A Novel Tri-Hydroxy-Methylated Chalcone Isolated from Chromolaena tacotana with Anti-Cancer Potential Targeting Pro-Survival Proteins.

Chromolaena tacotana (Klatt) R. M. King and H. Rob (Ch. tacotana) contains bioactive flavonoids that may have antioxidant and/or anti-cancer properties. This study investigated the potential anti-cancer properties of a newly identified chalcone isolated from the inflorescences of the plant Chromolaena tacotana (Klatt) R. M. King and H. Rob (Ch. tacotana). The chalcone structure was determined using HPLC/MS (QTOF), UV, and NMR spectroscopy. The compound cytotoxicity and selectivity were evaluated on prostate, cervical, and breast cancer cell lines using the MTT assay. Apoptosis and autophagy induction were assessed through flow cytometry by detecting annexin V/7-AAD, active Casp3/7, and LC3B proteins. These results were supported by Western blot analysis. Mitochondrial effects on membrane potential, as well as levels of pro- and anti-apoptotic proteins were analyzed using flow cytometry, fluorescent microscopy, and Western blot analysis specifically on a triple-negative breast cancer (TNBC) cell line. Furthermore, molecular docking (MD) and molecular dynamics (MD) simulations were performed to evaluate the interaction between the compounds and pro-survival proteins. The compound identified as 2',3,4-trihydroxy-4',6'-dimethoxy chalcone inhibited the cancer cell line proliferation and induced apoptosis and autophagy. MDA-MB-231, a TNBC cell line, exhibited the highest sensitivity to the compound with good selectivity. This activity was associated with the regulation of mitochondrial membrane potential, activation of the pro-apoptotic proteins, and reduction of anti-apoptotic proteins, thereby triggering the intrinsic apoptotic pathway. The chalcone consistently interacted with anti-apoptotic proteins, particularly the Bcl-2 protein, throughout the simulation period. However, there was a noticeable conformational shift observed with the negative autophagy regulator mTOR protein. Future studies should focus on the molecular mechanisms underlying the anti-cancer potential of the new chalcone and other flavonoids from Ch. tacotana, particularly against predominant cancer cell types.

A New Flavanone from Chromolaena tacotana (Klatt) R. M. King and H. Rob, Promotes Apoptosis in Human Breast Cancer Cells by Downregulating Antiapoptotic Proteins.

Chromolaena tacotana is a source of flavonoids with antiproliferative properties in human breast cancer cells, the most common neoplasm diagnosed in patients worldwide. Until now, the mechanisms of cell death related to the antiproliferative activity of its flavonoids have not been elucidated. In this study, a novel flavanone (3',4'-dihydroxy-5,7-dimethoxy-flavanone) was isolated from the plant leaves and identified by nuclear magnetic resonance (NMR) and mass spectrometry (MS). This molecule selectively inhibited cell proliferation of triple-negative human breast cancer cell lines MDA-MB-231 and MCF-7 whit IC50 values of 25.3 µg/mL and 20.8 µg/mL, respectively, determined by MTT assays with a selectivity index greater than 3. Early and late pro-apoptotic characteristics were observed by annexin-V/7-AAD detection, accompanied by a high percentage of the Bcl-2 anti-apoptotic protein inactivated and the activation of effector Caspase-3 and/or 7 in breast cancer cells. It was verified the decreasing of XIAP more than Bcl-2 anti-apoptotic proteins expression, as well as the XIAP/Caspase-7 and Bcl-2/Bax complexes dissociation after flavanone treatment. Docking and molecular modeling analysis between the flavanone and the antiapoptotic protein XIAP suggests that the natural compound inhibits XIAP by binding to the BIR3 domain of XIAP. In this case, we demonstrate that the new flavanone isolated from leaves of Chomolaena tacotana has a promising and selective anti-breast cancer potential that includes the induction of intrinsic apoptosis by downregulation of the anti-apoptotic proteins XIAP and Bcl-2. New studies should deepen these findings to demonstrate its potential as an anticancer agent.

Natural 2',4-Dihydroxy-4',6'-dimethoxy Chalcone Isolated from Chromolaena tacotana Inhibits Breast Cancer Cell Growth through Autophagy and Mitochondrial Apoptosis.

