The chemical composition of the volatile oil from berries of Croton macrostachyus Hochst. ex Del.... more The chemical composition of the volatile oil from berries of Croton macrostachyus Hochst. ex Del. was determined by GC and GC/MS. The oil was tested for its in vitro antileishmanial activity on two Leishmania strains, and its toxicity on the human monocytic leukemia (THP-1) cell line and erythrocytes from sheep blood. The main constituents of the oil were benzyl benzoate (51.8%), linalool (10.1%), γ-muurolene (9.3%), ( E,E)-α-farnesene (3.2%), δ-cadinene (2.8%) and α-curcumene (2.7%). The oil was effective against L. donovani and L. aethiopica promastigotes (MIC = 0.08 μL/mL and 0.16 μL/mL, respectively) and axenic amastigote stages (EC50 = 20.00 nL/mL and 6.66 nL/mL, respectively). The CC50 value for the oil was 10.00 nL/mL on THP-1 cells with selectivity index values of 0.5 for L. donovani and 1.5 for L. aethiopica. The median lethal concentration (LC50) of the oil was 2.45 μL/mL. Thus the observed high efficacy and moderate toxicity of the volatile oil from C. macrostachyus, make...
The present study assesses the quality and the physicochemical properties of paracetamol dosage f... more The present study assesses the quality and the physicochemical properties of paracetamol dosage forms (tablet, suppository and syrup samples) from different drug outlets in Addis Ababa. Identity, weight uniformity, disintegration and dissolution times, assay for active ingredient content and pH test (for syrup) were performed. Hardness and drug release (t50% and t90%) of the different brands of paracetamol tablets were also evaluated and compared. The study showed that none of the tablet samples did meet the USP specification for assay of active ingredient content. One of the syrup samples (Efferalgan®) tested, contained less than the specified amount of the active principle. Keywords : quality evaluation, physicochemical properties, paracetamol dosage forms, drug outlets, Addis Ababa Ethiopian Pharmaceutical Journal Vol. 26 (1) 2008: pp. 59-64
Essential oils of Artemisia abyssinica and Satureja punctata ssp. punctata from Ethiopia were ana... more Essential oils of Artemisia abyssinica and Satureja punctata ssp. punctata from Ethiopia were analyzed by GC and GC/MS, and screened for leishmanicidal activity against promastigote and axenic amastigotes of Leishmania donovani and L. aethiopica, including toxicity studies on human monocytic leukemia cells (THP-1) and erythrocytes in vitro. GC/MS of A. abyssinica oil revealed 67 compounds (99.94%) with the major constituents yomogi alcohol (38.47%), artemisyl acetate (24.88%), and artemisia alcohol (6.70%), and oxygenated monoterpenes (84.00%) as the dominant group. The oil of S. punctata contained 67 compounds (99.49%) with the main constituents geranial (27.62%), neral (21.72%), alpha-bisabolol (13.62%), and (E)-nerolidol (4.82%), of which oxygenated mono- and sesquiterpenes (58.39 and 26.91%, resp.) showed highest abundance. Both oils showed effect on promastigotes (MIC 76.5 to 312.5 nl/ml) and amastigotes (EC(50) 4.06 to 131.00 nl/ml) of L. donovani and L. aethiopica, and varying toxicities on THP-1 cells (CC(50) 0.013 to 350 nl/ml with selectivity index between 0.001 and 28) and erythrocytes (with LC(50) 0.35 to 1.52 microl/ml). S. punctata oil exerted highest activity against both Leishmania sp. and toxicity. The revealed antileishmanial activities support further isolation and investigation of oil constituents for in vitro/in vivo evaluation.
