As part of our effort to discover new -glucosidase inhibitors from natural sources, it was found... more As part of our effort to discover new -glucosidase inhibitors from natural sources, it was found that an aqueous extract from Melampodium perfoliatum (Cavanilles) Kunth (Asteraceae) inhibited the activity of rat-intestinal -glucosidases in a concentration dependent manner (IC 50 = 958 g/mL). Fractionation of the active extract led to the isolation of perfoliatin A (1), which was active against the mammal α-glucosidases and a recombinant α-glucosidase with maltase-glucoamylase activity obtained from Ruminococcus obeum. Kinetic analysis revealed that the interaction of 1 with R. obeum-α-glucosidase was noncompetitive. The calculated Ki was 0.68 ± 0.034 mM. In vivo testing using an oral sucrose tolerance test, in healthy and hyperglycemic mice, revealed that perfoliatin A (1) reduced significantly the postprandial peak, consistent with its α-glucosidase inhibitory activity. The effect was comparable or better to that of acarbose, a therapeutically used -glucosidase inhibitor. Altogether, these findings clearly supported the -glucosidase inhibitory activity of melampolide-type of sesquiterpene lactones.
Phytochemistry, Vol. 23, No. 8, pp. 16651668, 1984. Printed in Great Britain. 00319422 84 3.00+0.... more Phytochemistry, Vol. 23, No. 8, pp. 16651668, 1984. Printed in Great Britain. 00319422 84 3.00+0.00 Q 1984 Pergamon Press Ltd. SESQUITERPENE LACTONES OF ARTEMISIA MEXICANA VAR. ANGUSTIFOLIA RACHEL MATA, GUILLERMO DELGADO and ALFONSO ROMO ...
Bioactivity-directed fractionation of the fermentation broth and mycelium of the coprophilous fun... more Bioactivity-directed fractionation of the fermentation broth and mycelium of the coprophilous fungus Guanomyces polythrix led to the isolation of several phytotoxic compounds, including five new naphthopyranone derivatives (1-5). In addition, rubrofusarin B, emodin, citrinin, and 4-hydroxybenzoic acid methyl ester were obtained. The structures of the new compounds were established by spectral and chiroptical methods. The isolates caused significant inhibition of radicle growth of two weed seedlings (Amaranthus hypochondriacus and Echinochloa crusgalli) and interacted with both spinach and bovine brain calmodulins.
Reinvestigation of the fermentation broth and mycelium of the coprophilous fungus Guanomyces poly... more Reinvestigation of the fermentation broth and mycelium of the coprophilous fungus Guanomyces polythrix, grown in static conditions, led to the isolation of several phytotoxic compounds, including two new naphthopyranone derivatives, namely (2S, 3R)-5-hydroxy-6,8-dimethoxy-2,3-dimethyl-2,3-dihydro-4H-naphtho[2,3-b]-pyran-4-one and (2S, 3R)-5-hydroxy-6,8,10-trimethoxy-2,3-dimethyl-2,3-dihydro-4H-naphtho[2,3-b]-pyran-4-one. The structures of the new compounds were established by spectral and chiroptical methods. In addition, the structure of 8-hydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid methyl ester was unambiguously determined by X-ray analysis. The isolates caused significant inhibition of radicle growth of two weed seedlings (Amaranthus hypochondriacus and Echinochloa crusgalli) and interacted with both spinach and bovine brain calmodulins.
A new indole alkaloid, namely malbrancheamide B (2), was isolated from the culture medium and myc... more A new indole alkaloid, namely malbrancheamide B (2), was isolated from the culture medium and mycelia of the ascomycete Malbranchea aurantiaca along with malbrancheamide (1). Structural elucidation of 2 was carried out by a combination of mass spectrometry (MS) and 1 H and 13 C NMR spectroscopy analyses, as well as by comparison of the NMR data with those of 1. According to the conformational studies using molecular mechanics analyses, compound 2 exists in one preferred conformation, which was optimised by density functional theory (DFT) calculations. Compound 2 is the second chlorinated indole alkaloid possessing a bicyclo [2.2.2] ring with an unusual relative configuration at C12a in the bicyclo [2.2.2] diazaoctane ring system. So far, these structural features seem to be unique for the alkaloids biosynthesised by the fungus M. aurantiaca.
