Maurice Iwu - Academia.edu (original) (raw)
Papers by Maurice Iwu
Planta Medica, 2005
The dichloromethane-methanol (1/1) extract of the stem bark of Turraeanthus africanus (Meliaceae)... more The dichloromethane-methanol (1/1) extract of the stem bark of Turraeanthus africanus (Meliaceae) showed remarkable antimicrobial activity against Cryptococcus neoformans, Staphylococcus aureus and methicillin-resistant S. aureus. Phytochemical investigation of this extract afforded six new diterpenoid derivatives, (+)-16-acetoxy-12,15-epoxylabda-8(17),12,14-triene ( 3), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin A, 4), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin B, 5), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin C, 6), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin D, 7) and (12 S,13 S,15 R)-12,15-epoxy-15-methoxy- ent-labd-8(17)-en-16-al (turraeanin E, 9) together with the known compounds, 15,16-epoxy- ent-labda-8(17),13(16),14-triene ( 1), (+)-pumiloxide ( 2), ent-labda-8(17),12 ( E)-diene-15,16-dial ( 8) and 16-acetoxy-12( R),15-epoxy-15beta-hydroxylabda-8(17),13 (16)-diene ( 10). Compound 10 was obtained as its acetoxy derivative ( 10a) and compound 11 was the product of hydrolysis of 6. Antimicrobial activity of the isolates was assayed and compounds 8, 9, 10a and 11 exhibited significant activities.
Evidence-Based Complementary and Alternative Medicine, 2011
Managing schizophrenia has never been a trivial matter. Furthermore, while classical antipsychoti... more Managing schizophrenia has never been a trivial matter. Furthermore, while classical antipsychotics induce extrapyramidal side effects and hyperprolactinaemia, atypical antipsychotics lead to diabetes, hyperlipidaemia, and weight gain. Moreover, even with newer drugs, a sizable proportion of patients do not show significant improvement. Alstonine is an indole alkaloid identified as the major component of a plant-based remedy used in Nigeria to treat the mentally ill. Alstonine presents a clear antipsychotic profile in rodents, apparently with differential effects in distinct dopaminergic pathways. The aim of this study was to complement the antipsychotic profile of alstonine, verifying its effects on brain amines in mouse frontal cortex and striatum. Additionally, we examined if alstonine induces some hormonal and metabolic changes common to antipsychotics. HPLC data reveal that alstonine increases serotonergic transmission and increases intraneuronal dopamine catabolism. In relatio...
Healing Plants of Nigeria
Journal of Natural Products, 1997
Economic Botany, 1994
Handbook of African Medicinal Plants provides a comprehensive review of over 1,000 species of pla... more Handbook of African Medicinal Plants provides a comprehensive review of over 1,000 species of plants employed in indigenous African medicine. It gives a concise description of the materia medica of an enormous and extensively varied continent, with well over 2,000 ...
Andrographolide (1) a bitter, diterpenes lactone is the most biologically active constituent from... more Andrographolide (1) a bitter, diterpenes lactone is the most biologically active constituent from Andrographis paniculata. Andrographolide showed in vitro inhibition of the growth of Ebola virus (Zaire) with EC50 activity of 10 µM which is twenty-five-fold the activity of the control Favipiravir (EC50 = 250µM) in the Crystal violet (Plaque reduction/ Neutral red (Toxicity) assay. It also showed significant activity against Dengue fever virus with EC50 value of 0.56 µg/ml in the Visual (Cytopathic effect/ Toxicity) Assay and EC50 of 0.58 µg/ml in the Neutral Red (Cytopathic effect/ Toxicity) Assay (comparable to the values obtained with 6-Azauridine as the positive control EC50 = 0.32 µg/ml and 0.38 µg/ml in the respective bioassays; and against SARS Coronavirus. Andrographolide had an EC50 of 1.2 µg/ml in the Visual (cytopathic effect/toxicity) assay and 1.1 µg/ml in the Neutral Red (cytopathic effect/toxicity) assay. The compound exerts several immunomodulatory properties. In exper...
