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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Pharmaceutical and chemical analysis of the components carrying the antiplatelet activity of extracts from allium ursinum and allium sativum

Sabha, Dina Talat Tawfiq 09 January 2012 (has links) (PDF)
Allium sativum has a long tradition in medicine. While much is known about its potential healthy effects, nearly nothing is known about wild garlic (allium sativum, ramson), which is very common in the area of Leipzig and has been used as a herbal remedy since centuries. The goal of the present study was to assess a potential anti-platelet activity of these two allium species and to try to identify the chemical active principle. For that purpose various extracts (hydrophilic and lipophilic) were prepared from Allium sativum and Allium ursinum, and analysed using thin layer chromatography and HPLC. After identifying an active, i.e. antiaggregatory extract (see below), this was fractionated and the active fraction was further sub-fractionated for subsequent chemical analysis by mass spectroscopy, ESI (Electrospray ionization), and COSY (Correlation effect spectroscopy), and functional testing. Anti-platelet activity was assessed in human platelets (platelet rich plasma) using a classical turbidimetric method. Platelets were stimulated with various agonists (arachidonic acid, ADP, epinephrine, collagen, A23187) with and without the addition of the extracts or the fractions /sub-fractions. Both Allium Ursinum and Allium sativum extracts exert antiaggregatory effects with EC50 values around 0.1 mg/ml. The garlic extracts are acting by inhibition of the ADP pathway comparable as known from the clinically used drug clopidegrol.The pharmacological active antiaggregatory component of the extracts appears to be lipophilic rather than hydrophilic. This is the first report on an antiplatelet activity of Allium Ursinum. One final structure determined by HPLC, MS, ESI and COSY which exerts the antiplatelets inhibitory effect is β-sitosterol-3-O-β-D-glucoside of the fraction 7-14 crystals. It is considered that about three up to five grams of dried leaves might be enough to exert antiaggregatory effects (comment: in pharmacy normally dried plant material is used in therapy). The second compound with antiaggregatory activity was identified as 1-β-D-galactopyranoside-2, 3-bis-linolenic glycerate. The problem of loosing the active volatile oily components by drying the leaves in future studies looking for the clinical use may be solved by looking for a raw or a refined extract which would be the form of a real phytomedical drug; for example capsules about 120 to 200 micrograms of an alcoholic or better an heptane / oily extract gained from wood garlic leaves would be an useful drug formulation to reach respective concentrations in blood. However, we have to admit that since our investigations were in-vitro, the in-vivo situation is somewhat different due to the metabolism, which is nearly unknown. Nevertheless, this study shows for the first time that allium ursinum does exert anti-platelet activity and that both allium species can unfold antiaggregatory effects which are worth to be investigated in subsequent in-vivo studies. β-sitosterol-3-O-β-D-glucoside and 1-β-D-galactopyranoside-2, 3-bis-linolenic glycerate could be identified as active antiaggregatory principals.
2

Pharmaceutical and chemical analysis of the components carrying the antiplatelet activity of extracts from allium ursinum and allium sativum

Sabha, Dina Talat Tawfiq 15 November 2011 (has links)
Allium sativum has a long tradition in medicine. While much is known about its potential healthy effects, nearly nothing is known about wild garlic (allium sativum, ramson), which is very common in the area of Leipzig and has been used as a herbal remedy since centuries. The goal of the present study was to assess a potential anti-platelet activity of these two allium species and to try to identify the chemical active principle. For that purpose various extracts (hydrophilic and lipophilic) were prepared from Allium sativum and Allium ursinum, and analysed using thin layer chromatography and HPLC. After identifying an active, i.e. antiaggregatory extract (see below), this was fractionated and the active fraction was further sub-fractionated for subsequent chemical analysis by mass spectroscopy, ESI (Electrospray ionization), and COSY (Correlation effect spectroscopy), and functional testing. Anti-platelet activity was assessed in human platelets (platelet rich plasma) using a classical turbidimetric method. Platelets were stimulated with various agonists (arachidonic acid, ADP, epinephrine, collagen, A23187) with and without the addition of the extracts or the fractions /sub-fractions. Both Allium Ursinum and Allium sativum extracts exert antiaggregatory effects with EC50 values around 0.1 mg/ml. The garlic extracts are acting by inhibition of the ADP pathway comparable as known from the clinically used drug clopidegrol.The pharmacological active antiaggregatory component of the extracts appears to be lipophilic rather than hydrophilic. This is the first report on an antiplatelet activity of Allium Ursinum. One final structure determined by HPLC, MS, ESI and COSY which exerts the antiplatelets inhibitory effect is β-sitosterol-3-O-β-D-glucoside of the fraction 7-14 crystals. It is considered that about three up to five grams of dried leaves might be enough to exert antiaggregatory effects (comment: in pharmacy normally dried plant material is used in therapy). The second compound with antiaggregatory activity was identified as 1-β-D-galactopyranoside-2, 3-bis-linolenic glycerate. The problem of loosing the active volatile oily components by drying the leaves in future studies looking for the clinical use may be solved by looking for a raw or a refined extract which would be the form of a real phytomedical drug; for example capsules about 120 to 200 micrograms of an alcoholic or better an heptane / oily extract gained from wood garlic leaves would be an useful drug formulation to reach respective concentrations in blood. However, we have to admit that since our investigations were in-vitro, the in-vivo situation is somewhat different due to the metabolism, which is nearly unknown. Nevertheless, this study shows for the first time that allium ursinum does exert anti-platelet activity and that both allium species can unfold antiaggregatory effects which are worth to be investigated in subsequent in-vivo studies. β-sitosterol-3-O-β-D-glucoside and 1-β-D-galactopyranoside-2, 3-bis-linolenic glycerate could be identified as active antiaggregatory principals.

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