Plants are promising sources of new bioactive compounds. The aim of this study was to investigate the cytotoxic potential of nine plants found in Brazil. The species studied were: Annona pickelii Diels (Annonaceae), Annona salzmannii A. DC. (Annonaceae), Guatteria blepharophylla Mart. (Annonaceae), Guatteria hispida (R. E. Fr.) Erkens & Maas (Annonaceae), Hancornia speciosa Gomes (Apocynaceae), Jatropha curcas L. (Euphorbiaceae), Kielmeyera rugosa Choisy (Clusiaceae), Lippia gracilis Schauer (Verbenaceae), and Hyptis calida Mart. Ex Benth (Lamiaceae). Different types of extractions from several parts of plants resulted in 43 extracts. Their cytotoxicity was tested against HCT-8 (colon carcinoma), MDA-MB-435 (melanoma), SF-295 (glioblastoma), and HL-60 (promielocitic leukemia) human tumor cell lines, using the thiazolyl blue test (MTT) assay. The active extracts were those obtained from G. blepharophylla, G. hispida, J. curcas, K. rugosa, and L. gracilis. In addition, seven compounds isolated from the active extracts were tested; among them, β-pinene found in G. hispida and one coumarin isolated from K. rugora showed weak cytotoxic activity. In summary, this manuscript contributes to the understanding of the potentialities of Brazilian plants as sources of new anticancer drugs.

Medicinal plants are one of the most important sources of drugs used in the pharmaceutical industry. Among traditional medicinal plants, Lippia gracilis Schauer (Verbenaceae) had been used for several medicinal purposes in Brazilian northeastern. In this study, leaf essential oil (EO) of L. gracilis was prepared using hydrodistillation. Followed by GC-MS analysis, its composition was characterized by the presence of thymol (55.50%), as major constituent. The effects of EO on cell proliferation and apoptosis induction were investigated in HepG2 cells. Furthermore, mice bearing Sarcoma 180 tumor cells were used to confirm its in vivo effectiveness. EO and its constituents (thymol, p-cymene, γ-terpinene and myrcene) displayed cytotoxicity to different tumor cell lines. EO treatment caused G1 arrest in HepG2 cells accompanied by the induction of DNA fragmentation without affecting cell membrane integrity. Cell morphology consistent with apoptosis and a remarkable activation of caspase-3 were also observed, suggesting induction of caspase-dependent apoptotic cell death. In vivo antitumor study showed tumor growth inhibition rates of 38.5-41.9%. In conclusion, the tested essential oil of L. gracilis leaves, which has thymol as its major constituent, possesses significant in vitro and in vivo antitumor activity. These data suggest that leaf essential oil of L. gracilis is a potential medicinal resource.

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.

The aim of this study was to investigate the chemical composition and anticancer effect of the leaf essential oil of Xylopia frutescens in experimental models. The chemical composition of the essential oil was analysed by GC/FID and GC/MS. In vitro cytotoxic activity of the essential oil was determined on cultured tumour cells. In vivo antitumour activity was assessed in Sarcoma 180-bearing mice. The major compounds identified were (E)-caryophyllene (31.48%), bicyclogermacrene (15.13%), germacrene D (9.66%), δ-cadinene (5.44%), viridiflorene (5.09%) and α-copaene (4.35%). In vitro study of the essential oil displayed cytotoxicity on tumour cell lines and showed IC50 values ranging from 24.6 to 40.0 μg/ml for the NCI-H358M and PC-3M cell lines, respectively. In the in vivo antitumour study, tumour growth inhibition rates were 31.0-37.5%. In summary, the essential oil was dominated by sesquiterpene constituents and has some interesting anticancer activity.

Here, we describe the trypanocidal and antimalarial activities from essential oils extracted from Annona vepretorum (AVOE) and Annona squamosa (ASOE) (Annonaceae) leaves. The essential oils were obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS) and GC-flame ionization detection (GC-FID). A total of twenty-one compounds were identified in AVOE and twenty-three in ASOE. The sesquiterpenes are more abundant in the both essential oils. ASOE contained significant quantities of (E)-caryophyllene (27.4%), germacrene D (17.1%) and bicyclogermacrene (10.8%). The major compounds in AVOE were bicyclogermacrene (39.0%), spathulenol (14.0%) and α-phellandrene (11.5%). The essential oils demonstrated potent trypanocidal and antimalarial activities with values of IC 50 lower than 20 μg/mL, and a strong inhibition of the proliferation of amastigotes, the clinically relevant forms of Trypanosoma cruzi. In addition, through ultrastructural studies and flow cytometry analysis with trypomastigotes of T. cruzi, we identified significant ultrastructural alterations induced by the essential oils, especially in the cell membrane and mitochondria, which ultimately results in necrotic parasite death.