The present study was carried out to investigate the antimicrobial activity of crude extracts of ... more The present study was carried out to investigate the antimicrobial activity of crude extracts of Commiphora gum. Methanol extract of Commiphora myrrha was antifungal to Aspergillus niger, whereas petroleum ether extract of Commiphora myrrha was strongly antibacterial against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and antifungal to Aspergillus niger and Candida albicans. Pure quercetin and β-sitosterol were isolated from the fractions C1 and C2 of aqueous and petroleum ether extracts, respectively and screened in vitro for antimicrobial activity.
Narcissus pseudonarcissus is a member of the Amaryllidaceae family. Several members of this famil... more Narcissus pseudonarcissus is a member of the Amaryllidaceae family. Several members of this family contain Galanthamine. Galanthamine is an inhibitor of acetyl-cholinesterase (AChE) which is used as medicine to treat Alzheimer Disease (AD). Supercritical carbon dioxide extraction as an environmentally friendly method, has several advantages over the conventional extraction method for the isolation of this alkaloid from the waste of the bulbs left after flower production. However, for successful extraction, several process parameters (e.g. pressure, temperature, time of extraction, solvent flow rate) and raw material related parameters (particle morphology and size, moisture content, cell destruction, and chemical reactions for setting free extract compounds) should be taken in consideration for an optimal production. Temperature, pressure, particle size as well as type of modifier were investigated in this work. As comparison a classical extraction method was used, consisting of aci...
Narcissus, a member of Amaryllidaceae family, has yielded more than 100 of alkaloids. Galanthamin... more Narcissus, a member of Amaryllidaceae family, has yielded more than 100 of alkaloids. Galanthamine is one of the identified Narcissus alkaloids. It is a highly selective inhibitor of acetyl cholinesterase (AChE) at submicromolar concentration. AChE inhibitors are the only approved drug for treating Alzheimer patients. Acquiring galanthamine from natural sources as medicine involves a reliable “clean” process to conform to the pharmaceutical industries requirements. Supercritical carbon dioxide extraction is an environmentally friendly modern technology and has advantages over the conventional extraction method for isolation of natural compounds, such as a specific selectivity of compound and it provides higher purity. In this work, supercritical CO2 (SC CO2) extraction of galanthamine from Narcissus pseudonarcissus bulbs was optimized for added modifiers and extraction conditions. The extractability of Narcissus pseudonarcissus alkaloids was identified using GC-MS analysis and quant...
Brassica rapa (var. raapstelen) and Raphanus sativus (red radish) are being used as food and fodd... more Brassica rapa (var. raapstelen) and Raphanus sativus (red radish) are being used as food and fodder while also known as model in recent plant research due to the diversity of metabolites as well as genetic resemblance to Arabidopsis. This study explains the change in metabolites (amino acids, organic acids, chlorophyll, carotenoids, tocopherols, ascorbic acid, sucrose, phenylpropanoids and glucosinolates) during plant development. In present study the metabolomic variation in relation to plant growth has been evaluated, for Brassica rapa (var. raapstelen) and red radish (Raphanus sativus) at three different developmental stages. A non-targeted and targeted metabolomic approach by NMR and HPLC in combination with Principal component analysis (PCA) of the data was used to identify phytochemicals being influenced by plant growth. The results lead to the better understanding of metabolic changes during plant development and show the importance of plant age with respect to the metabolomi...
