Antifungal activity against anthracnose-causing species of homopterocarpin derivatives.

Derivatives of 3,9-dimethoxypterocarpan (1, homopterocarpin) were prepared by nitration, amination, and oxidation reactions, among others, and their antifungal activity was evaluated against the phytopathogenic fungi Colletotrichum gloeosporioides and C. lindemuthianum. Derivatives were purified by chromatographic techniques and identified by nuclear magnetic resonance spectroscopy. Eight derivatives were obtained from 1 corresponding to 3,9-dimethoxy-8-nitropterocarpan (2), 3,9-dimethoxy-2,8-dinitropterocarpan (3), 3,9-dimethoxy-2,8,10-trinitropterocarpan (4), 2,8-diamino-3,9-dimethoxypterocarpan (5), 3,9-dimethylcoumestan (6), medicarpin (7), 2'-hydroxy-4-(2-hydroxyethylsulfanyl)-7,4'-dimethoxyisoflavan (8), and 4-(2-hydroxyethylsulfanyl)-7,2',4'-trimethoxyisoflavan (9). The in vitro antifungal activity of the derivatives was determined at concentrations between 35 and 704 µM. Compounds 7 and 8 at 704 µM, showed an inhibition of radial growth and spore germination close to 100%, exceeding that found for the starting compound 1, which was 46%. Growth inhibition assays were also performed for the derivative 8 on papaya fruits (Carica papaya L. cv. Hawaiana) and mango (Mangifera indica L. cv. Hilacha) infected with C. gloeosporioides. Compound 8 showed fungal growth inhibition in fruits higher than that found for 1 and thymol (a recognized natural antifungal), under the same conditions. In general, derivatives that exhibited greater antifungal activity correspond to the compounds containing hydroxyl groups in the structure. Some of the compounds obtained could be considered promising for the control of phytopathogenic fungi.

Screening of Indanoyl-Type Compounds as Elicitors of Isoflavonoid Phytoalexins in Colombian Common Bean Cultivars.

Eleven indanoyl derivatives were synthesized and, along with methyl jasmonate, evaluated as isoflavonoid-phytoalexin elicitors in two cultivars of common bean (Phaseolus vulgaris L. cvs. ICA-Cerinza and Uribe Rosado, tolerant and susceptible to anthracnose, respectively). Indanoyl derivatives (an ester, two amides, and eight indanoyl-amino acid conjugates) were obtained from 1-oxo-indane-4-carboxylic acid. In general, the accumulation of isoflavonoid-type phytoalexins, such as isoflavones (genistein, daidzein, and 2'-hydroxygenistein), isoflavanones (dalbergioidin and kievitone), isoflavan (phaseollinisoflavan), coumestrol, and pterocarpans (phaseollidin and phaseollin), was dependent on the common bean cultivar, the post-induction time, and the elicitor structure. Isoflavones, dalbergioidin, and coumestrol reached their highest amounts during the first 48 to 72 h, whereas kievitone, phaseollinisoflavano, and the pterocarpans reached maximum levels between 72 and 96 h. The 1-oxo-indanoyl-L-isoleucine methyl ester elicited the highest levels of phytoalexins (similar to those elicited by the methyl jasmonate) and showed no significant phytotoxic effects on common bean seedlings. The indanoyl-type synthetic elicitor, 1-oxo-indanoyl-L-isoleucine methyl ester, may represent a promising agronomic alternative for disease control in common bean by enhancing the accumulation of antimicrobial isoflavonoid phytoalexins.

Elicitation of isoflavonoids in Colombian edible legume plants with jasmonates and structurally related compounds.