Breast cancer (BC) is one of the most common cancers among women. Effective treatment requires precise tailoring to the genetic makeup of the cancer for improved efficacy. Numerous research studies have concentrated on natural compounds and their anti-breast cancer properties to improve the existing treatment options. Chromolaena tacotana (Klatt) R.M. King and H. Rob (Ch. tacotana) is a notable source of bioactive hydroxy-methylated flavonoids. However, the specific anti-BC mechanisms of these flavonoids, particularly those present in the plant's inflorescences, remain partly undefined. This study focuses on assessing a chalcone derivative extracted from Ch. tacotana inflorescences for its potential to concurrently activate regulated autophagy and intrinsic apoptosis in luminal A and triple-negative BC cells. We determined the chemical composition of the chalcone using ultraviolet (UV) and nuclear magnetic resonance (NMR) spectroscopy. Its selective cytotoxicity against BC cell lines was assessed using the MTT assay. Flow cytometry and Western blot analysis were employed to examine the modulation of proteins governing autophagy and the intrinsic apoptosis pathway. Additionally, in silico simulations were conducted to predict interactions between chalcone and various anti-apoptotic proteins, including the mTOR protein. Chalcone was identified as 2',4-dihydroxy-4',6'-dimethoxy-chalcone (DDC). This compound demonstrated a selective inhibition of BC cell proliferation and triggered autophagy and intrinsic apoptosis. It induced cell cycle arrest in the G0/G1 phase and altered mitochondrial outer membrane potential (∆ψm). The study detected the activation of autophagic LC3-II and mitochondrial pro-apoptotic proteins in both BC cell lines. The regulation of Bcl-XL and Bcl-2 proteins varied according to the BC subtype, yet they showed promising molecular interactions with DDC. Among the examined pro-survival proteins, mTOR and Mcl-1 exhibited the most favorable binding energies and were downregulated in BC cell lines. Further research is needed to fully understand the molecular dynamics involved in the activation and interaction of autophagy and apoptosis pathways in cancer cells in response to potential anticancer agents, like the hydroxy-methylated flavonoids from Ch. tacotana.

Qualitative analysis of sequence specific binding of flavones to DNA using restriction endonuclease activity assays.

Flavones, found in nature as secondary plant metabolites, have shown efficacy as anti-cancer agents. We have examined the binding of two flavones, 5,7-dihydroxy-3,6,8-trimethoxy-2-phenyl-4H-chromen-4-one (5,7-dihydroxy-3,6,8-trimethoxy flavone; FlavA) and 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-chromen-4-one (3,5-dihydroxy-6,7,8-trimethoxy flavone; FlavB), to phiX174 RF DNA using restriction enzyme activity assays employing the restriction enzymes Alw44, AvaII, BssHII, DraI, MluI, NarI, NciI, NruI, PstI, and XhoI. These enzymes possess differing target and flanking sequences allowing for observation of sequence specificity analysis. Using restriction enzymes that cleave once with a mixture of supercoiled and relaxed DNA substrates provides for observation of topological effects on binding. FlavA and FlavB show differing sequence specificities in their respective binding to phiX. For example, with relaxed DNA, FlavA shows inhibition of cleavage with DraI (reaction site (5') TTTAAA) but not BssHII ((5') GCGCGC) while FlavB shows the opposite results. Evidence for tolological specificity is also observed, Molecular modeling and conformational analysis of the flavones suggests that the phenyl ring of FlavB is coplanar with the flavonoid ring while the phenyl ring of FlavA is at an angle relative to the flavonoid ring. This may account for aspects of the observed sequence and topological specificities in the effects on restriction enzyme activity.

Achyrocline B (3,5 dihydroxy-6,7,8-trimethoxyflavone) synergizes with 5-fluorouracil allowing for dose reduction and reduced off-target toxicity in the treatment of colonic and pancreatic cancers.

