Pharmacognostic investigation on fresh, powdered and anatomical sections of leaf of Mitracarpus v... more Pharmacognostic investigation on fresh, powdered and anatomical sections of leaf of Mitracarpus vilosus (S.W) D.C was carried out to determine its macromorphological, micromorphological and chemomicromorphological profiles. Qualitative and quantitative studies indicated presence ofamphicribal vascular bundle arrangement, characteristic asperites, cone-shaped clothing trichomes, simple leaf arrangement lanceolate shape, entire margin, cuneate base, parallel venation and opposite/decussate arrangement. Other features include presence of calcium oxalate crystals, lignin and oil globules with palisade ratio of 4 – 7 and stomatal number of 13.5. The relative similarities between the members of the Spermacoceae tribe, to which the plant belongs, coupled with lack of information towards monograph preparation on the plant necessitated this investigation. These findings will be useful towards establishing pharmacognostic standards on identification, purity, quality and classification o...
Hypoestoxide reduces human α-synuclein accumulation in a mouse model of PD. Mice brain sections w... more Hypoestoxide reduces human α-synuclein accumulation in a mouse model of PD. Mice brain sections were inmmunostained against human α-synuclein (Syn211 antibody) or C-terminal of human α-synuclein (Syn105 antibody). a Immunofluorescence analysis of human α-synuclein in the frontal cortex of non-tg and α-syn-tg mice treated with either vehicle or hypoestoxide. (n = 5 per group; unpaired t test; *p
The aqueous extract of the leaves of Andrographis paniculata (Family: Acanthaceae) was prepared a... more The aqueous extract of the leaves of Andrographis paniculata (Family: Acanthaceae) was prepared and tested on gastrointestinal smooth muscles of mice, rats and rabbits. The median lethal dose (LD50) of the extract was determined. The effects of the extract on rat ileum, rabbit jejunum, rat stomach fundus strip and mice gastrointestinal motility were evaluated. The LD50 value in mice was 950 mg/kg i.p. Low concentrations of the extract (1.0 â 4.0 mg/ml) relaxed the isolated rat ileum and rabbit jejunum but did not alter the intrinsic myogenic contraction of the isolated rat stomach fundus strip. Higher concentrations of the extract (8.0 â 32.0 mg/ml) produced a concentration â dependent contraction of the same tissues. Lower doses of the extract (16 â 32 mg/kg p.o.) reduced mice gastrointestinal motility while the higher doses (64 â 500 mg/kg p.o) increased the motility. The contractile effects of acetylcholine (5 ng/ml) and histamine (2.0 I¼g/ml; 0.04 mg/ml) were blocked b...
Cite this article as: Nneka N. Ibekwe, John B. Nvau, Peters O. Oladosu, Auwal M. Usman, Kolo Ibra... more Cite this article as: Nneka N. Ibekwe, John B. Nvau, Peters O. Oladosu, Auwal M. Usman, Kolo Ibrahim, Helena I. Boshoff, Cynthia S. Dowd, Abayomi T. Orisadipe, Olapeju Aiyelaagbe, Akinbo A. Adesomoju, Clifton E. Barry III, Joseph I. Okogun, in collaboration with 73 Visited Herbalists, Some Nigerian anti-ome ethnomedIcines: a Preliminary Efficacy Assessment, Journal of Ethnopharmacology, http://dx.doi.org/10.1016/j.jep.2014.05.059
African Journal of Traditional, Complementary and Alternative Medicines, 2009
The global threat of tuberculosis demands for search for alternative antimycobacterial drugs [1].... more The global threat of tuberculosis demands for search for alternative antimycobacterial drugs [1]. The crude methanolic extracts of eight Nigerian medicinal plant species used in the treatment of TB and other respiratory diseases were evaluated for activity against a clinical isolate of Mycobacterium tuberculosis and attenuated Mycobacterium bovis (BCG) using broth microdilution method. The plant parts used were obtained as described by the users from a forest near Baddegi, Niger State, Nigeria. Voucher specimens were deposited in the Herbarium at the Department of Biological Sciences, Ahmadu Bello University (ABU), Zaria, Nigeria and National Institute for Pharmaceutical Research and Development (NIPRD), Abuja, Nigeria. Two hundred grams (200g) of each dried plant material was powdered and extracted by maceration with methanol for 72h at room temperature (3 x 250mL). All the crude extracts were filtered and evaporated in vacuo (350C). Each extract was then partitioned with n-hexane-...
