Allium ursinum / Daslook

Daslook, goed voor de bloedvaten

Knoflook kent iedereen, zowel zijn geneeskrachtige als zijn culinaire kwaliteitenworden algemeen gewaardeerd. Een andere, inheemse looksoort, die massaal als grondbedekker in loofbossen voorkomt, is daslook, Allium ursinum.

Looksoorten werden reeds bij de Romeinen "allium" genoemd; maar ook "alium" of "aleum" was gebruikelijk. Mogelijk is allium van het Latijnse woord "olere", ruiken afgeleid. Het woord 'ursinum' is op het Latijnse ursinus (beer) terug te voeren. Reeds voor Linneaus werd deze aanduiding gebruikt; Plinius in zijn Historia Naturalis spreekt over een looksoort: "... silvestre (alium), quod ursinum volcano' . Ook Dodonaeus vermeld het derde geslacht van Look dat ' in Latijn Allium ursinum wordt genoemd. In Hoochduytsch Walt knobloch oder Knoblauch. In Neerduytsch Das Loock. In Franchois Aux d’ours/ ou Ail d;ours. Dit Loock schijnt wel te wesene dat loock dat Dioscorides Scorodoprassum heet/ oft als sommighe meynen dat Ampeloprasum. Volgens de Flora Batava zouden....'De bolletjes bezitten een wormdrijvende, bederfwerende en pislozende kracht...en volgens sommigen zouden deze planten kunnen dienen om er mede ratten en mollen te verdrijven.

Daslook en zwavel

Meer en meer wordt wetenschappelijk bekend dat ook deze daslook voor hart en bloedvaten een bijzonder waardevolle plant kan zijn. In daslook vind men dezelfde zwavelverbindingen als in knoflook, methyl-L-cysteinsulfoxide en allicine. Meer en meer fysiologen zijn van mening dat een zwavelrijke voeding zeer gunstig is voor een optimale werking van ons organisme. Daarom alleen al zijn de verschillende looksoorten een nuttige aanvulling in de voeding.

Ons lichaam dekt het tekort aan zwavel in de eerste plaats door de opname van aminozuren: methionine en cysteïne. In bepaalde omstandigheden, o.a. bij het ouder worden, kan deze zwavelreserve uitgeput geraken, waardoor een tekort aan glutathion kan ontstaan. Deze sterk werkende anti-oxydant kan vrije radicalen neutraliseren, die mede verant­woordelijk zijn voor bepaalde degeneratieve aandoenin­gen zoals dementie, aderverkalking en veroudering in het algemeen.

Daslook, aderverkalking en schuimcellen

Afzettingen op de vaatwanden, zogenaamde plaques, worden o.a. veroorzaakt door schuimcellen (histiocyten). Doordat deze in staat zijn om geoxideerde lipoproteïnen (LDL) op te nemen, komt het tot een verdikking van de vaatwand. Deze vervetting door schuimcellen heeft een vernauwing van de bloedvaten tot gevolg, waardoor een hartinfarct of een beroerte kan ontstaan.

De zwavelactieve stoffen van daslook zorgen er voor dat de lipoproteïnen niet meer kunnen worden opgenomen in de vaatwand. Door de aanwezigheid van glutamyl-peptiden in de bladeren heeft daslook ook een remmende werking op het ACE enzym dat de bloeddruk regelt. Zo kan daslook op verschillende manieren hart en bloedvaten beïnvloeden.

Daslook in de keuken

Daslookblad geplukt in maart en april is ook een lekkernij in de keuken. Je kan het bijvoorbeeld in olijfolie laten trekken en gebruiken in een vinaigrette. Ook voor het maken van aioli en pesto is het geschikt. Een voordeel is ook dat hoewel het zwavelgehalte bij Daslook veel hoger is dan bij Knoflook, je er geen stinkende adem aan overhoudt. Toch is dat zeker niet bij iedereen het geval. 

Bärlauch

Wilder Knoblauch, Zigeunerlauch, Waldknoblauch, Ramsell: Bezeichnungen gibt es viele für den Bärlauch (Allium ursinum), der zu der Subfamilie der Lauchgewächse (Allioideae) aus der Familie der Amaryllisgewächse gehört. Die krautige überdauernde Pflanze kommt in fast ganz Europa bis nach Nordasien vor. Nur in der Mittelmeerregion ist sie nicht zu finden. 

