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allium_sativum_l

Allium sativum L. - Liliaceae - 蒜 suan (chin.), (common) garlic, Knoblauch

Perennial herb, up to 90cm tall, only known in cultur, cultivated nearly everywhere as vegetable/spice; bulbs consisting of several bulbels, all inclosed in a silky white or pink general envelope; scape exceeding leaves; leaves linear to linear-lanceolate, arising near together at the soil-surface, blades flat, keeled on the back; umbel erect, producing ovoid bulblets and a few flowers, the involucre deciduous in one piece.
http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200027526

„Combined headspace gas chromatography-mass spectrometry (HSGC-MS) was used in the analysis of garlic volatile compounds. Twenty major components were identified in the gas phases enriched by fresh, sliced garlic cloves… Suspended dry garlic powder and crushed garlic, incubated in vegetable oil, revealed a different pattern since mainly the amounts of di- and trisulfides were decreased. The considerable compositional differences found in the analyses for the gas phase of garlic cloves, kept in oil, are likely associated with the poor stability of allicin in a lipophilic environment; a marked increase in the amounts of 2-propene-1-thiol, acetic acid, and ethanol was observed in the gas phase, whereas trisulfides were present in traces only. The occurrence of 2-propene-1-thiol and diallyl disulfide, the two principal sulfur components in exhaled air, also may indicate a rapid degradation of most garlic volatile components probably caused by the enzymatically active human salivary or digestive system.“
[Volatile garlic odor components: gas phases and adsorbed exhaled air analysed by headspace gas chromatography-mass spectrometry., Laakso, I., Seppänen-Laakso, T., Hiltunen, R., Müller, B., Jansen, H., Knobloch, K., Planta medica, Vol.55(3), 1989, 257-261]

allicin

„Thiosulfinates… originate from S-alk(en)yl-l-cysteine-S-oxide, located in the cytoplasm, through an enzymatic reaction catalyzed by alliinase, a C-S lyase present in the vacuoles, giving initially sulfenic acids. These are highly reactive intermediates that immediately produce thiosulfinates by condensation reaction.“
[The analysis of onion and garlic., Lanzotti, V., Journal of Chromatography A, 1112(1), 2006, 3-22]
http://herbs.ph/attachments/article/1157/The%20analysis%20of%20onion%20and%20garlic.pdf

Main product of alliinase action in fresh garlic extract is allicin (89%), together with some propenyl- and methyl-substituted allylthiosulfinates.
[Allium chemistry: HPLC analysis of thiosulfinates from onion, garlic, wild garlic (ramsoms), leek, scallion, shallot, elephant (great-headed) garlic, chive, and Chinese chive. Uniquely high allyl to methyl ratios in some garlic samples., Block, E., Naganathan, S., Putman, D., Zhao, S.H., Journal of Agricultural and Food Chemistry, Vol.40(12), 1992, 2418-2430]

„Several sampling techniques based on steam distillation (SD), simultaneous distillation and solvent extraction (SDE), solid-phase trapping solvent extraction (SPTE), and headspace solid-phase microextraction (HS-SPME) have been compared for the determination of Korean garlic flavor components by gas chromatography–mass spectrometry (GC–MS). Diallyl disulfide (57.88%), allyl sulfide (23.59%), and diallyl trisulfide (11.40%) were found to be the predominant flavor components of garlic samples extracted by SDE whereas these components were at levels of 89.77%, 2.43%, and 3.89% when the same sample was extracted by SD, 97.77%, 0.17%, and 0.10% by SPTE, and 97.85%, 0.01%, and 0.01% by HS-SPME using the 50/30-μm divinyl benzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber. Thermal degradation of components such as allyl methyl sulfide, dimethyl disulfide, and thiirane were observed for SDE and SD but not for SPTE or HS-SPME.“
[Comparative study of extraction techniques for determination of garlic flavor components by gas chromatography–mass spectrometry., Lee, S.N., Kim, N.S., Lee, D.S., Analytical and bioanalytical chemistry, Vol.377(4), 2003, 749-756]