Surgically unresectable colorectal and pancreatic carcinomas have a high rate of mortality as current therapeutic options are limited. One common chemotherapeutic used to broadly treat both cancers is 5-flurouracil (5-Fu); however, treatment serves only to slow progression of the disease and comes with many side effects due to 5-Fu's intrinsic toxicity. Thus, strategies to decrease the dose of 5-Fu utilized therapeutically as well as reduce 5-Fu's off-target toxicity are paramount. Using cell models of colorectal and pancreatic cancers, we show that cotreatment with Achyrocline B (3,5 dihydroxy-6,7,8-trimethoxyflavone, AcB), a natural flavone from Achyrocline bogotensis, allows for four-fold reduction in 5-Fu dosage without loss of efficacy. We further show that the action of AcB is due to continued cell cycle progression despite 5-Fu pressure to synchronize at the G1/S threshold. In addition to AcB's effect on cancer cells, we found that AcB can directly reduce toxicity of 5-Fu in cells mimicking non-cancerous tissues. These in vitro results are then supported by xenograft modeling. AcB was shown to increase apoptosis in tumors leading to degeneration of the outer tumoral boundary. Furthermore, in 5-Fu treated animals it was found that AcB provided protection to the intestinal tract as indicated by preserved histological and immunohistochemical features. These results show promise for a new adjuvant therapy for colorectal and pancreatic carcinomas that not only reduces tumor progression, but more importantly has the potential to improve patient quality of life.

Quantification of two isomeric flavones in rat colon tissue using reverse phase high performance liquid chromatography.

BACKGROUND: Antineoplastic activity has been previously shown for two isomeric flavones, 5,7-dihydroxy-3,6,8-trimethoxy flavone (flavone A) and 3,5-dihydroxy-6,7,8-trimethoxy flavone (flavone B), against colon cancer cell lines (Thomas et al. in PLoS ONE 7:e39806, 5). Here, we present modified methods for the extraction and quantification of flavones A and B in rat colon tissue after intravenous dosing via high performance liquid chromatography, from the originally described procedure for extraction and quantification in rat plasma (Whitted et al. in J Chromatogr B Analyt Technol Biomed Life Sci 1001:150-155, 7). RESULTS: Modifications included tissue homogenization (1 g tissue: 2 mL water), filtration of the supernatant with a PVDF membrane, and the use of only one calibration curve to determine the concentration of each flavone in colon tissue. Good separation was achieved and representative equations were linear with r 2  ≥ 0.99 for both flavones. Precision and accuracy for flavone A ranged from 0.88-24.03 and 109-116%. Precision and accuracy for flavone B ranged from 1.62-33.56 and 98-113%. Concentrations of 1639 ± 601 ng/g flavone A and 5975 ± 2480 ng/g of flavone B were detected in rat colon tissue 6 h post dosing. CONCLUSIONS: Modifications to the extraction methods for flavone A and flavone B from rat colon tissue had good separation, precision, and accuracy.

Development of reversed-phase high performance liquid chromatography methods for quantification of two isomeric flavones and the application of the methods to pharmacokinetic studies in rats.

Isomers 5,7-dihydroxy-3,6,8-trimethoxy-2-phenyl-4H-chromen-4-one (5,7-dihydroxy-3,6,8 trimethoxy flavone) (flavone A) and 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-chromen-4-one (3,5-dihydroxy-6,7,8-trimethoxy flavone) (flavone B) have recently demonstrated differential antineoplastic activities against pancreatic cancer in vitro. These studies also indicated that these compounds target highly tumorigenic cells while sparing normal cells. The in vivo antitumor activities of these flavones have not been determined, and detection protocols for these compounds are needed to conduct pre-clinical assays following intravenous dosing. Here, we report methods developed using acetonitrile to extract two flavone isomers and corresponding internal standards, celecoxib and diclofenac, from rat plasma. Separation was achieved using a Shimadzu liquid chromatography system with a C18 column and mobile phase acetonitrile/water (60:40 and 70:30 for flavones A and B, respectively) containing 0.2% acetic acid and 0.05% triethylamine at a flow rate of 0.4mL/min and detection at 245nm. Calibration curves ranging from 250 to 2500ng/mL and 2500 to 100,000ng/mL for both flavones were linear (r(2)≥0.99) with the lower limits of quantification being 250ng/mL. Recovery of concentrations 250, 1000, 2500, 5000, and 100,000ng/mL ranged from 87 to 116% and 84 to 103% (n=3) for flavone A and B, respectively. Stability of both flavones after a freezing/thawing cycle yielded a mean peak ratio ≥0.92 when compared to freshly extracted samples. Intravenous administration of a 20mg/kg dose in rats yielded half-lives of 83.68±56.61 and 107.45±53.31min with clearance values of 12.99±13.78 and 80.79±35.06mL/min/kg for flavones A and B, respectively.