Denn die Pflanze bevorzugt schattige, feuchte und humusreiche Standorte. In Auen- und Laubwäldern kommt sie daher häufig vor und kann dort große Flächen einnehmen, die schon von Weitem an ihrem charakteristischen knoblauchartigen Geruch zu erkennen sind.

 Ab März wachsen aus einer länglichen Zwiebel meist zwei Laubblätter, die schmal und lanzettförmig sind. In den Monaten April und Mai erscheinen dann die kleinen sternförmigen weißen Blüten, die in flachen Scheindolden angeordnet sind. Durch das frühe Erscheinen gilt der Bärlauch seit jeher als Frühlingsbote.

Er ist eine der ältesten Heilpflanzen Europas und war schon den Germanen und Kelten bekannt. Sie schätzten ihn als blutreinigendes und stärkendes Gewächs. Viele Mythen sind mit dem Bärlauch verbunden. So sollen Bären, die bei den Germanen als sogenannte Seelentiere als Sinnbild von Kraft und Er neuerung verehrt wurden, nach dem langen Winterschlaf aus ihrer Höhle kommen und die frischen Blätter des Bärlauch fressen. Dies sollte sie für das neue Jahr stärken. 

Vorgeschriebener Anbau im Mittelalter

Auch im Frühmittelalter war die Pflanze in Europa sehr beliebt. Karl der Große erließ in seiner Landgüterverordnung »Capitulare de villis vel curtis imperii« aus dem Jahr 812 nach Christus, dass Bärlauch eine der 73 Nutzpflanzen sein sollte, die neben 16 Baum­arten in allen kaiserlichen Gütern von den Verwaltern anzubauen waren. Lange Zeit blieb der Waldknoblauch eine geschätzte Heilpflanze. So beschrieb der deutsche Botaniker Hieronymus Bock den Bärlauch in seinem »Kreütter Buch« von 1539 ausführlich und verglich ihn darin mit dem Gartenknoblauch (Allium sativum): Der Waldknoblauch würde »übler stinken«, hätte aber vielleicht eine kräftigere Heilwirkung als dieser. Danach geriet der Bärlauch langsam in Vergessenheit, was vermutlich mit dem Siegeszug des Knoblauchs zusammenhing. Mittlerweile hat er aber wieder Einzug in deutsche Küchen gehalten und die Blätter werden gerne zu Suppen, Saucen, Salaten oder Pesto verarbeitet.

Schwefelhaltige Inhaltsstoffe

 Der knoblauchartige Geschmack und Geruch des Bärlauchs stammt von schwefelhaltigen Inhaltsstoffen, von denen eine Vielzahl vorhanden ist. Den größten Teil machen die Cystein-Sulfoxide Methiin und Alliin, aber auch Isoalliin und Propiin aus. Diese sekundären Pflanzenstoffe sind geruchlos und nicht flüchtig, werden aber durch hydrolytische Spaltung in eine ganze Reihe von flüchtigen Verbindungen wie Allicin, Thio-Sulfinate und Polysulfide umgewandelt, die den charakteristischen Duft ausmachen. Neben den schwefelhaltigen Verbindungen kommt noch eine Reihe von anderen Pflanzeninhaltstoffen vor, zu denen Polyphenole wie Flavonoide, steroidale Glykoside und Lectine gehören. Zudem enthält Allium ursinum nennenswerte Mengen an Magnesium, Mangan und Eisen und ist reich an Adenosin, das eine gefäßerweiternde Wirkung besitzt.

Angewendet wird der Bärlauch traditionell zur Kräftigung und »Reinigung des Blutes«. Dabei können alle Teile der Pflanze genutzt werden, denn alle sind essbar. Für medizinische Zwecke werden in der Regel die Blätter (Allii ursini folium/herba) in den Monaten April bis Mai oder die Zwiebeln (Allii ursini bulbus) in September und Oktober geerntet. Anders als häufig angenommen, können die Blätter auch verwendet werden, wenn die Pflanze bereits blüht. Allerdings sind sie dann weniger aromatisch, und die Konzentrationen der Inhaltsstoffe fallen geringer aus. Dem Bärlauch werden neben der kräftigenden auch verdauungsfördernde, antimikrobielle und entgiftende Wirkungen nachgesagt, und er soll vor Herz-Kreislauf-Erkrankungen schützen. Extern angewendet soll er die Wundheilung beschleunigen und bei chronischen Hauterkrankungen wirksam sein.

