The aromatic plant Hedeoma multiflora Beth. is endangered by both the overexploitation and the ad... more The aromatic plant Hedeoma multiflora Beth. is endangered by both the overexploitation and the advance of agricultural and urban borders. We report an efficient protocol for its in vitro propagation without using plant growth regulators (PGRs). Two in vitro plant lines, one initiated from seeds and other from binodal segments, remain stable and present high multiplication rates in half strength Murashigue and Skoog medium. Neither the addition of 1-naphthylacetic acid, kinetin or their combinations improved either growing or multiplication rates which reached 26.39 stems per initial explant after 12 weeks. A comparison toward three wild populations, harvested at both early and late summer time, shows that the morpho-anatomical characteristics of the aerial parts are fairly preserved although in vitro plants display more abundant but shorter roots. The profiles of volatile compounds from wild and in vitro specimens are quite similar, although hydrocarbon monoterpenes’ fraction is mor...
A preparation of β-ketosulfides avoiding the use of thiols is described. The combination of a mul... more A preparation of β-ketosulfides avoiding the use of thiols is described. The combination of a multicomponent reaction and a lipase-catalysed hydrolysis has been developed in order to obtain high chemical diversity employing a single sulfur donor. This methodology for the selective synthesis of a set of β-ketosulfides is performed under mild conditions and can be set up in one-pot two-step and on a gram-scale.
Although many countries banned the insecticide endosulfan, it is still an environmental pollutant... more Although many countries banned the insecticide endosulfan, it is still an environmental pollutant. Plants metabolize the two diastereomers of the formulations known as technical grade endosulfan (TGE) by two phase I pathways: hydrolysis leading to less toxic derivatives and oxidation giving endosulfan sulfate which is as toxic as endosulfan itself. We assessed the removal, bioaccumulation and phase I metabolization of TGE from water matrices using hairy root clones (HRs) of three edible species, Brassica napus, Raphanus sativus and Capsicum annuum. B. napus and C. annuum HRs removed 86% of TGE from the bioreaction media in 2 and 96 h, respectively, whereas R. sativus HRs removed 91% of TGE within 6 h of biotreatment. In the experiments with B. napus, only endosulfan sulfate was detected in both biomass and medium, whereas R. sativus and C. annuum accumulated endosulfan sulfate and endosulfan alcohol. Besides, endosulfan lactone was detected in C. annuum reaction medium. Acute ichthyotoxicity assays toward Poecilia reticulata showed that media contaminated with TGE lethal levels did not produce mortality after the phytotreatments. This research highlights the feasibility of using HRs to evaluate plant enzymatic abilities toward xenobiotics and their potential for the design of ex situ decontamination processes.
Boletín de la Sociedad Argentina de Botánica, 2008
Los vástagos de Poaceae pueden establecer con Ascomycetes (Balansieae) asociaciones simbióticas e... more Los vástagos de Poaceae pueden establecer con Ascomycetes (Balansieae) asociaciones simbióticas endofíticas denominadas micofilas. Las gramíneas no pueden sintetizar alcaloides en ausencia del endófito fúngico. Melica stuckertii Hack. es una Poaceae nativa de amplia distribución en el país. El objetivo de este trabajo fue estudiar tres poblaciones de M. stuckertii de San Luis (Argentina), considerando: la presencia y frecuencia de endófitos, la producción de alcaloides en la asociación y el simbionte fúngico. A partir de cariopsis se obtuvieron plántulas axénicas de las que se aisló el simbionte fúngico en medio sólido, siendo cultivado para su determinación taxonómica. Además, las plántulas axénicas se utilizaron para la determinación de alcaloides in planta y el aislamiento de endófito en medio líquido para la posterior detección de alcaloides in fungus. También se examinó la producción de alcaloides «en plantas a campo». Melica stuckertii resultó asociada formando micofilas con u...
