<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0034-7744</journal-id>
<journal-title><![CDATA[Revista de Biología Tropical]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. biol. trop]]></abbrev-journal-title>
<issn>0034-7744</issn>
<publisher>
<publisher-name><![CDATA[Universidad de Costa Rica]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0034-77442011000300011</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Antioxidant and antitopoisomerase activities in plant extracts of some Colombian flora from La Marcada Natural Regional Park]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Niño]]></surname>
<given-names><![CDATA[Jaime]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Correa]]></surname>
<given-names><![CDATA[YanedMilena]]></given-names>
</name>
<xref ref-type="aff" rid="A02"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cardona]]></surname>
<given-names><![CDATA[GermánDavid]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Mosquera]]></surname>
<given-names><![CDATA[Oscar Marino]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad Tecnológica de Pereira Escuela de Tecnología Química Grupo de Biotecnología-Productos Naturales]]></institution>
<addr-line><![CDATA[Pereira ]]></addr-line>
<country>Colombia</country>
</aff>
<aff id="A02">
<institution><![CDATA[,Universidad de Caldas, Manizales , Departamento de Química, Facultad de Ciencias Exactas y Naturales Grupo de Biotecnología-Productos Naturales]]></institution>
<addr-line><![CDATA[Manizales ]]></addr-line>
<country>Colombia</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>09</month>
<year>2011</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>09</month>
<year>2011</year>
</pub-date>
<volume>59</volume>
<numero>3</numero>
<fpage>1089</fpage>
<lpage>1097</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.sa.cr/scielo.php?script=sci_arttext&amp;pid=S0034-77442011000300011&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.sa.cr/scielo.php?script=sci_abstract&amp;pid=S0034-77442011000300011&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.sa.cr/scielo.php?script=sci_pdf&amp;pid=S0034-77442011000300011&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Many plants have been used to treat some diseases and infections since time immemorial, and this potential has been exploited by the pharmaceutical industry in the search of new analgesic, anticarcinogenic and antimicrobial agents, among other active agents. in order to contribute with bioprospection studies on the Colombian flora, 35 extracts from 13 plant species belonging to seven families (Apocynaceae, Cactaceae, Costaceae, Eremolepidaceae, Passifloraceae, Solanaceae and Urticaceae) were collected from La Marcada Natural Regional Park (LMNRP), Colombia. Dichloromethane, n-hexane and aqueous-methanol crude extracts were prepared and evaluated for their activity against Saccharomyces cerevisiae RS322N, R52Y and RS321 strains in the yeast mutant assay and their antioxidant capacity through the DPPH test. The dichloromethane extract from Myriocarpa stipitata (Urticaceae) showed moderate inhibitory activity against the three S. cerevisiae strains tested. The capacity of the dichloromethane extract from M. stipitata to inhibit the enzyme topoisomerase I and to cause DNA damage was inferred from these results. In the DPPH assay, the n-hexane crude extract from Costus sp. (Costaceae) showed good antioxidant activity (48%); in addition, the crude dichloromethane and aqueous-methanol extracts from Rhipsalis micrantha (Cactaceae) showed moderate antioxidant activity with percentage of 29 and 21%, respectively. Rev. Biol. Trop. 59 (3): 1089-1097. Epub 2011 September 01.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Desde tiempos inmemoriales, muchas plantas han sido usadas para el tratamiento de varias enfermedades e infecciones, este potencial ha sido explotado por la industria farmacéutica en la búsqueda de nuevos agentes analgésicos, anticancerígenos y antimicrobianos, entre otros. Consientes con esto, se evaluó la actividad de 35 extractos de 13 especies de plantas recolectadas en el Parque Regional Natural La Marcada (PRNLM, Colombia) contra las cepas mutadas de Saccharomyces cerevisiae RS322N, R52Y y RS321 en el ensayo de la levadura mutada y la capacidad antioxidante de los extractos a través del método del DPPH. El extracto crudo de diclorometano de Myriocarpa stipitata (Urticaceae) presentó actividad moderada contra las tres cepas de S. cerevisiae evaluadas. Lo cual permitió inferir la capacidad del extracto de diclorometano de esta especie para inhibir la enzima topoisomerasa I y causar daño al ADN. Además, en el ensayo del DPPH, el extracto de n-hexano crudo de Costus sp (Costaceae) mostró actividad antioxidante buena (48%), mientras que los extractos de diclorometano y acuoso metanólico crudos de Rhipsalis micrantha (Cactaceae) tuvieron actividad antioxidante moderada, con valores del 29 y 21%, respectivamente.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[DNA damage agent]]></kwd>
