IVAN ADDAE-MENSAH - Academia.edu (original) (raw)
Papers by IVAN ADDAE-MENSAH
A recently developed rapid semi-quantitative Thin Layer Chromatographic (TLC) assay method was ap... more A recently developed rapid semi-quantitative Thin Layer Chromatographic (TLC) assay method was applied in the determination of the existence of substandard or counterfeit artemisinin-based anti-malarial drugs in the Ghanaian market and also tested for its suitability for rapid assessment of drug quality prior to more rigorous analysis of any suspected counterfeit or substandard drugs. Three methods were employed – Basic Tests, Semi-quantitative TLC assay and High Performance Liquid Chromatographic (HPLC) assay. The basic tests showed that each drug contained the requisite active pharmaceutical ingredient (API). Out of the 49 samples (24 single dose and 25 fixed dose combination formulations) assayed by TLC, only 14 (28.6%) were found to comply with pharmacopoeial specifications. Out of the 24 single dose formulations, 9 of which had been found by the TLC assay likely to be within pharmacopoeial limits, only 4 were eventually found to be fully compliant by HPLC analyses. Two others were marginal. On the basis of the TLC assay, only 5 out of the 25 fixed dose combination formulations that are yet to be accurately assayed by HPLC, appear likely to meet pharmacopoeial specifications. The results of the semi-quantitative TLC technique compare favorably with those of the HPLC and hence the method can be used for rapid assessment of the quality of anti-malarial drugs. The results also indicate that the problem of distribution of substandard and possibly counterfeit artemisinin-based anti-malarial drugs exists in Ghana.
The outcomes from recent high profile deliberations concerning African health research and econom... more The outcomes from recent high profile deliberations concerning African health research and economic development all point towards the need for a mechanism to support health innovation on the continent. The mission of the African Network for Drugs and Diagnostics Innovation (ANDI), is to promote and sustain African-led health product innovation to address African public health needs through the assembly of research networks, and building of capacity to support human and economic development. ANDI is widely viewed as the vehicle to implementing some of these recommendations. There is tremendous opportunity for Africa, to leverage the expertise in natural products and traditional medicines in support of this objective to kick-start innovation. This report highlights key recommendations that have emerged through expert forums convened by ANDI on the challenges, opportunities and prospects for investing in this important area of research.
Journal of Applied Research on Medicinal and Aromatic Plants, 2016
Cryptolepis sanguinolenta is a medicinal plant widely used in the treatment of malaria in Ghana. ... more Cryptolepis sanguinolenta is a medicinal plant widely used in the treatment of malaria in Ghana. The increasing demand for its roots coupled with harvesting of the plant in non-sustainable ways has resulted in a substantial decline in its wild populations. The study was conducted to (1) determine the relatedness among C. sanguinolenta wild populations, (2) identify genotypes with high active ingredient (cryptolepine) concentrations and (3) understand the extent to which cryptolepine levels are influenced by soil. Root and stem samples for the study was collected from the Eastern, Ashanti, Brong Ahafo and Volta Regions of Ghana. C. sanguinolenta plants were found in sandy loam/sandy clay loam textured soils of acidic (4.3) to near neutral (6.7) pH ranges. Semi Quantitative Thin Layer Chromatography (SQ-TLC) and High Performance Liquid Chromatography (HPLC) methods were used to quantify the cryptolepine content in the stem and root samples. Cryptolepine concentrations in the stem and roots were not significantly influenced by location. No correlation was found between the soil properties studied and the cryptolepine content in the roots. Results from both SQ-TLC and HPLC analyses indicated that cryptolepine concentrations were on average, twice as much in the roots (0.84 mg/100 mg plant material) compared to the stem (0.42 mg/100 mg plant material). Results of the genetic diversity study showed a genetic diversity of 25% with genetic distances ranging between 0.08 and 0.14. Samples from the same location had the least genetic distances. Bootstrapping performed on the marker data and coefficient of variation calculated from distance resolutions obtained from 800 markers, proved to be of sufficient resolution. Sample sites did not reflect distinct sub-populations, a result of possible gene flow between sampling locations. Findings from this study will be useful for developing domestication protocols for C. sanguinolenta and subsequently the cultivation of elite genotypes.
Phytochemistry, 1990
... DITERPENE AND OTHER CONSTITUENTS OF CLERO DENDRON INERME BASUDEB ACHARI, CHANDANA CHAUDHURI, ... more ... DITERPENE AND OTHER CONSTITUENTS OF CLERO DENDRON INERME BASUDEB ACHARI, CHANDANA CHAUDHURI, CHITTA R. SAHA, PRADEEP K. DUTTA ... 10. Kuho, L, Lee, YW, Nair, V., Nakanishi, K. and Chapya, A. 6. Subramanian, SS, Nair, AGR and Vedantham ...