„Through the use of direct analysis in real time mass spectrometry (DART-MS), 2-propenesulfenic acid, an intermediate long postulated as being formed when garlic (Allium sativum) is crushed, has been detected for the first time and determined by mass spectrometric methods to have a half-life of <1 s at room temperature. Two other key intermediates, 2-propenesulfinic acid and diallyl trisulfane S-oxide, have also been detected for the first time in volatiles from crushed garlic, along with allicin and related thiosulfinates, allyl alcohol, sulfur dioxide, propene, and pyruvate as coproducts. A commercial dietary supplement containing garlic powder, which was sampled after crushing, was found to contain alliin, methiin, and S-allylcysteine and produced allicin upon addition of water… Disulfanes and polysulfanes are detected only when the Allium samples are heated, consistent with earlier conclusions that these are not primary products from cut or crushed alliums.“
[Applications of direct analysis in real time mass spectrometry (DART-MS) in Allium chemistry. 2-Propenesulfenic and 2-propenesulfinic acids, diallyl trisulfane S-oxide, and other reactive sulfur compounds from crushed garlic and other Alliums., Block, E., Dane, A.J., Thomas, S., Cody, R.B., Journal of agricultural and food chemistry, Vol.58(8), 2010, 4617-4625]


„The effect of aqueous garlic extract on the macromolecular synthesis of Candida albicans was studied. Protein and nucleic acid syntheses were inhibited to the same extent as growth, but lipid synthesis was completely arrested. Blockage of lipid synthesis is likely an important component of the anticandidal activity of garlic.“
[Allium sativum (garlic) inhibits lipid synthesis by Candida albicans., Adetumbi, M., Javor, G.T., Lau, B. H., Antimicrobial agents and chemotherapy, Vol.30(3), 1986, 499-501]

„The inhibitory effects of adenosine and 16 quantitatively determined organosulfur compounds derived from garlic cloves or commercial garlic preparations on collagen stimulated in vitro platelet aggregation in whole blood were determined… The best garlic powder tablets were equally as active as clove homogenates whereas steam-distilled oils were 35% as active and oil-macerates (due to low content) only 12% as active. A garlic product aged many months in aqueous alcohol had no activity. For steam-distilled oils, most of the activity was due to diallyl trisulfide. For the oil-macerates, most of the activity was due largely to the vinyl dithiins. Ajoene, an exclusive component of the oil-macerates, had highest specific activity of all the compounds tested but, because of its low concentration, had only 13% of the activity of diallyl trisulfide and 3% of the activity of allicin.“
[Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic products., Lawson, L.D., Ransom, D.K., Hughes, B.G., Thrombosis research, Vol.65(2), 1992, 141-156]

„Allicin, one of the active principles of freshly crushed garlic homogenates, has a variety of antimicrobial activities. Allicin in its pure form was found to exhibit i) antibacterial activity against a wide range of Gram-negative and Gram-positive bacteria, including multidrug-resistant enterotoxicogenic strains of Escherichia coli; ii) antifungal activity, particularly against Candida albicans; iii) antiparasitic activity, including some major human intestinal protozoan parasites such as Entamoeba histolytica and Giardia lamblia; and iv) antiviral activity. The main antimicrobial effect of allicin is due to its chemical reaction with thiol groups of various enzymes, e.g. alcohol dehydrogenase, thioredoxin reductase, and RNA polymerase, which can affect essential metabolism of cysteine proteinase activity involved in the virulence of E. histolytica.“
[Antimicrobial properties of allicin from garlic., Ankri, S., Mirelman, D., Microbes and infection, Vol.1(2), 1999, 125-129]

„Ajoene, a constituent of essential oil of garlic, has been shown to inhibit in vitro platelet aggregation in different species of animals i.e., cow, dog, guinea-pig, horse, monkey, pig, rabbit and rat. Under in vivo flow conditions and in the presence of physiological calcium levels, ajoene prevented thrombus formation induced by severe vascular damage, mainly in arterial sites with local low shear stress. Makheja and Bailey (1990) identified three main antiplatelet constituents, namely adenosine, allicin and polysulfides in garlic. Adenosine and allicin both inhibited platelet aggregation without affecting cyclooxygenase and lipoxygenase metabolites of arachidonic acid. The polysulfides inhibited platelet aggregation as well as thromboxane synthesis. The observed in vivo antiplatelet effects of ingesting garlic are attributable more to adenosine than to allicin and polysulfide constituents.“
[Effect of garlic on cardiovascular disorders: a review., Banerjee, S.K., Maulik, S.K., Nutrition journal, 1(1), 2002, 4]
http://www.nutritionj.com/content/1/1/4

knoblauch.jpg
Woodville, W., Medical botany, vol.3, t.168 (1793)
http://plantgenera.org/species.php?id_species=41121

allium_sativum_l.txt · Zuletzt geändert: 2015/06/13 11:36 (Externe Bearbeitung)