Common bean (Phaseolus vulgaris L.), soybean (Glycine max L.) and mung bean (Vigna radiata L. Wilczek) seedlings were treated with methyl jasmonate (MeJA); then, dose-response and time-course experiments were carried out. Isoflavonoid composition was evaluated by high performance liquid chromatography. As a result of MeJA induction, all leguminous plants increase the amount of isoflavonoids, at levels that depend on the concentration of the elicitor and the time after induction. However, the application of MeJA in concentrations higher than 2.22 mM showed deleterious effects on seedlings and strong decreases in the concentration of isoflavonoids. In addition, a series of compounds structurally related to MeJA, such as jasmonic acid, cis-jasmone, coronatine, and indanoyl derivatives, were evaluated as elicitors. The results show that coronatine and the indanoyl-amino acids conjugates displayed a significant elicitor effect of isoflavonoids in common bean (cvs. Cargamanto Mocho and Corpoica LAS 106) and soybean (cv. Soyica P-34) seedlings, even higher than that found with the recognized elicitors, benzo (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester (acibenzolar S-methyl) and benzo-(1,2,3) thiadiazole-7-carbothioic acid (acibenzolar acid). Leguminous plants can be treated with jasmonates and indanoyl derivatives to increase levels of bioactive isoflavonoids and consequently improve biological and functional properties and resistance against pests.

Coumaro-chalcones synthesized under solvent-free conditions as potential agents against malaria, leishmania and trypanosomiasis.

Leishmaniasis, trypanosomiasis, and malaria are a group of neglected tropical diseases present in tropical regions and they affect large numbers of people in developing countries. A series of thirteen coumaro-chalcones (A1-A13) were synthesized under solvent-free conditions and their in vitro anti-leishmanial, anti-plasmodial, anti-trypanosomal and cytotoxic activities were evaluated. One of these coumaro-chalcones, 3-[(2E)-3-(3-ethoxy-4-hydroxyphenyl)prop-2-enoyl]-2H-chromen-2-one (A12), is a new compound. Compounds 3-[(2E)-3-(3-hydroxyphenyl)prop-2-enoyl]-2H-chromen-2-one (A5), 3-[(2E)-3-(3-methoxyphenyl)prop-2-enoyl]-2H-chromen-2-one (A2) and 3-[(2E)-3-phenylprop-2-enoyl]-2H-chromen-2-one (A1) displayed strong inhibition against intracellular amastigotes of Leishmania panamensis with EC50 of 2.1 ± 0.1, 2.5 ± 0.2 and 3.7 ± 0.5 µM, respectively. In addition, Plasmodium falciparum was moderately inhibited by the coumarin-chalcone hybrids, particularly A12 (EC50: 15.0 ± 0.5 µM) and 3-[(2E)-3-(1,3-benzodioxol-5-yl)prop-2-enoyl]-2H-chromen-2-one (A13) (EC50: 15.2 ± 1.1 µM). Remarkably, the coumaro-chalcone A5 (EC50: 18.7 ± 2.4 µM) exhibited an inhibition of the Trypanosoma cruzi intracellular amastigotes similar to the commercial drug Benznidazole (EC50: 14.5 ± 0.1 µM). These results support the therapeutic potential of coumaro-chalcone hybrids.

Increased accumulation of isoflavonoids in common bean (Phaseolus vulgaris L.) tissues treated with 1-oxo-indane-4-carboxylic acid derivatives.

Isoflavonoid phytoalexins (isoflavones: genistein, 2'-hydroxygenistein, and daidzein; isoflavanones: dalbergioidin and kievitone; coumestrol; pterocarpans: phaseollidin and phaseollin; and the isoflavan: phaseollinisoflavan) production in response to the application of eleven 1-oxo-indane-4-carboxylic acid derivatives (indanoyl esters and indanoyl amino acids conjugates), in cotyledons and hypocotyl/root of two common bean (Phaseolus vulgaris L.) cultivars was evaluated. The content of isoflavonoids depended on the cultivar, the treated tissue, the time after induction, the structure and concentration of the elicitor. The highest isoflavonoid contents were found when 1-oxo-indanoyl-amino acids conjugates were used as elicitors. Cotyledons and hypocotyl/root of the anthracnose-resistant cultivar produced significantly higher isoflavonoid contents as compared to the susceptible one. Maximum levels of phaseollin were obtained using 0.66 mM 1-oxo-indanoyl-l-isoleucyl methyl ester and between 72 and 96 h post-induction. So, 1-oxo-indane-4-carboxylic acid derivatives, may be used to enhance the amount of isoflavonoid phytoalexins in common bean and protect crops from phytopathogenic microorganisms.

Mode of action of a formulation containing hydrazones and saponins against leishmania spp. Role in mitochondria, proteases and reinfection process.