The methanol extract of Peucedanum zenkeri L. seeds showed antimicrobial activity which is concen... more The methanol extract of Peucedanum zenkeri L. seeds showed antimicrobial activity which is concentrated in the n-hexane fraction. Bioactivity-guided chromatographic fractionation of the seeds of P. zenkeri led to the isolation and characterization of five major coumarins, umbelliprenin, imperatorin, bergapten, isopimpinellin and byakangelicin, as well as two minor coumarins, 7-methoxy coumarin and 5-hydroxy-8-methoxy psoralen. Amongst the isolated compounds only imperatorin, bergapten and isopimpinellin were found to possess anti-microbial activity.
Journal of Natural …, 1995
Until recently, the prevailing attitude in developed nations regarded the world's genetic... more Until recently, the prevailing attitude in developed nations regarded the world's genetic resources, which are mainly concentrated in the developing world, as a common resource of humankind, to be exploited freely irrespective of national origin. With the devastation being wreaked in the tropical rainforests and the resurgence in interest in recent years in the discovery of novel drugs from natural sources, particularly plants and marine organisms, the international scientific community has realized that the conservation of these global genetic resources and the indigenous knowledge associated with their use are of primary importance if their potential is to be fully explored. With this realization has come a recognition that these goals must be achieved through collaboration with, and fair and equitable compensation of, the scientists and communities of the genetically rich source countries. The signing of the United Nations Convention on Biological Diversity by nearly all of the World's nations has emphasized the need for the implementation of such policies. In this review, the articles of the Convention of relevance to the activities and practices of the natural products scientific community are briefly discussed. This discussion is followed by a summary of policies for international collaboration and compensation being implemented by several developed country organizations, and the perspectives on the current developments given by representatives of some of the source countries located in the regions of greatest biodiversity.
The study was aimed at investigating the antioxidant properties of lupeol isolated from the metha... more The study was aimed at investigating the antioxidant properties of lupeol isolated from the methanol leaf extract of Crateva adansonii. In order to assess the antioxidant effect of lupeol in vitro (1, 1-diphenyl-2-picrylhydrazyl radical (DPPH) spectrophotometric assay, Ferric reducing antioxidant power (FRAP) assay, Hydrogen peroxide scavenging assay, Hydroxyl radical scavenging assay, ABTS radical cation scavenging activity, Anti-lipid peroxidation assay, β -Carotene bleaching assay, Superoxide anion radical scavenging assay) and in vivo (Lipid peroxidation assay, Assay of catalase (CAT) activity, Assay of reduced glutathione (GSH) concentration) experimental models were used. The effect of DPPH (1, 1-diphenyl-2-picrylhydrazyl) free radical scavenging showed that lupeol had better percentage antioxidant activities at high concentrations when compared with ascorbic acid (88.40 % and 82.37 % at 800 μg/ml respectively). The FRAP (Ferric reducing antioxidant power) results were similar...
Natural Product Communications
From an extract of the stem bark of Xymalos monospora, a bis-benzylisoquinoline alkaloid (1), thr... more From an extract of the stem bark of Xymalos monospora, a bis-benzylisoquinoline alkaloid (1), three benzylisoquinoline alkaloids (mollinedine, 1-(p-methoxybenzyl)-6,7-methylenedioxyisoquino-line, doryafranine), and an aporphine alkaloid (N-methyllaurotetanine) were isolated. These compounds were tested for growth inhibitory activity against bloodstream forms of three strains of African trypanosomes. In vitro IC50 values starting from 1.8 μg /mL were obtained.