Mechanism of Action of Two Flavone Isomers Targeting Cancer Cells with Varying Cell Differentiation Status.

Apoptosis can be triggered in two different ways, through the intrinsic or the extrinsic pathway. The intrinsic pathway is mediated by the mitochondria via the release of cytochrome C while the extrinsic pathway is prompted by death receptor signals and bypasses the mitochondria. These two pathways are closely related to cell proliferation and survival signaling cascades, which thereby constitute possible targets for cancer therapy. In previous studies we introduced two plant derived isomeric flavonoids, flavone A and flavone B which induce apoptosis in highly tumorigenic cancer cells of the breast, colon, pancreas, and the prostate. Flavone A displayed potent cytotoxic activity against more differentiated carcinomas of the colon (CaCo-2) and the pancreas (Panc28), whereas flavone B cytotoxic action is observed on poorly differentiated carcinomas of the colon (HCT 116) and pancreas (MIA PaCa). Apoptosis is induced by flavone A in better differentiated colon cancer CaCo-2 and pancreatic cancer Panc 28 cells via the intrinsic pathway by the inhibition of the activated forms of extracellular signal-regulated kinase (ERK) and pS6, and subsequent loss of phosphorylation of Bcl-2 associated death promoter (BAD) protein, while apoptosis is triggered by flavone B in poorly differentiated colon cancer HCT 116 and MIA PaCa pancreatic cancer cells through the extrinsic pathway with the concomitant upregulation of the phosphorylated forms of ERK and c-JUN at serine 73. These changes in protein levels ultimately lead to activation of apoptosis, without the involvement of AKT.

Anti-neoplastic activity of two flavone isomers derived from Gnaphalium elegans and Achyrocline bogotensis.

Over 4000 flavonoids have been identified so far and among these, many are known to have antitumor activities. The basis of the relationships between chemical structures, type and position of substituent groups and the effects these compounds exert specifically on cancer cells are not completely elucidated. Here we report the differential cytotoxic effects of two flavone isomers on human cancer cells from breast (MCF7, SK-BR-3), colon (Caco-2, HCT116), pancreas (MIA PaCa, Panc 28), and prostate (PC3, LNCaP) that vary in differentiation status and tumorigenic potential. These flavones are derived from plants of the family Asteraceae, genera Gnaphalium and Achyrocline reputed to have anti-cancer properties. Our studies indicate that 5,7-dihydroxy-3,6,8-trimethoxy-2-phenyl-4H-chromen-4-one (5,7-dihydroxy-3,6,8-trimethoxy flavone) displays potent activity against more differentiated carcinomas of the colon (Caco-2), and pancreas (Panc28), whereas 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-chromen-4-one (3,5-dihydroxy-6,7,8-trimethoxy flavone) cytototoxic action is observed on poorly differentiated carcinomas of the colon (HCT116), pancreas (Mia PaCa), and breast (SK-BR3). Both flavones induced cell death (>50%) as proven by MTT cell viability assay in these cancer cell lines, all of which are regarded as highly tumorigenic. At the concentrations studied (5-80 µM), neither flavone demonstrated activity against the less tumorigenic cell lines, breast cancer MCF-7 cells, androgen-responsive LNCaP human prostate cancer line, and androgen-unresponsive PC3 prostate cancer cells. 5,7-dihydroxy-3,6,8-trimethoxy-2-phenyl-4H-chromen-4-one (5,7-dihydroxy-3,6,8-trimethoxy flavone) displays activity against more differentiated carcinomas of the colon and pancreas, but minimal cytotoxicity on poorly differentiated carcinomas of these organs. On the contrary, 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-chromen-4-one (3,5-dihydroxy-6,7,8-trimethoxy flavone) is highly cytotoxic to poorly differentiated carcinomas of the colon, pancreas, and breast with minimal activity against more differentiated carcinomas of the same organs. These differential effects suggest activation of distinct apoptotic pathways. In conclusion, the specific chemical properties of these two flavone isomers dictate mechanistic properties which may be relevant when evaluating biological responses to flavones.

Chemical and biological activity of leaf extracts of Chromolaena leivensis.

