Xylopia laevigata, popularly known as "meiú" and "pindaíba", is a medicinal plant used in the folk medicine of the Brazilian Northeast for several purposes. The chemical constituents of the essential oil from leaves of X. laevigata, collected from wild plants growing at three different sites of the remaining Atlantic forest in Sergipe State (Brazilian Northeast), were analyzed by GC/FID and GC/MS. The effect of the essential oil samples was assessed on tumor cells in culture, as well on tumor growth in vivo. All samples of the essential oil were dominated by sesquiterpene constituents. A total of 44 compounds were identified and quantified. Although some small differences were observed in the chemical composition, the presence of γ-muurolene (0.60-17.99%), δ-cadinene (1.15-13.45%), germacrene B (3.22-7.31%), α-copaene (3.33-5.98%), germacrene D (9.09-60.44%), bicyclogermacrene (7.00-14.63%), and (E)-caryophyllene (5.43-7.98%) were verified as major constituents in all samples of the essential oil. In the in vitro cytotoxic study, the essential oil displayed cytotoxicity to all tumor cell lines tested, with the different samples displaying a similar profile; however, they were not hemolytic or genotoxic. In the in vivo antitumor study, tumor growth inhibition rates were 37.3-42.5%. The treatment with the essential oil did not significantly affect body weight, macroscopy of the organs, or blood leukocyte counts. In conclusion, the essential oil from the leaves of X. laevigata is chemically characterized by the presence of γ-muurolene, δ-cadinene, germacrene B, α-copaene, germacrene D, bicyclogermacrene, and (E)-caryophyllene as major constituents and possesses significant in vitro and in vivo anticancer potential.

Imidazole (IMZ) rings catalyze many biological dephosphorylation processes. The methyl positioning effect on IMZs reactivity has long intrigued scientists and its full understanding comprises a promising tool for designing highly efficient IMZ-based catalysts. We evaluated all monosubstituted methylimidazoles (xMEI) in the reaction with diethyl 2,4-dinitrophenyl phosphate by kinetics studies, NMR analysis and DFT calculations. All xMEI showed remarkable rate enhancements, up to 1.9×10 fold, compared with spontaneous hydrolysis. Unexpectedly, the electron-donating methyl group acts to decrease the reactivity of the xMEI compared to IMZ, except for 4(5)methylimidazole, (4(5)MEI). This behavior was attributed to both electronic and steric effects. Moreover, reaction intermediates were monitored by NMR and surprisingly, the reactivity of the two different 4(5)MEI tautomers was distinguished.

Duguetia gardneriana, popularly known in the Brazilian northeast as "jaquinha", is a species belonging to the family Annonaceae. The aim of this work was to assess the chemical composition and antitumor properties of the essential oil from the leaves of D. gardneriana in experimental models. The chemical composition of the essential oil was analyzed via gas chromatography-flame ionization detector and gas chromatography-mass spectrometry. In vitro cytotoxic activity was determined in cultured tumor cells, and in vivo antitumor activity was assessed in B16-F10-bearing mice. The identified compounds were β-bisabolene (80.99%), elemicin (8.04%), germacrene D (4.15%), and cyperene (2.82%). The essential oil exhibited a cytotoxic effect, with IC50 values of 16.89, 19.16, 13.08, and 19.33 µg/mL being obtained for B16-F10, HepG2, HL-60, and K562 cell lines, respectively. On the other hand, β-bisabolene was inactive in all of the tested tumor cell lines (showing IC50 values greater than 25 µg/mL). The in vivo analysis revealed tumor growth inhibition rates of 5.37-37.52% at doses of 40 and 80 mg/kg/day, respectively. Herein, the essential oil from the leaves of D. gardneriana presented β-bisabolene as the major constituent and showed cytotoxic and antitumor potential.

Annona vepretorum Mart.

Zornia brasiliensis, popularly known as "urinária", "urinana", and "carrapicho", is a medicinal plant used in Brazilian northeast folk medicine as a diuretic and against venereal diseases. The aim of this study was to investigate the chemical composition and antitumor potential of the leaf essential oil of Z. brasiliensis. The essential oil was obtained by hydrodistillation using a Clevenger-type apparatus and analyzed by GC-MS and GC-FID. Its composition was characterized by the presence of trans-nerolidol, germacrene D, trans-caryophyllene, α-humulene, and farnesene as major constituents. In vitro cytotoxicity of the essential oil and some of its major constituents (trans-nerolidol, trans-caryophyllene, and α-humulene) was evaluated for tumor cell lines from different histotypes using the Alamar blue assay. The essential oil, but not the constituents tested, presented promising cytotoxicity. Furthermore, mice inoculated with B16-F10 mouse melanoma were used to confirm its in vivo effectiveness. An in vivo antitumor study showed tumor growth inhibition rates of 1.68-38.61 % (50 and 100 mg/kg, respectively). In conclusion, the leaf essential oil of Z. brasiliensis presents trans-nerolidol, germacrene D, trans-caryophyllene, α-humulene, and farnesene as major constituents and is able to inhibit cell proliferation in cultures as well as in tumor growth in mice.