An aqueous extract from the seeds of Swietenia humilis (31.6-100mg/kg bw) lowered (p&... more An aqueous extract from the seeds of Swietenia humilis (31.6-100mg/kg bw) lowered (p<0.05) blood glucose levels in normal and nicotinamide-streptozotocin (NA-STZ)-induced hyperglycemic mice. Furthermore, when administered to fructose-fed rats with metabolic syndrome, the decoction showed significant antihyperglycemic, hypoglycemic and hypolipidemic effects, as well as an augmentation of hepatic glycogen. Limonoids 2-hydroxy-destigloyl-6-deoxyswietenine acetate (1), humulin B (2), methyl-2-hydroxy-3-β-isobutyroxy-1-oxomeliac-8(30)-enate (3), methyl-2-hydroxy-3-β-tigloyloxy-1-oxomeliac-8(30)-enate (4), humilinolide G (5), humilinolide C (6), methyl-2-hydroxy-3-β-isobutyoyl-8α,30α-epoxy-1-oxo-meliacate (7), and humilinolide H (8), were isolated from a CH2Cl2-MeOH (1:1) extract of the seeds. Compounds 5 and 8 are analogs of compounds 6 and 7. The structure of 5 was unequivocally established by X-ray analysis. When tested in normal and NA-STZ-hyperglycemic mice, compounds 1, 2, and 4 (3.16-31.6 mg/kg bw) decreased glycemia during an oral glucose tolerance test. The present investigation sustains the contemporary popular uses of S. humilis seeds for treating metabolic disorders, including diabetes and dyslipidemia and demonstrates the potential of the mexicanolides as antihyperglycemic agents.
Two new compounds, pestalotin 4′-O-methyl-β-mannopyranoside (1) and 3S,4R-(+)-4hydroxymellein (2)... more Two new compounds, pestalotin 4′-O-methyl-β-mannopyranoside (1) and 3S,4R-(+)-4hydroxymellein (2), were isolated from an organic extract of a Xylaria feejeensis, which was isolated as an endophytic fungus from Hintonia latiflora. In addition, the known compounds 3S,4S-(+)-4-hydroxymellein (3), 3S-(+)-8-methoxymellein (4), and the quinone derivatives 2hydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione (5), 4S,5S,6S-4-hydroxy-3methoxy-5-methyl-5,6-epoxycyclohex-2-en-1-one (6), and 4R,5R-dihydroxy-3-methoxy-5methylcyclohexen-2-en-1-one (7) were obtained. The structures of 1 and 2 were elucidated using a set of spectroscopic and spectrometric techniques. The absolute configuration of the stereogenic centers of 1 and 2 was determined using ECD spectroscopy combined with timedependent density functional theory calculations. In the case of 1, comparison of the experimental and theoretical 3 J6-7 coupling constants provided further evidence for the stereochemical assignments. Compounds 2 and 3 inhibited Saccharomyces cerevisiae αglucosidase (αGHY), with IC50 values of 441 ± 23 and 549 ± 2.5 μM, respectively. Their activity was comparable to that of acarbose (IC50 = 545 ± 19 μM), used as positive control. Molecular docking predicted that both compounds bind to αGHY in a site different from the catalytic domain, which could imply an allosteric type of inhibition.