Heterocycles, 1984
From the stem bark of H.cris~iflorus twelve new isoprenylated indoles were isolated and their str... more From the stem bark of H.cris~iflorus twelve new isoprenylated indoles were isolated and their structures determined; some of these compounds exhibit antifungal activity. From the petrol ether extract of the stem hark of Hexalobus crispiflorus A.Rich. (Annonaceae) the di-isoprenylated indoles 1-13 were isolated (Table 1) .
European Journal of Pharmacology, Nov 1, 1983
The effects of wisanine and dihydrowisanine were studied on stereotyped and aggressive behaviour ... more The effects of wisanine and dihydrowisanine were studied on stereotyped and aggressive behaviour induced by apomorphine (0.5 mg/kg s.c.) in chicks. Pretreatment of chicks with wisanine (0.3-0.6 g/kg i.p.) and dihydrowisanine (0.2-0.4 g/kg i.p.) dose dependently antagonised fighting episodes and pecking of the chick's own feet and those of other chicks. It has been suggested that the antagonism is due to dopaminergic receptor blockade and demonstrates the antipsychotic effect of these drugs.
Journal of Essential Oil Research, Sep 1, 1994
The leaf oil of Diplolophium africanum Turcz. from the Koumondè region of northern Togo was analy... more The leaf oil of Diplolophium africanum Turcz. from the Koumondè region of northern Togo was analyzed using both Kovats indices and GC/MS. We identified 24 compounds including α-pinene (38%) and β-pinene (20%) as the major components followed by p-mentha-1,3,8-triene (11%). Except for a substantial decrease in the amount of the latter compound in one sample, the composition of the oil
Journal of Essential Oil Research, Nov 1, 2000
... tules Uniiersitc! dttl Q u 6 k d Chicoutimi Chicotitimi, QiiGbec G7H 2B1, Cunudu Ivan Addae-M... more ... tules Uniiersitc! dttl Q u 6 k d Chicoutimi Chicotitimi, QiiGbec G7H 2B1, Cunudu Ivan Addae-Mensah,* Dorcas Osei-Safu, William A. Asomanlng and Alfred Oteng-Yeboah Depurtment of Chemistry, Fucttllty of Sciences. Uniieisity ...
Journal of Essential Oil Research, May 1, 1996
The leaf oils of samples of Lippia multiflora Moldenke collected from different geographic areas ... more The leaf oils of samples of Lippia multiflora Moldenke collected from different geographic areas of Togo and from cultivated plants were analyzed by GC and GC/MS. Three types of essential oils were characterized, one which is rich in neral and geranial, (23–89%) and two other types, poor in neral and geranial, containing either 1,8-cineole (16–63%) or thymol (15–40%) and p-cymene
Chemischer Informationsdienst, Sep 28, 1982
ChemInform Abstract Isoliert wurden die Triacylbenzole (I) und (II) sowie der Ketoalkohol (III). ... more ChemInform Abstract Isoliert wurden die Triacylbenzole (I) und (II) sowie der Ketoalkohol (III). Die Strukturen wurden durch 1H-NMR-, UV-und Massenspektroskopie aufgeklärt.
Journal of Natural Products, Nov 1, 1984
Chemischer Informationsdienst, Jan 11, 1983
ChemInform Abstract Isoliert wurden die Triacylbenzole (I) und (II) sowie der Ketoalkohol (III). ... more ChemInform Abstract Isoliert wurden die Triacylbenzole (I) und (II) sowie der Ketoalkohol (III). Die Strukturen wurden durch 1H-NMR-, UV-und Massenspektroskopie aufgeklärt.
Phytochemistry, 1989
ABSTRACT A novel clerodane-type furano-diterpene with the 9,10-abeo-methyl group has been isolate... more ABSTRACT A novel clerodane-type furano-diterpene with the 9,10-abeo-methyl group has been isolated from Croton megalocarpus as a major constituent. Structure elucidation has been achieved by a combination of spectroscopic measurements including 2D-NMR and NOE experiments, on the parent compound as well as the monoacetyl derivative. Lupeol, betulin, β-sitosterol and long-chain aliphatic esters were also found and characterized.
Acta crystallographica, Mar 1, 1981
Croton membranaceous is a small tree whose roots are used for the treatment of ailments and as a ... more Croton membranaceous is a small tree whose roots are used for the treatment of ailments and as a general tonic in traditional West African medicine. It is often administered for improvement of male prostate health. We have been working on phytochemical analyses of the roots, stems, and leaves from C. membranaceus to identify small organic molecule components from each plant part. Further study of these components may lead to the use of the renewable plant parts in preparing tonics and natural medicines, which will help to sustain the tree's population.