Potential toxicity, costs, and drug-resistant pathogens necessitate the development of new antile... more Potential toxicity, costs, and drug-resistant pathogens necessitate the development of new antileishmanial agents. Medicinal and aromatic plants constitute a major source of natural organic compounds. In this study, essential oils of Artemisia absinthium L. and Echinops kebericho Mesfin were investigated by GC and GC/MS analyses. Isolated oils were screened for antileishmanial activity against two Leishmania strains (L. aethiopica and L. donovani), and toxicity on the human monocytic leukemia (THP-1) cell line and red blood cells in vitro. GC/MS Analysis revealed 65 compounds (93.74%) for Artemisia absinthium and 43 compounds (92.85%) for Echinops kebericho oil. The oils contained the oxygenated monoterpene camphor (27.40%) and the sesquiterpene lactone dehydrocostus lactone (41.83%) as major constituents, respectively. Both oils showed activity against promastigote (MIC 0.0097-0.1565 μl/ml) and axenic amastigote forms (EC(50) 0.24-42.00 nl/ml) of both leishmania species. Weak hemolytic effect was observed for both oils, showing a slightly decreased selectivity index (SI 0.8-19.2) against the THP-1 cell line. Among the two oils tested, E. kebericho exerted strong antileishmanial activity that was even higher than that of amphotericin B with significant cytotoxicity. This study, therefore, demonstrated the potential use of both oils as source of novel agents for the treatment of leishmaniasis.
Background: Ajuga remota Benth is traditionally used in Ethiopia for the management of diabetes m... more Background: Ajuga remota Benth is traditionally used in Ethiopia for the management of diabetes mellitus. Since this claim has not been investigated scientifically, the aim of this study was to evaluate the antidiabetic effect and phytochemical screening of the aqueous and 70% ethanol extracts on alloxan-induced diabetic mice.
Methods: After acute toxicity test, the Swiss albino mice were induced with alloxan to get experimental diabetes animals. The fasting mean blood glucose level before and after treatment for two weeks in normal, diabetic untreated and diabetic mice treated with aqueous and 70% ethanol extracts were performed. Data were statistically
evaluated by using Statistical Package for the Social Sciences software version 20. P-value <0.05 was considered statistically significant.
Results: The medium lethal doses (LD50) of both extracts were higher than 5000 mg/kg, indicating the extracts are not toxic under the observable condition. Aqueous extracts of A.remota (300 mg/kg and 500 mg/kg body weight) reduced elevated blood glucose levels by 27.83 ± 2.96% and 38.98 ± 0.67% (P < 0.0001), respectively while the 70% ethanol extract caused a reduction of 27.94 ± 1.92% (300 mg/kg) & 28.26 ± 1.82% (500 mg/kg). Treatment with the antidiabetic drug, Glibenclamide (10 mg/kg body weight) lowered blood glucose level by 51.06% (p < 0.05). Phytochemical screening of both extracts indicated the presence of phenolic compounds, flavonoids, saponins,
tannins, and steroids, which might contribute to the antidiabetic activity. The extracts, however, did not contain alkaloids and anthraquinones.
Conclusion: The aqueous extract (500 mg/kg) showed the highest percentage reduction in blood glucose levels and the ability of A. remota extracts in reducing blood glucose levels presumably due to the presence of antioxidant constituents such as flavonoids. The effect of the extract supported the traditional claim of the plant.
Keywords: Ajuga Remota, Antidiabetic activity, Blood glucose level, Diabetes mellitus, Glibenclamide, Phytochemical screening
Bioassay-guided fractionation using the human colorectal adenocarcinoma (HT-29) cell line of the ... more Bioassay-guided fractionation using the human colorectal adenocarcinoma (HT-29) cell line of the methanol extract of dried roots of Podocarpus falcatus led to the isolation of two new type C nagilactones, 16-hydroxynagilactone F (1) and 2β,16-dihydroxynagilactone F (2), and the new totarane-type bisditerpenoid 7β-hydroxymacrophyllic acid (4), along with the seven known compounds 2β-hydroxynagilactone F (3), macrophyllic acid (5), nagilactone D (6), 15-hydroxynagilactone D (7), nagilactone I (8), inumakiol D (9), and ponasterone A (10). The structures of the new compounds were determined by 1D and 2D NMR, HRESIMS, UV, and IR and by comparison with the reported spectroscopic data of their congeners. The orientation of the C-2 hydroxy group of 3 and 8 was revised to be β based on evidence from detailed analysis of 1D and 2D NMR data and single-crystal X-ray diffraction studies. Among the isolated compounds, the nagilactones, including the new dilactones 16-hydroxynagilactone F (1) and 2β,16-dihydroxynagilactone F (2), were the most active (IC50 0.3-5.1 μM range) against the HT-29 cell line, whereas the bisditerpenoids (4 and 5) and the other known compounds 9 and 10 were inactive. The presence of the bioactive nagilactones in P. falcatus supports its traditional use.