Six known compounds; β-sitosterol, ursolic acid, methyl chlorogenate, ethyl chlorogenate, rutin a... more Six known compounds; β-sitosterol, ursolic acid, methyl chlorogenate, ethyl chlorogenate, rutin and mannitol were isolated from the leaf extracts of Pavetta crassipes (Rubiaceae), a Nigerian medicinal plant used in the indigenous treatment of tuberculosis. Separation and isolation of the compounds were achieved by chromatographic techniques and the structures of isolated compounds were established by spectroscopic and chemical methods. The isolated compounds were screened for antimycobacterial activities against Mycobacterium tuberculosis H 37 Rv employing the green fluorescence protein reporter microplate assay and the broth microdilution method. Ursolic acid, methyl chlorogenate and ethyl chlorogenate were found moderately active in the broth microdilution assay with MICs of 200, 100 and 50 µg/ml, respectively while methyl chlorogenate and ethyl chlorogenate were active in the protein reporter microplate assay with MICs of 200 and 100 µg ml-1 , respectively. The presence of antimycobacterial terpenoids and quinate esters in leaves of Pavetta crassipes provides scientific evidence for the ethnomedicinal use of the plant as a traditional anti-tuberculosis remedy.
A comparative study of some of the hormones in acidic extracts obtained from fruits of cowpea was... more A comparative study of some of the hormones in acidic extracts obtained from fruits of cowpea was undertaken in relation to premature fruit abscission. Extracts were obtained from 6-day and 2-day old fruits from the lowest and upper racemes of the cowpea inflore5cence, respectively. In the cUltivar New Era, only growth inhibitors were detected in 2-day old fruits whereas inhibitors as well as gibberellins and auxins were detected in 6-day old fruits. In the cultivar Adzuki, gibberellin activity was detected in both 2-day old and 6-day old fruits. The results are discussed in relation to the abscission problem in cowpea.
Journal of the Chemical Society, Perkin Transactions 1, 1976
The reaction of copper(II) halides with o-aryloxybenzaldehydes to give xanthones is shown to be a... more The reaction of copper(II) halides with o-aryloxybenzaldehydes to give xanthones is shown to be a general one. 2-(6-Methoxy-2-naphthyloxy)benzaldehyde undergoes concomitant nuclear bromination to give 4-bromo-3-methoxybenzo[a]xanthen-12-one.
Ten Nigerian medicinal plants Abrus precatorius, Annona senegalensis, Anogeissus leiocarpus, Crat... more Ten Nigerian medicinal plants Abrus precatorius, Annona senegalensis, Anogeissus leiocarpus, Crateva adansonii, Detarium microcarpum, Faba spp, Neocarya macrophylla, Ocimum gratissimum, Securidaca longpenduculata and Terminalia avicennioides used by traditional medicine practitioners for the management of infectious and chronic diseases such as tuberculosis and whooping cough were investigated for in vitro antimycobacterial activity against attenuated strains of Mycobacterium bovis (BCG). Hexane and methanol extracts of the plant materials were obtained by maceration. The antimycobacterial activity was determined by the broth microdilution method. The hexane extracts of Anogeissus leiocarpus and Terminalia avicennioides showed strong inhibitory activity at 312µg/ml. Eight of the ten plant extracts showed moderate inhibitory activity in either hexane or methanol extract at 1250µg/ml. While the hexane and methanol extracts of Detarium microcarpum and Neocarya macrophylla did not exhibit any significant activity. These observed activities could be associated with secondary metabolites in these plants. This study demonstrates the efficacy of Nigerian medicinal plants as potential agents in the management of the tuberculosis disease.