Toxicity and poor adherence to treatment that favors the generation of resistance in the Leishmania parasites highlight the need to develop better alternatives. Here, we evaluated the in vitro effectiveness of hydrazone derived from chromanes 2-(2,3-dihydro-4H-1-benzothiopyran-4-ylidene) hydrazide (TC1) and 2-(2,3-dihydro-4H-1-benzopyran-4-ylidene) hydrazide (TC2) and the mixture of triterpene saponin hederagenin-3-O-(3,4-O-diacetyl-ß-D-xylopyranosyl-(1à3)-a-L- rhamnopyranosyl-(1à2)-a-L-arabinofuranoside, hederagenin-3-O-(3,4-O-diacetyl-a-L- arabinopyranosyl-(1à3)-a-L-rhamnopyranosyl-(1à2)-a-L-arabinofuranoside and, hederagenin-3-O-(4-O-acetyl-ß-D-xylopyranosyl-(1à3)-a-L-rhamnopyranosyl-(1à2)-a-L-arabinofuranoside from Sapindus saponaria (SS) on L. braziliensis and L. pifanoi. Mixtures of TC1 or TC2 with saponin were formulated for topical application and the therapeutic effectiveness was evaluated in the model for cutaneous leishmaniasis (CL) in golden hamster. The mode of action of these compounds was tested on various parasite processes and ultrastructural parasite modifications. TC1, TC2 and SS showed moderate cytotoxicity when tested independently but toxicity was improved when tested in combination. The compounds were more active against intracellular Leishmania amastigotes. In vivo studies showed that combinations of TC1 or TC2 with SS in 1:1 ratio (w/w) cured 100% of hamsters with no signs associated with toxicity. The compounds did cause changes in the mitochondrial activity of the parasite with a decrease in ATP levels and depolarization of membrane potential and overproduction of reactive oxygen species; nevertheless, these effects were not related to alterations in membrane permeability. The phagolysosome ultrastructure was also affected impacting the survival of Leishmania but the function of the lysosome nor the pH inside the phagolysosome did not change. Lastly, there was a protease inhibition which was directly related to the decrease in the ability of Leishmania to infect and multiply inside the macrophage. The results suggest that the combination of TC1 and TC2 with SS in a 1:1 ratio is capable of curing CL in hamsters. This effect may be due to the ability of these compounds to affect parasite survival and the ability to infect new cells.

In vitro and in silico anti-dengue activity of compounds obtained from Psidium guajava through bioprospecting.

BACKGROUND: For decades, bioprospecting has proven to be useful for the identification of compounds with pharmacological potential. Considering the great diversity of Colombian plants and the serious worldwide public health problem of dengue-a disease caused by the dengue virus (DENV)-in the present study, we evaluated the anti-DENV effects of 12 ethanolic extracts derived from plants collected in the Colombian Caribbean coast, and 5 fractions and 5 compounds derived from Psidium guajava. METHODS: The cytotoxicity and antiviral effect of 12 ethanolic extracts derived from plants collected in the Colombian Caribbean coast was evaluated in epithelial VERO cells. Five fractions were obtained by open column chromatography from the ethanolic extract with the highest selectivity index (SI) (derived from P. guajava, SI: 128.2). From the fraction with the highest selectivity (Pg-YP-I-22C, SI: 35.5), five compounds were identified by one- and two-dimensional nuclear magnetic resonance spectroscopy. The antiviral effect in vitro of the fractions and compounds was evaluated by different experimental strategies (Pre- and post-treatment) using non-toxic concentrations calculated by MTT method. The DENV inhibition was evaluated by plate focus assay. The results were analyzed by means of statistical analysis using Student's t-test. Finally the antiviral effect in Silico was evaluated by molecular docking. RESULTS: In vitro evaluation of these compounds showed that three of them (gallic acid, quercetin, and catechin) were promising antivirals as they inhibit the production of infectious viral particles via different experimental strategies, with the best antiviral being catechin (100% inhibition with a pre-treatment strategy and 91.8% with a post-treatment strategy). When testing the interactions of these compounds with the viral envelope protein in silico by docking, only naringin and hesperidin had better scores than the theoretical threshold of - 7.0 kcal/mol (- 8.0 kcal/mol and - 8.2 kcal/mol, respectively). All ligands tested except gallic acid showed higher affinity to the NS5 protein than the theoretical threshold. CONCLUSION: Even though bioprospecting has recently been replaced by more targeted tools for identifying compounds with pharmacological potential, our results show it is still useful for this purpose. Additionally, combining in vitro and in silico evaluations allowed us to identify promising antivirals as well as their possible mechanisms of action.