<kwd lng="en"><![CDATA[DPPH]]></kwd>
<kwd lng="en"><![CDATA[DNA topoisomerase inhibitors]]></kwd>
<kwd lng="en"><![CDATA[Saccharomyces cerevisiae]]></kwd>
<kwd lng="es"><![CDATA[agentes que dañan el ADN]]></kwd>
<kwd lng="es"><![CDATA[DPPH]]></kwd>
<kwd lng="es"><![CDATA[inhibidores de las ADN topoisomerasas]]></kwd>
<kwd lng="es"><![CDATA[Saccharomyces cerevisiae]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[ <div style="text-align: justify;">     <div style="text-align: center;"><font style="font-weight: bold;"  size="4"><span style="font-family: verdana;">Antioxidant and antitopoisomerase activities in plant extracts of some Colombian flora from La Marcada Natural Regional Park</span></font><br style="font-family: verdana;"> </div> <br style="font-family: verdana;">     <div style="text-align: left;"><font size="2"><span  style="font-family: verdana;">Jaime Ni&ntilde;o<a href="#aut1"><sup>1</sup></a>, Yaned Milena Correa<a href="#aut2"><sup>2</sup></a>, Germ&aacute;n David Cardona<sup><a  href="#aut1">1</a> </sup>&amp; Oscar Marino Mosquera<a href="#aut1"><sup>1</sup></a></span></font><br  style="font-family: verdana;"> <br style="font-family: verdana;"> <font size="2"><span style="font-family: verdana;"><a name="aut1"></a>1. Grupo de Biotecnolog&iacute;a-Productos Naturales, Escuela de Tecnolog&iacute;a Qu&iacute;mica, Universidad Tecnol&oacute;gica de Pereira, Pereira, Colombia;&nbsp; <a href="mailto:janino@utp.edu.co">janino@utp.edu.co</a>, <a href="mailto:paisa2106@hotmail.com">paisa2106@hotmail.com</a>, <a href="mailto:omosquer@utp.edu.co">omosquer@utp.edu.co</a></span></font><br  style="font-family: verdana;"> <font size="2"><span style="font-family: verdana;"><a name="aut2"></a>2. Grupo de Biotecnolog&iacute;a-Productos Naturales, Departamento de Qu&iacute;mica, Facultad de Ciencias Exactas y Naturales, Universidad de Caldas, Manizales, Colombia; <a  href="mailto:yaned.correa@ucaldas.edu.co">yaned.correa@ucaldas.edu.co </a></span></font><br  style="font-family: verdana;"> </div>     <br>     <font size="2"><span style="font-family: verdana;"><a      href="#correspondencia">Direcci&oacute;n     para correspondencia</a></span></font><br style="font-family: verdana;">     <font style="font-weight: bold;" size="3"><span      style="font-family: verdana;"></span></font>     <hr style="width: 100%; height: 2px;"><font style="font-weight: bold;"     ]]></body>
<body><![CDATA[ size="3"><span style="font-family: verdana;">Abstract</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">Many plants have     been used to treat     some diseases and infections since time immemorial, and this potential     has been exploited by the pharmaceutical industry in the search of new     analgesic, anticarcinogenic and antimicrobial agents, among other     active agents. in order to contribute with bioprospection studies on     the Colombian flora, 35 extracts from 13 plant species belonging to     ]]></body>
<body><![CDATA[seven families (Apocynaceae, Cactaceae, Costaceae, Eremolepidaceae,     Passifloraceae, Solanaceae and Urticaceae) were collected from La     Marcada Natural Regional Park (LMNRP), Colombia. Dichloromethane,     <span style="font-style: italic;">n</span>-hexane and aqueous-methanol     crude extracts were prepared and     evaluated for their activity against <span style="font-style: italic;">Saccharomyces</span>     <span style="font-style: italic;">cerevisiae</span> RS322N,     R52Y and RS321 strains in the yeast mutant assay and their antioxidant     capacity through the DPPH test. The dichloromethane extract from<span      style="font-style: italic;">     ]]></body>
<body><![CDATA[Myriocarpa stipitata</span> (Urticaceae) showed moderate inhibitory     activity     against the three<span style="font-style: italic;"> S. cerevisiae</span>     strains tested. The capacity of the     dichloromethane extract from <span style="font-style: italic;">M.     stipitata</span> to inhibit the enzyme     topoisomerase I and to cause DNA damage was inferred from these     results. In the DPPH assay, the <span style="font-style: italic;">n</span>-hexane     crude extract from <span style="font-style: italic;">Costus</span> sp.     (Costaceae) showed good antioxidant activity (48%); in addition, the     ]]></body>
