2,3-Dehydrosilybin (DHS) was previously shown to chelate and reduce both copper and iron ions. In this study, similar experiments with 2,3-dehydrosilychristin (DHSCH) showed that this congener of DHS also chelates and reduces both metals.... more
2,3-Dehydrosilybin (DHS) was previously shown to chelate and reduce both copper and iron ions. In this study, similar experiments with 2,3-dehydrosilychristin (DHSCH) showed that this congener of DHS also chelates and reduces both metals. Statistical analysis pointed to some differences between both compounds: in general, DHS appeared to be a more potent iron and copper chelator, and a copper reducing agent under acidic conditions, while DHSCH was a more potent copper reducing agent under neutral conditions. In the next step, both DHS and DHSCH were tested for metal-based Fenton chemistry in vitro using HPLC with coulometric detection. Neither of these compounds were able to block the iron-based Fenton reaction and, in addition, they mostly intensified hydroxyl radical production. In the copper-based Fenton reaction, the effect of DHSCH was again prooxidant or neutral, while the effect of DHS was profoundly condition-dependent. DHS was even able to attenuate the reaction under some ...
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Vitamin A is a group of vital micronutrients widely present in the human diet. Animal-based products are a rich source of the retinyl ester form of the vitamin, while vegetables and fruits contain carotenoids, most of which are provitamin... more
Vitamin A is a group of vital micronutrients widely present in the human diet. Animal-based products are a rich source of the retinyl ester form of the vitamin, while vegetables and fruits contain carotenoids, most of which are provitamin A. Vitamin A plays a key role in the correct functioning of multiple physiological functions. The human organism can metabolize natural forms of vitamin A and provitamin A into biologically active forms (retinol, retinal, retinoic acid), which interact with multiple molecular targets, including nuclear receptors, opsin in the retina and, according to the latest research, also some enzymes. In this review, we aim to provide a complex view on the present knowledge about vitamin A ranging from its sources through its physiological functions to consequences of its deficiency and metabolic fate up to possible pharmacological administration and potential toxicity. Current analytical methods used for its detection in real samples are included as well.
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Vitamin C (L-ascorbic acid) has been known as an antioxidant for most people. However, its physiological role is much larger and encompasses very different processes ranging from facilitation of iron absorption through involvement in... more
Vitamin C (L-ascorbic acid) has been known as an antioxidant for most people. However, its physiological role is much larger and encompasses very different processes ranging from facilitation of iron absorption through involvement in hormones and carnitine synthesis for important roles in epigenetic processes. Contrarily, high doses act as a pro-oxidant than an anti-oxidant. This may also be the reason why plasma levels are meticulously regulated on the level of absorption and excretion in the kidney. Interestingly, most cells contain vitamin C in millimolar concentrations, which is much higher than its plasma concentrations, and compared to other vitamins. The role of vitamin C is well demonstrated by miscellaneous symptoms of its absence—scurvy. The only clinically well-documented indication for vitamin C is scurvy. The effects of vitamin C administration on cancer, cardiovascular diseases, and infections are rather minor or even debatable in the general population. Vitamin C is r...
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Silymarin is a traditional drug and food supplement employed for numerous liver disorders. The available studies indicate that its activities may be broader, in particular due to claimed benefits in some cardiovascular diseases, but the... more
Silymarin is a traditional drug and food supplement employed for numerous liver disorders. The available studies indicate that its activities may be broader, in particular due to claimed benefits in some cardiovascular diseases, but the contributions of individual silymarin components are unclear. Therefore, we tested silymarin flavonolignans as pure diastereomers as well as their sulfated metabolites for potential vasorelaxant and antiplatelet effects in isolated rat aorta and in human blood, respectively. Eleven compounds from a panel of 17 tested exhibited a vasorelaxant effect, with half maximal effective concentrations (EC50) ranging from 20 to 100 µM, and some substances retained certain activity even in the range of hundreds of nM. Stereomers A were generally more potent as vasorelaxants than stereomers B. Interestingly, the most active compound was a metabolite—silychristin-19-O-sulfate. Although initial experiments showed that silybin, 2,3-dehydrosilybin, and 2,3-dehydrosil...