A recently developed rapid semi-quantitative Thin Layer Chromatographic (TLC) assay method was ap... more A recently developed rapid semi-quantitative Thin Layer Chromatographic (TLC) assay method was applied in the determination of the existence of substandard or counterfeit artemisinin-based anti-malarial drugs in the Ghanaian market and also tested for its suitability for rapid assessment of drug quality prior to more rigorous analysis of any suspected counterfeit or substandard drugs. Three methods were employed – Basic Tests, Semi-quantitative TLC assay and High Performance Liquid Chromatographic (HPLC) assay. The basic tests showed that each drug contained the requisite active pharmaceutical ingredient (API). Out of the 49 samples (24 single dose and 25 fixed dose combination formulations) assayed by TLC, only 14 (28.6%) were found to comply with pharmacopoeial specifications. Out of the 24 single dose formulations, 9 of which had been found by the TLC assay likely to be within pharmacopoeial limits, only 4 were eventually found to be fully compliant by HPLC analyses. Two others were marginal. On the basis of the TLC assay, only 5 out of the 25 fixed dose combination formulations that are yet to be accurately assayed by HPLC, appear likely to meet pharmacopoeial specifications. The results of the semi-quantitative TLC technique compare favorably with those of the HPLC and hence the method can be used for rapid assessment of the quality of anti-malarial drugs. The results also indicate that the problem of distribution of substandard and possibly counterfeit artemisinin-based anti-malarial drugs exists in Ghana.
The outcomes from recent high profile deliberations concerning African health research and econom... more The outcomes from recent high profile deliberations concerning African health research and economic development all point towards the need for a mechanism to support health innovation on the continent. The mission of the African Network for Drugs and Diagnostics Innovation (ANDI), is to promote and sustain African-led health product innovation to address African public health needs through the assembly of research networks, and building of capacity to support human and economic development. ANDI is widely viewed as the vehicle to implementing some of these recommendations. There is tremendous opportunity for Africa, to leverage the expertise in natural products and traditional medicines in support of this objective to kick-start innovation. This report highlights key recommendations that have emerged through expert forums convened by ANDI on the challenges, opportunities and prospects for investing in this important area of research.
Journal of Applied Research on Medicinal and Aromatic Plants, 2016
Cryptolepis sanguinolenta is a medicinal plant widely used in the treatment of malaria in Ghana. ... more Cryptolepis sanguinolenta is a medicinal plant widely used in the treatment of malaria in Ghana. The increasing demand for its roots coupled with harvesting of the plant in non-sustainable ways has resulted in a substantial decline in its wild populations. The study was conducted to (1) determine the relatedness among C. sanguinolenta wild populations, (2) identify genotypes with high active ingredient (cryptolepine) concentrations and (3) understand the extent to which cryptolepine levels are influenced by soil. Root and stem samples for the study was collected from the Eastern, Ashanti, Brong Ahafo and Volta Regions of Ghana. C. sanguinolenta plants were found in sandy loam/sandy clay loam textured soils of acidic (4.3) to near neutral (6.7) pH ranges. Semi Quantitative Thin Layer Chromatography (SQ-TLC) and High Performance Liquid Chromatography (HPLC) methods were used to quantify the cryptolepine content in the stem and root samples. Cryptolepine concentrations in the stem and roots were not significantly influenced by location. No correlation was found between the soil properties studied and the cryptolepine content in the roots. Results from both SQ-TLC and HPLC analyses indicated that cryptolepine concentrations were on average, twice as much in the roots (0.84 mg/100 mg plant material) compared to the stem (0.42 mg/100 mg plant material). Results of the genetic diversity study showed a genetic diversity of 25% with genetic distances ranging between 0.08 and 0.14. Samples from the same location had the least genetic distances. Bootstrapping performed on the marker data and coefficient of variation calculated from distance resolutions obtained from 800 markers, proved to be of sufficient resolution. Sample sites did not reflect distinct sub-populations, a result of possible gene flow between sampling locations. Findings from this study will be useful for developing domestication protocols for C. sanguinolenta and subsequently the cultivation of elite genotypes.
Phytochemistry, 1990
... DITERPENE AND OTHER CONSTITUENTS OF CLERO DENDRON INERME BASUDEB ACHARI, CHANDANA CHAUDHURI, ... more ... DITERPENE AND OTHER CONSTITUENTS OF CLERO DENDRON INERME BASUDEB ACHARI, CHANDANA CHAUDHURI, CHITTA R. SAHA, PRADEEP K. DUTTA ... 10. Kuho, L, Lee, YW, Nair, V., Nakanishi, K. and Chapya, A. 6. Subramanian, SS, Nair, AGR and Vedantham ...