Key Word Index*Esenbeckia yaxhoob^Rutaceae^imperatorin^"13S#!13!methyl!dammara! 19\14!diene!2b!yl... more Key Word Index*Esenbeckia yaxhoob^Rutaceae^imperatorin^"13S#!13!methyl!dammara! 19\14!diene!2b!yl!acetate^1!tridecanone^1!pentadecanone^5\09\03!trimethyl!1!penta! decanone^lupeol^asarinin^Amaranthus hypochondriacus^Echinochloa crus`alli^Lactuca sativaL ycopersicum esculentum^phytogrowth!inhibitory activity^uncoupler^Hill reaction inhibitorp hotosynthesis[ Abstract*Investigation of the aerial parts of Esenbeckia yaxhoob Lundell "Rutaceae# led to the isolation of a new dammarane!type of triterpene which was characterized by spectral means as "13S#!13!methyl!dammara! 19\14!diene!2b!yl!acetate[ In addition\ 1!tridecanone\ asarinin\ imperatorin\ lupeol and hesperidin were obtained[ "13S#!13!Methyl!dammara!19\14!diene!2b!yl!acetate\ 1!tridecanone\ asarinin and imperatorin caused signi_cant inhibition of the radicle growth and:or germination of seedlings of Amaranthus hypochon! driacus\ Echinochloa crus`alli\ Lactuca sativa and Lycopersicum esculentum[ Also\ it has been found that imperatorin inhibited ATP synthesis and both phosphorylating and uncoupled electron ~ow from H 1 O to K 2 ðFe"CN# 5 Ł[ On the other hand\ this coumarin stimulated the basal electron ~ow from H 1 O to K 2 ðFe"CN# 5 Ł and the activity of the light!activated Mg 1¦ !ATPase[ These e}ects were measured in freshly lysed illuminated spinach chloroplasts and allowed to determine that imperatorin acts as an uncoupler and as a Hill reaction inhibitor[ Þ 0887 Elsevier Science Ltd[ All rights reserved
Journal of Agricultural and Food Chemistry, Jul 8, 2005
A whole plant chloroform-methanol extract of the orchid Epidendrum rigidum inhibited radicle grow... more A whole plant chloroform-methanol extract of the orchid Epidendrum rigidum inhibited radicle growth of Amaranthus hypochondriacus seedlings (IC 50 ) 300 µg/mL). Bioassay-guided fractionation furnished four phytotoxins, namely, gigantol (1), batatasin III (2), 2,3-dimethoxy-9,10-dihydrophenathrene-4,7diol (9), and 3,4,9-trimethoxyphenanthrene-2,5-diol (11), along with the known flavonoids apigenin, vitexin, and isovetin and the triterterpenoids 24,24-dimethyl-9,19-cyclolanostane-25-en-3β-ol ( ) and 24-methyl-9,19-cyclolanostane-25-en-3β-ol (15). Stilbenoids 1, 2, 9, and 11 inhibited radicle growth of A. hypochondriacus with IC 50 values of 0.65, 0.1, 0.12, and 5.9 µM, respectively. Foliar application of gigantol (1) at 1 µM to 4 week old seedlings of A. hypochondriacus reduced shoot elongation by 69% and fresh weight accumulation by 54%. Bibenzyls 1 and 2, as well as synthetic analogues 4′hydroxy-3,3′,5-trimethoxybibenzyl (3), 3,3′,4′,5-tetramethoxybibenzyl (4), 3,4′-dihydroxy-5-methoxybibenzyl (5), 3′-O-methylbatatasin III (6), 3,3′,5-trihydroxybibenzyl (7), and 3,4′,5-trihydroxybibenzyl (8), were tested for phytotoxicity in axenic cultures of the small aquatic plant Lemna pausicostata. All bibenzyls derivatives except 7 and 8 inhibited growth and increased cellular leakage with IC 50 values of 89.9-180 and 89.9-166 µM, respectively. The natural and synthetic bibenzyls showed marginal cytotoxicity on animal cells. The results suggest that orchid bibenzyls may be good lead compounds for the development of novel herbicidal agents.
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Analytical and Bioanalytical Chemistry, Feb 14, 2012
This paper describes the development of a novel on-line biosensor based on a fluorescently labele... more This paper describes the development of a novel on-line biosensor based on a fluorescently labeled human calmodulin (CaM), hCaM M124C-mBBr, immobilized on controlled-pore glass (CPG), for the analysis of trifluoroperazine (TFP); a phenothiazine drug in human urine samples. The device was automated by packing hCaM M124C-mBBr-CPG in a continuous-flow microcell connected to a monitoring system, composed of a bifurcated optical fiber coupled to a spectrofluorometer. Operating parameters of the on-line biosensor (flow rate, sample injection volume, and carrier solution and buffer pH) were studied and optimized. Under the optimal conditions, the biosensor provides a detection and a quantification limit of 0.24 and 0.52 μg mL(-1), respectively, and a dynamic range from 0.52 to 61.05 μg mL(-1) TFP (n = 5, correlation coefficient 0.998). The response time (t(100)) was shorter than 42 s (recovery time <4.5 min) and reproducibility and repeatability of the TFP measurements, within the linear response range, were lower than 1.4 and 2.7%, respectively. The device was successfully applied to the analysis of TFP in spiked human urine samples with recoveries ranging between 97 and 101% and with RSDs lower than 5.9%.