The introduction of the concept of systems biology, enabling the study of living systems from a h... more The introduction of the concept of systems biology, enabling the study of living systems from a holistic perspective based on the profiling of a multitude of biochemical components, opens up a unique and novel opportunity to reinvestigate natural products. In the study of their bioactivity, the necessary reductionistic approach on single active components has been successful in the discovery of new medicines, but at the same time the synergetic effects of components were lost. Systems biology, and especially metabolomics, is the ultimate phenotyping. It opens up the possibility of studying the effect of complex mixtures, such as those used in Traditional Chinese Medicine, in complex biological systems; abridging it with molecular pharmacology. This approach is considered to have the potential to revolutionize natural product research and to advance the
Background: Rivipansel is a pan-selectin inhibitor in phase 3 development for treatment of sickle... more Background: Rivipansel is a pan-selectin inhibitor in phase 3 development for treatment of sickle cell disease vaso-occlusive crises. Previous studies have shown almost complete elimination of unchanged drug in urine following an intravenous (IV) infusion. The objective of this study was to evaluate the effect of varying degrees of renal impairment on the pharmacokinetics (PK), safety, and tolerability of rivipansel. Methods: A single 840-mg dose of open-label rivipansel was administered IV over 20 minutes to 7 subjects with mild, 7 with moderate, and 7 with severe renal impairment, and to 7 healthy subjects with normal renal function. Classification of renal impairment groups was based on the Cockroft-Gault estimated glomerular filtration rate (CGeGFR): 60-89 mL/min (mild), 30-59 mL/min (moderate), and <30 mL/min (severe). Normal renal function was CGeGFR ≥90 mL/min. Plasma and urine samples were collected for 96 hours postdose and analyzed by validated LC-MS/MS methods. Pharmac...
Descriptions of the use of natural products in traditional medicine have served as starting point... more Descriptions of the use of natural products in traditional medicine have served as starting points for new therapeutics. The details of the traditional use of these organisms can provide important information for future drug discovery and development efforts. Recent technologic advances provide the framework to leverage ethnopharmacologic data in the drug discovery process. Information on the traditional harvest, preparation, storage, and administration of the organisms, and the natural products they contain, provides valuable details regarding characteristics of the active compounds. Importantly, researchers can now rapidly analyze and identify the multiple, and often synergistic, compounds contained in these natural products. Although we are entering the acme of ethnopharmacology, where information regarding the traditional use of organisms can provide valuable natural product leads and accelerate the identification of new therapeutics, this ethnopharmacologic resource is threaten...
Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognite impairment a... more Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognite impairment and personality changes. The development of drugs for the treatment of the cognitive deficits of AD has focused on agents which counteract loss in cholinergic activities. These symptons of AD have been successfully treated with acetylcholinesterase (AchE) inhibitors (eg. galanthamine). There still is great interest in finding better AchE inhibitors. We use Ellmann's microplate assay and silica gel thin-layer chromatography (TLC) to screen natural products from plants as new sources of AchE inhibitors.
Factorial design was applied in order to study the effects of operating temperature , operating p... more Factorial design was applied in order to study the effects of operating temperature , operating pressure and matrix particle size in supercritical carbon dioxide (sc-CO2) extraction of Galanthamine (GAL) from dried bulbs of Narcissus pseudonarcissus var. Carlton. Statistical analysis was performed using the Design-Expert software package. The experiments show that operating temperature (X1) and particle size (X3) are significantly affecting the extracted amount of GAL. Within the experimental range of the studied variables, a model of linear empirical correlation resulted in a good agreement with the experimental results.
ABSTRACT This chapter presents characterization of some isoprenoid–biosynthetic enzymes from plan... more ABSTRACT This chapter presents characterization of some isoprenoid–biosynthetic enzymes from plant cell cultures. Plant secondary metabolites are biosynthesized from simple building blocks supplied by primary metabolism. Two important metabolic routes include the shikimate pathway and the isoprenoid biosynthesis. The shikimate pathway leads to the synthesis of phenolic compounds and the aromatic amino acids phenylalanine, tyrosine, and tryptophan. The isoprenoid biosynthesis is a heavily branched pathway leading to a broad spectrum of compounds. Plant enzymes can often be extracted with more ease and better yields from plant cell cultures as compared to the intact plants. Acetoacetyl-CoA thiolase catalyses the reversible condensation of 2 molecules of acetyl-CoA yielding acetoacetyl-CoA and CoASH. The spectrophotometric assay is based on the monitoring of the, CoASH depending, rate of consumption of acetoacetyl-CoA at 300 nm. 3-Hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase couples another acetyl-CoA molecule to acetoacetyl-CoA, yielding HMG-CoA and CoASH. The enzyme is irreversibly inhibited by L-659,699, a metabolite known to inhibit mammalian HMG-CoA synthase specifically, indicating a similar catalytic mechanism for the plant enzyme.