The flavonoids 3,5-dihydroxy-7-methoxy-flavanone, 3,5-dihydroxy-7-methoxyflavone and 3,5,7-trihydroxy-6-methoxyflavone were isolated from the leaves of C. leivensis. Preliminary observations in K562 cells (human erythroleukemia) using the trypan blue test, showed a 90% viability at a concentration of 100 microg/mL; however, further testing of the flavonoids at concentrations of 25, 50 and 100 microg/mL showed toxicity affecting the morphology of human erythroleukemia cells (K562) and human melanoma cells (A375). Induction of apoptosis was produced by 3,5-dihydroxy-7-methoxyflavone at 72 hours after treatment with arrest in the G2 / M phase of the cell cycle. The A375 cells treated with 50 microg/mL of 3,5-dihydroxy-7-methoxy-flavanone for 24, 48 and 72 hours, display effects on the behavior of the cell cycle. The flavonoid 3,5-dihydroxy-7-methoxyflavone has activity on the mitochondrial membrane at concentrations of 25, 50 and 100 microg/mL, at time intervals of 8 to 12 hours. The flavonoids 3,5-dihydroxy-7-methoxy-flavanone and 3,5-dihydroxy-7-methoxyflavone at a concentration of 25 microg/mL increased the expression of costimulatory molecules corresponding to the phenotype presented by mature dendritic cells with differentiation markers CD40, CD83, CD86 and HLA-DR. The two flavonoids at concentrations between 0.39 and 100 microg/mL slightly increased the proliferation of peripheral blood mononuclear cells in the presence and in the absence of phytohemagglutinin. These flavonoids at concentrations of 50 and 100 microg/mL slightly increased the proliferation of fibroblasts.

[Aluminium in chronic renal replacement therapy patients undergoing haemodialysis in two renal units in Bogotá]. / Aluminio en pacientes con terapia de reemplazo renal crónico con hemodiálisis en dos unidades renales en Bogotá.

OBJECTIVE: Determining aluminium concentrations in the serum of patients undergoing chronic renal replacement therapy with haemodialysis and concentration in distribution network water and dialysis in two renal units in Bogotá. MATERIAL AND METHODS: This was a descriptive study of 63 haemodialysed patients and 20 healthy subjects. Aluminium concentration was determined in water and serum using graphite furnace atomic absorption spectrometry with deuterium lamp background corrector. RESULTS: Average aluminium concentration was 26.5 µg/L in patients (ranging from 11.2 to 49.2 µg/L; 8.03 standard deviation) and 8.05 µg/L in healthy individuals (ranging from undetectable to 17.2 µg/L; 4.31 standard deviation). Aluminium concentration in dialysis water and distribution network water was below 2 µg/L and 200 µg/L, respectively. CONCLUSIONS: Aluminium concentration in water and serum in this study was below international standard values, thereby indicating appropriate treatment. Additionally, aluminium concentration in pre-HD and post-HD sera was below that reported previously. Aluminium hydroxide uptake increases aluminium concentration in serum. Personal situation regarding age, gender, civil and work status were not risk factors determining aluminium concentrations in serum.

Biomass productoon and heavy metal absorptionbyfour plants grown at the moraviia dump, medellín, Coommbia. / Producción de biomasa y absorción de metales pesados por cuatro plantas crecidas en el basurero Morovia, Medellín, Colombia.

Dumps are sites where the presence of high heavy metal (HM) concentration is a common occurrence, creating the need for implementing restoration processes immediately after their closure. In the 7.6 ha and 45 m high Morro de Moravia dump, arose from the disposal of Medellín solid wastes from 1974 to 1984, previous studies have demonstrated high contents of contaminants, including HM, prompting the need to identify effective mechanisms to implement its restoration. The objective of this study was to evaluate the adaptation, growth and phytoremediation capacity of Bidens pilosa, Lepidium virginicum, Brachiaria decumbens and Arachis pintoi. Content of HM (mg/kg) in Moravia residue matrix went from 17 to 8193 for Pb, 44 to 564 for Cr, 0.2 to 339 for Cd and 77 to 1679 for Ni. Measurements of plant cover, plant height and dry matter production at all plant species studied suggested adequate growth and adaptation to the Moravia dump conditions. Plant absorption of HM showed the pattern Cr > Cd > Ni > Pb. Estimated bioconcentration factors were generally low, and maximum values were 0.36 in A. pintoi (Cr), 2.96 in B. pilosa (Cd) and 0.26 in B. decumbens (Ni). However, our estimations of the phytoremediation potential of the assayed species, suggested they possess low remediation efficiency. Further investigation should be carried out in order to identify more efficient HM accumulators, and to test the use of technologies such as modification of pH, rhizoremediation or the use of genetically enhanced accumulators to increase HM availability to plants.