<body><![CDATA[crude dichloromethane and aqueous-methanol extracts from<span      style="font-style: italic;"> Rhipsalis     micrantha</span> (Cactaceae) showed moderate antioxidant activity with     percentage of 29 and 21%, respectively. Rev. Biol. Trop. 59 (3):     1089-1097. Epub 2011 September 01.</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana; font-weight: bold;">     <font size="2"><span style="font-family: verdana;"><span      style="font-weight: bold;">Key words:</span> DNA     damage agent, DPPH,     ]]></body>
<body><![CDATA[DNA topoisomerase inhibitors, <span style="font-style: italic;">Saccharomyces     cerevisiae</span>.</span></font><br style="font-family: verdana;">     <br style="font-family: verdana; font-weight: bold;">     <font style="font-weight: bold;" size="3"><span      style="font-family: verdana;">Resumen</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">Desde tiempos     inmemoriales, muchas     plantas han sido usadas para el tratamiento de varias enfermedades e     ]]></body>
<body><![CDATA[infecciones, este potencial ha sido explotado por la industria     farmac&eacute;utica en la b&uacute;squeda de nuevos agentes     analg&eacute;sicos, anticancer&iacute;genos y antimicrobianos, entre     otros. Consientes con esto, se evalu&oacute; la actividad de 35     extractos de 13 especies de plantas recolectadas en el Parque Regional     Natural La Marcada (PRNLM, Colombia) contra las cepas mutadas de     <span style="font-style: italic;">Saccharomyces cerevisiae</span>     RS322N, R52Y y RS321 en el ensayo de la     levadura mutada y la capacidad antioxidante de los extractos a     trav&eacute;s del m&eacute;todo del DPPH. El extracto crudo de     ]]></body>
<body><![CDATA[diclorometano de <span style="font-style: italic;">Myriocarpa stipitata</span>     (Urticaceae) present&oacute;     actividad moderada contra las tres cepas de <span      style="font-style: italic;">S. cerevisiae</span> evaluadas. Lo     cual permiti&oacute; inferir la capacidad del extracto de diclorometano     de esta especie para inhibir la enzima topoisomerasa I y causar     da&ntilde;o al ADN. Adem&aacute;s, en el ensayo del DPPH, el extracto     de <span style="font-style: italic;">n</span>-hexano crudo de <span      style="font-style: italic;">Costus</span> sp (Costaceae) mostr&oacute;     actividad     ]]></body>
<body><![CDATA[antioxidante buena (48%), mientras que los extractos de diclorometano y     acuoso metan&oacute;lico crudos de <span style="font-style: italic;">Rhipsalis     micrantha </span>(Cactaceae)     tuvieron actividad antioxidante moderada, con valores del 29 y 21%,     respectivamente. </span></font><br style="font-family: verdana;">     <br style="font-family: verdana; font-weight: bold;">     <font size="2"><span style="font-family: verdana;"><span      style="font-weight: bold;">Palabras clave:</span>     agentes que     da&ntilde;an el ADN, DPPH, inhibidores de las ADN topoisomerasas,     ]]></body>
<body><![CDATA[<span style="font-style: italic;">Saccharomyces cerevisiae</span>.</span></font><br      style="font-family: verdana;">     <hr style="width: 100%; height: 2px;"><font size="2"><span      style="font-family: verdana;">Many bioactive     compounds and their     derivatives have been shown to inhibit carcinogenesis in a number of     experimental systems involving initiation, promotion and progression     steps of this disease. Therefore, the discovery of novel naturally     occurring anticarcinogens which would prevent, slow down and/ or     reverse cancer induction and its subsequent development are of     ]]></body>
<body><![CDATA[paramount importance to produce new effective medicines&nbsp;     (Rajeshkumar <span style="font-style: italic;">et al</span>. 2002).</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">DNA topoisomerases     play important     functions in transmission and expression of genetic information,     because these enzymes carry out critical roles in DNA replication,     transcription and recombination, as well as chromosome condensation and     segregation (Colley <span style="font-style: italic;">et al</span>.     ]]></body>
<body><![CDATA[2004). Two major classes of topoisomerase     enzymes have been identified, type I and type II. The former one     introduces one break, while the last type produces transient double     strand breaks in DNA (Dong <span style="font-style: italic;">et al</span>.     2000). Topoisomerase inhibitors     constitute a class of chemopreventive agents that hamper carcinogenesis     via their antiproliferative or cell-differentiating action     (Ramirez-Mares <span style="font-style: italic;">et al</span>. 2004).     Antitopoisomerase drugs bind and stabilize     the complex (DNA Topoisomerase) and the enzyme cannot relax (Zhang     ]]></body>