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Isoflavones are commonly consumed in many Asian countries and have potentially positive effects on human being. Only a few and rather controversial data on their interactions with copper and iron are available to date. 13 structurally... more
Isoflavones are commonly consumed in many Asian countries and have potentially positive effects on human being. Only a few and rather controversial data on their interactions with copper and iron are available to date. 13 structurally related isoflavones were tested in the competitive manner for their Cu/Fe-chelating/reducing properties. Notwithstanding the 5-hydroxy-4-keto chelation site was associated with ferric, ferrous, and cupric chelation, the chelation potential of isoflavones was low and no cuprous chelation was observed. None of isoflavones was able to substantially reduce ferric ions, but the vast majority reduced cupric ions. The most important feature for cupric reduction was the presence of an unsubstituted 4′-hydroxyl; contrarily the presence of a free 5-hydroxyl decreased or abolished the reduction due to chelation of cupric ions. The results from this study may enable additional experiments which might clarify the effects of isoflavones on human being and/or mechani...
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Isoflavones are commonly consumed in many Asian countries and have potentially positive effects on human being. Only a few and rather controversial data on their interactions with copper and iron are available to date. 13 structurally... more
Isoflavones are commonly consumed in many Asian countries and have potentially positive effects on human being. Only a few and rather controversial data on their interactions with copper and iron are available to date. 13 structurally related isoflavones were tested in the competitive manner for their Cu/Fe-chelating/reducing properties. Notwithstanding the 5-hydroxy-4-keto chelation site was associated with ferric, ferrous, and cupric chelation, the chelation potential of isoflavones was low and no cuprous chelation was observed. None of isoflavones was able to substantially reduce ferric ions, but the vast majority reduced cupric ions. The most important feature for cupric reduction was the presence of an unsubstituted 4′-hydroxyl; contrarily the presence of a free 5-hydroxyl decreased or abolished the reduction due to chelation of cupric ions. The results from this study may enable additional experiments which might clarify the effects of isoflavones on human being and/or mechani...
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Isoflavones are commonly consumed in many Asian countries and have potentially positive effects on human being. Only a few and rather controversial data on their interactions with copper and iron are available to date. 13 structurally... more
Isoflavones are commonly consumed in many Asian countries and have potentially positive effects on human being. Only a few and rather controversial data on their interactions with copper and iron are available to date. 13 structurally related isoflavones were tested in the competitive manner for their Cu/Fe-chelating/reducing properties. Notwithstanding the 5-hydroxy-4-keto chelation site was associated with ferric, ferrous, and cupric chelation, the chelation potential of isoflavones was low and no cuprous chelation was observed. None of isoflavones was able to substantially reduce ferric ions, but the vast majority reduced cupric ions. The most important feature for cupric reduction was the presence of an unsubstituted 4′-hydroxyl; contrarily the presence of a free 5-hydroxyl decreased or abolished the reduction due to chelation of cupric ions. The results from this study may enable additional experiments which might clarify the effects of isoflavones on human being and/or mechani...
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Two new isoquinoline alkaloids, named fumaranine (2) and fumarostrejdine (10), along with 18 known alkaloids were isolated from aerial parts of Fumaria officinalis. The structures of the isolated compounds were elucidated on the basis of... more
Two new isoquinoline alkaloids, named fumaranine (2) and fumarostrejdine (10), along with 18 known alkaloids were isolated from aerial parts of Fumaria officinalis. The structures of the isolated compounds were elucidated on the basis of spectroscopic analyses and by comparison with literature data. The absolute configuration of the new compound 2 was determined by comparing its circular dichroism spectra with those of known analogs. Compounds isolated in sufficient amounts were evaluated for their acetylcholinesterase, butyrylcholinesterase, prolyl oligopeptidase (POP), and glycogen synthase kinase-3β inhibitory activities. Parfumidine (8) and sinactine (15) exhibited potent POP inhibition activities (IC50 99±5 and 53±2 μM, resp.).
