Guttiferone E Displays Antineoplastic Activity Against Melanoma Cells.

Guttiferone E (GE) is a benzophenone found in Brazilian red propolis. In the present study, the effect of GE on human (A-375) and murine (B16-F10) melanoma cells was investigated. GE significantly reduced the cellular viability of melanoma cells in a time-dependent manner. In addition, GE demonstrated antiproliferative effect, with IC50 values equivalent to 9.0 and 6.6 µM for A-375 and B16-F10 cells, respectively. The treatment of A-375 cells with GE significantly increased cell populations in G0/G1 phase and decreased those in G2/M phase. Conversely, on B16-F10 cells, GE led to a significant decrease in the populations of cells in G0/G1 phase and concomitantly an increase in the population of cells in phase S. A significantly higher percentage of apoptotic cells was observed in A-375 (43.5%) and B16-F10 (49.9%) cultures after treatment with GE. Treatments with GE caused morphological changes and significant decrease to the melanoma cells' density. GE (10 µM) inhibited the migration of melanoma cells, with a higher rate of inhibition in B16-F10 cells (73.4%) observed. In addition, GE significantly reduced the adhesion of A375 cells, but showed no effect on B16-F10. Treatment with GE did not induce changes in P53 levels in A375 cultures. Molecular docking calculations showed that GE is stable in the active sites of the tubulin dimer with a similar energy to taxol chemotherapy. Taken together, the data suggest that GE has promising antineoplastic potential against melanoma.

In vitro evaluation of the antibacterial and cytotoxic activities of the Euclea natalensis crude extract and fractions against oral infection agents.

OBJECTIVE: This study aimed (i) to evaluate the antibacterial and cytotoxic activities of the crude extract and fractions obtained from Euclea natalensis A.D.C. roots against bacteria that cause periodontal disease and caries and (ii) to identify the isolated compounds. DESIGN: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the extract and fractions were determined by the microplate dilution assay. The cytotoxicity of the extract and fractions was evaluated by using the XTT colorimetric assay and normal human fibroblast cells (GM07492A, lung fibroblasts). The compounds present in the most promising fraction were determined by qualitative analysis through liquid chromatography coupled to mass spectrometry (HPLC-MS-ESI). RESULTS: The MIC results ranged from 25 to > 400 µg/mL for the extract and from 1.56 to > 400 µg/mL for the fractions. To evaluate cytotoxicity, the tested concentrations of the extract and fractions ranged from 19.5 to 2500 µg/mL; IC50 values between 625 and 1250 µg/mL were obtained. Analysis of the main bioactive fraction by HPLC-MS-ESI identified phenolic acids, coumarins, naphthoquinones, lignans, and fatty acids. CONCLUSIONS: The E. natalensis root extract and fractions displayed good antibacterial activity against periodontal pathogenic and cariogenic bacteria. The antibacterial activity may be due to compounds present in the extract and fractions, which also showed low cytotoxicity to normal human cells. These data are relevant and encourage further research into this plant species, which may contribute to the discovery of new herbal medicines that will help to mitigate the problems caused by oral pathogenic bacteria.

Toxicological and chemoprevention studies of Dalbergia ecastaphyllum (L.) Taub. stem, the botanical source of Brazilian red propolis.

OBJECTIVES: 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. METHODS AND RESULTS: 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. CONCLUSIONS: These results indicate the involvement of anti-inflammatory and antiproliferative pathways in the protective effect of DEHE.

Chemical study of Adenocalymma axillarum crude leaf extract and isolated compounds

Abstract Adenocalymma axillarum (K.Schum.) L.G. Lohmann is a liana belonging to the family Bignoniaceae. In traditional medicine, the genus Adenocalymma is used to treat fever, skin ailments, and body, joint, and facial muscle pains, and it is also applied as cosmetic. Biological assays conducted with the A. axillarum crude leaf ethanol extract have indicated leishmanicidal activity and absence of cytotoxicity. This study aimed to analyze the A. axillarum leaf ethanol crude extract by high-performance liquid chromatography-high-resolution mass spectrometry- diode array detector (HPLC-HRMS-DAD) and to evaluate the leishmanicidal and cytotoxic activities of this crude extract, its fractions, and isolated compounds. HPLC-HRMS-DAD analysis of this extract revealed that it consisted mainly of flavonoids, with nine major compounds. Extract purification yielded 4-hydroxy-N-methylproline, 6-β-hydroxyipolamiide, quercetin-3-O-robinobioside, hyperin, isorhamnetin-3-O-robinobioside, and 3'-O-methylhyperin, which were identified by Nuclear Magnetic Resonance. The isolated compounds were inactive against Leishmania amazonensis promastigotes and human lung fibroblast cells.

Manool, a diterpene from Salvia officinalis, exerts preventive effects on chromosomal damage and preneoplastic lesions.

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.

Lipophilic gold(I) complexes with 1,3,4-oxadiazol-2-thione or 1,3-thiazolidine-2-thione moieties: synthesis and their cytotoxic and antimicrobial activities.

