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Ashafa AOT, Grierson DS, Afolayan AJ. In vitro antioxidant activity of extracts from the leaves of Felicia muricata thunb. An underutilized medicinal plant in the Eastern Cape Province, South Africa. Afr J Tradit Complement Altern Med 2010; 7:296-302. [PMID: 21731160 PMCID: PMC3005399 DOI: 10.4314/ajtcam.v7i4.56695] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Felicia muricata is a medicinal plant used for the management of different human and livestock diseases in the Eastern Cape Province of South Africa. The antioxidant potential of the leaves from this herb was investigated using its water, methanol, acetone and ethanol extracts. All the extracts were rich in phenols, proanthocyanidins and flavonols but low in flavonoids. The water extract exhibited low DPPH scavenging activity while the methanol, acetone and ethanol extracts showed higher activities. Again all the extracts showed high ABTS scavenging activity with a correlation between total phenolic content (R2 = 0.9965), DPPH (R2 = 0.982) and ABTS (R2 = 0.927). Traditionally, however, plant extracts are prepared with water as infusions, decoction and poultice. Our results have shown that both the water and ethanol extracts from Felicia muricata displayed strong antioxidant activity. Therefore, it would seem likely that both solvents were able to extract those compounds which are responsible for the antioxidant activity of F. muricata.
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Affiliation(s)
- A O T Ashafa
- Centre for Phytomedicine Research, Department of Botany, University of Fort Hare, Alice 5700, South Africa
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Liu J, Grierson DS, Moldovan N, Notbohm J, Li S, Jaroenapibal P, O'Connor SD, Sumant AV, Neelakantan N, Carlisle JA, Turner KT, Carpick RW. Preventing nanoscale wear of atomic force microscopy tips through the use of monolithic ultrananocrystalline diamond probes. Small 2010; 6:1140-1149. [PMID: 20486220 DOI: 10.1002/smll.200901673] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Nanoscale wear is a key limitation of conventional atomic force microscopy (AFM) probes that results in decreased resolution, accuracy, and reproducibility in probe-based imaging, writing, measurement, and nanomanufacturing applications. Diamond is potentially an ideal probe material due to its unrivaled hardness and stiffness, its low friction and wear, and its chemical inertness. However, the manufacture of monolithic diamond probes with consistently shaped small-radius tips has not been previously achieved. The first wafer-level fabrication of monolithic ultrananocrystalline diamond (UNCD) probes with <5-nm grain sizes and smooth tips with radii of 30-40 nm is reported, which are obtained through a combination of microfabrication and hot-filament chemical vapor deposition. Their nanoscale wear resistance under contact-mode scanning conditions is compared with that of conventional silicon nitride (SiN(x)) probes of similar geometry at two different relative humidity levels (approximately 15 and approximately 70%). While SiN(x) probes exhibit significant wear that further increases with humidity, UNCD probes show little measurable wear. The only significant degradation of the UNCD probes observed in one case is associated with removal of the initial seed layer of the UNCD film. The results show the potential of a new material for AFM probes and demonstrate a systematic approach to studying wear at the nanoscale.
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Affiliation(s)
- J Liu
- University of Wisconsin-Madison Madison, WI 53706, USA
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Appidi JR, Yakubu MT, Grierson DS, Afolayan AJ. Antidiarrheal activity of aqueous extract of Hermannia incana Cav. leaves in Wistar rats. Methods Find Exp Clin Pharmacol 2010; 32:27-30. [PMID: 20383343 DOI: 10.1358/mf.2010.32.1.1464613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Hermannia incana Cav. is a prostrate herb used to treat diarrhea, stomach ache, nausea and vomiting, by the people of Eastern Cape Province, South Africa. The phytochemical screening as well as the antidiarrheal activity of H. incana leaf extract at 200, 400 and 600 mg/kg body weight was evaluated in rats. Phytochemical screening revealed the presence of bioactive agents such as alkaloids, tannins, saponins, phenolics, triterpenes, cardiac glycosides, flavonoids, cardenolides and dienolides. The extract significantly prolonged the time of induction of diarrhea, reduced the frequency of diarrheal episodes and water content of the feces, and inhibited castor oil-induced enteropooling. The extract also suppressed intestinal propulsive movement of a charcoal meal through the gastrointestinal tract. These results demonstrate the antidiarrheal properties of the extract, thereby supporting the folkloric use of the plant as an antidiarrheal agent in the Eastern Cape of South Africa.