The synthesis of a novel series of 1H-pyrazole derivatives was achieved by condensation of pyrazo... more The synthesis of a novel series of 1H-pyrazole derivatives was achieved by condensation of pyrazole aldehyde 1 with hydrazine hydrate to give hydrazone 7. On the other hand, cyclization of α,β-unsaturated ketone counterpart 2 using hydrazine hydrate in liquid aliphatic acids rendered compounds 4-6 and hydrazine hydrate in ethanol afforded compound 3. The later was allowed to react with aroyl chloride giving rise to compounds 8, 9. All compounds were tested for their in vivo anti-malarial and in vitro antileishmanial activities. The anti-malarial activity was performed using Plasmodium berghei infected mice, while the anti-leishmanial activity of the compounds was determined against Leishmania aethiopica promastigotes using alamar blue reduction assay. Compound 3, 1-(4-methylphenyl)-3-phenyl-4-[3-(2-thienyl)-2-pyrazolin-5-yl]-1H-pyrazole, possessed the highest anti-malarial activity with suppression of 70.26%. The highest anti-leishmanial activity was exhibited by compound 2, 1-(4-me...
A validated HPLC method for the simultaneous determination of diminazene diaceturate and phenazon... more A validated HPLC method for the simultaneous determination of diminazene diaceturate and phenazone has been established for the analysis of the compounds in veterinary granules for injection and in bulk powders. The compounds were separated using a Symmetry RP 18 analytical column and detected by UV absorbance at 250 nm. Linearity, accuracy as well as the intra-assay precision, inter-day precision and specificity of the method were established. The limits of detection and quantification were 3.2 and 9.7 μg mL-1 for diminazene diaceturate and 9.57 and 28.99 μg mL-1 for phenazone. Method had the potential to determine these drugs simultaneously from dosage forms without any interference with each other.
ABSTRACT Essential oil (EO) from the seeds and husks of Aframomum corrorima (Braun) P.C.M. Jansen... more ABSTRACT Essential oil (EO) from the seeds and husks of Aframomum corrorima (Braun) P.C.M. Jansen were analyzed by gas chromatography (GC/FID and GC/MS), and fifty-five compounds were identified. The main constituents found in the seed EO were the monoterpenes 1,8-cineole (44.3 %) and sabinene (17.3 %), whereas sesquiterpenic structures (2 %) such as (E)-nerolidol (17.2 %), beta-caryophyllene (9.7 %) and caryophyllene oxide (6.9 %) were dominating in husk EO.
The chemical composition of the volatile oil from berries of Croton macrostachyus Hochst. ex Del.... more The chemical composition of the volatile oil from berries of Croton macrostachyus Hochst. ex Del. was determined by GC and GC/MS. The oil was tested for its in vitro antileishmanial activity on two Leishmania strains, and its toxicity on the human monocytic leukemia (THP-1) cell line and erythrocytes from sheep blood. The main constituents of the oil were benzyl benzoate (51.8%), linalool (10.1%), γ-muurolene (9.3%), ( E,E)-α-farnesene (3.2%), δ-cadinene (2.8%) and α-curcumene (2.7%). The oil was effective against L. donovani and L. aethiopica promastigotes (MIC = 0.08 μL/mL and 0.16 μL/mL, respectively) and axenic amastigote stages (EC50 = 20.00 nL/mL and 6.66 nL/mL, respectively). The CC50 value for the oil was 10.00 nL/mL on THP-1 cells with selectivity index values of 0.5 for L. donovani and 1.5 for L. aethiopica. The median lethal concentration (LC50) of the oil was 2.45 μL/mL. Thus the observed high efficacy and moderate toxicity of the volatile oil from C. macrostachyus, make...