Ethnobotanical survey revealed that the dried fruits of Acacia nilotica Linn Willd of the family ... more Ethnobotanical survey revealed that the dried fruits of Acacia nilotica Linn Willd of the family mimosaceae are used locally in various parts of Nigeria for the treatment of boil, cough and chest infections. This prompted the phytochemical and antitubercular screening of its fruit extracts. Preliminary Antitubercular activity of its aqueous methanolic extract was carried out by the use of BCG as test organism. It showed antitubercular activity with MIC of 1250µg/ml. Gradient column chromatographic separation of the whole extract yielded six fractions (FR1-FR6). These fractions were evaluated for antitubercular activities. Fractions FR2, FR3 & FR4 showed significant antitubercular activities with MIC of 78µg/ml. Phytochemical spray with ferric chloride solution showed that the active fractions (FR2-FR4) are mainly polyphenolics (tannins). The antitubercular activity of this extract is being reported for the first time. Further studies to isolate and characterize the bioactive compounds are ongoing.
Nigerian Journal of Natural Products and Medicine, 1997
3b, 19a-dihydroxyurs-12-ene-28oic acid, caffeic acid, and chlorgenic were isolated from the fruit... more 3b, 19a-dihydroxyurs-12-ene-28oic acid, caffeic acid, and chlorgenic were isolated from the fruits and 3b, 19a-hydroxyurs-12-ene-28-oic acid, ferulic acid and p-coumaric acid from the roots of Kigelia pinnata. Key Words: Kigelia pinnata, Bignoniaceae, Triterpenoids, Phenolic acids Nig. J. Nat. Prod. And Med. Vol.1 1997: 40-41
An ethnobotanical survey revealed that the dried fallen leaves of Terminalia catappa Linn. are us... more An ethnobotanical survey revealed that the dried fallen leaves of Terminalia catappa Linn. are used locally in various parts of Nigeria for the management of sickle cell anaemia. This research investigated if Terminalia catappa leaf interferes with the basic mechanism of erythrocyte sickling. Powdered dried fallen leaves of Terminalia catappa was extracted with 90% methanol by maceration. Bioactivity of the extract was studied by investigating its effect on inhibition of erythrocyte sickling (membrane effect). Bioactivity guided fractionation showed that the highest antisickling activity in the erythrocyte-1 sickling model resided in its triterpenoids components (fraction F3, K = 0.0037 min). This fraction drastically reduced the rate of erythrocyte sickling and is very significantly more active than the control (P<0.001). Bioactivity guided separation of the extract was carried out on flash chromatography using RP18 and Silica gel stationary phases respectively. Final separation was done by HPLC on Cyanosilica column. Structural elucidation of bioactive compounds was carried out by Nuclear magnetic resonance (NMR) and mass spectrometry (MS). The most active compounds were established to be two triterpenic acids (1) 2á, 3â ,24-Trihydroxyurs-12-en-28-oic acid and (2) 2á, 3â, 24-trihydroxy-12, 20 (30)-ursandien-28-oic acid. This work therefore shows that there is a scientific basis for the application of this extract in the management of sickle cell anaemia in traditional medicine.
Details of the preparation from zanthoxylol of a new anti-sickling agent, 3,4-dihydro-2,2-dimethy... more Details of the preparation from zanthoxylol of a new anti-sickling agent, 3,4-dihydro-2,2-dimethyl-2-H-1 bezophyran-6-butyric acid, DBA, are given. The reaction involved converting zanthoxylol to its iodo-compound. This in turn was subsequently hydrolysed to DBA. DBA dose-dependently inhibited carrageein-induced rat paw oedema. The ED 50 was approximately 60 mg kg -1 . Indomethacin and aspirin were similarly effective with ED 50 of 2.2 and 91 mg kg -1 respectively. DBA also inhibited acetic acid induced squirming in mice. The ED 50 was 58 mg kg -1 compared with 75 mg kg for aspirin. DBA, indomethacin and aspirin inhibited generation of prostaglandin-like activity by isolated segments of rabbit jejunum as well as the production of PG-like activity from arachidonic by cell-free homogenates of guinea-pig lung. It is concluded that the mechanism of anti-inflammatory and analgesic activity of DBA, like that of aspirin and indomethacin, may involve inhibition of prostaglandin synthesis.