Antileishmanial activity and cytotoxicity of ent-beyerene diterpenoids.

We describe the in vitro activity of two natural isomeric ent-beyerene diterpenes, several derivatives and synthetic intermediates. Beyerenols 1 and 2 showed EC50 of 4.6 ±â€¯9.4 and 5.3 ±â€¯9.4 µg/mL against amastigotes of L. (V) brazilensis, with SI of 5.1 and 7.7, respectively. Beyerenol 1 was synthesized from stevioside. In vivo experiments with bereyenols showed cure in 50% of hamsters infected with L. (V) brazilensis topically applied as Cream I (beyerenol 1, 0.81%, w/w) and Cream III (beyerenol 2, 1.96%, w/w). These results suggest that beyerenols are potential candidates for cutaneous leishmaniasis chemotherapy by topical application. In vitro assays of amastigotes of L. (V) brazilensis showed EC50 of 1.1 ±â€¯0.1 and 1.3 ±â€¯0.04 µg/mL, with SI of 3.1 and 3.5 for hydrazone intermediates 10 and 11, respectively.

Why do we have so many molecules and biodiversity but so few antiparasite medicines? / Porqué tenemos tantas moléculas bioactivas y biodiversidad pero tan pocas medicinas antiparasitarias?

Natural products are isolated from biodiversity, that is, from plants, microorganisms, insects, and marine organisms; most of the biodiversity is found in about 10-12 countries located around the Equator. For a long time, people chose this option to alleviate diseases and the industry to discover new medicines; however, from the 70's onwards synthetic products have displaced them. Today there is a rebirth of natural products research and annually hundreds of new natural and synthetic bioactive molecules are reported in specialized journals. On the other hands, new drugs are continually required and especially there is a deficit of them to treat the so-called Neglected Diseases, which affect and threaten the health of billions of people in the world. These diseases paradoxically affect almost all megadiverse countries. Thus, the richest countries in biodiversity do not benefit from the use of natural products because research, development and production of new medicines are carried out in more technologically advanced countries. Why do we have so many molecules in biodiversity and journals but so few medicines? How could new antiparasite drugs be developed quickly and cheaply in the countries affected by Neglected Diseases? A feasible alternative is the Mining in Press, that is, the search of molecules in scientific literature. In this paper we analyze the reasons why these valuable substances have not become drugs and remain curiosities of laboratories and libraries, and the advantages of using this approach as a source of drugs or templates to other bioactive molecules.

Los productos naturales son aislados de la biodiversidad, es decir, de plantas, microorganismos y organismos marinos; gran parte de la biodiversidad se encuentra en cerca de 10-12 paises localizados alrededor del Ecuador. Por mucho tiempo, la gente ha seleccionado esta opción para aliviar sus enfermedades y la industria para descubrir nuevas medicinas; sin embargo, desde los años 70s los productos sintéticos los han desplazado. Hoy hay un renacimiento de la investigación de productos naturales y anualmente cientos de nuevas moléculas naturales y sintéticas bioactivas son reportados en las publicaciones especializadas. De otro lado, continuamente se requieren nuevas drogas y especialmente hay un déficit de ellas para tratar las llamadas Enfermedades Olvidadas, que afectan y amenazan la salud de miles de millones de personas en el mundo. Estas enfermedades paradójicamente afectan casi todos los países megadiversos. De esta manera, los países más ricos en biodiversidad no se benefician del uso de productos naturales, ya que la investigación, el desarrollo y la producción de nuevas medicinas se lleva a cabo en países tecnológicamente avanzados. Por qué tenemos tantas moléculas en la biodiversidad y en las publicaciones, pero tan pocas medicinas? Cómo podrían las drogas antiparasitarias ser desarrolladas de manera mas rápida y barata en los países afectados por las Enfermedades Olvidadas? Una posible alternativa es la Minería de las Publicaciones, es decir, la búsqueda de moléculas en la literatura científica. En este artículo nosotros analizamos las razones por la cuales esas valiosas sustancias no han llegado a ser drogas y permanecen como curiosidades de los laboratorios y bibliotecas, y las ventajas de usar esta aproximación como una fuente de drogas o modelos de otras moléculas bioactivas.