<body><![CDATA[&amp; Siede 2003). in this manner, several studies have shown the     usefulness of the yeast <span style="font-style: italic;">Saccharomyces     cerevisiae</span> Meyen ex E.C. Hansen     as a model organism for characterization and screening of anticancer     drugs with inhibitory properties against topoisomerases I and II (Simon     <span style="font-style: italic;">et al</span>. 2000, Ni&ntilde;o <span      style="font-style: italic;">et al</span>. 2007).</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">On the other hand,     ]]></body>
<body><![CDATA[in living     organisms the reactive oxygen species (ROS) and reactive nitrogen     species (RNS) are known to cause damage to lipids, proteins, enzymes     and nucleic acids leading to cell or tissue injury, implicated in the     processes of aging as well as in a wide range of degenerative diseases     including inflammation, cancer, atherosclerosis, diabetes, liver     injury, Alzheimer, Parkinson and coronary heart pathologies, among     others (Moon &amp; Shibamoto 2009). However, cells have defence systems     to protect and keep their cellular constituents in the right redox     state; this includes two different pathways: enzymatic and non     ]]></body>
<body><![CDATA[enzymatic ones. The former one includes enzymatic systems such as the     superoxide dismutase, catalase, glutathione peroxidase, glutathione     reductase and glutathione-S-transferase. <span      style="font-style: italic;">In vivo</span>, these antioxidant     enzymes should have the proper equilibrium to reduce and to prevent ROS     and RNS species generation within the cells and to protect cellular     constituents from oxidative damage (Gasparri 2005). The non enzymatic     one includes small antioxidant molecules like ascorbate, chlorogenic     acids, polyunsaturated fatty acids, sugars and vitamin E, among others     (Reddy <span style="font-style: italic;">et al</span>. 2008).</span></font><br     ]]></body>
<body><![CDATA[ style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">Continuing with the     bioprospection     study on the flora from La Marcada Natural Regional Park (LMNRP,     Risaralda, Colombia) as a source of new secondary metabolites with     diverse grade of biological activities and taking in consideration the     fact that there is still great interest in finding novel and better     inhibitory agents against topoisomerases or with antioxidant     activities, prompted us to screen <span style="font-style: italic;">n</span>-hexane,     ]]></body>
<body><![CDATA[dichloromethane and     aqueous- methanol crude extracts belonging to the selected families     collected to study these activities.</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana; font-weight: bold;">     <font style="font-weight: bold;" size="3"><span      style="font-family: verdana;">Material and methods</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;"><span     ]]></body>
<body><![CDATA[ style="font-weight: bold;">Plant material:</span> The     adult aerial     plant samples (leaves and branches) used for this study were collected     in June-July 2005 in La Marcada Natural Regional Park (LMNRP, Colombia)     with an altitudinal range between 1 600-2 000m.a.s.l., a temperature     variation between 16-22&deg;C and an average rainfall of 2 464mm/year.     The plants were identified taxonomically by Dr. F.J. Rold&aacute;n and     a voucher specimen for each plant material was deposited at the     University of Antioquia Herbarium, Medell&iacute;n, Colombia (<a      href="/img/revistas/rbt/v59n3/a11t1.gif">Table 1</a>).</span></font><br     ]]></body>
<body><![CDATA[ style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">Plant samples (<a      href="/img/revistas/rbt/v59n3/a11t1.gif">Table     1</a>) were oven     dried at 50&deg;C for 48h, the dry materials were ground to a fine     powder and aliquots of 300g were extracted by maceration with 900mL of     methanol (three times each). Then, the solvent was pulled out and     concentrated to dryness in a rotary evaporator at 45&ordm;C. A total of     25g of each concentrated methanol extract was dissolved in 100mL of a     ]]></body>
<body><![CDATA[mixture of methanolwater (2:8) and were successively partitioned with     300mL of <span style="font-style: italic;">n</span>-hexane and     dichloromethane to obtain the <span style="font-style: italic;">n</span>-hexane,     dichloromethane and aqueous-methanol extracts, for each plant. The     different extracts were concentrated to dryness at reduce pressure and     stored at -10&deg;C until assayed.</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">In this study, the     solvents     ]]></body>