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The ethanol extracts of 47 mushroom species from the order Boletales were tested for their free radical scavenging activities by means of the DPPH free-radical scavenging and hydrogen peroxide-induced luminol chemiluminescence assays. In... more
The ethanol extracts of 47 mushroom species from the order Boletales were tested for their free radical scavenging activities by means of the DPPH free-radical scavenging and hydrogen peroxide-induced luminol chemiluminescence assays. In the DPPH radical scavenging test, 26 species gave EC50 values of less than 1 mg/mL. The highest activity was exhibited by Gyrodon lividus (0.05 mg/mL). However, in the hydrogen peroxide-induced luminol chemiluminescence assay, only 4 species had EC50 values of less than 1 mg/mL, with the highest activity being exhibited by Strobilomyces floccopus (0.26 mg/mL). When compared with known antioxidants, all the mushroom extracts exhibited relatively low activity in both assays. The free radical scavenging results appeared to be correlated with the total phenol contents of the extracts.
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Alzheimer's disease (AD), characterized by the death of nerve cells in the cerebral cortex, is the most common subtype of dementia. Despite the exponential growth in the number of AD patients, acetylcholinesterase... more
Alzheimer's disease (AD), characterized by the death of nerve cells in the cerebral cortex, is the most common subtype of dementia. Despite the exponential growth in the number of AD patients, acetylcholinesterase (AChE) inhibitors are currently used to treat AD. Plants of the Amaryllidaceae family are known to synthesize a particular type of bioactive compounds, named Amaryllidaceae alkaloids, which have shown AChE inhibitory activity. Alkaloid extracts of three species of Amaryllidaceae were studied with respect to their acetylcholinesterase and butyrylcholinesterase inhibitory activity and alkaloid patterns. Eleven alkaloids were identified by GC/MS. Significant cholinesterase inhibitory activity was demonstrated by the alkaloid extract of N. undulata (IC50,(HuAChE) = 14.3 +/- 1.2 microg/mL; IC50,(HuBuChE) = 33.9 +/- 1.9 microg/mL).
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ABSTRACT
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Alzheimer's disease (AD), characterized by the death of nerve cells in the cerebral cortex, is the most common subtype of dementia. Despite the exponential growth in the number of AD patients, acetylcholinesterase (AChE) inhibitors... more
Alzheimer's disease (AD), characterized by the death of nerve cells in the cerebral cortex, is the most common subtype of dementia. Despite the exponential growth in the number of AD patients, acetylcholinesterase (AChE) inhibitors are currently used to treat AD. Plants of the Amaryllidaceae family are known to synthesize a particular type of bioactive compounds, named Amaryllidaceae alkaloids, which have shown AChE inhibitory activity. Alkaloid extracts of three species of Amaryllidaceae were studied with respect to their acetylcholinesterase and butyrylcholinesterase inhibitory activity and alkaloid patterns. Eleven alkaloids were identified by GC/MS. Significant cholinesterase inhibitory activity was demonstrated by the alkaloid extract of N. undulata (IC50,(HuAChE) = 14.3 +/- 1.2 microg/mL; IC50,(HuBuChE) = 33.9 +/- 1.9 microg/mL).
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Prolyl oligopeptidase is a cytosolic serine peptidase that hydrolyses proline-containing peptides at the carboxy terminus of proline residues. It has been associated with schizophrenia, bipolar affective disorder, and related... more
Prolyl oligopeptidase is a cytosolic serine peptidase that hydrolyses proline-containing peptides at the carboxy terminus of proline residues. It has been associated with schizophrenia, bipolar affective disorder, and related neuropsychiatric disorders and therefore may have important clinical implications. Thirty-one isoquinoline alkaloids of various structural types, previously isolated in our laboratory, were screened for their ability to inhibit prolyl oligopeptidase. Promising results have been showed by alkaloids californidine (IC50 = 55.6 ± 3.5 μM), dihydrosanquinarine (IC50 = 99.1 ± 7.6 μM), corypalmine (IC50 = 128.0 ± 10.5 μM) and N-methyllaurotetanine (IC50 = 135.0 ± 11.7 μM).