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Affiliation(s)
- J R Appidi
- Department of Botany, University of Fort Hare, Alice, South Africa
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Pendota SC, Yakubu MT, Grierson DS, Afolayan AJ. Effect of administration of aqueous extract of hippobromus pauciflorus leaves in male Wistar rats. Afr J Tradit Complement Altern Med 2009; 7:40-6. [PMID: 21304611 DOI: 10.4314/ajtcam.v7i1.57237] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effect of administration of aqueous extract of Hippobromus pauciflorus (L.f.) Radlk (Sapindaceae) leaves at 50, 100 and 200 mg/kg body weight for 14 days on some biochemical parameters in male Wistar rats was investigated. The extract at all the doses tested did not significantly (P>0.05) alter the levels of white blood cells, red blood cells, mean corpuscular volume, platelets, neutrophils, monocytes, lymphocytes and large unstained cells. While the levels of haemoglobin, packed cell volume and basophils increased significantly (P<0.05) at specific doses, the mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration and eosinophils decreased significantly (P<0.05). Again, the extract did not significantly (P<0.05) alter the computed liver- and kidney-body weight ratios, sodium, chloride and total protein, though, the levels of potassium, inorganic phosphorus, globulin, urea, total and conjugated bilirubin increased significantly (P<0.05) at certain doses. In contrast, the levels of albumin and creatinine also decreased significantly (P<0.05) at specific doses. While the activities of alkaline phosphatase, gamma glutamyl transferase and alanine aminotransferase remained significantly (P<0.05) unaltered in the serum, aspartate aminotransferase activity increased only at 200 mg/kg body weight. The atherogenic index as well as the concentrations of cholesterol, high- and low-density lipoprotein cholesterol in the serum of the animals were not significantly (P>0.05) altered. However, the extract significantly (P<0.05) increased the concentration of triacylglycerol. The results suggest that the extract has mild and dose specific haemato-, hepato- and nephrotoxic effects and may not be completely safe as oral remedy at the doses investigated.
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Affiliation(s)
- S C Pendota
- Department of Botany, University of Fort Hare, Alice 5700, South Africa
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Abstract
An ethnobotanical study of plants used for the treatment of diarrhoea in the Eastern Cape Province, South Africa was carried out, using a questionnaire which was administered to herbalists, traditional healers and rural dwellers. Information collected revealed the names of plants used for the treatment of diarrhoea, the parts used and the methods of preparation. This survey indicated a total of 17 plant species from 14 families used in the Province. Elephantorrhiza elephantina, Hermannia incana, Pelargonium reniforme, Alepidea amatymbica and Bulbine latifolia were the most frequently mentioned and highly recommended plants for the treatment of diarrhoea by both the traditional healers and rural dwellers. Roots, bark and leaves are the common parts of plants used, while decoctions and infusions are the main methods of preparation.
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Affiliation(s)
- J R Appidi
- Department of Botany, University of Fort Hare, Alice 5700, South Africa
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Abstract
The structure and distribution of foliar appendages on the leaves of this plant were investigated with the JEOL (JSM-6390LV) scanning electron microscope (SEM). Both glandular and non-glandular trichomes were observed, which differed from each other in morphology and location on the leaves. Long stalked glandular trichomes were present on both the abaxial and adaxial surfaces while short stalked glandular trichomes were present only on the adaxial surface. Glandular trichomes were capitate while non-glandular trichomes were stellate with many arms. Some crystal deposits were observed on the surfaces of the leaves. Energy dispersive X-ray spectroscopy-SEM of these crystals showed that Al, Ca, K, Na, Ti and Si were the major constituents. We hypothesize that the bioactive therapeutic compounds secreted by H. incana may be produced in the glandular trichomes.
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Affiliation(s)
- J R Appidi
- Department of Botany, University of Fort Hare, Alice 5700, South Africa
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Pendota SC, Grierson DS, Afolayan AJ. An ethnobotanical study of plants used for the treatment of eye infections in the Eastern Cape Province, South Africa. Pak J Biol Sci 2008; 11:2051-2053. [PMID: 19266917 DOI: 10.3923/pjbs.2008.2051.2053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Information on medicinal plants, used by the people of the Eastern Cape for the treatment of eye infections, was collected through questionnaires which were administered to herbalists, traditional healers and rural dwellers. The information collected revealed 12 plant species. These plants belong to 9 families, of which Sapindaceae was the most prominent. The leaves were reported to be the most used part of the plants, constituting 75% of herbal preparations. This was followed by bark and roots which constituted 25%. Generally, the plant parts are crushed and the sap squeezed directly into the infected eyes. In few cases, the material is mixed with water and boiled; after cooling, the extract is applied to the infected eyes. Hippobromus pauciflorus was the most commonly used plant species for the treatment of eye infections in the province. Majority of the plants used have been reported in literature to possess some other pharmacological activities.
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Affiliation(s)
- S C Pendota
- Department of Botany, University of Fort Hare, Alice 5700, South Africa
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Abstract
Foliar micromorphology of Hippobromus pauciflorus (L.f.) Radlk (Sapindaceae) was investigated by scanning electron microscope examination. The leaves were characterized by anisocytic stomata which were found only on the abaxial surface. The leaves have long unicellular non-glandular trichomes which were distributed over the mid rib and densely populated at the edges of the upper and lower surfaces. Crystal deposits were also observed on the abaxial surface of the leaves. Energy dispersive X-ray spectroscopy SEM of the crystals showed predominant mineral components of Na, Al, Si, K and Ca ions. These micro (Si, Na and Al) and macro (K and Ca) elements are very essential to plant growth. Their presence in the trichomes could contribute to the mechanical stability of the leaf appendages.
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Affiliation(s)
- S C Pendota
- Department of Botany, University of Fort Hare, Alice, 5700, South Africa
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Abstract
The foliar micromorphology of Felicia muricata (Thunb.) Nees (Asteraceae) was observed with the JEOL (JSM-6390LV) Scanning Electron Microscope (SEM). Both the abaxial and adaxial surfaces were characterized by anisocytic stomata which were more prevalent on the abaxial surface than the adaxial surface. The leaves have only one type of multicellular non-glandular trichomes that are long and cylindrical, tapering to a sharp point and running parallel to the leaf surface in the direction of the apices. Crystal deposits were also observed on the surfaces of the leaves near the stomata. Energy dispersive X-ray spectroscopy-SEM shows that Na, Al, Si, and K were the major constituents of the crystal analyzed. Since no glandular trichomes were present on the leaves of this herb, the bioactive components present in this plant may be produced in some other tissues in the leaf other than the trichomes.