En los basureros se observan altas concentraciones de metales pesados (MP), creando la necesidad de conducir procesos de restauración en dichos lugares. En el Morro de basuras de Moravia, con 7,6 ha y 45 m de altura, conformado por la disposición de los residuos sólidos de la ciudad de Medellín entre 1974 y 1984, estudios anteriores demostraron alto contenido MP, evidenciando la necesidad de identificar mecanismos efectivos para su restauración. El objetivo de este estudio fue evaluar la adaptación, crecimiento y capaci-dad fitorremediadora de Bidens pilosa, Lepidium virginicum, Brachiaria decumbens y Arachis pintoi. El contenido de MP (mg/kg) en la matriz de residuos de Moravia varió entre 17 y 8.193 para Pb, 44 a 564 para Cr, 0,2 a 339 para Cd y 77 a 1.679 para Ni. Las mediciones de cobertura, altura y producción de materia seca mostraron que todas las especies evaluadas tuvieron un nivel adecuado de adaptación y crecimiento a las condiciones del basurero de Moravia. La absorción de MP presentó el orden Cr > Cd> Ni > Pb. Los factores de bioconcentración estimados fueron bajos, siendo los valores máximos: 0,36 (A. pintoi, Cr), 2,96 (B. pilosa, Cd) y 0,26 (B. decumbens, Ni). Sin embargo, nuestras estimaciones del potencial de fitorremediación de las plantas evaluadas sugieren que éstas poseen baja eficiencia fitorremediadora. Debe dirigirse investigación con el fin de identificar especies acumuladoras de MP más eficientes o introducir tecnologías que aumenten la disponi-bilidad de los MP, tales como la modificación del pH, rizorremediación o el uso de plantas acumuladoras genéticamente modificadas.

Aluminio en pacientes con terapia de reemplazo renal crónico con hemodiálisis en dos unidades renales en Bogotá / Aluminium in chronic renal replacement therapy patients undergoing haemodialysis in two renal units in Bogotá

Objetivo Determinar las concentraciones de aluminio en suero de pacientes con terapia de reemplazo renal crónico con hemodiálisis y las concentraciones en agua de redes de distribución y diálisis en dos unidades renales en Bogotá. Material y Métodos Estudio descriptivo en 63 pacientes en hemodiálisis y 20 individuos sanos. Las concentraciones de aluminio se determinaron por espectrofotometría de absorción atómica horno de grafito con corrección de lámpara de deuterio. Resultados El promedio de las concentraciones de aluminio en suero de los pacientes fue de 26,5 µg/L (11,2 a 49,2 µg/L, DE=8,03), en individuos sanos de 8,05 µg/L (menor al Límite de Detección a 17,2 µg/L, DE=4,31), en agua de diálisis fue menor a 2 µg/L y en agua de las redes de distribución menor a 200 µg/L. Conclusiones Las concentraciones de aluminio en el agua de la red de distribución y diálisis estudiadas se encontraron por debajo de los valores establecidos internacionalmente indicando un adecuado tratamiento de las mismas. Igualmente las concentraciones de aluminio pre-HD y post-HD observadas en los pacientes se encontraron por debajo de las reportadas en la literatura. El consumo de hidróxido de aluminio aumenta significativamente la concentración de aluminio en suero. Variables como edad, género, estado civil y situación laboral no son factores de riesgo que alteren significativamente las concentraciones de aluminio en suero.