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A new benzyldihydroisoquinoline alkaloid (1) was isolated from the tubers of Corydalis cava and named corylucinine. Additionally, 8-trichloromethyl-7,8-dihydropalmatine (2), an isolation artifact of tetrahydropalmatine, was obtained. The... more
A new benzyldihydroisoquinoline alkaloid (1) was isolated from the tubers of Corydalis cava and named corylucinine. Additionally, 8-trichloromethyl-7,8-dihydropalmatine (2), an isolation artifact of tetrahydropalmatine, was obtained. The structures were established by spectroscopic (including 2D NMR and optical rotation) and HR-ESI-MS methods. Both compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibitory activity. In comparison with the used standards, both compounds showed only moderate inhibitory activity against HuAChE (IC50,. HuAChE = 127.6 +/- 5.2 microM for 1, and IC50, HuAChE = 82.9 +/- 3.9 microM for 2) and none against HuBuChE.
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Alkaloid extracts of four Amaryllidaceae species were studied with respect to their acetylcholinesterase and butyrylcholinesterase inhibitory activity and alkaloid patterns. Twenty-one alkaloids were determined by GC/MS, and seventeen of... more
Alkaloid extracts of four Amaryllidaceae species were studied with respect to their acetylcholinesterase and butyrylcholinesterase inhibitory activity and alkaloid patterns. Twenty-one alkaloids were determined by GC/MS, and seventeen of them identified from their mass spectra and retention times. The GC/MS analysis of the alkaloid extract of Nerine filamentosa is the first phytochemical investigation of this species. Promising erythrocytic acetylcholinesterase inhibitory activity was demonstrated by the alkaloid extracts of Narcissus poeticus var recurvus, Nerine filifolia and N. filamentosa (IC(50,HuAChE) = 6.0 +/- 0.1 microg/mL; IC(50,HuAChE) = 18.5 +/- 0.8 microg/mL, IC(50,HuAChE) = 21.6 +/- 1.1 microg/mL). The most potent inhibitory activity against serum butyrylcholinesterase was shown by extracts of Sternbergia lutea and Nerinefilamentosa (IC(50,HuBuChE) = 3.7 +/- 0.1 microg/mL; IC(50.HuBuChE) = 13.0 +/- 0.7 microg/mL).
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Amaryllidaceae species are known as ornamental plants. Some contain galanthamine, an acetylcholinesterase inhibitor. The chemical composition of the alkaloid extract of bulbs of Nerine bowdenii Watson has been analyzed by means of GC/MS.... more
Amaryllidaceae species are known as ornamental plants. Some contain galanthamine, an acetylcholinesterase inhibitor. The chemical composition of the alkaloid extract of bulbs of Nerine bowdenii Watson has been analyzed by means of GC/MS. Twenty-two compounds were detected and nineteen of them identified, one of which was belladine. The alkaloid extract showed promising cholinesterase inhibitory activities against human blood acetylcholinesterase (HuAChE; IC50 = 87.9 +/- 3.5 microg/mL) and human plasma butyrylcholinesterase (HuBuChE; IC50 = 14.8 +/- 1.1 microg/mL). Belladine inhibited HuAChE and HuBuChE in a dose-dependent manner with IC50 values of 781 +/- 12.5 microM and 284.8 +/-4.2 microM, respectively.