The present study assesses the quality and the physicochemical properties of paracetamol dosage f... more The present study assesses the quality and the physicochemical properties of paracetamol dosage forms (tablet, suppository and syrup samples) from different drug outlets in Addis Ababa. Identity, weight uniformity, disintegration and dissolution times, assay for active ingredient content and pH test (for syrup) were performed. Hardness and drug release (t50% and t90%) of the different brands of paracetamol tablets were also evaluated and compared. The study showed that none of the tablet samples did meet the USP specification for assay of active ingredient content. One of the syrup samples (Efferalgan®) tested, contained less than the specified amount of the active principle. Keywords : quality evaluation, physicochemical properties, paracetamol dosage forms, drug outlets, Addis Ababa Ethiopian Pharmaceutical Journal Vol. 26 (1) 2008: pp. 59-64
Essential oils of Artemisia abyssinica and Satureja punctata ssp. punctata from Ethiopia were ana... more Essential oils of Artemisia abyssinica and Satureja punctata ssp. punctata from Ethiopia were analyzed by GC and GC/MS, and screened for leishmanicidal activity against promastigote and axenic amastigotes of Leishmania donovani and L. aethiopica, including toxicity studies on human monocytic leukemia cells (THP-1) and erythrocytes in vitro. GC/MS of A. abyssinica oil revealed 67 compounds (99.94%) with the major constituents yomogi alcohol (38.47%), artemisyl acetate (24.88%), and artemisia alcohol (6.70%), and oxygenated monoterpenes (84.00%) as the dominant group. The oil of S. punctata contained 67 compounds (99.49%) with the main constituents geranial (27.62%), neral (21.72%), alpha-bisabolol (13.62%), and (E)-nerolidol (4.82%), of which oxygenated mono- and sesquiterpenes (58.39 and 26.91%, resp.) showed highest abundance. Both oils showed effect on promastigotes (MIC 76.5 to 312.5 nl/ml) and amastigotes (EC(50) 4.06 to 131.00 nl/ml) of L. donovani and L. aethiopica, and varying toxicities on THP-1 cells (CC(50) 0.013 to 350 nl/ml with selectivity index between 0.001 and 28) and erythrocytes (with LC(50) 0.35 to 1.52 microl/ml). S. punctata oil exerted highest activity against both Leishmania sp. and toxicity. The revealed antileishmanial activities support further isolation and investigation of oil constituents for in vitro/in vivo evaluation.
Potential toxicity, costs, and drug-resistant pathogens necessitate the development of new antile... more Potential toxicity, costs, and drug-resistant pathogens necessitate the development of new antileishmanial agents. Medicinal and aromatic plants constitute a major source of natural organic compounds. In this study, essential oils of Artemisia absinthium L. and Echinops kebericho Mesfin were investigated by GC and GC/MS analyses. Isolated oils were screened for antileishmanial activity against two Leishmania strains (L. aethiopica and L. donovani), and toxicity on the human monocytic leukemia (THP-1) cell line and red blood cells in vitro. GC/MS Analysis revealed 65 compounds (93.74%) for Artemisia absinthium and 43 compounds (92.85%) for Echinops kebericho oil. The oils contained the oxygenated monoterpene camphor (27.40%) and the sesquiterpene lactone dehydrocostus lactone (41.83%) as major constituents, respectively. Both oils showed activity against promastigote (MIC 0.0097-0.1565 μl/ml) and axenic amastigote forms (EC(50) 0.24-42.00 nl/ml) of both leishmania species. Weak hemolytic effect was observed for both oils, showing a slightly decreased selectivity index (SI 0.8-19.2) against the THP-1 cell line. Among the two oils tested, E. kebericho exerted strong antileishmanial activity that was even higher than that of amphotericin B with significant cytotoxicity. This study, therefore, demonstrated the potential use of both oils as source of novel agents for the treatment of leishmaniasis.
Background: Ajuga remota Benth is traditionally used in Ethiopia for the management of diabetes m... more Background: Ajuga remota Benth is traditionally used in Ethiopia for the management of diabetes mellitus. Since this claim has not been investigated scientifically, the aim of this study was to evaluate the antidiabetic effect and phytochemical screening of the aqueous and 70% ethanol extracts on alloxan-induced diabetic mice.
Methods: After acute toxicity test, the Swiss albino mice were induced with alloxan to get experimental diabetes animals. The fasting mean blood glucose level before and after treatment for two weeks in normal, diabetic untreated and diabetic mice treated with aqueous and 70% ethanol extracts were performed. Data were statistically
evaluated by using Statistical Package for the Social Sciences software version 20. P-value <0.05 was considered statistically significant.