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Affiliation(s)
- A O T Ashafa
- Department of Botany, University of Fort Hare, Alice 5700, South Africa
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Konicek AR, Grierson DS, Gilbert PUPA, Sawyer WG, Sumant AV, Carpick RW. Origin of ultralow friction and wear in ultrananocrystalline diamond. Phys Rev Lett 2008; 100:235502. [PMID: 18643515 DOI: 10.1103/physrevlett.100.235502] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Indexed: 05/26/2023]
Abstract
The impressively low friction and wear of diamond in humid environments is debated to originate from either the stability of the passivated diamond surface or sliding-induced graphitization/rehybridization of carbon. We find ultralow friction and wear for ultrananocrystalline diamond surfaces even in dry environments, and observe negligible rehybridization except for a modest, submonolayer amount under the most severe conditions (high load, low humidity). This supports the passivation hypothesis, and establishes a new regime of exceptionally low friction and wear for diamond.
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Affiliation(s)
- A R Konicek
- Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA, 19104, USA
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Abstract
The volatile components obtained by hydrodistillation of Solanum pseudocapsicum roots were analyzed by gas chromatography-mass spectrometry. A total of 41 compounds, representing 50% of the oil, were identified. The oil was found to contain fatty acids (26.8%), terpenoids (7.6%), and aldehydes (5.3%) as the major components. The dominant compounds were hexadecanoic acid (24.1%), 2-methoxy-3-isopropylpyrazine (2.8%), and 15-methylhexadecanoic acid (2.1%). Other notable components include beta-elemene and delta-elemene. The high proportion of fatty acids in this plant could contribute to its medicinal properties.
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Affiliation(s)
- A A Aliero
- Department of Botany, University of Fort Hare, Alice, South Africa
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Maillard P, Loock B, Grierson DS, Laville I, Blais J, Doz F, Desjardins L, Carrez D, Guerquin-Kern JL, Croisy A. In vitro phototoxicity of glycoconjugated porphyrins and chlorins in colorectal adenocarcinoma (HT29) and retinoblastoma (Y79) cell lines. Photodiagnosis Photodyn Ther 2007; 4:261-8. [PMID: 25047563 DOI: 10.1016/j.pdpdt.2007.05.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 05/11/2007] [Accepted: 05/23/2007] [Indexed: 10/23/2022]
Abstract
BACKGROUND Retinoblastoma is the most common malignant intraocular tumor in children. The current treatment gives a good vital prognostic but there are several drawbacks to the arsenal of "classical antitumoral" therapies. Photodynamic therapy (PDT) could be an exciting non-toxic and non-mutagenic alternative protocol. METHOD In this paper, we report about the screening of the in vitro photocytotoxicity of hydrophenylporphyrins and chlorins and their glycoconjugated derivatives in a human retinoblastoma cell line (Y79) and for comparison in a colorectal adenocarcinoma cell line (HT29). RESULTS Despite lower photodynamic activity than that observed for hydroxylated photosensitizers, in particular Foscan(®) glycoconjugated derivatives display phototoxicity (IC50 2.4-0.05μM ±10%) against Y79 cells with examples of significant intrinsic cytotoxicity. Amongst them the triglucosyl porphyrin 10 is highly photocytotoxic (IC50 0.9μM ±10%) but is fully devoid of cytotoxicity (IC50>15μM). The photoactivity is highly modulated by the presence of a diethyleneglycol spacer between the chromophore and the glycoside (compounds 14-17, IC50 0.5, 0.6, 0.05 and 0.35μM ±10%) and by the anomeric configuration of the sugar (compound 15 and 17, IC50 0.6 and 0.05μM ±10% respectively). One of the main problems for the use of Foscan(®) is its poor solubility which might be improved by glycoconjugation. Moreover Foscan has been shown to induce necrosis after PDT leading to a possible ulceration of surrounding tissues unsuitable for a conservative treatment. A preferential mitochondrial subcellular localization which has been previously reported for some glycoconjugated photosensitizers could enhance the contribution of apoptosis process. CONCLUSION Tri-α-O-galactosyl porphyrin 16 is a better candidate than Foscan(®) for a clinical application of PDT for a conservative therapy of retinoblastoma.