Bioactivity-directed fractionation of extracts from the fungus Phoma herbarum led to the isolatio... more Bioactivity-directed fractionation of extracts from the fungus Phoma herbarum led to the isolation of two new phytotoxic nonenolides: (7S,8S,9R)-7,8-dihydroxy-9-propyl-5-nonen-9-olide (1) and (2R,7S,8S,9R)-2,7,8-trihydroxy-9-propyl-5-nonen-9-olide (2), which were named herbarumins I and II, respectively. The stereostructures were elucidated by spectroscopic methods and a combination of molecular modeling, NOESY and 1H–1H coupling constant data, which revealed that in CDCl3 solution, 1 exists in one
In the present work, the compound 3´-(2,6-dimethoxybenzoyl)-benzyl 2,6-dimethoxybenzoate (RM4) wa... more In the present work, the compound 3´-(2,6-dimethoxybenzoyl)-benzyl 2,6-dimethoxybenzoate (RM4) was evaluated for its ability as a corrosion inhibitor in a 3% chloride medium and using an API 5L X70 steel working electrode. The electrochemical system was evaluated by electrochemical techniques such as polarization curves (CP) and electrochemical impedance spectroscopy (EIS), finding through the values obtained in polarization curves that the efficiency of the inhibitor at 50 ppm reached 73.2% against the corrosion phenomenon. The inhibition kinetics study shows that the evaluated organic compound maintains its protection against corrosion in a period of 120 hours of immersion.
Related Article: Brisa Verastegui-Omana, Daniela Rebollar-Ramos, Araceli Perez-Vasquez, Ana Laura... more Related Article: Brisa Verastegui-Omana, Daniela Rebollar-Ramos, Araceli Perez-Vasquez, Ana Laura Martinez, Abraham Madariaga-Mazon, Laura Flores-Bocanegra, Rachel Mata|2017|J.Nat.Prod.|80|190|doi:10.1021/acs.jnatprod.6b00977
As part of our effort to discover new -glucosidase inhibitors from natural sources, it was found... more As part of our effort to discover new -glucosidase inhibitors from natural sources, it was found that an aqueous extract from Melampodium perfoliatum (Cavanilles) Kunth (Asteraceae) inhibited the activity of rat-intestinal -glucosidases in a concentration dependent manner (IC 50 = 958 g/mL). Fractionation of the active extract led to the isolation of perfoliatin A (1), which was active against the mammal α-glucosidases and a recombinant α-glucosidase with maltase-glucoamylase activity obtained from Ruminococcus obeum. Kinetic analysis revealed that the interaction of 1 with R. obeum-α-glucosidase was noncompetitive. The calculated Ki was 0.68 ± 0.034 mM. In vivo testing using an oral sucrose tolerance test, in healthy and hyperglycemic mice, revealed that perfoliatin A (1) reduced significantly the postprandial peak, consistent with its α-glucosidase inhibitory activity. The effect was comparable or better to that of acarbose, a therapeutically used -glucosidase inhibitor. Altogether, these findings clearly supported the -glucosidase inhibitory activity of melampolide-type of sesquiterpene lactones.
Phytochemistry, Vol. 23, No. 8, pp. 16651668, 1984. Printed in Great Britain. 00319422 84 3.00+0.... more Phytochemistry, Vol. 23, No. 8, pp. 16651668, 1984. Printed in Great Britain. 00319422 84 3.00+0.00 Q 1984 Pergamon Press Ltd. SESQUITERPENE LACTONES OF ARTEMISIA MEXICANA VAR. ANGUSTIFOLIA RACHEL MATA, GUILLERMO DELGADO and ALFONSO ROMO ...
Bioactivity-directed fractionation of the fermentation broth and mycelium of the coprophilous fun... more Bioactivity-directed fractionation of the fermentation broth and mycelium of the coprophilous fungus Guanomyces polythrix led to the isolation of several phytotoxic compounds, including five new naphthopyranone derivatives (1-5). In addition, rubrofusarin B, emodin, citrinin, and 4-hydroxybenzoic acid methyl ester were obtained. The structures of the new compounds were established by spectral and chiroptical methods. The isolates caused significant inhibition of radicle growth of two weed seedlings (Amaranthus hypochondriacus and Echinochloa crusgalli) and interacted with both spinach and bovine brain calmodulins.