Cannabis is one of the oldest known medicinal plants, and a large variety of biological activitie... more Cannabis is one of the oldest known medicinal plants, and a large variety of biological activities have been described. The main constituents, the cannabinoids, are thought to be most important for these activities. Although smoking of cannabis is by far the most common way of ...
Natural deep eutectic solvents (NADES) are combinations of two, or in a few cases three, common p... more Natural deep eutectic solvents (NADES) are combinations of two, or in a few cases three, common primary metabolites that form a liquid when mixed in a determined ratio in certain conditions (Dai et al., 2013a). Their components are mono or disaccharides, amino acids, simple organic acids (malic, lactic or citric acid) and other compounds such as choline chloride. The NADES have several advantages over other eutectic solvents or ionic liquids, being non-toxic, cheap and having all features of a “green solvent”. They have been proved to increase the solubility of a great variety of scarcely water-soluble compounds such as rutin, quercetin, cinnamic acid, taxol, carthamin, ginkgolide B as well as the macromolecules gluten, DNA, and starch (Dai et al., 2013b, 2013c, 2014). There are different types of NADES according to the nature of their components: acid, basic, neutral or ionic liquids. In this case, Narcissus pseudonarcissus alkaloids were extracted from dried bulb material with hot...
Catharanthus roseus is still the only source for the powerful antitumour drugs vinblastine and vi... more Catharanthus roseus is still the only source for the powerful antitumour drugs vinblastine and vincristine. Some other pharmaceutical compounds from this plant, ajmalicine and serpentine are also of economical importance. Although C. roseus has been studied extensively and was subject of numerous publications, a full characterization of its alkaloid pathway is not yet achieved. Here we review some of the recent work done on this plant. Most of the work focussed on early steps of the pathway, particularly the discovery of the 2-C-methyl-d-erythritol 4-phosphate (MEP)-pathway leading to terpenoids. Both mevalonate and MEP pathways are utilized by plants with apparent cross-talk between them across different compartments. Many genes of the early steps in Catharanthus alkaloid pathway have been cloned and overexpressed to improve the biosynthesis. Research on the late steps in the pathway resulted in cloning of several genes. Enzymes and genes involved in indole alkaloid biosynthesis an...
The present study was carried out to investigate the antimicrobial activity of crude extracts of ... more The present study was carried out to investigate the antimicrobial activity of crude extracts of Commiphora gum. Methanol extract of Commiphora myrrha was antifungal to Aspergillus niger, whereas petroleum ether extract of Commiphora myrrha was strongly antibacterial against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and antifungal to Aspergillus niger and Candida albicans. Pure quercetin and β-sitosterol were isolated from the fractions C1 and C2 of aqueous and petroleum ether extracts, respectively and screened in vitro for antimicrobial activity.
Narcissus pseudonarcissus is a member of the Amaryllidaceae family. Several members of this famil... more Narcissus pseudonarcissus is a member of the Amaryllidaceae family. Several members of this family contain Galanthamine. Galanthamine is an inhibitor of acetyl-cholinesterase (AChE) which is used as medicine to treat Alzheimer Disease (AD). Supercritical carbon dioxide extraction as an environmentally friendly method, has several advantages over the conventional extraction method for the isolation of this alkaloid from the waste of the bulbs left after flower production. However, for successful extraction, several process parameters (e.g. pressure, temperature, time of extraction, solvent flow rate) and raw material related parameters (particle morphology and size, moisture content, cell destruction, and chemical reactions for setting free extract compounds) should be taken in consideration for an optimal production. Temperature, pressure, particle size as well as type of modifier were investigated in this work. As comparison a classical extraction method was used, consisting of aci...
Narcissus, a member of Amaryllidaceae family, has yielded more than 100 of alkaloids. Galanthamin... more Narcissus, a member of Amaryllidaceae family, has yielded more than 100 of alkaloids. Galanthamine is one of the identified Narcissus alkaloids. It is a highly selective inhibitor of acetyl cholinesterase (AChE) at submicromolar concentration. AChE inhibitors are the only approved drug for treating Alzheimer patients. Acquiring galanthamine from natural sources as medicine involves a reliable “clean” process to conform to the pharmaceutical industries requirements. Supercritical carbon dioxide extraction is an environmentally friendly modern technology and has advantages over the conventional extraction method for isolation of natural compounds, such as a specific selectivity of compound and it provides higher purity. In this work, supercritical CO2 (SC CO2) extraction of galanthamine from Narcissus pseudonarcissus bulbs was optimized for added modifiers and extraction conditions. The extractability of Narcissus pseudonarcissus alkaloids was identified using GC-MS analysis and quant...