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Affiliation(s)
- Ph Maillard
- UMR 176 CNRS, Institut Curie, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France; Institut Curie, Section de Recherches, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France
| | - B Loock
- UMR 176 CNRS, Institut Curie, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France; Institut Curie, Section de Recherches, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France
| | - D S Grierson
- UMR 176 CNRS, Institut Curie, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France; Institut Curie, Section de Recherches, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France
| | - I Laville
- BIOMOCETI, UMR CNRS 7033/Université Pierre et Marie Curie, 2 place Jussieux, Univ P. et M. Curie, Paris F-75005, France
| | - J Blais
- BIOMOCETI, UMR CNRS 7033/Université Pierre et Marie Curie, 2 place Jussieux, Univ P. et M. Curie, Paris F-75005, France
| | - F Doz
- Oncologie Pédiatrique, Ophtalmologie, Hôpital Cl. Regaud, 26 rue d'Ulm, Institut Curie, Paris F-75005, France
| | - L Desjardins
- Oncologie Pédiatrique, Ophtalmologie, Hôpital Cl. Regaud, 26 rue d'Ulm, Institut Curie, Paris F-75005, France
| | - D Carrez
- Institut Curie, Section de Recherches, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France; Inserm Unité 759 Institut Curie, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France
| | - J-L Guerquin-Kern
- Institut Curie, Section de Recherches, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France; Inserm Unité 759 Institut Curie, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France
| | - A Croisy
- Institut Curie, Section de Recherches, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France; Inserm Unité 759 Institut Curie, Centre Universitaire, Univ Paris-Sud, Orsay, F-91405, France
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Erasto P, Grierson DS, Afolayan AJ. Bioactive sesquiterpene lactones from the leaves of Vernonia amygdalina. J Ethnopharmacol 2006; 106:117-20. [PMID: 16458461 DOI: 10.1016/j.jep.2005.12.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Revised: 11/18/2005] [Accepted: 12/09/2005] [Indexed: 05/06/2023]
Abstract
Phytochemical analysis of the leaves of Vernonia amygdalina yielded two known sesquiterpene lactones: vernolide and vernodalol. The two compounds were tested by agar dilution method against 10 bacteria strains and 5 fungi species. Both compounds exhibited a significant bactericidal activity against five Gram positive bacteria while lacking efficacy against the Gram negative strains. In the antifungal test, while vernolides exhibited high activity with LC(50) values of 0.2, 0.3 and 0.4 mg/ml against Penicillium notatum, Aspergillus flavus, Aspergillus niger and Mucor hiemalis, respectively, vernodalol showed moderate inhibitions against Aspergillus flavus, Penicillium notatum and Aspergillus niger with LC(50) values of 0.3, 0.4 and 0.5 mg/ml, respectively. Both compounds were ineffective against Fusarium oxysporum, a microbe known to be highly resistant to chemical agents. However, the antimicrobial results of this study correspond positively with the claimed ethnomedical uses of the leaves of Vernonia amygdalina in the treatment of various infectious diseases.
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Affiliation(s)
- P Erasto
- Department of Botany, University of Fort Hare, Alice 5700, South Africa
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Laville I, Pigaglio S, Blais JC, Loock B, Maillard P, Grierson DS, Blais J. A study of the stability of tri(glucosyloxyphenyl)chlorin, a sensitizer for photodynamic therapy, in human colon tumoural cells: a liquid chromatography and MALDI-TOF mass spectrometry analysis. Bioorg Med Chem 2004; 12:3673-82. [PMID: 15186852 DOI: 10.1016/j.bmc.2004.04.022] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2003] [Accepted: 04/15/2004] [Indexed: 11/23/2022]
Abstract
Asymmetrical glycoconjugated tetrapyrrolic macrocycles are under study as efficient sensitizers for photodynamic therapy (PDT). In this context, tri(meta-O-beta-glucopyranosyloxyphenyl)chlorin [TPC(m-O-Glu)(3)] 2a/3a was found to be four times more photoactive in vitro than Foscan. In a further study of this interesting glycoconjugate, its metabolism by cellular glycosidases in HT29 cells has to be explored. Cellular extracts of HT29 cells incubated with TPC(m-O-Glu)(3) (24h, 6microM) were analyzed by MALDI-TOF mass spectrometry and high performance liquid chromatography (HPLC). In MALDI-TOF mass spectra, the presence of compounds distinct from TPC(m-O-Glu)(3) (m/z 1151) were observed at m/z 989, 827 and 665 corresponding to the loss of one, two or three glucose units (162u) and were be ascribed to TPC(m-OH)(m-O-Glu)(2) 2/3b,b',b", TPC(m-OH)(2)(m-O-Glu) 2/3c,c',c" and TPC(m-OH)(3) isomers 2d/3d, respectively. The porphyrins resulting from chlorin oxidation TPP(m-O-Glu)(3) 4a, TPP(m-OH)(m-O-Glu)(2) 4b,b", TPP(m-OH)(2)(m-O-Glu) 4c,c" and TPP(m-OH)(3) 4d were also observed. The HPLC profile (lambda(anal)=420 nm) showed eight peaks consistent with mass spectra. The kinetics of deglucosylation was studied from HPLC profiles between 1 and 48h incubation. The concentration of triglucoconjugated and diglucoconjugated molecules was maximum around 3 and 8h incubation, respectively, whereas, totally deglucosylated species appeared only after incubation for more than 10h. The fully deglycosylated porphyrin TPP(m-OH)(3) is the final metabolite, being observed at a concentration 15 times higher than that of the remaining TPC(m-O-Glu)(3) 2a/3a. Compared to the photobiological activity of the parent molecule [TPC(m-O-Glu)(3)], a three times higher TPP(m-OH)(3) concentration was necessary to observe a similar in vitro photoactivity.