Reinvestigation of the fermentation broth and mycelium of the coprophilous fungus Guanomyces poly... more Reinvestigation of the fermentation broth and mycelium of the coprophilous fungus Guanomyces polythrix, grown in static conditions, led to the isolation of several phytotoxic compounds, including two new naphthopyranone derivatives, namely (2S, 3R)-5-hydroxy-6,8-dimethoxy-2,3-dimethyl-2,3-dihydro-4H-naphtho[2,3-b]-pyran-4-one and (2S, 3R)-5-hydroxy-6,8,10-trimethoxy-2,3-dimethyl-2,3-dihydro-4H-naphtho[2,3-b]-pyran-4-one. The structures of the new compounds were established by spectral and chiroptical methods. In addition, the structure of 8-hydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid methyl ester was unambiguously determined by X-ray analysis. The isolates caused significant inhibition of radicle growth of two weed seedlings (Amaranthus hypochondriacus and Echinochloa crusgalli) and interacted with both spinach and bovine brain calmodulins.
A new indole alkaloid, namely malbrancheamide B (2), was isolated from the culture medium and myc... more A new indole alkaloid, namely malbrancheamide B (2), was isolated from the culture medium and mycelia of the ascomycete Malbranchea aurantiaca along with malbrancheamide (1). Structural elucidation of 2 was carried out by a combination of mass spectrometry (MS) and 1 H and 13 C NMR spectroscopy analyses, as well as by comparison of the NMR data with those of 1. According to the conformational studies using molecular mechanics analyses, compound 2 exists in one preferred conformation, which was optimised by density functional theory (DFT) calculations. Compound 2 is the second chlorinated indole alkaloid possessing a bicyclo [2.2.2] ring with an unusual relative configuration at C12a in the bicyclo [2.2.2] diazaoctane ring system. So far, these structural features seem to be unique for the alkaloids biosynthesised by the fungus M. aurantiaca.
An aqueous extract from the seeds of Swietenia humilis (31.6-100mg/kg bw) lowered (p&... more An aqueous extract from the seeds of Swietenia humilis (31.6-100mg/kg bw) lowered (p<0.05) blood glucose levels in normal and nicotinamide-streptozotocin (NA-STZ)-induced hyperglycemic mice. Furthermore, when administered to fructose-fed rats with metabolic syndrome, the decoction showed significant antihyperglycemic, hypoglycemic and hypolipidemic effects, as well as an augmentation of hepatic glycogen. Limonoids 2-hydroxy-destigloyl-6-deoxyswietenine acetate (1), humulin B (2), methyl-2-hydroxy-3-β-isobutyroxy-1-oxomeliac-8(30)-enate (3), methyl-2-hydroxy-3-β-tigloyloxy-1-oxomeliac-8(30)-enate (4), humilinolide G (5), humilinolide C (6), methyl-2-hydroxy-3-β-isobutyoyl-8α,30α-epoxy-1-oxo-meliacate (7), and humilinolide H (8), were isolated from a CH2Cl2-MeOH (1:1) extract of the seeds. Compounds 5 and 8 are analogs of compounds 6 and 7. The structure of 5 was unequivocally established by X-ray analysis. When tested in normal and NA-STZ-hyperglycemic mice, compounds 1, 2, and 4 (3.16-31.6 mg/kg bw) decreased glycemia during an oral glucose tolerance test. The present investigation sustains the contemporary popular uses of S. humilis seeds for treating metabolic disorders, including diabetes and dyslipidemia and demonstrates the potential of the mexicanolides as antihyperglycemic agents.