<body><![CDATA[<span style="font-style: italic;">n</span>-hexane, dichloromethane,     dimethylsulfoxid (DMSO), methanol and     ethanol (analytical grade) were purchased from Mallinckrodt     (Phillipsburg, NJ, USA). 1,1-diphenyl-2-picrylhydrazyl (DPPH),     Nystatine and D-glucose were obtained from Sigma-Aldrich (St. Louis,     MO, USA). Yeast extract, peptone and agar were acquired from Oxoid     (Basingtoke, United Kingdom). Silica gel plates (F<sub>254</sub> 0.2mm     layer     thickness) were purchased from Merck (Darmstadt, Germany).</span></font><br      style="font-family: verdana;">     ]]></body>
<body><![CDATA[<br style="font-family: verdana; font-weight: bold;">     <font size="2"><span style="font-family: verdana;"><span      style="font-weight: bold;">Yeast mutant     bioassay:</span> The     bioactivity of the crude plant extracts against <span      style="font-style: italic;">Saccharomyces     cerevisiae</span> was determined by the well diffusion method according     to     R&iacute;os <span style="font-style: italic;">et al</span>. (1988). <span      style="font-style: italic;">S. cerevisiae</span> mutant strains     ]]></body>
<body><![CDATA[RS322N, R52Y     and RS321 were supplied by Dr. David G.I. Kingston and were used for     the topoisomerase assay. <span style="font-style: italic;">S.     cerevisiae </span>strains were cultured in     erlenmeyers containing YPD broth. Each microorganism was diluted with a     sodium chloride isotonic solution to obtain 25% of transmittance     (optical density at 600nm). One milliliter of this microorganism     suspension was thoroughly mixed with 20mL of sterile YPD agar in each     Petri dish.</span></font><br style="font-family: verdana;">     <br style="font-family: verdana;">     ]]></body>
<body><![CDATA[<font size="2"><span style="font-family: verdana;">After     solidification, seven wells     (6.0mm diameter each) were made in each plate under sterile conditions.     Each well was filled with 20<span style="font-style: italic;">&micro;</span>L     of each one of the five different     concentrations tested (4 000, 2 000, 1 000, 500 and 250mg/L) for each     plant extract. A volume of 20<span style="font-style: italic;">&micro;</span>L     of nystatin at 30, 150, 40mg/L     for RS322N, R52Y and RS321 strains, were used as positive control,     respectively; 20<span     ]]></body>
<body><![CDATA[ style="text-decoration: underline; font-style: italic;">&micro;</span>L     of DMSOEtOH- H<sub>2</sub>O (1:1:2) (for no-polar     extracts) and EtOH-H<sub>2</sub>O (1:4) (for polar extracts) were used     as negative     controls. All plates were incubated at 30&deg;C for 24h. Inhibition     zone diameters around each well were measured and recorded at the end     of the incubation time. All determinations were performed in triplicate     with two replicates, and the mean standard deviations (&plusmn;SD) were     obtained with these values. Activity was determined from a dose to     response curve and is reported as IC<sub>12</sub>(<span     ]]></body>
<body><![CDATA[ style="font-style: italic;">&micro;</span>g/mL) values, which is     the concentration required for an extract to produce an inhibition zone     of 12mm in diameter, around each 6.0mm diameter well in this bioassay     (Gunatilaka &amp; Kingston 1998).</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">In this bioassay, an     extract is     considered active if it displays selective activity against one or more     repair deficient yeast. For instance, an agent that displays greater     ]]></body>
<body><![CDATA[activity against RS321 rather than to RS322N, with an IC<sub>12</sub>     less than     one third between both yeast strains and in general if they exhibit an     IC<sub>12</sub> less than 2 000, most probably mediates its inhibitory     activity     through topoisomerase II. Conversely, greater activity against RS322N     implies an inhibitory DNA topoisomerase I mechanism (Gunatilaka &amp;     Kingston 1998, Zhou <span style="font-style: italic;">et al</span>.     2000).</span></font><br style="font-family: verdana;">     <br style="font-family: verdana; font-weight: bold;">     ]]></body>