Pharmacognostic investigation on fresh, powdered and anatomical sections of leaf of Mitracarpus v... more Pharmacognostic investigation on fresh, powdered and anatomical sections of leaf of Mitracarpus vilosus (S.W) D.C was carried out to determine its macromorphological, micromorphological and chemomicromorphological profiles. Qualitative and quantitative studies indicated presence ofamphicribal vascular bundle arrangement, characteristic asperites, cone-shaped clothing trichomes, simple leaf arrangement lanceolate shape, entire margin, cuneate base, parallel venation and opposite/decussate arrangement. Other features include presence of calcium oxalate crystals, lignin and oil globules with palisade ratio of 4 – 7 and stomatal number of 13.5. The relative similarities between the members of the Spermacoceae tribe, to which the plant belongs, coupled with lack of information towards monograph preparation on the plant necessitated this investigation. These findings will be useful towards establishing pharmacognostic standards on identification, purity, quality and classification o...
Hypoestoxide reduces human α-synuclein accumulation in a mouse model of PD. Mice brain sections w... more Hypoestoxide reduces human α-synuclein accumulation in a mouse model of PD. Mice brain sections were inmmunostained against human α-synuclein (Syn211 antibody) or C-terminal of human α-synuclein (Syn105 antibody). a Immunofluorescence analysis of human α-synuclein in the frontal cortex of non-tg and α-syn-tg mice treated with either vehicle or hypoestoxide. (n = 5 per group; unpaired t test; *p
The aqueous extract of the leaves of Andrographis paniculata (Family: Acanthaceae) was prepared a... more The aqueous extract of the leaves of Andrographis paniculata (Family: Acanthaceae) was prepared and tested on gastrointestinal smooth muscles of mice, rats and rabbits. The median lethal dose (LD50) of the extract was determined. The effects of the extract on rat ileum, rabbit jejunum, rat stomach fundus strip and mice gastrointestinal motility were evaluated. The LD50 value in mice was 950 mg/kg i.p. Low concentrations of the extract (1.0 â 4.0 mg/ml) relaxed the isolated rat ileum and rabbit jejunum but did not alter the intrinsic myogenic contraction of the isolated rat stomach fundus strip. Higher concentrations of the extract (8.0 â 32.0 mg/ml) produced a concentration â dependent contraction of the same tissues. Lower doses of the extract (16 â 32 mg/kg p.o.) reduced mice gastrointestinal motility while the higher doses (64 â 500 mg/kg p.o) increased the motility. The contractile effects of acetylcholine (5 ng/ml) and histamine (2.0 I¼g/ml; 0.04 mg/ml) were blocked b...
Cite this article as: Nneka N. Ibekwe, John B. Nvau, Peters O. Oladosu, Auwal M. Usman, Kolo Ibra... more Cite this article as: Nneka N. Ibekwe, John B. Nvau, Peters O. Oladosu, Auwal M. Usman, Kolo Ibrahim, Helena I. Boshoff, Cynthia S. Dowd, Abayomi T. Orisadipe, Olapeju Aiyelaagbe, Akinbo A. Adesomoju, Clifton E. Barry III, Joseph I. Okogun, in collaboration with 73 Visited Herbalists, Some Nigerian anti-ome ethnomedIcines: a Preliminary Efficacy Assessment, Journal of Ethnopharmacology, http://dx.doi.org/10.1016/j.jep.2014.05.059
African Journal of Traditional, Complementary and Alternative Medicines, 2009
The global threat of tuberculosis demands for search for alternative antimycobacterial drugs [1].... more The global threat of tuberculosis demands for search for alternative antimycobacterial drugs [1]. The crude methanolic extracts of eight Nigerian medicinal plant species used in the treatment of TB and other respiratory diseases were evaluated for activity against a clinical isolate of Mycobacterium tuberculosis and attenuated Mycobacterium bovis (BCG) using broth microdilution method. The plant parts used were obtained as described by the users from a forest near Baddegi, Niger State, Nigeria. Voucher specimens were deposited in the Herbarium at the Department of Biological Sciences, Ahmadu Bello University (ABU), Zaria, Nigeria and National Institute for Pharmaceutical Research and Development (NIPRD), Abuja, Nigeria. Two hundred grams (200g) of each dried plant material was powdered and extracted by maceration with methanol for 72h at room temperature (3 x 250mL). All the crude extracts were filtered and evaporated in vacuo (350C). Each extract was then partitioned with n-hexane-...