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Affiliation(s)
- I Laville
- LPBC, UMR CNRS 7033, Université Pierre et Marie Curie, 4 place Jussieu, case 138, 75252 Paris Cedex 05, France
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Laville I, Figueiredo T, Loock B, Pigaglio S, Maillard P, Grierson DS, Carrez D, Croisy A, Blais J. Synthesis, cellular internalization and photodynamic activity of glucoconjugated derivatives of tri and tetra(meta-hydroxyphenyl)chlorins. Bioorg Med Chem 2003; 11:1643-52. [PMID: 12659750 DOI: 10.1016/s0968-0896(03)00050-6] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Glucoconjugated tri and tetra(meta-hydroxyphenyl)chlorins have been synthesized in order to explore how glucoconjugation of the macrocycle affects the photoactivity of the molecule. Internalization processes, photosensitizing efficacy of TPC(m-O-GluOH)(3) and TPC(m-O-GluOH)(4), in HT29 human adenocarcinoma cells have been compared to those of tetra(meta-hydroxyphenyl) chlorin (m-THPC, Foscan). The tetra glucoconjugated chlorin, TPC(m-O-GluOH)(4), was found to be poorly internalized and weakly photoactive. In contrast, the asymmetric and more amphiphilic compound TPC(m-O-GluOH)(3), exhibited superior phototoxicity compared to m-THPC. Drug concentration, temperature and sodium azide effects indicated that TPC(m-O-GluOH)(3) internalization partly proceeds via an active receptor-mediated endocytosis mechanism. Cellular uptake appeared as a saturable process and remained 30% lower than for mTHPC. However, a maximum phototoxicity in HT29 cells (survival fraction of 2+/-0.6%) were observed for concentration as low as 2 microM. A 4-fold higher concentration of m-THPC was necessary to observe the same level of photoactivity. This higher phototoxicity has been correlated to a greater mitochondrial affinity. On the basis of these results, work is in progress to further evaluate the potential of glycosylated chlorins in photodynamic therapy (PDT).
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Affiliation(s)
- I Laville
- LPBC, UMR CNRS 7033 and Université Pierre et Marie Curie, 4 Place Jussieu, case 138, 75252 Paris Cedex 05, France
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Motorina IA, Huel C, Quiniou E, Mispelter J, Adjadj E, Grierson DS. Phenylisoserine: a versatile amino acid for the construction of novel beta-peptide structures. J Am Chem Soc 2001; 123:8-17. [PMID: 11273595 DOI: 10.1021/ja002700+] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The N-Boc O-tert-butyldimethysilyl-substituted hexa-beta-peptide methyl ester 18 was constructed from the O-TBS ether of (-)-(2R, 3S)-phenylisoserine. By NMR, it was determined that this homo beta-peptide adopts a highly stable beta-strand-type secondary structure in chloroform solution, which is stabilized by both hydrophobic interactions involving the OTBS methyl groups of residues i and i + 2, and inter-(five-membered)/intra (six-membered)-residue H-bonding interactions. These interactions are systematically repeated along the peptide chain and, thereby, operate in concert to stabilize the observed conformation of 18.
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Affiliation(s)
- I A Motorina
- UMR 176 CNRS, Laboratoire de Pharmacochimie, Institut Curie Section de Recherche, Batiment 110, Centre Universitaire, 91405 Orsay, France
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Abstract
Several series of cyclin-dependent kinase inhibitors previously prepared in our laboratory were compared using 3D-QSAR (CDK1) and docking (CDK2) techniques. Evaluation of our own library of 93 purine derivatives served to establish the model which was validated by evaluation of an external library of 71 compounds. The best predictions were obtained with the CoMFA standard model (q(2) = 0.68, r(2) = 0.90) and with the CoMSIA combined steric, electrostatic, and lipophilic fields (q(2) = 0.74, r(2) = 0.90). The CDK1 3D-QSAR model was then superimposed to the ATP/CDK2 binding site, giving direct contour maps of the different fields. Although too few compounds were evaluated on CDK5 to derive a 3D-QSAR model, some interesting SARs have been deduced. Comparison of the results obtained from both methods helped with understanding the specific activity of some compounds and designing new specific CDK inhibitors.
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Affiliation(s)
- P Ducrot
- Institut Curie, Section de Recherche, UMR 176 CNRS, Bât. 110-112, Centre Universitaire, 91405 Orsay Cedex, France
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18
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Pontikis R, Dollé V, Guillaumel J, Dechaux E, Note R, Nguyen CH, Legraverend M, Bisagni E, Aubertin AM, Grierson DS, Monneret C. Synthesis and evaluation of "AZT-HEPT", "AZT-pyridinone", and "ddC-HEPT" conjugates as inhibitors of HIV reverse transcriptase. J Med Chem 2000; 43:1927-39. [PMID: 10821705 DOI: 10.1021/jm991125l] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To test the concept that HIV reverse transcriptase could be effectively inhibited by "mixed site inhibitors", a series of seven conjugates containing both a nucleoside analogue component (AZT 1, ddC 2) and a nonnucleoside type inhibitor (HEPT analogue 12, pyridinone 27) were synthesized and evaluated for their ability to block HIV replication. The (N-3 and C-5)AZT-HEPT conjugates 15, 22, and 23 displayed 2-5 microM anti-HIV activity, but they had no effect on the replication of HIV-2 or the HIV-1 strain with the Y181C mutation. The (C-5)AZT-pyridinone conjugates 34-37 were found to be inactive. In marked contrast, the ddC-HEPT molecule 26 displayed the same potency (EC(50) = 0.45 microM) against HIV-1 (wild type and the Y181C nevirapine-resistant strain) and HIV-2 in cell culture. No synergistic effect was observed for these bis-substrate inhibitors, suggesting that the two individual inhibitor components in these molecules do not bind simultaneously in their respective sites. Interestingly, however, the results indicate that the AZT-HEPT conjugates and the ddC-HEPT derivative 26 inhibit reverse transcriptase (RT) in an opposite manner. One explanation for this difference is that the former compounds interact preferentially with the hydrophobic pocket in RT, whereas 26 (after supposed triphosphorylation) inhibits RT through binding in the catalytic site.