Food Research International
The baobab (Adansonia digitata L.) is a magnificent tree revered throughout Africa and is becomin... more The baobab (Adansonia digitata L.) is a magnificent tree revered throughout Africa and is becoming recognized for its high nutritional and medicinal values. Despite numerous reports on the pharmacological potential, little is known about its chemical compositions. In this study, four hydroxycinnamic acid glycosides (1-4), six iridoid glycosides (5-10), and three phenylethanoid glycosides (11-13) were isolated from the dried baobab fruit pulp. Their structures were determined by means of spectroscopic analyses, including HRMS, 1H and 13C NMR and 2D experiments (COSY, HSQC, HMBC, and ROESY). All 13 compounds isolated were reported for the first time in the genus of Adansonia. An ultra high-performance liquid chromatography high-resolution accurate-mass mass spectrometry (UHPLC HRAM MS) method was used to conduct further investigation of the chemical compositions of the hydro-alcohol baobab fruit pulp extract. Hydroxycinnamic acid glycosides, iridoid glycosides and phenylethanoid glycosides were found to be the main components in baobab fruit pulp.
Public reporting burden for this collection of information is estimated to average 1 hour per res... more Public reporting burden for this collection of information is estimated to average 1 hour per response, including me time for reviewing instructions, searching existing data sources, gathering and maintaining the data needei and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Washington
Functional Foods and Nutraceuticals, 2016
Http Www Libreriasaulamedica Com, 1993
Phytother Res, 1990
... MM IWU, 0. A. IGBOKO AND 0. K. ELEKWA ... It has also been observed that the compound causes ... more ... MM IWU, 0. A. IGBOKO AND 0. K. ELEKWA ... It has also been observed that the compound causes specific changes in the nucleolus, and increased synthesis of guanine and cysteine-rich RNA occurs, with concomitant decrease in ribosomal RNA in the cytoplasm (Zimmerman ...
... Brunelli G. (1987) Des esprits aux microbes, sant6 et societ6 en transformation chez les Zor6... more ... Brunelli G. (1987) Des esprits aux microbes, sant6 et societ6 en transformation chez les Zor6 de l'Amazonie Br6silliene ... Costa-Campos L, Elisabetsky E, Lara DR, Nunes DS, Carlson TJ, King SR, Ubilas R, Iwu M. (1999) Antipsichotics profile of alstonine: ethnopharmacology of a ...
Advances in Phytomedicine, 2002
Planta Medica, 2005
The dichloromethane-methanol (1/1) extract of the stem bark of Turraeanthus africanus (Meliaceae)... more The dichloromethane-methanol (1/1) extract of the stem bark of Turraeanthus africanus (Meliaceae) showed remarkable antimicrobial activity against Cryptococcus neoformans, Staphylococcus aureus and methicillin-resistant S. aureus. Phytochemical investigation of this extract afforded six new diterpenoid derivatives, (+)-16-acetoxy-12,15-epoxylabda-8(17),12,14-triene ( 3), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin A, 4), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin B, 5), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin C, 6), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin D, 7) and (12 S,13 S,15 R)-12,15-epoxy-15-methoxy- ent-labd-8(17)-en-16-al (turraeanin E, 9) together with the known compounds, 15,16-epoxy- ent-labda-8(17),13(16),14-triene ( 1), (+)-pumiloxide ( 2), ent-labda-8(17),12 ( E)-diene-15,16-dial ( 8) and 16-acetoxy-12( R),15-epoxy-15beta-hydroxylabda-8(17),13 (16)-diene ( 10). Compound 10 was obtained as its acetoxy derivative ( 10a) and compound 11 was the product of hydrolysis of 6. Antimicrobial activity of the isolates was assayed and compounds 8, 9, 10a and 11 exhibited significant activities.
Evidence-Based Complementary and Alternative Medicine, 2011
Managing schizophrenia has never been a trivial matter. Furthermore, while classical antipsychoti... more Managing schizophrenia has never been a trivial matter. Furthermore, while classical antipsychotics induce extrapyramidal side effects and hyperprolactinaemia, atypical antipsychotics lead to diabetes, hyperlipidaemia, and weight gain. Moreover, even with newer drugs, a sizable proportion of patients do not show significant improvement. Alstonine is an indole alkaloid identified as the major component of a plant-based remedy used in Nigeria to treat the mentally ill. Alstonine presents a clear antipsychotic profile in rodents, apparently with differential effects in distinct dopaminergic pathways. The aim of this study was to complement the antipsychotic profile of alstonine, verifying its effects on brain amines in mouse frontal cortex and striatum. Additionally, we examined if alstonine induces some hormonal and metabolic changes common to antipsychotics. HPLC data reveal that alstonine increases serotonergic transmission and increases intraneuronal dopamine catabolism. In relatio...