Six known compounds; β-sitosterol, ursolic acid, methyl chlorogenate, ethyl chlorogenate, rutin a... more Six known compounds; β-sitosterol, ursolic acid, methyl chlorogenate, ethyl chlorogenate, rutin and mannitol were isolated from the leaf extracts of Pavetta crassipes (Rubiaceae), a Nigerian medicinal plant used in the indigenous treatment of tuberculosis. Separation and isolation of the compounds were achieved by chromatographic techniques and the structures of isolated compounds were established by spectroscopic and chemical methods. The isolated compounds were screened for antimycobacterial activities against Mycobacterium tuberculosis H 37 Rv employing the green fluorescence protein reporter microplate assay and the broth microdilution method. Ursolic acid, methyl chlorogenate and ethyl chlorogenate were found moderately active in the broth microdilution assay with MICs of 200, 100 and 50 µg/ml, respectively while methyl chlorogenate and ethyl chlorogenate were active in the protein reporter microplate assay with MICs of 200 and 100 µg ml-1 , respectively. The presence of antimycobacterial terpenoids and quinate esters in leaves of Pavetta crassipes provides scientific evidence for the ethnomedicinal use of the plant as a traditional anti-tuberculosis remedy.
A comparative study of some of the hormones in acidic extracts obtained from fruits of cowpea was... more A comparative study of some of the hormones in acidic extracts obtained from fruits of cowpea was undertaken in relation to premature fruit abscission. Extracts were obtained from 6-day and 2-day old fruits from the lowest and upper racemes of the cowpea inflore5cence, respectively. In the cUltivar New Era, only growth inhibitors were detected in 2-day old fruits whereas inhibitors as well as gibberellins and auxins were detected in 6-day old fruits. In the cultivar Adzuki, gibberellin activity was detected in both 2-day old and 6-day old fruits. The results are discussed in relation to the abscission problem in cowpea.
Journal of the Chemical Society, Perkin Transactions 1, 1976
The reaction of copper(II) halides with o-aryloxybenzaldehydes to give xanthones is shown to be a... more The reaction of copper(II) halides with o-aryloxybenzaldehydes to give xanthones is shown to be a general one. 2-(6-Methoxy-2-naphthyloxy)benzaldehyde undergoes concomitant nuclear bromination to give 4-bromo-3-methoxybenzo[a]xanthen-12-one.
Ten Nigerian medicinal plants Abrus precatorius, Annona senegalensis, Anogeissus leiocarpus, Crat... more Ten Nigerian medicinal plants Abrus precatorius, Annona senegalensis, Anogeissus leiocarpus, Crateva adansonii, Detarium microcarpum, Faba spp, Neocarya macrophylla, Ocimum gratissimum, Securidaca longpenduculata and Terminalia avicennioides used by traditional medicine practitioners for the management of infectious and chronic diseases such as tuberculosis and whooping cough were investigated for in vitro antimycobacterial activity against attenuated strains of Mycobacterium bovis (BCG). Hexane and methanol extracts of the plant materials were obtained by maceration. The antimycobacterial activity was determined by the broth microdilution method. The hexane extracts of Anogeissus leiocarpus and Terminalia avicennioides showed strong inhibitory activity at 312µg/ml. Eight of the ten plant extracts showed moderate inhibitory activity in either hexane or methanol extract at 1250µg/ml. While the hexane and methanol extracts of Detarium microcarpum and Neocarya macrophylla did not exhibit any significant activity. These observed activities could be associated with secondary metabolites in these plants. This study demonstrates the efficacy of Nigerian medicinal plants as potential agents in the management of the tuberculosis disease.