<body><![CDATA[<font size="2"><span style="font-family: verdana;"><span      style="font-weight: bold;">Antioxidant     activity: </span>The     antioxidant activities were measured through the DPPH radical     scavenging activity by the method of Brand-Williams <span      style="font-style: italic;">et al</span>. (1995), with     minor modifications; for example, the <span style="font-style: italic;">n</span>-hexane,     dichloromethane and     aqueous-methanol extracts were dissolved in the same mixtures used in     the yeast mutant assay and they were also used as blank in the DPPH     ]]></body>
<body><![CDATA[assay (A<sub>517 Blank</sub>). All plant extracts were evaluated at     250mg/L by     mixing 0.75mL of each one with 1.5mL of a freshly prepared DPPH     solution (20mg/L) and stood for 20 minutes under light protection at     room temperature (A<sub>517 Sample</sub>). Then, the absorbances were     measured at     517nm and the percentage of DPPH radical scavenging activity for each     plant extract was calculated by applying the equation: (1%)=(A<sub>517     Blank</sub>-A<sub>517 Sample</sub>)/ A<sub>517 Blank</sub>)x100. Each     assay was performed in     ]]></body>
<body><![CDATA[triplicate with two replicates in different times. With these values     the mean standard deviations (&plusmn;SD) were calculated.</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;"><span      style="font-weight: bold;">Phytochemical     screening:</span> For each     plant extract a phytochemical screening was performed testing the     presence of secondary metabolites by using TLC analysis. The solvent     systems n-hexane-ethyl acetate (6:4) was used for development of     ]]></body>
<body><![CDATA[<span style="font-style: italic;">n</span>-hexane extracts; while,     ethyl acetate- methanol-water (100:13.5:10)     was used for elution of dichloromethane and the aqueous-methanol     extracts, respectively. The following spray reagents Dragendorff,     anisaldehyde-sulphuric acid, 1% vanillin in sulphuric acid-ethanol, 2%     aluminium chloride in ethanol, 1% ferric chloride, and     hydroxylamine-ferric chloride were used as chromogenic agents for     alkaloids, sterols, saponins, flavonoids, tannins and lactones,     respectively </span></font><font size="2"><span      style="font-family: verdana;">(Wagner &amp; Bladt     ]]></body>
<body><![CDATA[1996). All     determinations were done in duplicates.</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font style="font-weight: bold;" size="3"><span      style="font-family: verdana;">Results</span></font><br      style="font-family: verdana; font-weight: bold;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;"><span      style="font-weight: bold;">Yeast mutant     ]]></body>
<body><![CDATA[bioassay:</span> A total of     35 different crude plant extracts (<span style="font-style: italic;">n</span>-hexane,     dichloromethane and     aqueous-methanol) were screened for their activity against<span      style="font-style: italic;"> S.     cerevisiae</span> strains in the yeast mutant assay. The results are     shown in     <a href="/img/revistas/rbt/v59n3/a11t1.gif">Table 1</a>. The     dichloromethane extracts from <span style="font-style: italic;">Myriocarpa     stipitata</span> Benth.     ]]></body>
<body><![CDATA[(Urticaceae) was the only one that showed moderate topoisomerase I     activity.</span></font><br style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;"><span      style="font-weight: bold;">Phytochemical     screening:</span> The     phytochemical screening of the <span style="font-style: italic;">n</span>-hexane,     dichloromethane and     aqueous-methanol extracts showed the presence of different types of     secondary metabolites, namely saponins, tannins, flavonoids and     ]]></body>
<body><![CDATA[terpenes (<a href="/img/revistas/rbt/v59n3/a11t2.gif">Table 2</a>).     These phytocompounds were present in almost all the     extracts tested. However, <span style="font-style: italic;">M.     stipitata</span> (Urticaceae) extracts did not     show evidence of flavonoids and <span style="font-style: italic;">Costus</span>     sp. (Costaceae) did not display     the presence of tannins neither lactones (<a      href="/img/revistas/rbt/v59n3/a11t2.gif">Table 2</a>).</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana; font-weight: bold;">     ]]></body>
<body><![CDATA[<font size="2"><span style="font-family: verdana;"><span      style="font-weight: bold;">Antioxidant     activity:</span> <a href="/img/revistas/rbt/v59n3/a11t3.gif">Table 3</a>     shows     the percentage of antioxidant activity from the plant extracts studied.     The aqueous-methanol extracts were the most effective in the DPPH     assay. But, the <span style="font-style: italic;">n</span>-hexane     extract of <span style="font-style: italic;">Costus </span>sp.     exhibited the highest     percentage (48%) of antioxidant activity while hydroquinone (the     ]]></body>