Einige Wirkungen sind in In-vitro-Unter­su­chun­gen belegt. 

Einen Überblick über die Studien­lage geben Danuta Sobolewska von der Jagiellonian-Universität in Krakau, Polen, und Kolleginnen im Fachjournal »Phytochemistry Reviews« (doi: 10.1007/s11101-013-9334-0). Dem Artikel zufolge hat Bärlauch ein kardio­pro­tek­tives Potenzial. So können Bärlauch-Extrakte die Plättchen-Aggregation, die Cholesterol-Synthese und die Aktivität des Angiotensin-konvertierenden Enzyms (ACE) hemmen. Bei Fütterungsversuchen mit Ratten zeigte sich, dass Tiere, die über acht Wochen pulverisierte Bärlauchblätter verspeist hatten, eine signifikant niedrigere Plasma-ACE-Aktivität aufwiesen als Kontrolltiere. In Untersuchungen mit spontan hypertensiven Ratten, die über 45 Tage eine mit Bärlauch angereicherte Kost erhielten, hatten diese einen signifikant niedrigeren Blutdruck als Kontrolltiere

Antimikrobiell wirksam

 Auch eine antimikrobielle Aktivität von Allium ursinum ist in vitro belegt. So konnten Extrakte das Wachstum von verschiedenen Bakterienspezies wie Staphylococcus aureus, Bacillus subtilis oder Salmonella enteritidis und von Pilzen sowie von Nematoden hemmen. Die antimikrobielle Wirkung korreliert dabei mit dem Gehalt an schwefelhaltigen Substanzen.

Trotz der jahrtausendealten Tradition von Bärlauch als Heilpflanze stecke die Erforschung des therapeutischen Nutzens noch in den Kinderschuhen, folgern Sobolewska und ihre Kolleginnen. Er habe aber durchaus therapeutisches Potenzial, das weiter untersucht werden sollte. Schon jetzt ist Bärlauch in Europa als Nahrungsergänzungsmittel und auch in Form einer homöopathischen Urtinktur erhältlich. Frisch verzehrt ist er aber leckerer. Dass man nach dem Verzehr nicht nach Knoblauch riecht, ist allerdings ein Gerücht. /

Allium ursinum: botanical, phytochemical and pharmacological overview. 

Danuta Sobolewska,corresponding author Irma Podolak, and Justyna Makowska-Wąs. Phytochem Rev. 2015; 14(1): 81–97. 

Ramson has been used for centuries to promote general health, and as the old English proverb says:

Eat leeks in Lide [March] and ramsons in May

And all the year after the physicians may play.

There is good evidence for the use of ramson by Mesolithic people. Charred bulbs of A. ursinum were identified—in the late Mesolithic settlement at Halsskov in Denmark (Kubiak-Martens 2002). It was hypothesized that ramson was one of the plants that contributed to the hunter-gatherer diet. A. ursinum was known to the early Celts and to the ancient Romans. The Greek physician Dioscorides mentioned four kinds of onion, among them A. ursinum and also attributed a detoxifying effect to the plant (Meyer et al. 1999; Richter 1999). Ramson was well known also in the Middle Ages; it belongs to the group of plants often found at medieval West Slavic archeological sites (Celka 2011). King Charles the Great, also known as Charlemagne, included A. ursinum in his Capitulare de Villis imperialibis, where he formally cataloged plants, mostly those possessing medicinal properties, and documented how the gardens should be planned and cared for (Clickner 2011). Hieronymus Bock provided drawings of the plant in his Kreutterbuch, Lonicerus judged wild garlic to be superior to regular garlic (Richter 1999; Błażewicz-Woźniak et al. 2011; Strzelecka and Kowalski 2000; Madaus 1938).

All parts of the plant are edible. For medical purposes leaves/herb—Allii ursini folium/herba, collected in April and May, and bulbs—Allii ursini bulbus, collected in September and October, are used. Ramson is usually collected from the wild. However, in Poland this species, which belongs to the group of 11 alliaceous plants growing wild there, has been partially protected since 2004 and is listed in the “Red list of plants and fungi in Poland”, what made it impossible to be wild-harvested (Szafer et al. 1988; Zarzycki and Mirek 2006).