Objective Determining aluminium concentrations in the serum of patients undergoing chronic renal replacement therapy with haemodialysis and concentration in distribution network water and dialysis in two renal units in Bogotá. Material and Methods This was a descriptive study of 63 haemodialysed patients and 20 healthy subjects. Aluminium concentration was determined in water and serum using graphite furnace atomic absorption spectrometry with deuterium lamp background corrector. Results Average aluminium concentration was 26.5 µg/L in patients (ranging from 11.2 to 49.2 µg/L; 8.03 standard deviation) and 8.05 µg/L in healthy individuals (ranging from undetectable to 17.2 µg/L; 4.31 standard deviation). Aluminium concentration in dialysis water and distribution network water was below 2 µg/L and 200 µg/L, respectively. Conclusions Aluminium concentration in water and serum in this study was below international standard values, thereby indicating appropriate treatment. Additionally, aluminium concentration in pre-HD and post-HD sera was below that reported previously. Aluminium hydroxide uptake increases aluminium concentration in serum. Personal situation regarding age, gender, civil and work status were not risk factors determining aluminium concentrations in serum.

Nueva fuente de quinoles, la superficie foliar de Pentacalia ledifolia y Pentacalia corymbosa y sus propiedades antifúngicas / Nova fonte de quinóides, a superficie foliar de Pentacalia lediflora e Pentacalia corymbosa e suas propriedades antifúngicas / New source of quinols, the surface of Pentacalia ledifolia and Pentacalia corymbosa leaves and its antifungal activity

Foi demonstrada a ação antifúngica do extrato clorofórmico e de duas substâncias isoladas da superfície foliar de Pentacalia ledifolia (H.B.K.) Cuatr. e P. corymbosa (Benth) Cuatr. frente aos fungos fitopatógenos Fusarium oxysporum e Botrytis cinerea, cultivados em BDA (batata-dextrose-ágar). Destes extratos foram isolados, além de cumarinas já identificadas em estudos anteriores, dois derivados quinóides: (1-hidroxi-4-oxo-2,5-ciclohexadienil) acetato de metila ou jacaranona e (1-hidroxi-4-oxo-2,5-ciclohexadienil) acetato de etila ou metiljacaranona. Para o (1-hidroxi-4-oxo-2,5-ciclohexadienil) acetato de etila foi calculado CI50 de 650 μg/mL para os dois tipos de fungos e o (1-hidroxi-4-oxo-2,5-ciclohexadienil) acetato de metila teve um CI50 de 660 μg/mL.

Quinols identified in the surface waxes of Pentacalia ledifolia (H.B.K.) Cuatr and P. corymbosa (Benth) Cuatr. leaves, possess antifungal activity against Fusarium oxysporum and Botrytis cinerea, cultured on PDA (potato-dextrose-agar) medium. These extracts were prepared by dipping fresh leaves in chloroform for 5 min, and afforded ethyl-(1-hydroxy-4-oxocyclohexa-2,5-dien-1-yl) acetate and methyl-(1-hydroxy-4-oxocyclohexa-2,5-dien-1-yl) acetate, the major surface compounds.

Efectos citotoxicos in vitro de extractos y fracciones de Espeletia killipii Cuatr. frente a lineas celulares tumorales humanos / Efeitos citotóxicos in vitro de extratos e frações de Espeletia killipii Cuatr. frente a linhas celulares tumorais humanas / In vitro cytotoxic effects of extract and fractions of Espeletia killipii Cuatr. against human tumor cell lines

O extrato etanólico e as frações de Espeletia killipii (espécie endêmica da vegetação dos páramos do altiplano Cundiboyacense); mostraram atividade citotóxica significativa in vitro nas linhagens celulares tumorais humanas de câncer de mama MCF-7, CSC-1170, CSC-1595, CSC-3322, CSC-3325 e na linhagem Hep-2 de laringe. A fração CH2Cl2 e suas sub-frações foram ativas contra as linhagens celulares cancerígenas de mama na concentração de 50 µg/mL, obtendo-se percentagens de viabilidade entre 13 e 20 por cento. O principio ativo ainda não identificado foi obtido por ensaios bioguiados sucessivos e apresentou valores de Concentração Citotóxica media (CC50) menores que 1 µg/mL para as linhagens celulares colombianas CSC-1170, CSC-1595, CSC-3322 e CSC-3325; CC50 = 1 µg/mL contra MDA MB 435 e NCl-H23; contra MCF-7 uma CC50 = 2 µg/mL e uma CC50 superior a 16 µg/mL contra PC-3 e U-251.