<body><![CDATA[positive control) showed a percentage of 26%. </span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font style="font-weight: bold;" size="3"><span      style="font-family: verdana;">Discussion</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">Since the crude     dichloromethane     extract from <span style="font-style: italic;">M. stipitata</span>     ]]></body>
<body><![CDATA[(Urticaceae) showed an IC<sub>12</sub> against the     RS322N strain (835&plusmn;4&#956;g/mL) rather than to RS321 strain (1     306&plusmn;3&#956;g/mL), this implies that this plant extracts showed     moderate DNA topoisomerase I inhibitory activity; the other plant     extracts did not show any DNA topoisomerase I or II inhibitory activity     at all. The last results correlate for instance, with the extract of     some Cactaceae species (<span style="font-style: italic;">Rhipsalis     baccifera</span> (Mill.) Stearn and     <span style="font-style: italic;">Rhipsalis mesembryanthemoides</span>     Steud.) that were not active against any     ]]></body>
<body><![CDATA[of <span style="font-style: italic;">S. cerevisiae</span> strains     assayed (Valente <span style="font-style: italic;">et al</span>. 2007).</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">The result with <span      style="font-style: italic;">M.     stipitata</span> is in     concordance with those found for the antineoplastic activity from     B<span style="font-style: italic;">oehmeria siamensis</span> Craib     (Urticaceae), because both plants contain     ]]></body>
<body><![CDATA[alkaloid. From<span style="font-style: italic;"> B. siamensis</span>     has been isolated the     phenanthroquinolizidine type alkaloids boehmeriasin A and B, and the     latter one showed antitumor activity as evidenced by an <span      style="font-style: italic;">in vitro</span>     bioassay (Luo <span style="font-style: italic;">et al</span>. 2003,     Yan <span style="font-style: italic;">et al</span>. 2006). According     to the     phytochemical screening (<a href="/img/revistas/rbt/v59n3/a11t2.gif">Table     2</a>), it can be deduced that the     ]]></body>
<body><![CDATA[biological activity showed by the crude dichloromethane extract from <span      style="font-style: italic;">M.     stipitata</span> could be attributed to phytocompounds such as alkaloid     or     saponin present on this extract. The relevance of DNA topoisomerase I     inhibitory activity displayed by <span style="font-style: italic;">M.     stipitata</span> extract is based on the     fact that there are not reports on the phytocompounds neither on the     biological activity for this species or genus in the yeast mutant assay     (Dyer <span style="font-style: italic;">et al</span>. 2003).</span></font><br     ]]></body>
<body><![CDATA[ style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">Furthermore, these     results on the     DPPH assay suggest that the <span style="font-style: italic;">n</span>-hexane     extract from <span style="font-style: italic;">Costus</span> sp. is a     powerful natural antioxidant and according to the phytochemical     screening this activity could be explained based on its saponin     contents. From <span style="font-style: italic;">Costus speciosus</span>     SM. and <span style="font-style: italic;">Costus spicatus</span> Sw.     ]]></body>
<body><![CDATA[(Costaceae)     there has been isolated a series of furostanol saponins (Sigh &amp;     Thakur 1982, Da Silva <span style="font-style: italic;">et al</span>.     1999) which could explain their <span style="font-style: italic;">in     vitro</span>     antioxidant activity.</span></font><br style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">Recently, interest     has increased     considerably in finding saponins with antioxidant properties. They have     ]]></body>
<body><![CDATA[been described as antioxidant agents against free radical mediated     cellular damage (Somova <span style="font-style: italic;">et al</span>.     2003, Garcez et al. 2006, Dini <span style="font-style: italic;">et al</span>.     2009), inhibitors of membrane lipid peroxidation (Yoshiki <span      style="font-style: italic;">et al</span>. 1996,     Keum <span style="font-style: italic;">et al.</span> 2000) and     protection against low density lipoproteins     oxidation (Li <span style="font-style: italic;">et al</span>. 2008).</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     ]]></body>