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Beside ecdysone (1), ecdysterone (2) is one of the most common 5beta-cholest-7-en-6-one (ecdysteroid) derivatives, which, besides having a hormonal effect on invertebrates, possesses a number of favorable non-hormonal biological effects... more
Beside ecdysone (1), ecdysterone (2) is one of the most common 5beta-cholest-7-en-6-one (ecdysteroid) derivatives, which, besides having a hormonal effect on invertebrates, possesses a number of favorable non-hormonal biological effects on mammals. The most interesting of these is that on degenerative diseases, one of which, up to now not clarified in detail, is the so-called adaptogenic effect (protection of the organism against adverse stress factors) associated with anabolic, gastroprotective, and antioxidant effects. A second group of favorable effects is the possibility of suppression of neurodegenerative processes and protection of the cardiovascular system (metabolic syndrome symptom suppression, antidiabetic activity, and protection of heart and blood vessels). Because of these properties, ecdysterone has the potential to be developed as a medicinal agent.
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The underivatized alkaloid mixture extracted from the bulbs of Chlidanthus fragrans Herb. was investigated by capillary GC/MS for the first time. Fifteen known Amaryllidaceae alkaloids of five structure types were identified. The main... more
The underivatized alkaloid mixture extracted from the bulbs of Chlidanthus fragrans Herb. was investigated by capillary GC/MS for the first time. Fifteen known Amaryllidaceae alkaloids of five structure types were identified. The main alkaloids were tazzetine (9, tazettine-type), chlidanthine (2, galanthamine-type), belladine (8, belladine-type) and lycorine (12, lycorine-type). The alkaloid extract from the bulbs showed promising human blood acetylcholinesterase (IC50 = 20.1 +/- 2.9 microg/mL) and human plasma butyrylcholinesterase (IC50 = 136.8 +/- 6.9 microg/mL) inhibitory activity.
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From the bulbs of Zephyranthes robusta Baker (Amaryllidaceae), seven known compounds, belonging to four structural types of Amaryllidaceae alkaloids, were identified and quantified by GC-MS. The alkaloid extract from the bulbs showed... more
From the bulbs of Zephyranthes robusta Baker (Amaryllidaceae), seven known compounds, belonging to four structural types of Amaryllidaceae alkaloids, were identified and quantified by GC-MS. The alkaloid extract from the bulbs showed promising acetylcholinesterase and butyrylcholinesterase inhibitory activities against HuAChE (IC50 = 35.9 +/- 3.5 microg/mL) and HuBuChE (IC50 = 190.9 +/- 8.2 microg/mL).
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The ethanol extracts of 47 mushroom species from the order Boletales were tested for their free radical scavenging activities by means of the DPPH free-radical scavenging and hydrogen peroxide-induced luminol chemiluminescence assays. In... more
The ethanol extracts of 47 mushroom species from the order Boletales were tested for their free radical scavenging activities by means of the DPPH free-radical scavenging and hydrogen peroxide-induced luminol chemiluminescence assays. In the DPPH radical scavenging test, 26 species gave EC50 values of less than 1 mg/mL. The highest activity was exhibited by Gyrodon lividus (0.05 mg/mL). However, in the hydrogen peroxide-induced luminol chemiluminescence assay, only 4 species had EC50 values of less than 1 mg/mL, with the highest activity being exhibited by Strobilomyces floccopus (0.26 mg/mL). When compared with known antioxidants, all the mushroom extracts exhibited relatively low activity in both assays. The free radical scavenging results appeared to be correlated with the total phenol contents of the extracts.
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Ongoing studies of Zephyranthes robusta resulted in the isolation of the lycorine-type alkaloid previously called carinatine and 10-O-demethylgalanthine. The NMR data given previously for this compound were revised and completed by... more
Ongoing studies of Zephyranthes robusta resulted in the isolation of the lycorine-type alkaloid previously called carinatine and 10-O-demethylgalanthine. The NMR data given previously for this compound were revised and completed by two-dimensional 1H-1H and 1H-13C chemical shift correlation experiments. The name of the isolated compound was corrected to 9-O-demethylgalanthine in accordance with the currently used system of numbering of lycorine-type alkaloids. 9-O-Demethylgalanthine and galanthine, a previously isolated alkaloid from Z robusta, were inactive in acetylcholinesterase/butyrylcholinesterase assays (IC50 > 500 microM), but showed important prolyl oligopeptidase inhibition activity.
