Peter A Segun | University of Ibadan Nigeria (original) (raw)
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Centaurea asutro-anatolica Hub.-Mor. and C. kizildaghensis Uzunh., E. Doğan & H. Duman, two i... more Centaurea asutro-anatolica
Hub.-Mor. and
C. kizildaghensis
Uzunh., E. Doğan & H. Duman,
two indigenous perennial herbs from the Turkish flora, belong to the medicinally important
genus
Centaurea
L. (fam: Asteraceae), which comprises
ca
. 600 species worldwide. While
various
Centaurea
species are well-known for producing alkaloids, flavonoids, lignans and
terpenoids, there is no report on any thorough phytochemical work on any of these two
species available to date. In continuation of our phytochemical and bioactivity studies on
the Turkish
Centaurea
species, four flavonoids apigenin (
1
), apigenin 7,4’-dimethyl ether
(
2
), genkwanin (
3
) and quercetin (
4
) were isolated from the methanol extracts of the aerial
parts of
C. austro-anatolica
and
C. kizildaghensis
, for the very first time. The structures of
the flavonoids were elucidated conclusively by spectroscopic means,
i.e.
, UV, MS and 1D
and 2D NMR data analyses. The distribution of these flavonoids (
1
-
4
) within the genus
Centaurea
and their possible chemotaxonomic implications within the genus
Centaurea
or the family Asteraceae have been discussed
Background: Cancer is a leading cause of death worldwide , with approximately 17.5 million new ca... more Background: Cancer is a leading cause of death worldwide , with approximately 17.5 million new cases and 8.7 million cancer related deaths in 2015. The problems of poor selectivity and severe side effects of the available anticancer drugs, have demanded the need for the development of safer and more effective chemotherapeutic agents. The present study was aimed at determining the cytotoxicities of 31 medicinal plants extracts, used in Nigerian ethnomedicine for the treatment of cancer. Methods: The plant extracts were screened for cytotoxicity, using the brine shrimp lethality assay (BSLA) and MTT cytotoxicity assay. Rhabdomyosarcoma (RD) cell line, normal Vero cell line and the normal prostate (PNT2) cell line were used for the MTT assay, while Artemia salina nauplii was used for the BSLA. The phytochemical composition of the active plant extracts was determined by high performance liquid chromatography (HPLC) analysis.
This work compared the compressional, mechanical and drug release properties of paracetamol table... more This work compared the compressional, mechanical and drug release properties of paracetamol tablets produced through direct compression with those obtained from wet granulation.
Compressional properties were analyzed using density measurements, angle of repose, Carr’s index and Hausner’s ratio. The mechanical properties of the tablets were assessed using the crushing strength (CS), friability(F) and crushing strength-friability ratio (CSFR) of the tablets, while drug release properties were assessed using disintegration time and dissolution profile. The granules possessed better flow properties than the powder mixtures for direct compression.
Paracetamol tablets prepared by wet granulation were harder than those prepared by direct compression as shown by the CS. The evaluation of the release properties showed that the amount of paracetamol released at any given time was higher for tablets prepared by direct compression than those prepared by wet granulation. Thus, wet granulation with carefully selected drug excipients may be a better method over direct compression in paracetamol tablets formulation.
A small library of benzimidazoles with a range of side-chain substituents have been synthesized t... more A small library of benzimidazoles with a range of side-chain substituents have been synthesized
through the condensation reaction of o-phenylenediamine derivatives and several other commercially
available materials. The reactions were catalyzed by either 4M HCl or 1,3-dibromo-5,5-
dimethylhydantoin (DBDMH). The compounds synthesized using DBDMH as the catalyst required a
shorter reaction time, the yield was higher and the workup procedure was not as tedious as those
produced using 4M HCl as the catalyst. The structural elucidations of synthesized compounds have
been confirmed through spectroscopic analysis. 13C NMR analysis of some of the synthesized
compounds showed that the appearance of carbon signals in the NMR spectrum is affected by the
nature of the NMR solvent and temperature.The exchange-induced broadening of the 13C NMR signal
was probably facilitated by the intermolecular proton exchange between the NH of the benzimidazole
and the H2O present in the DMSO-d6 solvent.