Isoflavonoid composition and biological activity of extracts from soybean seedlings treated by different elicitors.

Time-course and dose-response experiments were carried out to establish the ability for synthesizing isoflavonoids of soybean seedlings (cv. Soyica P34) treated with salicylic (SA) and isonicotinic acids (INA). Then, 25 structurally-related compounds were evaluated for their isoflavonoid-eliciting activity. Next, the antimicrobial and antioxidant activities of EtOAc-soluble fraction from soybean seedlings treated with some synthetic elicitors were determined. Results showed that the concentration of isoflavonoids in soybean seedlings was significantly increased by the application of SA and INA. The major isoflavonoids detected were the malonyl-glycosidic isoflavones, followed by genistin and daidzin. The isoflavone aglycones (genistein, daidzein, and formononetin), coumestrol and glyceollins were found in lower concentrations. Maximum accumulation of glyceollins was detected after 48 and 144 h in soybean seedlings treated with 1.6 mM INA and SA, respectively. EtOAc-extracts from soybean seedlings treated with two structurally-related compounds to INA displayed a significant antimicrobial and antioxidant activity. Therefore, INA, SA and structurally-related compounds can be used to increase the amounts of natural antioxidant or antimicrobial compounds in soybean, either to protect the plant directly against pathogens or as a natural source for subsequent isolation of isoflavonoids or bioactive extracts, which have potential application in functional foods or pharmaceutical and personal care products.

Methyl-N-methylanthranilate, a pungent compound from Citrus reticulata Blanco leaves.

CONTEXT: More analgesic compounds are needed in medicine against pain since the available drugs displayed secondary effects. Natural products are a source of molecules to develop new analgesics, using the information of plants, applied against pain, with effects such as pungency, tingling, and needle, due to their possible role in the central nervous system (NCS). Citrus reticulata Blanco (Rutaceae) leaves are usually bitten to flavor the mouth and possess this type effect in lips and tongues; due to this fact the structure of the bioctive compound could be the source of other types of analgesics. OBJECTIVE: The objective of this study is to determine the causal agent of the pungent effect in mandarin essential oil. MATERIALS AND METHODS: Mandarin essential oil was obtained and then purified by column chromatography. Each fraction was tested and pungency was detected only in the first fraction which was pure. RESULTS: The compound responsible for the pungency in the essential oils of leaves from Citrus reticulata (mandarin) was purified and the structure was assigned as methyl-N-methylanthranilate, on the basis of NMR 1D and 2D and MS. This substance corresponds to another type of molecule involving an antinociceptive effect. CONCLUSIONS: Terpenes are compounds found in essential oils. The compound responsible for the pungency of mandarin and other citrus leaves was isolated, and surprisingly it was identified as a methyl-N-methylanthranilate. This kind of molecules with this activity could be used to discover new analgesics in human therapy against pain.

In vivo Antimalarial Activity of α-Mangostin and the New Xanthone δ-Mangostin.

Based on the previously reported in vitro antiplasmodial activity of several xanthones from Garcinia mangostana, two xanthones, α-mangostin and a new compound, δ-mangostin, were isolated from mangosteen husk, and the in vitro antiplasmodial and cytotoxic effects were determined. α-Mangostin was more active against the resistant Plasmodium falciparum chloroquine-resistant (FCR3) strain (IC50 = 0.2 ± 0.01 µM) than δ-mangostin (IC50 = 121.2 ± 1.0 µM). Furthermore, the therapeutic response according to the administration route was evaluated in a Plasmodium berghei malarial murine model. The greatest therapeutic response was obtained with intraperitoneal administration; these xanthones reduced parasitemia by approximately 80% with a daily dose of 100 mg/kg administered twice a day for 7 days of treatment. Neither compound was effective by oral administration. Noticeable toxicological effects were not observed. In addition to the antimalarial effect of these xanthones isolated from G. mangostana husk, the availability of larger amounts of husk raw material to purify the bioactive xanthones is advantageous, permitting additional preclinical assays or chemical transformations to enhance the biological activity of these substances.

