work deals with the chromatographic analysis of the ethanolic extract of Croton nepetaefolius stalk. It allowed the isolation and characterization of two diterpenoids named 1,4-dihydroxy-2E,6E,12E-trien-5-one-casbane and 4-hydroxy-2E,6E,12E-5-one-casbane, two acetophenones named 2-hydroxy-4,6-dimethoxyacetophenone and 2-hydroxy-3,4,6-trimethoxyacetophenone and the steroids 3-O-b-D-glucopiranosylsitosterol and a mixture of b-sitosterol and stigmasterol. Structural elucidation was done on the basis of spectral data, mainly high field NMR and EIMS.

Two new compounds, 5 and 8, and an epimeric mixture 4a/4b were isolated from hardwood of Auxemma glazioviana. Their structures and relative configurations were determined by modern spectroscopic analysis to be rel-10alpha,11alpha-epoxy-11beta-ethoxy-8alpha- hydroxy-2-methoxy -8abeta-methyl-5,6,7,8,8a,9,10,10abeta-octahydro-1,4-anthracenedione (or rel-2R,2aR,5R,5aS ,10bS,10cS-2-ethoxy-5-hydroxy-8-methoxy-5a-methyl- 2a,3,4,5,5a,6,10b,10c-octahydro-2H-anthra[9,1-bc]furan-7,10-dione, 4a), rel-10alpha,11alpha- epoxy-11alpha-ethoxy-8alpha-hydroxy-2-methoxy-8abeta-methyl-5,6,7,8,8a,9,10,10abeta-octahydro- 1,4-anthracenedione (or rel-2S,2aR,5R,5aS ,10bS,10cS-2-ethoxy-5-hydroxy-8-methoxy- 5a-methyl-2a,3,4,5,5a,6,10b10c-octahydro-2H-anthra[9,1-bc]furan-7,10-dione, 4b), rel-10alpha,11alpha-epoxy-8alpha,11-dihydroxy-2-methoxy-8abeta-methyl-5,6,7,8,8a,9,10,10abeta- octahydro-1,4-anthracenedione (or rel-2S,2aR,5R,5aS ,10bS,10cS-2,5-dihydroxy-8- methoxy-5a-methyl-2a,3,4,5,5a,6,10b,10c-octahydro-2H-anthra[9,1-bc]furan-7,10 -dione, 5) and rel-10,11-epoxy-8abeta-methyl-1,4,5alpha,9alpha-tetrahydroxy-5,6,7,8,8a,9,10,10a- octahydro-8-anthracenone (or rel-2aS,5aS,6R,10bR ,10c5-2a,6,7,10-tetrahydroxy-5a-methyl-2a,3,4,5,5a,6,10b,10c-octahydro-2H-anthra [9,1-bc]-furan-5-one, 8). In addition, known compounds were also isolated.

Thirteen compounds, 3-O-acetyloleanolic acid (1), methyl 3,4-dihydroxy benzoate (2), lapachenol (3), tecomaquinone (4), tectoquinone (5), tectol (6), acetilated tectol (7), quercetin (8), luteolin (9), glucoluteolin (10), lippisidoquinone (11), taxifolin (12) and isolariciresinol (13), were isolated from ethanol extract of Lippia sidoides. Their structures were assigned unambiguously by a combination of 1D and 2D NMR, IR and EIMS spectral data analysis and comparison with the published data for structurally related compounds. In brazilian traditional medicine the aerial parts of this specie are used as anti-infective agent, particularly as antiseptic.