Two new compounds, pestalotin 4′-O-methyl-β-mannopyranoside (1) and 3S,4R-(+)-4hydroxymellein (2)... more Two new compounds, pestalotin 4′-O-methyl-β-mannopyranoside (1) and 3S,4R-(+)-4hydroxymellein (2), were isolated from an organic extract of a Xylaria feejeensis, which was isolated as an endophytic fungus from Hintonia latiflora. In addition, the known compounds 3S,4S-(+)-4-hydroxymellein (3), 3S-(+)-8-methoxymellein (4), and the quinone derivatives 2hydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione (5), 4S,5S,6S-4-hydroxy-3methoxy-5-methyl-5,6-epoxycyclohex-2-en-1-one (6), and 4R,5R-dihydroxy-3-methoxy-5methylcyclohexen-2-en-1-one (7) were obtained. The structures of 1 and 2 were elucidated using a set of spectroscopic and spectrometric techniques. The absolute configuration of the stereogenic centers of 1 and 2 was determined using ECD spectroscopy combined with timedependent density functional theory calculations. In the case of 1, comparison of the experimental and theoretical 3 J6-7 coupling constants provided further evidence for the stereochemical assignments. Compounds 2 and 3 inhibited Saccharomyces cerevisiae αglucosidase (αGHY), with IC50 values of 441 ± 23 and 549 ± 2.5 μM, respectively. Their activity was comparable to that of acarbose (IC50 = 545 ± 19 μM), used as positive control. Molecular docking predicted that both compounds bind to αGHY in a site different from the catalytic domain, which could imply an allosteric type of inhibition.
Key Word Index*Esenbeckia yaxhoob^Rutaceae^imperatorin^"13S#!13!methyl!dammara! 19\14!diene!2b!yl... more Key Word Index*Esenbeckia yaxhoob^Rutaceae^imperatorin^"13S#!13!methyl!dammara! 19\14!diene!2b!yl!acetate^1!tridecanone^1!pentadecanone^5\09\03!trimethyl!1!penta! decanone^lupeol^asarinin^Amaranthus hypochondriacus^Echinochloa crus`alli^Lactuca sativaL ycopersicum esculentum^phytogrowth!inhibitory activity^uncoupler^Hill reaction inhibitorp hotosynthesis[ Abstract*Investigation of the aerial parts of Esenbeckia yaxhoob Lundell "Rutaceae# led to the isolation of a new dammarane!type of triterpene which was characterized by spectral means as "13S#!13!methyl!dammara! 19\14!diene!2b!yl!acetate[ In addition\ 1!tridecanone\ asarinin\ imperatorin\ lupeol and hesperidin were obtained[ "13S#!13!Methyl!dammara!19\14!diene!2b!yl!acetate\ 1!tridecanone\ asarinin and imperatorin caused signi_cant inhibition of the radicle growth and:or germination of seedlings of Amaranthus hypochon! driacus\ Echinochloa crus`alli\ Lactuca sativa and Lycopersicum esculentum[ Also\ it has been found that imperatorin inhibited ATP synthesis and both phosphorylating and uncoupled electron ~ow from H 1 O to K 2 ðFe"CN# 5 Ł[ On the other hand\ this coumarin stimulated the basal electron ~ow from H 1 O to K 2 ðFe"CN# 5 Ł and the activity of the light!activated Mg 1¦ !ATPase[ These e}ects were measured in freshly lysed illuminated spinach chloroplasts and allowed to determine that imperatorin acts as an uncoupler and as a Hill reaction inhibitor[ Þ 0887 Elsevier Science Ltd[ All rights reserved
Journal of Agricultural and Food Chemistry, Jul 8, 2005
A whole plant chloroform-methanol extract of the orchid Epidendrum rigidum inhibited radicle grow... more A whole plant chloroform-methanol extract of the orchid Epidendrum rigidum inhibited radicle growth of Amaranthus hypochondriacus seedlings (IC 50 ) 300 µg/mL). Bioassay-guided fractionation furnished four phytotoxins, namely, gigantol (1), batatasin III (2), 2,3-dimethoxy-9,10-dihydrophenathrene-4,7diol (9), and 3,4,9-trimethoxyphenanthrene-2,5-diol (11), along with the known flavonoids apigenin, vitexin, and isovetin and the triterterpenoids 24,24-dimethyl-9,19-cyclolanostane-25-en-3β-ol ( ) and 24-methyl-9,19-cyclolanostane-25-en-3β-ol (15). Stilbenoids 1, 2, 9, and 11 inhibited radicle growth of A. hypochondriacus with IC 50 values of 0.65, 0.1, 0.12, and 5.9 µM, respectively. Foliar application of gigantol (1) at 1 µM to 4 week old seedlings of A. hypochondriacus reduced shoot elongation by 69% and fresh weight accumulation by 54%. Bibenzyls 1 and 2, as well as synthetic analogues 4′hydroxy-3,3′,5-trimethoxybibenzyl (3), 3,3′,4′,5-tetramethoxybibenzyl (4), 3,4′-dihydroxy-5-methoxybibenzyl (5), 3′-O-methylbatatasin III (6), 3,3′,5-trihydroxybibenzyl (7), and 3,4′,5-trihydroxybibenzyl (8), were tested for phytotoxicity in axenic cultures of the small aquatic plant Lemna pausicostata. All bibenzyls derivatives except 7 and 8 inhibited growth and increased cellular leakage with IC 50 values of 89.9-180 and 89.9-166 µM, respectively. The natural and synthetic bibenzyls showed marginal cytotoxicity on animal cells. The results suggest that orchid bibenzyls may be good lead compounds for the development of novel herbicidal agents.