<body><![CDATA[<font size="2"><span style="font-family: verdana;">In addition, the     antioxidant     activity of <span style="font-style: italic;">Rhipsalis micrantha</span>     DC (Cactaceae) correlates well with the     antioxidant activities of<span style="font-style: italic;"> Opuntia     ficus-indica</span> (L.) Mill.; however, in     the last species this activity could be explained based on its     flavonoid contents such as quercetin and myricetin present in their     extracts (Lee <span style="font-style: italic;">et al</span>. 2002);     while in the former one this activity could     ]]></body>
<body><![CDATA[not be explained based on its flavonoids contents, since in our     phytochemical screening this type of phytocompounds were not detected.</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">On the other hand,     the     aqueous-methanol extract from <span style="font-style: italic;">Mandevilla     veraguensis</span> Hemsl.     (Apocynaceae) showed a moderate percentage of antioxidant activity.     This result is in concordance with the rate and the antioxidant     ]]></body>
<body><![CDATA[activity displayed by <span style="font-style: italic;">Holarrhena     pubescens</span> Wall. (Apocynaceae) in the     total antioxidant <span style="font-style: italic;">in vitro</span>     assay (Palasuwan <span style="font-style: italic;">et al</span>.     2005), and with a     moderate antioxidant activity of aqueous extract from <span      style="font-style: italic;">Mandevilla     pentlandiana</span> (A.DC) Woodson (Borneo <span      style="font-style: italic;">et al</span>. 2009); furthermore,     <span style="font-style: italic;">Rauvolfia sellowii </span>M&uuml;ll.     ]]></body>
<body><![CDATA[Arg. (Apocynaceae) also displayed good     scavenging activity in the DPPH test (Menezes <span      style="font-style: italic;">et al</span>. 2004). Moreover,     the aqueous-methanol extract from<span style="font-style: italic;">     Solanum aturense</span> Humb. &amp; Bonpl.     Ex Dunal (Solanaceae) also showed a moderate percentage of antioxidant     activity and this result correlates with the high antioxidant activity     exhibited by the methanol extracts of <span style="font-style: italic;">Solanum     nigrum </span>L. fruits in the     DPPH assay (Al-Fatimi <span style="font-style: italic;">et al</span>.     ]]></body>
<body><![CDATA[2007).</span></font><br style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">Our results suggest     that the crude     dichloromethane extracts from <span style="font-style: italic;">Myriocarpa     stipitata</span> (Urticaceae) and     <span style="font-style: italic;">Rhipsalis micrantha</span>     (Cactaceae), as well as the <span style="font-style: italic;">n</span>-hexane     extract from     <span style="font-style: italic;">Costus</span> sp. (Costaceae) showed     ]]></body>
<body><![CDATA[good bioactivity that provide evidence     related to the potentiality from the LMNRP flora in the search for     novel antioxidant compounds. In addition, the fact that the     dichloromethane extract from <span style="font-style: italic;">M.     stipitata</span> (Urticaceae) displayed     topoisomerase I inhibition is a good argument in the search of     anticarcinogenic agents from plant sources. Further research is needed     to isolate the compounds responsible for these biological activities. </span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     ]]></body>
<body><![CDATA[<font style="font-weight: bold;" size="3"><span      style="font-family: verdana;">Acknowledgments</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">The authors would     like to thank the     Universidad Tecnol&oacute;gica de Pereira for the financial support to     the project, and to the Corporaci&oacute;n Aut&oacute;noma Regional de     Risaralda (CARDER) for granting permission to access plant collection.     The authors also wish to thank to D.G.I. Kingston, of the Chemistry     ]]></body>
<body><![CDATA[Department, Virginia Polytechnic institute and State University (VA,     USA) for providing the yeast strains used in this work.<br      style="font-family: verdana;">     </span></font>     <hr style="width: 100%; height: 2px;"><font style="font-weight: bold;"      size="3"><span style="font-family: verdana;">References</span></font><br      style="font-family: verdana;">     <br style="font-family: verdana;">     <font size="2"><span style="font-family: verdana;">Al-Fatimi, M., M.     Wurster, G.     ]]></body>
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Corrected 06-II-2011. Accepted 04-II-2011.</span></font></div> </div>      ]]></body><back>
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