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Eleven Amaryllidaceae alkaloids (1-11) were isolated from fresh bulbs of Chlidanthus fragrans Herb. The chemical structures were elucidated by MS, and 1D and 2D NMR spectroscopic experiments. Complete NMR assignments were achieved for... more
Eleven Amaryllidaceae alkaloids (1-11) were isolated from fresh bulbs of Chlidanthus fragrans Herb. The chemical structures were elucidated by MS, and 1D and 2D NMR spectroscopic experiments. Complete NMR assignments were achieved for deoxypretazzetine (1). All compounds were evaluated for their erythrocytic acetylcholinesterase and serum butyrylcholinesterase inhibition activity using Ellman's method. In the prolyl oligopeptidase assay, Z-Gly-Pro-p-nitroanilide was used as substrate. In biological assays, only the crinine type Amaryllidaceae alkaloid undulatine showed promising acetylcholinesterase and prolyl oligopeptidase inhibition activity with IC50 values of 23.0 +/- 1.0 microM and 1.96 +/- 0.12 mM, respectively. Other isolated compounds were considered inactive.
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The roots and aerial parts of Eschscholzia californica Cham. (Papaveraceae) were extracted with ethanol. Repeated column chromatography, preparative TLC, and crystallization led to the isolation of fourteen isoquinoline alkaloids, the... more
The roots and aerial parts of Eschscholzia californica Cham. (Papaveraceae) were extracted with ethanol. Repeated column chromatography, preparative TLC, and crystallization led to the isolation of fourteen isoquinoline alkaloids, the structures of which were determined on the basis of spectroscopic techniques and by comparison with literature values. One of the compounds isolated, 1-(3-hydroxy-4-methoxybenzyl)-2-methyl-6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinoline (14), has not previously been isolated from a natural source. All isolated compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibition activity. None of the compounds isolated significantly inhibited both HuAChE and HuBuChE, but the two benzylisoquinoline alkaloids, reticuline 9 and 14, showed promising inhibitory activity against HuBuChE.
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Tubers of Corydalis cava were extracted with ethanol and fractionated using n-hexane, chloroform and ethanol. Repeated column chromatography, preparative TLC and crystallization led to the isolation of fifteen isoquinoline alkaloids. The... more
Tubers of Corydalis cava were extracted with ethanol and fractionated using n-hexane, chloroform and ethanol. Repeated column chromatography, preparative TLC and crystallization led to the isolation of fifteen isoquinoline alkaloids. The chemical structures of the isolated compounds were determined on the basis of spectroscopic techniques and by comparison with literature data. All isolated compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibitory activity. (+)-Canadaline inhibited acetylcholinesterase as well as butyrylcholinesterase in a dose-dependent manner with IC50 values of 20.1 +/- 1.1 microM and 85.2 +/- 3.2 microM, respectively. (+)-Canadine, with an IC50 value of 12.4 +/- 0.9 microM, was the most potent inhibitor of acetylcholinesterase, whilst (+/-)-corycavidine and (+)-bulbocapnine were effective inhibitors of butyrylcholinesterase with IC50 values of 46.2 +/- 2.4 microM and 67.0 +/- 2.1 microM, respe...