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Analytical and Bioanalytical Chemistry, Feb 14, 2012
This paper describes the development of a novel on-line biosensor based on a fluorescently labele... more This paper describes the development of a novel on-line biosensor based on a fluorescently labeled human calmodulin (CaM), hCaM M124C-mBBr, immobilized on controlled-pore glass (CPG), for the analysis of trifluoroperazine (TFP); a phenothiazine drug in human urine samples. The device was automated by packing hCaM M124C-mBBr-CPG in a continuous-flow microcell connected to a monitoring system, composed of a bifurcated optical fiber coupled to a spectrofluorometer. Operating parameters of the on-line biosensor (flow rate, sample injection volume, and carrier solution and buffer pH) were studied and optimized. Under the optimal conditions, the biosensor provides a detection and a quantification limit of 0.24 and 0.52 μg mL(-1), respectively, and a dynamic range from 0.52 to 61.05 μg mL(-1) TFP (n = 5, correlation coefficient 0.998). The response time (t(100)) was shorter than 42 s (recovery time <4.5 min) and reproducibility and repeatability of the TFP measurements, within the linear response range, were lower than 1.4 and 2.7%, respectively. The device was successfully applied to the analysis of TFP in spiked human urine samples with recoveries ranging between 97 and 101% and with RSDs lower than 5.9%.
Bioactivity-directed fractionation of extracts from the fungus Phoma herbarum led to the isolatio... more Bioactivity-directed fractionation of extracts from the fungus Phoma herbarum led to the isolation of two new phytotoxic nonenolides: (7S,8S,9R)-7,8-dihydroxy-9-propyl-5-nonen-9-olide (1) and (2R,7S,8S,9R)-2,7,8-trihydroxy-9-propyl-5-nonen-9-olide (2), which were named herbarumins I and II, respectively. The stereostructures were elucidated by spectroscopic methods and a combination of molecular modeling, NOESY and 1H–1H coupling constant data, which revealed that in CDCl3 solution, 1 exists in one
In the present work, the compound 3´-(2,6-dimethoxybenzoyl)-benzyl 2,6-dimethoxybenzoate (RM4) wa... more In the present work, the compound 3´-(2,6-dimethoxybenzoyl)-benzyl 2,6-dimethoxybenzoate (RM4) was evaluated for its ability as a corrosion inhibitor in a 3% chloride medium and using an API 5L X70 steel working electrode. The electrochemical system was evaluated by electrochemical techniques such as polarization curves (CP) and electrochemical impedance spectroscopy (EIS), finding through the values obtained in polarization curves that the efficiency of the inhibitor at 50 ppm reached 73.2% against the corrosion phenomenon. The inhibition kinetics study shows that the evaluated organic compound maintains its protection against corrosion in a period of 120 hours of immersion.
Related Article: Brisa Verastegui-Omana, Daniela Rebollar-Ramos, Araceli Perez-Vasquez, Ana Laura... more Related Article: Brisa Verastegui-Omana, Daniela Rebollar-Ramos, Araceli Perez-Vasquez, Ana Laura Martinez, Abraham Madariaga-Mazon, Laura Flores-Bocanegra, Rachel Mata|2017|J.Nat.Prod.|80|190|doi:10.1021/acs.jnatprod.6b00977
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