In this work, we report the synthesis of a series of derivatives of N-benzyl-2-phenylethanamine w... more In this work, we report the synthesis of a series of derivatives of N-benzyl-2-phenylethanamine which is the framework of norbelladine, the natural common precursor of the Amaryllidaceae alkaloids. These compounds were assessed in the inhibition of both AChE and BChE which are the enzymes responsible for the breakdown of acetylcholine and hence they constitute targets in the palliative treatment of Alzheimer's disease. In particular, brominated derivatives exhibited the lowest IC50 values against AChE. Interestingly, the presence of iodine in one of the aromatic rings highly increased the inhibition of BChE compared to its analogues, with an IC50 value similar to that of galantamine, which is the reference compound currently used in the treatment of AD. A possible mechanism of action for these compounds was determined by molecular modeling studies using combined techniques of docking and molecular dynamics simulations.
Grape stalks—the lignocellulosic skeleton of the grape raceme- are accumulated in massive piles i... more Grape stalks—the lignocellulosic skeleton of the grape raceme- are accumulated in massive piles immediately after harvest and become a concentrated pollutant. Fungi cause several rots in grapevine and other fruit cultivars and albeit biocontrol agents are available, superior technologies must be developed to rival synthetic counterparts. In this work, we describe the preparation of grape stalk lipophilic extracts from Malbec, Cabernet sauvignon, Chardonnay and Pedro Gimenez as biocontrol tools against Aspergillus candidus, Penicillium chrysogenum, and Rhizopus sp., which are pathogenic for grapes and other fruits. Grape stalk extracts were obtained with hexane, diethyl ether, ethyl acetate, and ethanol. Yields were in the range of 1 to 23% w/w according to solvent polarity. Extracts were separated into lipophilic sub-extracts—yields varied from 70 up to 12% w/w due to solvent polarity. Sub-extracts were assayed for antifungal activity in vitro and the one obtained from Pedro Gimenez with ethanol exhibited the broadest biocontrol spectrum at 2.5 × 104 mg/L. This sub-extract was separated into components by column chromatography to inquire further on its biocontrol activity. A bioactivity-guided test against Rhizopus sp. revealed that this effect relies on gamma-sitosterol and a biocontrol cut-off value of 5.1 × 103 mg/L was estimated.
ABSTRACT The profile of volatile compounds from the aerial parts of Eupatorium buniifolium was as... more ABSTRACT The profile of volatile compounds from the aerial parts of Eupatorium buniifolium was assessed by capturing the aroma of fresh plants using three commercial SPME phases. These headspace solid phase microextraction procedures (HS-SPME) were coupled to GC-FID and GC-MS analysis. Hydrocarbon sesquiterpenes were the main components of E. buniifolium volatiles, followed by hydrocarbon monoterpenes. The three fiber performances were statistically comparable in the extraction of both terpene groups. E. buniifolium essential oil (EO) was obtained by steam distillation (SD) and assessed by both, direct injection and HS-SPME. The three fibers could reliably adsorb/absorb the aromas of E. buniifolium EOs, with comparable with EO composition. The fresh plant volatile profile significantly differed from its EO because some sesquiterpene fraction remained in the biomass after SD. Extracts of the fresh plant material were obtained using organic solvents and evaluated by direct injection. Ethanol and ethyl acetate extracts gave a different aroma profile of E. bunnifolium than the EO.