Furan type lignans with antimycobacterial activity / Lignanos del tipo furano con actividad antimicobacterial

Compounds such as triclosan, diclofenac and trimetropin posses antibacterial activity, including mycobacterial; their structures are based on two aromatic rings joined by a methylene or a heteroatom. Since a similar structural system is found in natural diarylfuran- based lignans, we studied plants known with this type of lignans, as potential active against Mycobacterium tuberculosis. Fractions of the active extracts were tested for anti-TB activity and their chemical constituents analyzed by NMR spectroscopy. Several extracts and chromatographical fractions exhibited > 90 percent inhibition of M. tuberculosis at 128 ug/mL. Methylpluviatilol, a pure compound isolated from Virola sebifera, was active at this concentration.. These findings suggest that plant species of the families here studied may yield novel lead compounds for the development of antimycobacterial agents.

Compuestos tales como triclosan, diclofenac y trimetoprim poseen actividad antibacterial, incluyendo la antimicobacterial; sus estructuras están basadas en dos anillos aromáticos unidos por un metileno o un heteroátomo. Debido a que en la naturaleza se encuentra un sistema estructural similar del tipo diarilfurano en los lignanos, así como otros subtipos, nosotros estudiamos plantas contra Mycobacterium tuberculosis, de las que se sabe contienen lignanos Las fracciones cromatográficas de los extractos activos fueron ensayadas para actividad anti.Tb y sus constituyentes químicos se analizaron por espectroscopía de RMN. Varios extractos y fracciones cromatográficas exhibieron una inhibición superior al 90 por ciento a 128 ug/mL; el compuesto metilpluviatilol, aislado de mostró una inhibición del 99 por ciento a esa concentración. Esos hechos sugieren que las especies de plantas de las familias aquí estudiadas podrían suministrar nuevos compuestos líderes para el desarrollo de agentes antimicobacteriales.

Leishmanicidal and trypanocidal activity of Sapindus saponaria / Actividad leishmanicida y tripanocida de Sapindus saponaria

Leishmaniasis and trypanosomiasis are parasitic diseases with a high infection rate, being a serious public health issue in the new world. Unfortunately, there are few available commercial drugs, poorly efficient and with increasing parasite resistance. Under these condi- tions, there is a need for new molecules to develop new and better drugs. One approach to carry out this search is using traditional medicine as information source to obtain new molecules or extracts to control these parasite diseases. Sapindus saponaria (Sapindaceae) fruit resin is used in Colombia to treat ulcers caused by Leishmaniasis. In a bioguided study, we have analyzed the in vitro effect of fruit resin, chroma- tographical fractions from fruit resin and also pure compounds against Leishmania species (L. panamensis, L. braziliensis, L. amazonensis and L. donovani) and Trypanosoma cruzi. The in vivo antileishmanial effect was established under the hamster model for cutaneous leish- maniasis by L. panamensis; refined extract of S. saponaria and pure saponins displayed high in vitro and in vivo activity as leishmanicides. In addition, extracts caused low viability on T. cruzi amastigotes. The use of the crude extract can be a good alternative against cutaneous leishmaniasis, due to its activity, reduced hemolytic effect, and easy production procedures.

La Leishmaniasis y la tripanosomiasis son enfermedades parasitarias con una alta incidencia, siendo un serio asunto de salud pública en el nuevo mundo. Desafortunadamente, hay pocas drogas comerciales disponibles, con pobre eficiencia y con una creciente resis- tencia parasitaria. Bajo esas condiciones, se necesitan nuevas moléculas para desarrollar nuevas y mejores drogas. Una aproximación para llevar a cabo esa búsqueda es usar la medicina tradicional como fuente de información para obtener nuevas moléculas o extractos para con- trolar esas enfermedades parasitarias. La resina de Sapindus saponaria (Sapindaceae) se usa en Colombia para tratar úlceras causadas por la Leishmaniasis. En un estudio bioguiado, se analizó el efecto in vitro de varios extractos de la resina, sus fracciones cromatográficas y algu- nos compuestos puros, contra varias especies de Leishmania (L. panamensis, L. braziliensis, L. amazonensis y L. donovani) panamensis y Trypanosoma cruzi. El efecto lesihmanicida in vivo fue establecido usando el modelo en hamster de leishmaniasis cutánea producida por L. panamensis; los extractos refinados de S. saponaria y las saponinas puras mostraron alta actividad in vitro e in vivo como leishmanicidas. Además, los extractos causaron una baja viabilidad en amastigotes de T. cruzi. El uso de extractos refinados en vez de saponinas puras podría ser una buena alternativa contra leishmaniasis cutánea debido a su actividad, poco efecto hemolítico y procedimientos de producción mucho más fáciles.