Novel lipophilic gold(I) complexes containing 1,3,4-oxadiazol-2-thione or 1,3-thiazolidine-2-thione derivatives were synthesized and characterized by IR, high resolution mass spectrometry, and 1H, 13C 31P NMR. The cytotoxicity of the compounds was evaluated considering cisplatin and/or auranofin as reference in different tumor cell lines: colon cancer (CT26WT), metastatic skin melanoma (B16F10), breast adenocarcinoma (MCF-7), cervical carcinoma (HeLa), glioblastoma (M059 J). Normal human lung fibroblasts (GM07492-A) and kidney normal cell (BHK-21) were also evaluated. The gold(I) complexes were more active than their respective free ligands and cisplatin. Furthermore, antibacterial activity was evaluated against Gram-positive bacteria Staphylococcus aureus ATCC 25213, Staphylococcus epidermidis ATCC 12228 and Gram-negative bacteria Escherichia coli ATCC 11229 and Pseudomonas aeruginosa ATCC 27853 and expressed as the minimum inhibitory concentration (MIC). The complexes exhibited lower MIC values when compared to the ligands and chloramphenicol against Gram-positive bacteria and Gram-negative bacteria. Escherichia coli was sensitive one to the action of gold(I) complexes.

Toxicogenetic study of Persea americana fruit pulp oil and its effect on genomic instability.

Persea americana Mill., commonly known as avocado, is a tree native to Central America that is widely used as a food source and for the treatment of diseases. This plant has various biological properties such as analgesic, anti-inflammatory and total cholesterol-lowering activity. In view of its pharmacological potential, we conducted a toxicogenetic study of the fruit pulp oil of P. americana (PAO) and investigated its influence on genotoxicity induced by methyl methanesulfonate (MMS) and doxorubicin. V79 cells and Swiss mice were used for the assays. The results showed no genotoxic effects of PAO in the in vitro or in vivo test systems. However, the highest PAO dose tested led to an increase in the levels of aspartate aminotransferase, indicating hepatic/tissue damage. This effect may be related to high concentrations of palmitic acid, the main component of PAO. Furthermore, PAO was effective in reducing the chromosome damage induced by MMS and doxorubicin. These results contribute to the safety assessment of PAO as a medicinal plant for human use.

Influence of Styrax camporum and of Chemical Markers (Egonol and Homoegonol) on DNA Damage Induced by Mutagens with Different Mechanisms of Action.

This study evaluated the influence of Styrax camporum stems hydroalcoholic extract (SCHE) and of chemical markers of the genus, egonol (EG) and homoegonol (HE), on DNA damage induced in V79 cells by mutagens with different mechanisms of action. These natural products were combined with different mutagens [methyl methanesulfonate (MMS), hydrogen peroxide (H2O2), (S)-(+)-camptothecin (CPT), and etoposide (VP-16)] to evaluate the modulatory effect on DNA damage. The results showed that SCHE was genotoxic at the highest concentration tested (60 µg/mL). Treatment with EG or HE alone induced no genotoxic effect, while genotoxic activity was observed when the two compounds were combined. The SCHE extract was able to reduce the frequency of micronuclei induced by H2O2 and VP-16. Similar results were observed when the cell cultures were treated with EG and/or HE plus VP-16. In contrast, the highest concentration (40 µg/mL) SCHE potentiated DNA damage induced by VP-16. Neolignan EG alone or combined with HE also potentiated H2O2-induced genotoxicity. However, these natural products did not influence the frequency of DNA damage induced by MMS or CPT. Therefore, the influence of SCHE and of chemical markers (EG and HE) of the genus on the induction of DNA damage depends on the concentration tested and on the mutagen used.

Differential effect of manool--a diterpene from Salvia officinalis, on genotoxicity induced by methyl methanesulfonate in V79 and HepG2 cells.

Salvia officinalis (sage) is a perennial woody subshrub native to the Mediterranean region that is commonly used as a condiment and as an anti-inflammatory, antioxidant and antimicrobial agent due to its biological activities. Manool is the most abundant micro-metabolite found in Salvia officinalis essential oils and extracts. We therefore decided to evaluate the cytotoxic, genotoxic and antigenotoxic potential of manool in Chinese hamster lung fibroblasts (V79) and human hepatoma cells (HepG2). Cytotoxicity was assessed by the colony-forming assay in V79 cells and toxic effects were observed at concentrations of up to 8.0 µg/mL. The micronucleus test was used to evaluate the genotoxicity and antigenotoxicity of manool in V79 and HepG2 cells at concentrations of 0.5-6.0 µg/mL and 0.5-8.0 µg/mL, respectively. For evaluation of antigenotoxicity, the concentrations of manool were combined with methyl methanesulfonate (MMS, 44 µg/mL). The results showed a significant increase in the frequency of micronuclei in cultures of both cell lines treated with the highest concentration tested, demonstrating a genotoxic effect. On the other hand, manool exhibited a protective effect against chromosome damage induced by MMS in HepG2 cells, but not in V79 cells. These data suggest that some manool metabolite may be responsible for the antigenotoxic effect observed in HepG2 cells.