Journal of Photochemistry and Photobiology B: Biology
Secondary metabolites play a major role in the adaptation of plants to the environment. Furan neo... more Secondary metabolites play a major role in the adaptation of plants to the environment. Furan neo-clerodane diterpenes are characteristic secondary metabolites in Baccharis flabellata Hook. & Arn. var. flabellata. One of the main compounds is the diene ent-15,16-epoxy-19-hydroxy-1,3,13(16),14-clerodatetraen-18-oic acid (DAC). In this work a new dimeric compound (DACD) has been isolated and identified by NMR and MS techniques. The presence of other minor dimers was also observed in the same plant methanolic extracts. Assuming that they may be the products of [4 + 2] condensation of two monomeric moieties, the formation of adducts by photochemical dimerization was checked by inducing the in vitro [4 + 2] cycloaddition of DAC. Moreover, the DAC and DACD accumulation rates in aerial parts of B. flabellata specimens were analyzed monthly during a complete phenological cycle. The accumulation of monomer depends on the plant phonological stage; meanwhile the dimer proportion arises in detriment of the monomer as the solar UV radiation increases. Since plants exposed to strong UV intensities produce radical species, the scavenger properties of these compounds toward reactive nitrogen species (RNS), and reactive oxygen species (ROS), were analyzed. Albeit DAC and DACD show significant superoxide radical scavenger activities, the monomer proved to be more effective than the dimer toward ROS, while DACD was an excellent RNS scavenger.
Abstract Essential oils (EOs) are complex chemical matrices on which whole cell biotransformation... more Abstract Essential oils (EOs) are complex chemical matrices on which whole cell biotransformations have not had much success due to their well-known antimicrobial activities. The approach in this work is to use endophytic microorganisms to increase the chemical diversification of Eupatorium buniifolium EO by biocatalysis. Three endophytic fungal strains showing ability to biotransform the EO and four of the EO main pure components, R-(+)-limonene, α-(−)-pinene, α-(+)-pinene and sabinene, were isolated from E. buniifolium plants. Two strains were characterized up to species level as Fusarium solani Eb01 and Alternaria alternata Eb03 and the third strain at genus level as Neofusicoccum sp. Eb04. The three fungi, as resting cell systems, allowed to access to three new complex volatile matrixes from E. buniifolium EO by increasing its degree of oxyfunctionalization. The robustness and biocatalytic skills of these microorganisms make them worth their inclusion within the tool-box for the generation of new valuable bioproducts from hydrocarbon monoterpene rich feedstocks.
The aromatic plant Hedeoma multiflora Beth. is endangered by both the overexploitation and the ad... more The aromatic plant Hedeoma multiflora Beth. is endangered by both the overexploitation and the advance of agricultural and urban borders. We report an efficient protocol for its in vitro propagation without using plant growth regulators (PGRs). Two in vitro plant lines, one initiated from seeds and other from binodal segments, remain stable and present high multiplication rates in half strength Murashigue and Skoog medium. Neither the addition of 1-naphthylacetic acid, kinetin or their combinations improved either growing or multiplication rates which reached 26.39 stems per initial explant after 12 weeks. A comparison toward three wild populations, harvested at both early and late summer time, shows that the morpho-anatomical characteristics of the aerial parts are fairly preserved although in vitro plants display more abundant but shorter roots. The profiles of volatile compounds from wild and in vitro specimens are quite similar, although hydrocarbon monoterpenes’ fraction is mor...
A preparation of β-ketosulfides avoiding the use of thiols is described. The combination of a mul... more A preparation of β-ketosulfides avoiding the use of thiols is described. The combination of a multicomponent reaction and a lipase-catalysed hydrolysis has been developed in order to obtain high chemical diversity employing a single sulfur donor. This methodology for the selective synthesis of a set of β-ketosulfides is performed under mild conditions and can be set up in one-pot two-step and on a gram-scale.