Differential accumulation of defense-related isoflavonoids inhypocotyls/roots of common bean (Phaseolus vulgaris L. ) cultivars treatedwith salicylic acid and structurally related compounds / Acumulación diferencial de isoflavonoides relacionados con la defensa en hipocótilos/raíces de variedades deporoto (Phaseolus vulgaris L. ) tratados con ácido salicílico y compuestos estructuralmente relacionados

Hypocotyls/roots of four (anthracnose-resistant: ICA Quimbaya and CORPOICA 106; anthracnose-susceptible: Cargamanto Rojo and Cargamanto Mocho) common bean cultivars treated with salicylic acid (SA) as elicitor, were analyzed to determine the capacity for synthesizing defense-related isoflavonoids. Time-course and dose-response studies indicated that the maximum levels of isoflavonoids, occurred at 1.45 mM SA and between 96 and 144 h post-induction. Overall, anthracnose-resistant cultivars produced the defense-related isoflavonoids to superior amounts than the susceptible ones. Additionally, crude isoflavonoid extracts from SA-treated tissues cvs. ICA Quimbaya and Cargamanto Rojo displayed higher inhibitory effect against C. lindemuthianum than those from water-treated tissues. A comparison of the isoflavonoid-eliciting activity of a series of structurally-related compounds to SA revealed that isoflavonoid production may be differentially controlled. Acetyl-salicylic acid showed the best isoflavonoid-inducing effect. Results might be useful for crop protection programs through the selecting of common bean cultivars with better prospects of disease resistance, and the development of better isoflavonoid-eliciting agents.

Los hipocótilos/raíces de cuatro variedades de poroto (resistente a antracnosis: ICA Quimbaya y CORPOICA 106; susceptible a antracnosis: Cargamanto Rojo y Cargamanto Mocho) tratados con ácido salicílico (AS) como elicitor, se analizaron para determinar la capacidad para sintetizar isoflavonoides relacionados con la defensa. Los estudios en el curso del tiempo y dosis-respuesta indicaron que los niveles máximos de isoflavonoides, ocurrieron a una concentración de AS de 1.45 mM y entre 96 y 144 h post-inducción. En general, las variedades resistentes a la antracnosis produjeron los isoflavonoides relacionados con la defensa en cantidades superiores en comparación con las variedades susceptibles. Adicionalmente, los extractos de isoflavonoides crudos provenientes de tejidos tratados con AS var. ICA Quimbaya y Cargamanto Rojo desplegaron un efecto inhibitorio contra C. lindemuthianum mayor que aquellos resultantes de tejidos tratados con agua. Una comparación de la actividad inductora de isoflavonoides de una serie de compuestos estructuralmente relacionados con el AS reveló que la producción de isoflavonoides puede ser controlada diferencialmente. El ácido acetilsalicílico mostró el mejor efecto inductor de isoflavonoides. Los resultados pueden ser útiles para los programas de protección a cultivos a través de la selección de variedades con mejores perspectivas de resistencia a enfermedades, y el desarrollo de mejores agentes elicitores de isoflavonoides.

Effect of salicylic acid and structurally related compounds in the accumulation of phytoalexins in cotyledons of common bean (Phaseolus vulgaris L.) cultivars.