It was found that the ethanol extracts and fractions of Espeletia killipii (an endemic species of the páramo vegetation of the Cundiboyacense plateau) exhibited cytotoxic activity against several human tumor cell lines. Thus, the extracts and fractions exhibited significant cytotoxic activity against both the human tumor cell lines of breast cancer MCF-7, CSC-1170, CSC-1595, CSC-3322, CSC-3325 and the Hep-2 cell lines of laryns. The CH2Cl2 fraction and its sub-fractions were active against the breast lines at concentration of 50 µg/mL, with a viability percentage between 13 and 20 percent. The active principle, not identified yet, was obtained by successive bio-directed assays. It showed activity against the Colombian cell lines CSC-1170, CSC-1595, CSC-3322 and CSC-3325 at a half Cytotoxic Concentration (CC50) less than 1 µg/mL, against MDA MB-435 and NCI-H23 at CC50= 1 µg/mL against MCF-7 at CC50= 2 µg/mL, and against PC-3 and U-251 at CC50 greater than 16 µg/mL.

Principio activo citotoxico de Espeletia killipii Cuatr. sobre células tumorales y su toxicidad frente a células normales humanas / Princípio ativo citotóxico de Espeletia killipii Cuatr. sobre células tumorais e sua toxicidade frente a células normais humanas

De Espeletia killipi Cuart. foi isolado uma sesquiterpenlactona identificada como acetato de longipilina que mostrou atividade citotóxica. A citotoxidade foi avaliada em células normais obtidas de sangue periférico, tiróide, testículo e epitélio da boca. Células da medula óssea de pacientes com leucemia crônica mielóide, linfoma de Hodking (do Instituto Nacional de Câncer de Bogotá, Colômbia) e células K562 também foram avaliadas. A citotoxidade foi determinada através do teste MTT (3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl Tetrazolium Bromid). Os ensaios mostraram que a substância não é tóxica para células normais mas a 3 mg/mL apresentou significante atividade em células tumorais e linhagem K562. Conseqüentemente, lavando-se em conta essa significante ação, novas investigações podem ser consideradas plausíveis.

The compound responsible for the citotoxic effect was identified as longipilin acetate, a sesquiterpenelactone isolated from Espeletia killipi Cuatr. Citotoxicity was assessed by using normal cells obtained from peripheral blood, thyroid, testicle and mouth epithelium. Bone marrow cells from patients with chronic myeloid leukemia, Hodking lymphoma (from Cancer National Institute, Bogotá Colombia) and the cell line K562 were also assayed. Citotoxicity was determined by the MTT cell viability test (3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl Tetrazolium Bromid]. The assays revealed that the substance is risk-free on normal cells but at 3 mg/mL has significant activity on tumor cells and K562 cell line. Consequently, taken into account this significant action, new research approaches can be foreseen.

Triterpenos aislados de corteza de Bursera graveolens (Burseraceae) y su actividad biologica

Bursera graveolens (Burseraceae), known in Colombia as "sasafrás", is useful for its medicinal properties and is rich in secondary metabolites. In our research, we carried out antimicrobial tests of several fractions and ethanolic extracts from aerial parts against Bacillus subtilis and Staphylococcus aureus, that showed growth inhibitory activity when applied at 250 mg/mL for extracts and 150 mg/mL for fractions. We carried out an antiinflamatory assay also, that showed 71 por ciento of inhibition by extracts (81 por ciento of Indomethacin) and 70 por ciento of inhibition by fractions (78 por ciento of Indomethacin). Phytochemical investigation of the bark of Bursera graveolens (Burseraceae) yielded three tetracyclic triterpene acids that have oxygenation in C-3, carboxylic acid in C-21 and unsaturation in C-24 and have been identified as 3-oxotirucalla-8,24-dien-21-oic acid (b-elemonic acid), 3a-hydroxytirucalla-8,24-dien-21-oic acid (a-elemolic acid) and 3a-hydroxytirucalla-7,24-dien-21-oic acid. The isolated compounds were identified using spectroscopic methods including one and two-dimensional Nuclear Magnetic Resonance (COSY, HMQC, HMBC, NOESY) experiments and comparison with published data. This is the first report of the isolated compounds in Bursera graveolens and they have a very important chemotaxonomic significance within the Burseraceae family and related families from the order Rutales.