Healing Plants of Nigeria
Journal of Natural Products, 1997
Economic Botany, 1994
Handbook of African Medicinal Plants provides a comprehensive review of over 1,000 species of pla... more Handbook of African Medicinal Plants provides a comprehensive review of over 1,000 species of plants employed in indigenous African medicine. It gives a concise description of the materia medica of an enormous and extensively varied continent, with well over 2,000 ...
Andrographolide (1) a bitter, diterpenes lactone is the most biologically active constituent from... more Andrographolide (1) a bitter, diterpenes lactone is the most biologically active constituent from Andrographis paniculata. Andrographolide showed in vitro inhibition of the growth of Ebola virus (Zaire) with EC50 activity of 10 µM which is twenty-five-fold the activity of the control Favipiravir (EC50 = 250µM) in the Crystal violet (Plaque reduction/ Neutral red (Toxicity) assay. It also showed significant activity against Dengue fever virus with EC50 value of 0.56 µg/ml in the Visual (Cytopathic effect/ Toxicity) Assay and EC50 of 0.58 µg/ml in the Neutral Red (Cytopathic effect/ Toxicity) Assay (comparable to the values obtained with 6-Azauridine as the positive control EC50 = 0.32 µg/ml and 0.38 µg/ml in the respective bioassays; and against SARS Coronavirus. Andrographolide had an EC50 of 1.2 µg/ml in the Visual (cytopathic effect/toxicity) assay and 1.1 µg/ml in the Neutral Red (cytopathic effect/toxicity) assay. The compound exerts several immunomodulatory properties. In exper...
The methanol extract of Peucedanum zenkeri L. seeds showed antimicrobial activity which is concen... more The methanol extract of Peucedanum zenkeri L. seeds showed antimicrobial activity which is concentrated in the n-hexane fraction. Bioactivity-guided chromatographic fractionation of the seeds of P. zenkeri led to the isolation and characterization of five major coumarins, umbelliprenin, imperatorin, bergapten, isopimpinellin and byakangelicin, as well as two minor coumarins, 7-methoxy coumarin and 5-hydroxy-8-methoxy psoralen. Amongst the isolated compounds only imperatorin, bergapten and isopimpinellin were found to possess anti-microbial activity.
Journal of Natural …, 1995
Until recently, the prevailing attitude in developed nations regarded the world's genetic... more Until recently, the prevailing attitude in developed nations regarded the world's genetic resources, which are mainly concentrated in the developing world, as a common resource of humankind, to be exploited freely irrespective of national origin. With the devastation being wreaked in the tropical rainforests and the resurgence in interest in recent years in the discovery of novel drugs from natural sources, particularly plants and marine organisms, the international scientific community has realized that the conservation of these global genetic resources and the indigenous knowledge associated with their use are of primary importance if their potential is to be fully explored. With this realization has come a recognition that these goals must be achieved through collaboration with, and fair and equitable compensation of, the scientists and communities of the genetically rich source countries. The signing of the United Nations Convention on Biological Diversity by nearly all of the World's nations has emphasized the need for the implementation of such policies. In this review, the articles of the Convention of relevance to the activities and practices of the natural products scientific community are briefly discussed. This discussion is followed by a summary of policies for international collaboration and compensation being implemented by several developed country organizations, and the perspectives on the current developments given by representatives of some of the source countries located in the regions of greatest biodiversity.