Brassica rapa (var. raapstelen) and Raphanus sativus (red radish) are being used as food and fodd... more Brassica rapa (var. raapstelen) and Raphanus sativus (red radish) are being used as food and fodder while also known as model in recent plant research due to the diversity of metabolites as well as genetic resemblance to Arabidopsis. This study explains the change in metabolites (amino acids, organic acids, chlorophyll, carotenoids, tocopherols, ascorbic acid, sucrose, phenylpropanoids and glucosinolates) during plant development. In present study the metabolomic variation in relation to plant growth has been evaluated, for Brassica rapa (var. raapstelen) and red radish (Raphanus sativus) at three different developmental stages. A non-targeted and targeted metabolomic approach by NMR and HPLC in combination with Principal component analysis (PCA) of the data was used to identify phytochemicals being influenced by plant growth. The results lead to the better understanding of metabolic changes during plant development and show the importance of plant age with respect to the metabolomi...
The introduction of the concept of systems biology, enabling the study of living systems from a h... more The introduction of the concept of systems biology, enabling the study of living systems from a holistic perspective based on the profiling of a multitude of biochemical components, opens up a unique and novel opportunity to reinvestigate natural products. In the study of their bioactivity, the necessary reductionistic approach on single active components has been successful in the discovery of new medicines, but at the same time the synergetic effects of components were lost. Systems biology, and especially metabolomics, is the ultimate phenotyping. It opens up the possibility of studying the effect of complex mixtures, such as those used in Traditional Chinese Medicine, in complex biological systems; abridging it with molecular pharmacology. This approach is considered to have the potential to revolutionize natural product research and to advance the
Background: Rivipansel is a pan-selectin inhibitor in phase 3 development for treatment of sickle... more Background: Rivipansel is a pan-selectin inhibitor in phase 3 development for treatment of sickle cell disease vaso-occlusive crises. Previous studies have shown almost complete elimination of unchanged drug in urine following an intravenous (IV) infusion. The objective of this study was to evaluate the effect of varying degrees of renal impairment on the pharmacokinetics (PK), safety, and tolerability of rivipansel. Methods: A single 840-mg dose of open-label rivipansel was administered IV over 20 minutes to 7 subjects with mild, 7 with moderate, and 7 with severe renal impairment, and to 7 healthy subjects with normal renal function. Classification of renal impairment groups was based on the Cockroft-Gault estimated glomerular filtration rate (CGeGFR): 60-89 mL/min (mild), 30-59 mL/min (moderate), and <30 mL/min (severe). Normal renal function was CGeGFR ≥90 mL/min. Plasma and urine samples were collected for 96 hours postdose and analyzed by validated LC-MS/MS methods. Pharmac...
Descriptions of the use of natural products in traditional medicine have served as starting point... more Descriptions of the use of natural products in traditional medicine have served as starting points for new therapeutics. The details of the traditional use of these organisms can provide important information for future drug discovery and development efforts. Recent technologic advances provide the framework to leverage ethnopharmacologic data in the drug discovery process. Information on the traditional harvest, preparation, storage, and administration of the organisms, and the natural products they contain, provides valuable details regarding characteristics of the active compounds. Importantly, researchers can now rapidly analyze and identify the multiple, and often synergistic, compounds contained in these natural products. Although we are entering the acme of ethnopharmacology, where information regarding the traditional use of organisms can provide valuable natural product leads and accelerate the identification of new therapeutics, this ethnopharmacologic resource is threaten...
Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognite impairment a... more Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognite impairment and personality changes. The development of drugs for the treatment of the cognitive deficits of AD has focused on agents which counteract loss in cholinergic activities. These symptons of AD have been successfully treated with acetylcholinesterase (AchE) inhibitors (eg. galanthamine). There still is great interest in finding better AchE inhibitors. We use Ellmann's microplate assay and silica gel thin-layer chromatography (TLC) to screen natural products from plants as new sources of AchE inhibitors.