Ethnobotanical survey revealed that the dried fruits of Acacia nilotica Linn Willd of the family ... more Ethnobotanical survey revealed that the dried fruits of Acacia nilotica Linn Willd of the family mimosaceae are used locally in various parts of Nigeria for the treatment of boil, cough and chest infections. This prompted the phytochemical and antitubercular screening of its fruit extracts. Preliminary Antitubercular activity of its aqueous methanolic extract was carried out by the use of BCG as test organism. It showed antitubercular activity with MIC of 1250µg/ml. Gradient column chromatographic separation of the whole extract yielded six fractions (FR1-FR6). These fractions were evaluated for antitubercular activities. Fractions FR2, FR3 & FR4 showed significant antitubercular activities with MIC of 78µg/ml. Phytochemical spray with ferric chloride solution showed that the active fractions (FR2-FR4) are mainly polyphenolics (tannins). The antitubercular activity of this extract is being reported for the first time. Further studies to isolate and characterize the bioactive compounds are ongoing.
Nigerian Journal of Natural Products and Medicine, 1997
3b, 19a-dihydroxyurs-12-ene-28oic acid, caffeic acid, and chlorgenic were isolated from the fruit... more 3b, 19a-dihydroxyurs-12-ene-28oic acid, caffeic acid, and chlorgenic were isolated from the fruits and 3b, 19a-hydroxyurs-12-ene-28-oic acid, ferulic acid and p-coumaric acid from the roots of Kigelia pinnata. Key Words: Kigelia pinnata, Bignoniaceae, Triterpenoids, Phenolic acids Nig. J. Nat. Prod. And Med. Vol.1 1997: 40-41
An ethnobotanical survey revealed that the dried fallen leaves of Terminalia catappa Linn. are us... more An ethnobotanical survey revealed that the dried fallen leaves of Terminalia catappa Linn. are used locally in various parts of Nigeria for the management of sickle cell anaemia. This research investigated if Terminalia catappa leaf interferes with the basic mechanism of erythrocyte sickling. Powdered dried fallen leaves of Terminalia catappa was extracted with 90% methanol by maceration. Bioactivity of the extract was studied by investigating its effect on inhibition of erythrocyte sickling (membrane effect). Bioactivity guided fractionation showed that the highest antisickling activity in the erythrocyte-1 sickling model resided in its triterpenoids components (fraction F3, K = 0.0037 min). This fraction drastically reduced the rate of erythrocyte sickling and is very significantly more active than the control (P<0.001). Bioactivity guided separation of the extract was carried out on flash chromatography using RP18 and Silica gel stationary phases respectively. Final separation was done by HPLC on Cyanosilica column. Structural elucidation of bioactive compounds was carried out by Nuclear magnetic resonance (NMR) and mass spectrometry (MS). The most active compounds were established to be two triterpenic acids (1) 2á, 3â ,24-Trihydroxyurs-12-en-28-oic acid and (2) 2á, 3â, 24-trihydroxy-12, 20 (30)-ursandien-28-oic acid. This work therefore shows that there is a scientific basis for the application of this extract in the management of sickle cell anaemia in traditional medicine.
Details of the preparation from zanthoxylol of a new anti-sickling agent, 3,4-dihydro-2,2-dimethy... more Details of the preparation from zanthoxylol of a new anti-sickling agent, 3,4-dihydro-2,2-dimethyl-2-H-1 bezophyran-6-butyric acid, DBA, are given. The reaction involved converting zanthoxylol to its iodo-compound. This in turn was subsequently hydrolysed to DBA. DBA dose-dependently inhibited carrageein-induced rat paw oedema. The ED 50 was approximately 60 mg kg -1 . Indomethacin and aspirin were similarly effective with ED 50 of 2.2 and 91 mg kg -1 respectively. DBA also inhibited acetic acid induced squirming in mice. The ED 50 was 58 mg kg -1 compared with 75 mg kg for aspirin. DBA, indomethacin and aspirin inhibited generation of prostaglandin-like activity by isolated segments of rabbit jejunum as well as the production of PG-like activity from arachidonic by cell-free homogenates of guinea-pig lung. It is concluded that the mechanism of anti-inflammatory and analgesic activity of DBA, like that of aspirin and indomethacin, may involve inhibition of prostaglandin synthesis.
Uploads
Papers by Joseph Okogun