Although many countries banned the insecticide endosulfan, it is still an environmental pollutant... more Although many countries banned the insecticide endosulfan, it is still an environmental pollutant. Plants metabolize the two diastereomers of the formulations known as technical grade endosulfan (TGE) by two phase I pathways: hydrolysis leading to less toxic derivatives and oxidation giving endosulfan sulfate which is as toxic as endosulfan itself. We assessed the removal, bioaccumulation and phase I metabolization of TGE from water matrices using hairy root clones (HRs) of three edible species, Brassica napus, Raphanus sativus and Capsicum annuum. B. napus and C. annuum HRs removed 86% of TGE from the bioreaction media in 2 and 96 h, respectively, whereas R. sativus HRs removed 91% of TGE within 6 h of biotreatment. In the experiments with B. napus, only endosulfan sulfate was detected in both biomass and medium, whereas R. sativus and C. annuum accumulated endosulfan sulfate and endosulfan alcohol. Besides, endosulfan lactone was detected in C. annuum reaction medium. Acute ichthyotoxicity assays toward Poecilia reticulata showed that media contaminated with TGE lethal levels did not produce mortality after the phytotreatments. This research highlights the feasibility of using HRs to evaluate plant enzymatic abilities toward xenobiotics and their potential for the design of ex situ decontamination processes.
Boletín de la Sociedad Argentina de Botánica, 2008
Los vástagos de Poaceae pueden establecer con Ascomycetes (Balansieae) asociaciones simbióticas e... more Los vástagos de Poaceae pueden establecer con Ascomycetes (Balansieae) asociaciones simbióticas endofíticas denominadas micofilas. Las gramíneas no pueden sintetizar alcaloides en ausencia del endófito fúngico. Melica stuckertii Hack. es una Poaceae nativa de amplia distribución en el país. El objetivo de este trabajo fue estudiar tres poblaciones de M. stuckertii de San Luis (Argentina), considerando: la presencia y frecuencia de endófitos, la producción de alcaloides en la asociación y el simbionte fúngico. A partir de cariopsis se obtuvieron plántulas axénicas de las que se aisló el simbionte fúngico en medio sólido, siendo cultivado para su determinación taxonómica. Además, las plántulas axénicas se utilizaron para la determinación de alcaloides in planta y el aislamiento de endófito en medio líquido para la posterior detección de alcaloides in fungus. También se examinó la producción de alcaloides «en plantas a campo». Melica stuckertii resultó asociada formando micofilas con u...
In this work, we report the synthesis of a series of derivatives of N-benzyl-2-phenylethanamine w... more In this work, we report the synthesis of a series of derivatives of N-benzyl-2-phenylethanamine which is the framework of norbelladine, the natural common precursor of the Amaryllidaceae alkaloids. These compounds were assessed in the inhibition of both AChE and BChE which are the enzymes responsible for the breakdown of acetylcholine and hence they constitute targets in the palliative treatment of Alzheimer's disease. In particular, brominated derivatives exhibited the lowest IC50 values against AChE. Interestingly, the presence of iodine in one of the aromatic rings highly increased the inhibition of BChE compared to its analogues, with an IC50 value similar to that of galantamine, which is the reference compound currently used in the treatment of AD. A possible mechanism of action for these compounds was determined by molecular modeling studies using combined techniques of docking and molecular dynamics simulations.
Grape stalks—the lignocellulosic skeleton of the grape raceme- are accumulated in massive piles i... more Grape stalks—the lignocellulosic skeleton of the grape raceme- are accumulated in massive piles immediately after harvest and become a concentrated pollutant. Fungi cause several rots in grapevine and other fruit cultivars and albeit biocontrol agents are available, superior technologies must be developed to rival synthetic counterparts. In this work, we describe the preparation of grape stalk lipophilic extracts from Malbec, Cabernet sauvignon, Chardonnay and Pedro Gimenez as biocontrol tools against Aspergillus candidus, Penicillium chrysogenum, and Rhizopus sp., which are pathogenic for grapes and other fruits. Grape stalk extracts were obtained with hexane, diethyl ether, ethyl acetate, and ethanol. Yields were in the range of 1 to 23% w/w according to solvent polarity. Extracts were separated into lipophilic sub-extracts—yields varied from 70 up to 12% w/w due to solvent polarity. Sub-extracts were assayed for antifungal activity in vitro and the one obtained from Pedro Gimenez with ethanol exhibited the broadest biocontrol spectrum at 2.5 × 104 mg/L. This sub-extract was separated into components by column chromatography to inquire further on its biocontrol activity. A bioactivity-guided test against Rhizopus sp. revealed that this effect relies on gamma-sitosterol and a biocontrol cut-off value of 5.1 × 103 mg/L was estimated.