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Affiliation(s)
- R Pontikis
- UMR 176 CNRS/Institut Curie, Section de Recherche, 26 rue d'Ulm, F-75248 Paris Cedex 05, France
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19
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Legraverend M, Tunnah P, Noble M, Ducrot P, Ludwig O, Grierson DS, Leost M, Meijer L, Endicott J. Cyclin-dependent kinase inhibition by new C-2 alkynylated purine derivatives and molecular structure of a CDK2-inhibitor complex. J Med Chem 2000; 43:1282-92. [PMID: 10753466 DOI: 10.1021/jm9911130] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new series of 2,6,9-trisubstituted purines, characterized by the presence of a common alkynyl substituent at C-2 and a range of different anilino/benzylamino groups at C-6, were synthesized. These compounds were evaluated for their capacity to inhibit cyclin-dependent kinase activity (CDK1-cyclin B) in vitro. Compounds 4e (N-6-p-Cl-benzylamino derivative) and 5e (N-6-m-Cl-anilino derivative) exhibited the strongest inhibitory activity with an IC(50) of 60 nM. The structure of compound 4b (N-6-p-methoxybenzylamino derivative) in complex with human CDK2 was determined by X-ray crystallography, revealing the molecular basis of inhibition by this molecule. Subsequent molecular modeling studies allowed us to rationalize the SAR observed for these compounds.
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Affiliation(s)
- M Legraverend
- Section de Recherche, Institut Curie, UMR 176 CNRS, Bât. 110-112, Centre Universitaire, 91405 Orsay Cedex, France.
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20
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Abstract
The people of the Eastern Cape Province, South Africa, still depend, to a large extent, on traditional herbal medicine for the treatment of various diseases and ailments. This includes the use of plants for the treatment of wounds. Information collected from the traditional healers, the Sangomas, has revealed 38 plant species that are used for the treatment of wounds in the Province. The plants belong to 26 families of which Asteraceae, Asphodelaceae and Solanaceae are the most represented. The use of plant leaves as a poultice and infusions are the commonest categories of herbal preparations. In all cases, the treatment of wounds involved the external application of the herbal medicine.
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Affiliation(s)
- D S Grierson
- Botany Department, University of Fort Hare, Alice, South Africa
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21
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Grierson DS, Afolayan AJ. Antibacterial activity of some indigenous plants used for the treatment of wounds in the Eastern Cape, South Africa. J Ethnopharmacol 1999; 66:103-6. [PMID: 10432215 DOI: 10.1016/s0378-8741(98)00202-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The use of medicinal plants in the world, and especially in South Africa, contributes significantly to primary health care. This paper presents the findings of an initial survey of plants used for the treatment of wounds in the Eastern Cape Province, South Africa. Ethnomedical information gathered from surveys at clinics, hospitals as well as interviews with traditional healers and rural dwellers has revealed that Grewia occidentalis, Polystichum pungens, Cheilanthes viridis and Malva parvifolia are the most commonly used plants for the treatment of wounds in the province. The methanol extracts of G. occidentalis, P. pungens and C. viridis showed significant inhibition against gram-positive and gram-negative bacteria, while the acetone extract of P. pungens inhibited the gram-positive bacteria only. Extracts from M. parvifolia did not show any antibacterial activity at 5.0 mg/ml. Generally, the antibacterial property of the plants appears to have justified their use for the treatment of wounds, which are contaminated through bacterial infection, in the province.
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Affiliation(s)
- D S Grierson
- Botany Department, University of Fort Hare, Alice, South Africa
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22
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Pontikis R, Note R, Dechaux E, Guillaumel J, Aubertin AM, Grierson DS, Monneret C. "Mixed inhibitors" of HIV-reverse transcriptase: synthesis and antiviral activity. Nucleosides and Nucleotides 1999; 18:707-8. [PMID: 10432669 DOI: 10.1080/15257779908041548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Some "AZT-HEPT" and "ddC-HEPT" conjugates were designed, synthesized and evaluated for their anti-HIV activity.
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Affiliation(s)
- R Pontikis
- Institut Curie, Section Recherche, UMR-176 CNRS-IC, Paris, France
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23
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Adams DR, Boyd AS, Ferguson R, Grierson DS, Monneret C. Heterocyclic nucleoside analogues by cycloaddition reactions of 1-vinylthymine with 1,3-dipoles. Nucleosides Nucleotides 1998; 17:1053-75. [PMID: 9708322 DOI: 10.1080/07328319808004220] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
1,3-Dipolar cycloaddition of 1-vinylthymine to azides, nitrile oxides, nitrones and nitronates has been investigated as a route to heterocyclic nucleoside analogues in which the nucleoside ribose moiety has been replaced by an alternative heterocycle. Reaction of 1-vinylthymine with highly reactive nitrile oxides affords 1-(isoxazolin-5-yl)thymine products in excellent yield at room temperature. The less reactive nitrone dipoles undergo cycloaddition to 1-vinylthymine at elevated temperature to afford 1-(isoxazolidin-5-yl)thymine cycloadducts in good-to-moderate yields, but show a tendency to eliminate thymine from the cycloaddition products over long reaction times. Azide cycloadditions to 1-vinylthymine proceed only under forcing conditions to which the fragile triazoline products are unstable.