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ABSTRACT Export Date: 18 October 2014
The objective of this study was to investigate the effects of a preparation from herbal extracts (PHE) on libido and semen quality in breeding artificial insemination boars. Ten fertile boars were divided into control and experimental... more
The objective of this study was to investigate the effects of a preparation from herbal extracts (PHE) on libido and semen quality in breeding artificial insemination boars. Ten fertile boars were divided into control and experimental groups according to significant difference of libido. There were no differences in semen quality between groups. Animals were fed a commercial feeding mixture for boars. The feeding mixture for the experimental group was enriched with PHE, which was prepared from Eurycoma longifolia, Tribulus terrestris and Leuzea carthamoides. Duration of the experiment was 10 weeks. Samples of ejaculate were collected weekly. Libido was evaluated according to a scale of 0-5 points. Semen volume, sperm motility, percentage of viable spermatozoa, sperm concentration, morphologically abnormal spermatozoa, daily sperm production and sperm survival were assessed. Amounts of mineral components and free amino acids were analysed in seminal plasma. Significant differences were found in these parameters: libido (4.05 ± 0.22 vs 3.48 ± 0.78; p < 0.001), semen volume (331.75 ± 61.91 vs 263.13 ± 87.17 g; p < 0.001), sperm concentration (386.25 ± 107.95 vs 487.25 ± 165.50 × 10(3) /mm(3); p < 0.01), morphologically abnormal spermatozoa (15.94 ± 11.08 vs 20.88 ± 9.19%; p < 0.001) and Mg concentration (28.36 ± 11.59 vs 20.27 ± 13.93 mm; p < 0.05). The experimental group's libido was increased by 20% in comparison with the beginning of the experiment. Results of this study showed positive effect of PHE on libido and some parameters of boar semen quality.
Research Interests: Reproduction, Biological Sciences, Animal Feed, Animals, Male, and 4 moreSemen Analysis, Swine, Semen, and Spermatozoa
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A new natural flavonoid patuletin 3'-beta-xylofuranoside was isolated from Leuzea carthamoides leaves. The antioxidant... more
A new natural flavonoid patuletin 3'-beta-xylofuranoside was isolated from Leuzea carthamoides leaves. The antioxidant activity of this compound was evaluated by the DPPH radical assay and ferric reducing antioxidant power (FRAP) assay, and the results were compared with those for trolox and quercetin. DPPH radical scavenging activity of the tested compounds was expressed by the parameter EC50: patuletin 3'-beta-xylofuranoside (56.0 microM), trolox (27.8 microM), and quercetin (25.3 microM). The ferric reducing activity of the compounds was demonstrated as FRAP values at 4 and 60 min: patuletin 3'-beta-xylofuranoside (28.4 microM, 35.8 microM), trolox (19.3 microM, 20.2 microM), and quercetin (54.3 microM, 79.9 microM). The structure/activity relationship of the flavonoid is also discussed. The results indicate significant antioxidant potency of patuletin 3'-beta-xylofuranoside.
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Coumarins have attracted intense interest in recent years because of their diverse pharmacological properties. According to our continuing investigations of biological effects of several coumarins, the structure-antioxidant activity... more
Coumarins have attracted intense interest in recent years because of their diverse pharmacological properties. According to our continuing investigations of biological effects of several coumarins, the structure-antioxidant activity relationships (SARs) of six naturally occurring coumarins and their 16 synthesized analogues were established. For this purpose, the very reliable colorimetric assay (ferric reducing antioxidant power) modified to be used in 96-well microplates was used. This approach, which determines the reducing capacity of tested compounds directly, has previously been used for the determination of SARs of flavonoids, but has not been used for SAR determination of coumarins. It is known that the biological properties and consequently, therapeutic application of simple coumarins depends upon the pattern of substitution. It was established that 7,8-dihydroxy- and 6,7-dihydroxy-4-methylcoumarins have shown excellent ferric-reducing properties.
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The bulbs of Zephyranthes robusta (Amaryllidaceae) have been extensively analyzed for their chemical constituents, resulting in the isolation of 13 alkaloids. The chemical structures of the isolated compounds were elucidated by... more
The bulbs of Zephyranthes robusta (Amaryllidaceae) have been extensively analyzed for their chemical constituents, resulting in the isolation of 13 alkaloids. The chemical structures of the isolated compounds were elucidated by mass-spectrometric, and 1D- and 2D-NMR spectroscopic experiments. The complete NMR assignments were achieved for hippeastidine. All isolated alkaloids were evaluated for their erythrocytic acetylcholinesterase and serum butyrylcholinesterase inhibitory activities using the Ellman's method. Significant acetylcholinesterase inhibition activity was exhibited by 8-O-demethylmaritidine (IC₅₀ (HuAChE) 28.0±0.9 μM).