The study was aimed at investigating the antioxidant properties of lupeol isolated from the metha... more The study was aimed at investigating the antioxidant properties of lupeol isolated from the methanol leaf extract of Crateva adansonii. In order to assess the antioxidant effect of lupeol in vitro (1, 1-diphenyl-2-picrylhydrazyl radical (DPPH) spectrophotometric assay, Ferric reducing antioxidant power (FRAP) assay, Hydrogen peroxide scavenging assay, Hydroxyl radical scavenging assay, ABTS radical cation scavenging activity, Anti-lipid peroxidation assay, β -Carotene bleaching assay, Superoxide anion radical scavenging assay) and in vivo (Lipid peroxidation assay, Assay of catalase (CAT) activity, Assay of reduced glutathione (GSH) concentration) experimental models were used. The effect of DPPH (1, 1-diphenyl-2-picrylhydrazyl) free radical scavenging showed that lupeol had better percentage antioxidant activities at high concentrations when compared with ascorbic acid (88.40 % and 82.37 % at 800 μg/ml respectively). The FRAP (Ferric reducing antioxidant power) results were similar...
Natural Product Communications
From an extract of the stem bark of Xymalos monospora, a bis-benzylisoquinoline alkaloid (1), thr... more From an extract of the stem bark of Xymalos monospora, a bis-benzylisoquinoline alkaloid (1), three benzylisoquinoline alkaloids (mollinedine, 1-(p-methoxybenzyl)-6,7-methylenedioxyisoquino-line, doryafranine), and an aporphine alkaloid (N-methyllaurotetanine) were isolated. These compounds were tested for growth inhibitory activity against bloodstream forms of three strains of African trypanosomes. In vitro IC50 values starting from 1.8 μg /mL were obtained.
Food Research International
The baobab (Adansonia digitata L.) is a magnificent tree revered throughout Africa and is becomin... more The baobab (Adansonia digitata L.) is a magnificent tree revered throughout Africa and is becoming recognized for its high nutritional and medicinal values. Despite numerous reports on the pharmacological potential, little is known about its chemical compositions. In this study, four hydroxycinnamic acid glycosides (1-4), six iridoid glycosides (5-10), and three phenylethanoid glycosides (11-13) were isolated from the dried baobab fruit pulp. Their structures were determined by means of spectroscopic analyses, including HRMS, 1H and 13C NMR and 2D experiments (COSY, HSQC, HMBC, and ROESY). All 13 compounds isolated were reported for the first time in the genus of Adansonia. An ultra high-performance liquid chromatography high-resolution accurate-mass mass spectrometry (UHPLC HRAM MS) method was used to conduct further investigation of the chemical compositions of the hydro-alcohol baobab fruit pulp extract. Hydroxycinnamic acid glycosides, iridoid glycosides and phenylethanoid glycosides were found to be the main components in baobab fruit pulp.
Public reporting burden for this collection of information is estimated to average 1 hour per res... more Public reporting burden for this collection of information is estimated to average 1 hour per response, including me time for reviewing instructions, searching existing data sources, gathering and maintaining the data needei and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Washington
Functional Foods and Nutraceuticals, 2016
Http Www Libreriasaulamedica Com, 1993
Phytother Res, 1990
... MM IWU, 0. A. IGBOKO AND 0. K. ELEKWA ... It has also been observed that the compound causes ... more ... MM IWU, 0. A. IGBOKO AND 0. K. ELEKWA ... It has also been observed that the compound causes specific changes in the nucleolus, and increased synthesis of guanine and cysteine-rich RNA occurs, with concomitant decrease in ribosomal RNA in the cytoplasm (Zimmerman ...
... Brunelli G. (1987) Des esprits aux microbes, sant6 et societ6 en transformation chez les Zor6... more ... Brunelli G. (1987) Des esprits aux microbes, sant6 et societ6 en transformation chez les Zor6 de l'Amazonie Br6silliene ... Costa-Campos L, Elisabetsky E, Lara DR, Nunes DS, Carlson TJ, King SR, Ubilas R, Iwu M. (1999) Antipsichotics profile of alstonine: ethnopharmacology of a ...
Advances in Phytomedicine, 2002