In the present work, isoflavonoid phytoalexin production in response to the application of salicylic acid in cotyledons of four common bean (Phaseolus vulgaris) cultivars (SA) was evaluated. The time-course and dose-response profiles of the induction process were established by quantifying the isoflavonoids by HPLC. Cotyledons of anthracnose-resistant cultivars induced by SA produced substantially higher phytoalexin contents as compared to the susceptible ones. In addition, maximum levels of phytoalexins (50-100 fold increases) were reached between 96 and 144 h, and when a concentration of SA from 3.62 to 14.50 mM was used. The observations also indicate that there was a relatively good correlation between the phytoalexin contents and the inhibitory effect against C. lindemuthianum; the higher antifungal activity was observed during the first 48 hours for extracts from cotyledons treated with SA at 1.45 and 3.62 mM, and between 96 and 144 h after induction. Finally, compounds structurally related to SA (dihydro-quinazolinones and some imines) showed a strong elicitor effect. Moreover, induced extracts from cotyledons treated with these potential elicitors, besides the properly elicitors, displayed a weak to moderated antifungal activity. These compounds may be considered good candidates for developing of new phytoprotectants. Furthermore, phytoalexin-eliciting substances may contribute for selecting disease resistant cultivars.

O-Methylation of phenylphenalenone phytoalexins in Musaacuminata and Wachendorfia thyrsiflora.

Biosynthetic O-methylation at various sites along the backbone of inducible phenylphenalenones in Musaacuminata var. "Williams" (Musaceae) and Wachendorfiathyrsiflora (Haemodoraceae) was investigated using 13C-labelled precursors. The inducibility of O-methylated metabolites was demonstrated in both species and the origin of methoxyl group from [methyl-13C]L-methionine was confirmed. In addition to known phenylphenalenones, a methoxylated metabolite, 4-(4-hydroxy-3-methoxy-phenyl)-benzo[de]isochromene-1,3-dione, was detected and its structure elucidated mainly by NMR spectroscopic techniques. The experiments were used to discriminate methionine-derived and artificial methoxy groups formed during methanolic extraction. Finally, demethylation of 4'-methoxycinnamic acid and subsequent conversion to 3',4'-methylenedioxycinnamic acid was demonstrated in M.acuminata.

Effects of diterpenes from latex of Euphorbia lactea and Euphorbia laurifolia on human immunodeficiency virus type 1 reactivation.

The persistence of latent HIV-infected cellular reservoirs represents the major hurdle to virus eradication in patients treated with highly active antiretroviral therapy, referred to as HAART. HIV-1 reservoirs are long-lived resting CD4+ memory cells containing the virus latently integrated. Since the HIV-1 reservoirs are not targeted by HAART, reactivation therapy has been suggested to purge viral latency. Bioassay-guided study of an ethyl acetate extract of Euphorbia laurifolia afforded two isomeric diterpenes that showed differential activity over HIV-1 reactivation. A previously reported compound was isolated too from Euphorbia lactea. This compound showed a potent HIV-1 reactivating effect. Bioassays results showed that HIV-1 reactivation activity is influenced by distinct structural characteristics.

Leishmanicidal activity of aliphatic and aromatic lactones: correlation structure-activity.

Several aliphatic and aromatic lactones and two dimers were synthesized using the sequence: allylation - esterification - metathesis. These compounds were active in vitro against intracellular amastigotes of Leishmania panamensis. The structure-activity relationship showed the importance of the aliphatic side chain to enhance the biological activity and to obtain lower cytotoxicity. It was also observed that a decrease in the size of the lactone ring increases the selectivity index.

In vitro anti-influenza screening of several Euphorbiaceae species: structure of a bioactive Cyanoglucoside from Codiaeum variegatum.

A bio-guided screening against influenza A virus (FLUAV) was carried out with seven Euphorbiaceae species. The results showed that chromatographic fractions from Phyllantus niruri, Euphorbia pulcherrima and Codiaeum variegatum had relevant anti-FLUAV activity, although only chromatographical subfractions from C. variegatum kept the activity. From this plant, the active compound against FLUAV was isolated. Its structure was assigned as 2-(3,4,5)-trihydroxy-6-hydroxymethyltetrahydropyran-2-yloxymethyl)acrylonitrile (1) on the basis of NMR, mass spectrometry and X-ray diffraction analysis. The compound displayed virucidal activity without impairment of haemagglutination properties of the used virus strain. This is the first report indicating antiviral activity of a cyanoglucoside.