Centaurea asutro-anatolica Hub.-Mor. and C. kizildaghensis Uzunh., E. Doğan & H. Duman, two i... more Centaurea asutro-anatolica
Hub.-Mor. and
C. kizildaghensis
Uzunh., E. Doğan & H. Duman,
two indigenous perennial herbs from the Turkish flora, belong to the medicinally important
genus
Centaurea
L. (fam: Asteraceae), which comprises
ca
. 600 species worldwide. While
various
Centaurea
species are well-known for producing alkaloids, flavonoids, lignans and
terpenoids, there is no report on any thorough phytochemical work on any of these two
species available to date. In continuation of our phytochemical and bioactivity studies on
the Turkish
Centaurea
species, four flavonoids apigenin (
1
), apigenin 7,4’-dimethyl ether
(
2
), genkwanin (
3
) and quercetin (
4
) were isolated from the methanol extracts of the aerial
parts of
C. austro-anatolica
and
C. kizildaghensis
, for the very first time. The structures of
the flavonoids were elucidated conclusively by spectroscopic means,
i.e.
, UV, MS and 1D
and 2D NMR data analyses. The distribution of these flavonoids (
1
-
4
) within the genus
Centaurea
and their possible chemotaxonomic implications within the genus
Centaurea
or the family Asteraceae have been discussed
Background: Cancer is a leading cause of death worldwide , with approximately 17.5 million new ca... more Background: Cancer is a leading cause of death worldwide , with approximately 17.5 million new cases and 8.7 million cancer related deaths in 2015. The problems of poor selectivity and severe side effects of the available anticancer drugs, have demanded the need for the development of safer and more effective chemotherapeutic agents. The present study was aimed at determining the cytotoxicities of 31 medicinal plants extracts, used in Nigerian ethnomedicine for the treatment of cancer. Methods: The plant extracts were screened for cytotoxicity, using the brine shrimp lethality assay (BSLA) and MTT cytotoxicity assay. Rhabdomyosarcoma (RD) cell line, normal Vero cell line and the normal prostate (PNT2) cell line were used for the MTT assay, while Artemia salina nauplii was used for the BSLA. The phytochemical composition of the active plant extracts was determined by high performance liquid chromatography (HPLC) analysis.
This work compared the compressional, mechanical and drug release properties of paracetamol table... more This work compared the compressional, mechanical and drug release properties of paracetamol tablets produced through direct compression with those obtained from wet granulation.
Compressional properties were analyzed using density measurements, angle of repose, Carr’s index and Hausner’s ratio. The mechanical properties of the tablets were assessed using the crushing strength (CS), friability(F) and crushing strength-friability ratio (CSFR) of the tablets, while drug release properties were assessed using disintegration time and dissolution profile. The granules possessed better flow properties than the powder mixtures for direct compression.
Paracetamol tablets prepared by wet granulation were harder than those prepared by direct compression as shown by the CS. The evaluation of the release properties showed that the amount of paracetamol released at any given time was higher for tablets prepared by direct compression than those prepared by wet granulation. Thus, wet granulation with carefully selected drug excipients may be a better method over direct compression in paracetamol tablets formulation.
A small library of benzimidazoles with a range of side-chain substituents have been synthesized t... more A small library of benzimidazoles with a range of side-chain substituents have been synthesized
through the condensation reaction of o-phenylenediamine derivatives and several other commercially
available materials. The reactions were catalyzed by either 4M HCl or 1,3-dibromo-5,5-
dimethylhydantoin (DBDMH). The compounds synthesized using DBDMH as the catalyst required a
shorter reaction time, the yield was higher and the workup procedure was not as tedious as those
produced using 4M HCl as the catalyst. The structural elucidations of synthesized compounds have
been confirmed through spectroscopic analysis. 13C NMR analysis of some of the synthesized
compounds showed that the appearance of carbon signals in the NMR spectrum is affected by the
nature of the NMR solvent and temperature.The exchange-induced broadening of the 13C NMR signal
was probably facilitated by the intermolecular proton exchange between the NH of the benzimidazole
and the H2O present in the DMSO-d6 solvent.