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Affiliation(s)
- D R Adams
- Chemistry Department, Heriot-Watt University, Riccarton, Edinburgh, UK
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24
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Kireev DB, Chrétien JR, Grierson DS, Monneret C. A 3D QSAR study of a series of HEPT analogues: the influence of conformational mobility on HIV-1 reverse transcriptase inhibition. J Med Chem 1997; 40:4257-64. [PMID: 9435895 DOI: 10.1021/jm970110p] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Quantitative structure-activity relationships (QSAR) have been established for 87 analogues of 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT), a potent inhibitor of the HIV-1 reverse transcriptase (RT). Of these 87 nonnucleoside RT inhibitors, 9 novel HEPT analogues were used in the study and the others were taken from the literature. The predictive ability of these relationships has been evaluated using a large set of 54 compounds which were not used to derive the activity model. Descriptors related to the conformational changes were found to be an important factor which underlies RT inhibitory activity in the HEPT series. Indeed, the QSAR model provides evidence concerning the conformational transformations the molecules may undergo during the inhibition process. The established relationships are supplementary to the experimental study on the binding of HEPT type inhibitors to RT by Hopkins et al. (J. Med. Chem. 1996, 39, 1589-1600). The present study suggests a quantitative interpretation of the structure-activity relationships which otherwise cannot be explained within the framework of the crystal inhibitor-protein model. This information is pertinent to the further design of new HEPT type RT inhibitors.
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Affiliation(s)
- D B Kireev
- Laboratoire de Chimiométrie, Université d'Orléans, France
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25
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Pontikis R, Benhida R, Aubertin AM, Grierson DS, Monneret C. Synthesis and anti-HIV activity of novel N-1 side chain-modified analogs of 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT). J Med Chem 1997; 40:1845-54. [PMID: 9191961 DOI: 10.1021/jm960765a] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A series of 33 N-1 side chain-modified analogs of 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (1, HEPT) were synthesized and evaluated for their anti-HIV-1 activity. In particular, the influence of substitution of the terminal hydroxy group of the acyclic structure of HEPT and the structural rigidity of this side chain were investigated. Halo (7, 8), azido (9), and amino (10-15) derivatives were synthesized from HEPT via the p-tosylate derivative 6. Acylation of the primary amine 15 afforded the amido analogs 16-20. The diaryl derivatives 26-29 were prepared by reaction of HEPT, or of the 6-(2-pyridylthio) analog 23, with diaryl disulfides in the presence of tri-n-butylphosphine. Compounds 39-41, in which the N-1 side chain is rigidified by incorporation of an E-configured double bond, were obtained by palladium(0)-catalyzed coupling of several different 6-(arylthio)uracil derivatives (37, 38) with allyl acetates 33. Compounds 13, 40a,c,d,f, and 41, incorporating an aromatic ring at the end of the acyclic side chain, were found to be more potent than the known diphenyl-substituted HEPT analog BPT (2), two of them, 40c,d, being 10-fold more active.
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Affiliation(s)
- R Pontikis
- Institut Curie, Section Recherche, UMR CNRS 176, Paris, France
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26
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Adams DR, Perez C, Maillard M, Florent JC, Evers M, Hénin Y, Litvak S, Litvak L, Monneret C, Grierson DS. Preparation and anti-HIV activity of N-3-substituted thymidine nucleoside analogs. J Med Chem 1997; 40:1550-8. [PMID: 9154976 DOI: 10.1021/jm9600095] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A series of 22 derivatives of AZT substituted at the N-3 position of the thymine base were prepared and evaluated for anti-HIV activity in cell culture (Lai strain of HIV-1 in CEM-c113 cells). The AZT analogs bearing a N-3 amino group (7), a hydroxyalkyl chain (12f), and a phosphonomethyl (12k) substituent displayed activities in the 0.045-0.082 microM range. The analogs 12d, 12e, 12q, 15, and 19 were active at <0.5 microM concentration. Compound 18 in which two molecules of AZT are connected at N-3 via a two-carbon link and "dimer" 11 also displayed significant activity. To obtain information concerning the mechanism of RT inhibition by these AZT analogs, compounds 7, 12d, 12e, and 12q were incubated with recombinant HIV-1 RT in the presence of poly(A)-oligo[dT(12-18)] and poly(C)-oligo[dG(12-18)] template-primers. In contrast to AZT-TP (control), none of these nucleosides displayed any significant inhibition of RT in the recombinant enzyme assay, indicating that phosphorylation is a necessary prerequisite for activity.
