Heloiza Diniz Nicolella

The lignoid fraction (LF) of Ocotea fasciculata, which is rich in yangambin and its epimer, epi-yangambin, showed promising activity against Leishmania sp. Subsequently, LF was incorporated into a solid lipid nanoparticle (SLN) in order to increase its pharmacological efficacy and decrease toxicity. In this regard, the present study was carried out to evaluate the cytotoxic and toxicogenetic potential of LF and LF-SLN in mammalian cells in vitro and in vivo. The cytotoxic activity was evaluated in a non-tumor human cell line (GM07492A) and the toxicogenetic potential was assessed in vitro in a Chinese hamster lung fibroblast cell line (V79) and in Swiss mice. LF-SLN showed no cytotoxic effect at the highest concentration tested (5,000 µg/mL), while LF exhibited an IC₅₀ equivalent to 1,047 ± 4.50 µg/mL. The frequencies of micronuclei observed in vitro and in vivo in mammalian cells treated with different concentrations of LF and LF-SLN did not differ significantly from the negative control group. Therefore, LF and LF-SLN did not show genotoxic or cytotoxic effects under the experimental conditions used. These results contribute to the development of a drug for the treatment of leishmaniasis that is more effective and safer for human health.

Dalbergia ecastaphyllum (L.) Taub. is a semi-prostrate species associated with estuaries, mangroves and dunes. This plant species has great ecological and economic importance, especially concerning apiculture pasture and Brazilian red propolis production. In this study, non-clinical toxicological evaluations of the hydroalcoholic extract of D. ecastaphyllum stems (DEHE), the resin production source, were conducted. In addition, the action of DEHE on genomic instability and colon carcinogenesis was investigated. The extract’s chemical profile was analysed by HPLC, and medicarpin, vestitol and neovestitol were found as major compounds. DEHE showed an IC50 equivalent to 373.2 µg/ml and LC50 equal 24.4 mg/L, when evaluated using the XTT colorimetric test and the zebrafish acute toxicity assay, respectively. DEHE was neither genotoxic nor cytotoxic at the highest dose, 2000 mg/kg, by peripheral blood micronucleus test. The treatments DEHE (6 and 24 mg/kg) led to the reduction of micronuclei induced by doxorubicin (DXR) in mice. Furthermore, significantly higher serum levels of reduced glutathione were observed in animals treated with DEHE plus DXR, revealing an antioxidant effect. Treatments with DEHE (48 mg/kg) led to a significant reduction in pre-neoplastic lesions induced by the 1,2-dimethylhydrazine (DMH) carcinogen in the rat colon. Immunohistochemical analysis revealed significantly lower levels of expression of COX-2 (86%) and PCNA (83%) in the colon of rats treated with DEHE plus DMH, concerning those treated with the carcinogen. These results indicate the involvement of anti-inflammatory and antiproliferative pathways in the protective effect of DEHE.

The manool diterpene, found in abundance in Salvia officinalis L., showed a selective cytotoxic effect against murine melanoma cells. Therefore, the present study aimed to evaluate the antitumor potential of manool in a murine melanoma model, administered by three routes: oral, subcutaneous, and intraperitoneal. In addition, the antimelanoma effect of manool (orally) combined with cisplatin (subcutaneous) was evaluated. The results obtained revealed that manool, administered by the three routes, was able to significantly decrease the mass and frequency of mitosis of the tumor tissue. The data obtained revealed that manool, at a dose of 20 mg/kg, was able to significantly decrease the tumor mass when administered by the three routes, with the percentages of reduction being equivalent to 62.4% (oral), 48.5% (intraperitoneal), and 38.8% (subcutaneous), without toxic effects. The treatment of manool plus cisplatin led to 86.7% reduction in tumor mass, higher than that observed in treatment with manool or cisplatin alone (50.7%), although signs of toxicity have been observed. The results also showed that treatments with manool (20 mg/kg orally) and/or cisplatin did not alter the activity of caspase 3 cleaved in tumor tissue. Therefore, manool revealed a promising antimelanoma effect, but without involvement of the caspase 3 cleaved pathway.

The present study aimed to evaluate the effect of the manool diterpene on genomic integrity. For this purpose, we evaluated the influence of manool on genotoxicity induced by mutagens with different mechanisms of action, as well as on colon carcinogenesis. The results showed that manool (0.5 and 1.0 µg/ml) significantly reduced the frequency of micronuclei induced by doxorubicin (DXR) and hydrogen peroxide in V79 cells but did not influence genotoxicity induced by etoposide. Mice receiving manool (1.25 mg/kg) exhibited a significant reduction (79.5%) in DXR-induced chromosomal damage. The higher doses of manool (5.0 and 20 mg/kg) did not influence the genotoxicity induced by DXR. The anticarcinogenic effect of manool (0.3125, 1.25 and 5.0 mg/kg) was also observed against preneoplastic lesions chemically induced in rat colon. A gradual increase in manool doses did not cause a proportional reduction of preneoplastic lesions, thus demonstrating the absence of a dose–response relationship. The analysis of serum biochemical indicators revealed the absence of hepatotoxicity and nephrotoxicity of treatments. To explore the chemopreventive mechanisms of manool via anti-inflammatory pathways, we evaluated its effect on nitric oxide (NO) production and on the expression of the NF-kB gene. At the highest concentration tested (4 μg/ml), manool significantly increased NO production when compared to the negative control. On the other hand, in the prophylactic treatment model, manool (0.5 and 1.0 μg/ml) was able to significantly reduce NO levels produced by macrophages stimulated with lipopolysaccharide. Analysis of NF-kB in hepatic and renal tissues of mice treated with manool and DXR revealed that the mutagen was unable to stimulate expression of the gene. In conclusion, manool possesses antigenotoxic and anticarcinogenic effects and its anti-inflammatory potential might be related, at least in part, to its chemopreventive activity.

Essential oils, which may be extracted from several parts of plants, have different biological activities. The Brazilian Cerrado has a large variety of plants that yield essential oils, even though many have not been studied yet. Taking into account the biodiversity of this biome, this study aimed at evaluating the antiproliferative activity of essential oils extracted from three species of plants of the Cerrado in Goiás state: Campomanesia adamantium (Cambess.) O. Berg, Protium ovatum (Engl. in Mart.) and Cardiopetalum calophyllum (Schltdl.). Essential oils were extracted from both C. adamantium and C. calophyllum leaves and from P. ovatum leaves and green fruits by hydrodistillation carried out by a Clevenger-type apparatus. The chemical composition of the essential oils was determined by Gas Chromatography coupled to Mass Spectrometry (GC-MS). The following major chemical constituents were identified in the essential oils under investigation: β-myrcene (62.00%), spathulenol (28.78%), germacrene-B (18.27%), β-caryophyllene oxide (16.40%), β-caryophyllene (14.00%), α-pinene (11.30%), viridiflorol (9.99%), limonene (7.30%) and (Z,E)-pharnesol (6.51%). The antiproliferative activity was evaluated in different human tumor cell lines: breast adenocarcinoma (MCF-7), cervical adenocarcinoma (HeLa) and glioblastoma (M059J). A normal human cell line was included (GM07492A, lung fibroblasts). Results showed that essential oils from C. adamantium leaves got the lowest values of IC₅₀ in all strains of tumor cells under evaluation. They were significantly lower than the ones of the normal cell line, an evidence of selectivity. It is worth mentioning that this is the first report of the antiproliferative activity of essential oils from C. adamantium , P. ovatum and C. calophyllum against human tumor cells.