ABSTRACT The profile of volatile compounds from the aerial parts of Eupatorium buniifolium was as... more ABSTRACT The profile of volatile compounds from the aerial parts of Eupatorium buniifolium was assessed by capturing the aroma of fresh plants using three commercial SPME phases. These headspace solid phase microextraction procedures (HS-SPME) were coupled to GC-FID and GC-MS analysis. Hydrocarbon sesquiterpenes were the main components of E. buniifolium volatiles, followed by hydrocarbon monoterpenes. The three fiber performances were statistically comparable in the extraction of both terpene groups. E. buniifolium essential oil (EO) was obtained by steam distillation (SD) and assessed by both, direct injection and HS-SPME. The three fibers could reliably adsorb/absorb the aromas of E. buniifolium EOs, with comparable with EO composition. The fresh plant volatile profile significantly differed from its EO because some sesquiterpene fraction remained in the biomass after SD. Extracts of the fresh plant material were obtained using organic solvents and evaluated by direct injection. Ethanol and ethyl acetate extracts gave a different aroma profile of E. bunnifolium than the EO.
Journal of Photochemistry and Photobiology B: Biology
Secondary metabolites play a major role in the adaptation of plants to the environment. Furan neo... more Secondary metabolites play a major role in the adaptation of plants to the environment. Furan neo-clerodane diterpenes are characteristic secondary metabolites in Baccharis flabellata Hook. & Arn. var. flabellata. One of the main compounds is the diene ent-15,16-epoxy-19-hydroxy-1,3,13(16),14-clerodatetraen-18-oic acid (DAC). In this work a new dimeric compound (DACD) has been isolated and identified by NMR and MS techniques. The presence of other minor dimers was also observed in the same plant methanolic extracts. Assuming that they may be the products of [4 + 2] condensation of two monomeric moieties, the formation of adducts by photochemical dimerization was checked by inducing the in vitro [4 + 2] cycloaddition of DAC. Moreover, the DAC and DACD accumulation rates in aerial parts of B. flabellata specimens were analyzed monthly during a complete phenological cycle. The accumulation of monomer depends on the plant phonological stage; meanwhile the dimer proportion arises in detriment of the monomer as the solar UV radiation increases. Since plants exposed to strong UV intensities produce radical species, the scavenger properties of these compounds toward reactive nitrogen species (RNS), and reactive oxygen species (ROS), were analyzed. Albeit DAC and DACD show significant superoxide radical scavenger activities, the monomer proved to be more effective than the dimer toward ROS, while DACD was an excellent RNS scavenger.
Abstract Essential oils (EOs) are complex chemical matrices on which whole cell biotransformation... more Abstract Essential oils (EOs) are complex chemical matrices on which whole cell biotransformations have not had much success due to their well-known antimicrobial activities. The approach in this work is to use endophytic microorganisms to increase the chemical diversification of Eupatorium buniifolium EO by biocatalysis. Three endophytic fungal strains showing ability to biotransform the EO and four of the EO main pure components, R-(+)-limonene, α-(−)-pinene, α-(+)-pinene and sabinene, were isolated from E. buniifolium plants. Two strains were characterized up to species level as Fusarium solani Eb01 and Alternaria alternata Eb03 and the third strain at genus level as Neofusicoccum sp. Eb04. The three fungi, as resting cell systems, allowed to access to three new complex volatile matrixes from E. buniifolium EO by increasing its degree of oxyfunctionalization. The robustness and biocatalytic skills of these microorganisms make them worth their inclusion within the tool-box for the generation of new valuable bioproducts from hydrocarbon monoterpene rich feedstocks.
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Papers by Marcela Kurina-sanz