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Affiliation(s)
- D R Adams
- Institut de Chimie des Substances Naturelles CNRS, Gif-sur-Yvette, France
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27
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Chiaroni A, Riche C, Guerrier L, Royer J, Grierson DS, Husson HP. X-ray diffraction analysis of two hexahydropyrido[2,1-b][1,3,4]oxadiazines: evidence for the effect of steric congestion on anion formation at the aminonitrile centre. Acta Crystallogr C 1993. [DOI: 10.1107/s0108270193002136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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28
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Frances B, Gouarderes C, Moisand C, Cros J, Jimonet P, Moy L, Chiaroni A, Riche C, Grierson DS, Husson HP. Synthesis of C-2 substituted 1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocines: binding studies on opioid receptors. Eur J Med Chem 1992. [DOI: 10.1016/0223-5234(92)90150-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
The purpose of this study was to determine the pharmacokinetics of intravenous streptokinase in humans. Five patients with myocardial infarction, six patients with venous thromboembolism, and two normal volunteers were studied. The patients with myocardial infarction received 500,000 U over 30 minutes, the patients with venous thromboembolism received 250,000 U over 30 minutes followed by 100,000 U/hr over 16 to 78 hours, and the normal volunteers received 100,000 U over 15 minutes. Plasma streptokinase levels were measured based on the amidolytic activity of the streptokinase-plasminogen complex on the chromogenic substrate S-2251. Pharmacokinetic parameters were: biologic half-life 82 +/- 25 minutes, total clearance 10.8 +/- 8.8 ml/min, and apparent volume of distribution 1.10 +/- 0.71 l. Streptokinase levels declined progressively during the continuous, prolonged infusion in the patients with venous thromboembolism over 60 hours of treatment. We conclude that there are distinct time-dependent changes in the pharmacokinetics of streptokinase during continuous intravenous infusion and that this phenomenon is likely to be associated with progressively decreasing thrombolytic efficacy.
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30
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Hamilton KK, Fretto LJ, Grierson DS, McKee PA. Effects of plasmin on von Willebrand factor multimers. Degradation in vitro and stimulation of release in vivo. J Clin Invest 1985; 76:261-70. [PMID: 3160727 PMCID: PMC423761 DOI: 10.1172/jci111956] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
von Willebrand factor (vWF), a multimeric protein that mediates platelet adhesion, circulates in association with the procoagulant Factor VIII (FVIII). In previous reports, plasmin was shown in vitro to inactivate FVIII and cleave the vWF subunit extensively, but to cause only a modest decrease in vWF platelet-agglutinating activity. In the present study, the digestion of vWF multimers by plasmin was analyzed by sodium dodecyl sulfate-agarose gel electrophoresis and radioimmunoblotting. In vitro, plasmin degraded the large vWF multimers to smaller forms that could be distinguished from the small multimers present before digestion only by a slightly increased electrophoretic mobility. These plasmin-cleaved "multimers" were composed of disulfide-linked fragments with no intact vWF subunits. Thus, many plasmin cleavages occur within disulfide loops. The slight increase in mobility of plasmin-digested vWF is in part explained by the early cleavage from the multimers of a 34,000-mol wt peptide, which was purified and partially sequenced. The amino-terminal sequence (33 residues) agrees with the previously reported sequence (15 residues) for the amino terminus of the intact vWF subunit. Analysis of plasmin-digested vWF allowed deduction of a model for the native vWF structure, including the approximate location of the interprotomer disulfide bond(s). To determine whether plasmin would digest vWF in vivo, plasmas from 12 patients and 2 normal volunteers who received intravenous streptokinase (SK) were analyzed. Rather than vWF digestion, a two- to threefold rise in vWF antigen and platelet-agglutinating activity occurred within 2 h after a single SK dose, and the increase was greatest among the largest multimers. In contrast, FVIII clotting activity dropped to 10-20% of pre-SK levels. Thus, although plasmin destroys FVIII, a pharmacologically induced fibrinolytic state is associated with significant release of vWF from endothelial cells, platelets, or some other storage pool.
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31
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Stack RS, Phillips HR, Grierson DS, Behar VS, Kong Y, Peter RH, Swain JL, Greenfield JC. Functional improvement of jeopardized myocardium following intracoronary streptokinase infusion in acute myocardial infarction. J Clin Invest 1983; 72:84-95. [PMID: 6874955 PMCID: PMC1129163 DOI: 10.1172/jci110987] [Citation(s) in RCA: 197] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The effect of reperfusion on regional left ventricular performance following acute myocardial infarction in man was determined. Intracoronary streptokinase was administered in 24 patients within 6 h of the onset of symptoms. 15 patients (62%) were successfully recanalized during the initial study. Mean percent radial shortening (%RS) in both the jeopardized and compensatory regions were determined using 23 radii from the centroid of diastolic and systolic angiographic silhouettes. Sequential measurements were obtained during repeat cardiac catheterization studies at 24 h in 19 patients and before discharge from the hospital (16 +/- 11 d) in 15 patients. At the time of the predischarge study, each acutely reperfused patient showed improvement in %RS in the jeopardized region (P = 0.01) with 56% returning to the normal range. Despite the uniform improvement in the contractile function of the jeopardized region in each reperfused patient, the global ejection fraction showed no improvement or a decrease at the time of the chronic study in 44%. This was due to a decrease in the compensatory wall motion in the uninvolved segments between the acute and chronic study in each case. Neither the %RS nor the ejection fraction changed significantly at the time of the chronic study in the patients who could not be acutely recanalized. These data indicate (a) significant salvage of jeopardized myocardium associated with recovery of contractile function in patients reperfused during the first 6 h of chest pain following acute myocardial infarction; (b) no improvement in regional or global left ventricular performance in patients who could not be reperfused acutely; and (c) the ejection fraction is strongly influenced by changes in the compensatory wall motion of the uninvolved segments and does not accurately reflect changes in the contractile function of the jeopardized myocardium.
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