Factorial design was applied in order to study the effects of operating temperature , operating p... more Factorial design was applied in order to study the effects of operating temperature , operating pressure and matrix particle size in supercritical carbon dioxide (sc-CO2) extraction of Galanthamine (GAL) from dried bulbs of Narcissus pseudonarcissus var. Carlton. Statistical analysis was performed using the Design-Expert software package. The experiments show that operating temperature (X1) and particle size (X3) are significantly affecting the extracted amount of GAL. Within the experimental range of the studied variables, a model of linear empirical correlation resulted in a good agreement with the experimental results.
ABSTRACT This chapter presents characterization of some isoprenoid–biosynthetic enzymes from plan... more ABSTRACT This chapter presents characterization of some isoprenoid–biosynthetic enzymes from plant cell cultures. Plant secondary metabolites are biosynthesized from simple building blocks supplied by primary metabolism. Two important metabolic routes include the shikimate pathway and the isoprenoid biosynthesis. The shikimate pathway leads to the synthesis of phenolic compounds and the aromatic amino acids phenylalanine, tyrosine, and tryptophan. The isoprenoid biosynthesis is a heavily branched pathway leading to a broad spectrum of compounds. Plant enzymes can often be extracted with more ease and better yields from plant cell cultures as compared to the intact plants. Acetoacetyl-CoA thiolase catalyses the reversible condensation of 2 molecules of acetyl-CoA yielding acetoacetyl-CoA and CoASH. The spectrophotometric assay is based on the monitoring of the, CoASH depending, rate of consumption of acetoacetyl-CoA at 300 nm. 3-Hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase couples another acetyl-CoA molecule to acetoacetyl-CoA, yielding HMG-CoA and CoASH. The enzyme is irreversibly inhibited by L-659,699, a metabolite known to inhibit mammalian HMG-CoA synthase specifically, indicating a similar catalytic mechanism for the plant enzyme.
Cannabis is one of the oldest known medicinal plants, and a large variety of biological activitie... more Cannabis is one of the oldest known medicinal plants, and a large variety of biological activities have been described. The main constituents, the cannabinoids, are thought to be most important for these activities. Although smoking of cannabis is by far the most common way of ...
Natural deep eutectic solvents (NADES) are combinations of two, or in a few cases three, common p... more Natural deep eutectic solvents (NADES) are combinations of two, or in a few cases three, common primary metabolites that form a liquid when mixed in a determined ratio in certain conditions (Dai et al., 2013a). Their components are mono or disaccharides, amino acids, simple organic acids (malic, lactic or citric acid) and other compounds such as choline chloride. The NADES have several advantages over other eutectic solvents or ionic liquids, being non-toxic, cheap and having all features of a “green solvent”. They have been proved to increase the solubility of a great variety of scarcely water-soluble compounds such as rutin, quercetin, cinnamic acid, taxol, carthamin, ginkgolide B as well as the macromolecules gluten, DNA, and starch (Dai et al., 2013b, 2013c, 2014). There are different types of NADES according to the nature of their components: acid, basic, neutral or ionic liquids. In this case, Narcissus pseudonarcissus alkaloids were extracted from dried bulb material with hot...
Catharanthus roseus is still the only source for the powerful antitumour drugs vinblastine and vi... more Catharanthus roseus is still the only source for the powerful antitumour drugs vinblastine and vincristine. Some other pharmaceutical compounds from this plant, ajmalicine and serpentine are also of economical importance. Although C. roseus has been studied extensively and was subject of numerous publications, a full characterization of its alkaloid pathway is not yet achieved. Here we review some of the recent work done on this plant. Most of the work focussed on early steps of the pathway, particularly the discovery of the 2-C-methyl-d-erythritol 4-phosphate (MEP)-pathway leading to terpenoids. Both mevalonate and MEP pathways are utilized by plants with apparent cross-talk between them across different compartments. Many genes of the early steps in Catharanthus alkaloid pathway have been cloned and overexpressed to improve the biosynthesis. Research on the late steps in the pathway resulted in cloning of several genes. Enzymes and genes involved in indole alkaloid biosynthesis an...
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Papers by Robert Verpoorte