Heterocycles, 1984
From the stem bark of H.cris~iflorus twelve new isoprenylated indoles were isolated and their str... more From the stem bark of H.cris~iflorus twelve new isoprenylated indoles were isolated and their structures determined; some of these compounds exhibit antifungal activity. From the petrol ether extract of the stem hark of Hexalobus crispiflorus A.Rich. (Annonaceae) the di-isoprenylated indoles 1-13 were isolated (Table 1) .
European Journal of Pharmacology, Nov 1, 1983
The effects of wisanine and dihydrowisanine were studied on stereotyped and aggressive behaviour ... more The effects of wisanine and dihydrowisanine were studied on stereotyped and aggressive behaviour induced by apomorphine (0.5 mg/kg s.c.) in chicks. Pretreatment of chicks with wisanine (0.3-0.6 g/kg i.p.) and dihydrowisanine (0.2-0.4 g/kg i.p.) dose dependently antagonised fighting episodes and pecking of the chick's own feet and those of other chicks. It has been suggested that the antagonism is due to dopaminergic receptor blockade and demonstrates the antipsychotic effect of these drugs.
Journal of Essential Oil Research, Sep 1, 1994
The leaf oil of Diplolophium africanum Turcz. from the Koumondè region of northern Togo was analy... more The leaf oil of Diplolophium africanum Turcz. from the Koumondè region of northern Togo was analyzed using both Kovats indices and GC/MS. We identified 24 compounds including α-pinene (38%) and β-pinene (20%) as the major components followed by p-mentha-1,3,8-triene (11%). Except for a substantial decrease in the amount of the latter compound in one sample, the composition of the oil
Journal of Essential Oil Research, Nov 1, 2000
... tules Uniiersitc! dttl Q u 6 k d Chicoutimi Chicotitimi, QiiGbec G7H 2B1, Cunudu Ivan Addae-M... more ... tules Uniiersitc! dttl Q u 6 k d Chicoutimi Chicotitimi, QiiGbec G7H 2B1, Cunudu Ivan Addae-Mensah,* Dorcas Osei-Safu, William A. Asomanlng and Alfred Oteng-Yeboah Depurtment of Chemistry, Fucttllty of Sciences. Uniieisity ...
Journal of Essential Oil Research, May 1, 1996
The leaf oils of samples of Lippia multiflora Moldenke collected from different geographic areas ... more The leaf oils of samples of Lippia multiflora Moldenke collected from different geographic areas of Togo and from cultivated plants were analyzed by GC and GC/MS. Three types of essential oils were characterized, one which is rich in neral and geranial, (23–89%) and two other types, poor in neral and geranial, containing either 1,8-cineole (16–63%) or thymol (15–40%) and p-cymene
Chemischer Informationsdienst, Sep 28, 1982
ChemInform Abstract Isoliert wurden die Triacylbenzole (I) und (II) sowie der Ketoalkohol (III). ... more ChemInform Abstract Isoliert wurden die Triacylbenzole (I) und (II) sowie der Ketoalkohol (III). Die Strukturen wurden durch 1H-NMR-, UV-und Massenspektroskopie aufgeklärt.
Journal of Natural Products, Nov 1, 1984
Chemischer Informationsdienst, Jan 11, 1983
ChemInform Abstract Isoliert wurden die Triacylbenzole (I) und (II) sowie der Ketoalkohol (III). ... more ChemInform Abstract Isoliert wurden die Triacylbenzole (I) und (II) sowie der Ketoalkohol (III). Die Strukturen wurden durch 1H-NMR-, UV-und Massenspektroskopie aufgeklärt.
Phytochemistry, 1989
ABSTRACT A novel clerodane-type furano-diterpene with the 9,10-abeo-methyl group has been isolate... more ABSTRACT A novel clerodane-type furano-diterpene with the 9,10-abeo-methyl group has been isolated from Croton megalocarpus as a major constituent. Structure elucidation has been achieved by a combination of spectroscopic measurements including 2D-NMR and NOE experiments, on the parent compound as well as the monoacetyl derivative. Lupeol, betulin, β-sitosterol and long-chain aliphatic esters were also found and characterized.
Acta crystallographica, Mar 1, 1981
Croton membranaceous is a small tree whose roots are used for the treatment of ailments and as a ... more Croton membranaceous is a small tree whose roots are used for the treatment of ailments and as a general tonic in traditional West African medicine. It is often administered for improvement of male prostate health. We have been working on phytochemical analyses of the roots, stems, and leaves from C. membranaceus to identify small organic molecule components from each plant part. Further study of these components may lead to the use of the renewable plant parts in preparing tonics and natural medicines, which will help to sustain the tree's population.