Results: The medium lethal doses (LD50) of both extracts were higher than 5000 mg/kg, indicating the extracts are not toxic under the observable condition. Aqueous extracts of A.remota (300 mg/kg and 500 mg/kg body weight) reduced elevated blood glucose levels by 27.83 ± 2.96% and 38.98 ± 0.67% (P < 0.0001), respectively while the 70% ethanol extract caused a reduction of 27.94 ± 1.92% (300 mg/kg) & 28.26 ± 1.82% (500 mg/kg). Treatment with the antidiabetic drug, Glibenclamide (10 mg/kg body weight) lowered blood glucose level by 51.06% (p < 0.05). Phytochemical screening of both extracts indicated the presence of phenolic compounds, flavonoids, saponins,
tannins, and steroids, which might contribute to the antidiabetic activity. The extracts, however, did not contain alkaloids and anthraquinones.
Conclusion: The aqueous extract (500 mg/kg) showed the highest percentage reduction in blood glucose levels and the ability of A. remota extracts in reducing blood glucose levels presumably due to the presence of antioxidant constituents such as flavonoids. The effect of the extract supported the traditional claim of the plant.
Keywords: Ajuga Remota, Antidiabetic activity, Blood glucose level, Diabetes mellitus, Glibenclamide, Phytochemical screening
Bioassay-guided fractionation using the human colorectal adenocarcinoma (HT-29) cell line of the ... more Bioassay-guided fractionation using the human colorectal adenocarcinoma (HT-29) cell line of the methanol extract of dried roots of Podocarpus falcatus led to the isolation of two new type C nagilactones, 16-hydroxynagilactone F (1) and 2β,16-dihydroxynagilactone F (2), and the new totarane-type bisditerpenoid 7β-hydroxymacrophyllic acid (4), along with the seven known compounds 2β-hydroxynagilactone F (3), macrophyllic acid (5), nagilactone D (6), 15-hydroxynagilactone D (7), nagilactone I (8), inumakiol D (9), and ponasterone A (10). The structures of the new compounds were determined by 1D and 2D NMR, HRESIMS, UV, and IR and by comparison with the reported spectroscopic data of their congeners. The orientation of the C-2 hydroxy group of 3 and 8 was revised to be β based on evidence from detailed analysis of 1D and 2D NMR data and single-crystal X-ray diffraction studies. Among the isolated compounds, the nagilactones, including the new dilactones 16-hydroxynagilactone F (1) and 2β,16-dihydroxynagilactone F (2), were the most active (IC50 0.3-5.1 μM range) against the HT-29 cell line, whereas the bisditerpenoids (4 and 5) and the other known compounds 9 and 10 were inactive. The presence of the bioactive nagilactones in P. falcatus supports its traditional use.
The synthesis of a novel series of 1H-pyrazole derivatives was achieved by condensation of pyrazo... more The synthesis of a novel series of 1H-pyrazole derivatives was achieved by condensation of pyrazole aldehyde 1 with hydrazine hydrate to give hydrazone 7. On the other hand, cyclization of α,β-unsaturated ketone counterpart 2 using hydrazine hydrate in liquid aliphatic acids rendered compounds 4-6 and hydrazine hydrate in ethanol afforded compound 3. The later was allowed to react with aroyl chloride giving rise to compounds 8, 9. All compounds were tested for their in vivo anti-malarial and in vitro antileishmanial activities. The anti-malarial activity was performed using Plasmodium berghei infected mice, while the anti-leishmanial activity of the compounds was determined against Leishmania aethiopica promastigotes using alamar blue reduction assay. Compound 3, 1-(4-methylphenyl)-3-phenyl-4-[3-(2-thienyl)-2-pyrazolin-5-yl]-1H-pyrazole, possessed the highest anti-malarial activity with suppression of 70.26%. The highest anti-leishmanial activity was exhibited by compound 2, 1-(4-me...
A validated HPLC method for the simultaneous determination of diminazene diaceturate and phenazon... more A validated HPLC method for the simultaneous determination of diminazene diaceturate and phenazone has been established for the analysis of the compounds in veterinary granules for injection and in bulk powders. The compounds were separated using a Symmetry RP 18 analytical column and detected by UV absorbance at 250 nm. Linearity, accuracy as well as the intra-assay precision, inter-day precision and specificity of the method were established. The limits of detection and quantification were 3.2 and 9.7 μg mL-1 for diminazene diaceturate and 9.57 and 28.99 μg mL-1 for phenazone. Method had the potential to determine these drugs simultaneously from dosage forms without any interference with each other.
ABSTRACT Essential oil (EO) from the seeds and husks of Aframomum corrorima (Braun) P.C.M. Jansen... more ABSTRACT Essential oil (EO) from the seeds and husks of Aframomum corrorima (Braun) P.C.M. Jansen were analyzed by gas chromatography (GC/FID and GC/MS), and fifty-five compounds were identified. The main constituents found in the seed EO were the monoterpenes 1,8-cineole (44.3 %) and sabinene (17.3 %), whereas sesquiterpenic structures (2 %) such as (E)-nerolidol (17.2 %), beta-caryophyllene (9.7 %) and caryophyllene oxide (6.9 %) were dominating in husk EO.
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Papers by A. Hymete
Methods: After acute toxicity test, the Swiss albino mice were induced with alloxan to get experimental diabetes animals. The fasting mean blood glucose level before and after treatment for two weeks in normal, diabetic untreated and diabetic mice treated with aqueous and 70% ethanol extracts were performed. Data were statistically
evaluated by using Statistical Package for the Social Sciences software version 20. P-value <0.05 was considered statistically significant.
Results: The medium lethal doses (LD50) of both extracts were higher than 5000 mg/kg, indicating the extracts are not toxic under the observable condition. Aqueous extracts of A.remota (300 mg/kg and 500 mg/kg body weight) reduced elevated blood glucose levels by 27.83 ± 2.96% and 38.98 ± 0.67% (P < 0.0001), respectively while the 70% ethanol extract caused a reduction of 27.94 ± 1.92% (300 mg/kg) & 28.26 ± 1.82% (500 mg/kg). Treatment with the antidiabetic drug, Glibenclamide (10 mg/kg body weight) lowered blood glucose level by 51.06% (p < 0.05). Phytochemical screening of both extracts indicated the presence of phenolic compounds, flavonoids, saponins,
tannins, and steroids, which might contribute to the antidiabetic activity. The extracts, however, did not contain alkaloids and anthraquinones.
Conclusion: The aqueous extract (500 mg/kg) showed the highest percentage reduction in blood glucose levels and the ability of A. remota extracts in reducing blood glucose levels presumably due to the presence of antioxidant constituents such as flavonoids. The effect of the extract supported the traditional claim of the plant.
Keywords: Ajuga Remota, Antidiabetic activity, Blood glucose level, Diabetes mellitus, Glibenclamide, Phytochemical screening
Methods: After acute toxicity test, the Swiss albino mice were induced with alloxan to get experimental diabetes animals. The fasting mean blood glucose level before and after treatment for two weeks in normal, diabetic untreated and diabetic mice treated with aqueous and 70% ethanol extracts were performed. Data were statistically
evaluated by using Statistical Package for the Social Sciences software version 20. P-value <0.05 was considered statistically significant.
Results: The medium lethal doses (LD50) of both extracts were higher than 5000 mg/kg, indicating the extracts are not toxic under the observable condition. Aqueous extracts of A.remota (300 mg/kg and 500 mg/kg body weight) reduced elevated blood glucose levels by 27.83 ± 2.96% and 38.98 ± 0.67% (P < 0.0001), respectively while the 70% ethanol extract caused a reduction of 27.94 ± 1.92% (300 mg/kg) & 28.26 ± 1.82% (500 mg/kg). Treatment with the antidiabetic drug, Glibenclamide (10 mg/kg body weight) lowered blood glucose level by 51.06% (p < 0.05). Phytochemical screening of both extracts indicated the presence of phenolic compounds, flavonoids, saponins,
tannins, and steroids, which might contribute to the antidiabetic activity. The extracts, however, did not contain alkaloids and anthraquinones.
Conclusion: The aqueous extract (500 mg/kg) showed the highest percentage reduction in blood glucose levels and the ability of A. remota extracts in reducing blood glucose levels presumably due to the presence of antioxidant constituents such as flavonoids. The effect of the extract supported the traditional claim of the plant.
Keywords: Ajuga Remota, Antidiabetic activity, Blood glucose level, Diabetes mellitus, Glibenclamide, Phytochemical screening