In European traditional medicine ramson has been generally recommended as digestive stimulant, antimicrobial agent, removing toxins from the body, and to prevent cardiovascular diseases (Treben 1992; Macků and Krejča 1989; Leporatti and Ivancheva 2003). It was often applied as a remedy in respiratory problems, such as common cold with fever or bronchitis. A. ursinum has been effective when used externally to support wound healing, in chronic skin disorders, and in acne.

In recent years there has been a growing interest in its use as a dietary supplement and food. There are some records that in the nineteenth century Switzerland butter made from milk of cows fed on ramson were used. Such milk tasted slightly of garlic. Apparently in Eberbach in Germany there is a festival called Bärlauchtage—Bear’s Garlic Days, which is devoted to this plant. Today, it is a common practice to use ramson in cuisine. Fresh leaves can be eaten raw or cooked, and as a kind of pesto. They are often added to soups, gnocchi, risotto, ravioli, and as a spice to flavor hard cheeses or spreads based on cottage cheeses. Leaves and flowers can be used as a garnish to salads, while ramson’s bulbs can be used like common garlic.

Allium ursinum is also a component of dietary supplements available on the European market. For example, it is one of constituents found in the recipes used therapeutically in the University Hospital of Bucharest (Romania) (Epure et al. 2011). Such products as Api Ursomax and Memo Ursomax are recommended as detoxifying and antiatherogenic medicines. The former is additionally advertised as a mineralizing agent, while Memo Ursomax is claimed to be a memory stimulant.

Pharmacological studies

Modern pharmacological studies have confirmed many of the above mentioned traditional indications of ramson. For example, a great number of in vitro and in vivo experiments showed that A. ursinum is a plant with a high potential for the prevention and treatment of cardiovascular system diseases. Different extracts obtained from the fresh leaves of A. ursinum were tested in vitro on human platelet aggregation. The results showed a significant inhibitory activity of the ethanol extract on ADP-induced aggregation. The mechanism of action was similar to that of a reference drug Clopidogrel (Hiyasat et al. 2009). It was suggested, that the active compounds exerting antiaggregatory effect are 1,2-di-O-α-linolenoyl-3-O-β-d-galactopyranosyl-sn-glycerol (DLGG) (Fig. 5) and β-sitosterol 3-O-β-d-glucopyranoside (Sabha et al. 2012). DLGG has previously been identified in a number of medicinal and food plants, and has been shown to possess anti-inflmmatory activity (Larsen and Christensen2007).

Moreover, two of the flavonoids present in ramson leaves: kaempferol 3-O-β-neohesperidoside-7-O-β-d-glucopyranoside and 3-O-β-neohesperidoside (Fig. 6), showed in vitro inhibitory activity on platelet aggregation induced by collagen (Carotenuto et al. 1996). As other kaempferol glycosides were inactive, it was concluded that the presence of p-coumaroyl group in the molecule and the increase in the number of monosaccharides in the sugar residue deplete the antiplatelet potential of these compounds.

Ramson’s administration affects also the activity of ACE. In vitro tests on the water extract from the leaves (at the concentration of 0.3 mg/ml), showed higher inhibition of this enzyme activity as compared to garlic leaves extract (58 vs. 30 %) (Sendl et al. 1992a). This probably resulted from the differences in glutamyl peptides contents. The in vitro study on the effect of the ramson essential oil on the artificial liposome membrane model demonstrated that the fluidity of the membrane close to the surface was statistically non-significantly changed, while in deeper layers the fluidity increased (Godevac et al. 2008). The authors postulated that further studies should be continued to estimate the role of A. ursinum volatile oil in the regulation of membrane functions in hypertension.

In vivo experiments on rats fed for 8 weeks standard diet with 2 % of pulverized A. ursinum leaves showed significantly lower plasma ACE activity in the ramson group as compared to control (Rietz et al. 1993). The studies performed on Spontaneously Hypertensive Rats (Okamoto strain) that were fed with diet containing 1 % w/w ramson (Pfannenschmidt, Inc. of Hamburg) showed that after 45 days it reduced final mean systolic blood pressure when compared to control (173 ± 0.7 vs. 189 ± 1.2 mm Hg respectively) (Preuss et al. 2001). Diet enrichment with ramson was more effective than with garlic at the same concentration (the final SBP—175 ± 1.2 mm Hg). A. ursinum decreased elevated circulating insulin concentration and total cholesterol level, however HDL tended to increase. Similarly, when both garlics were consumed at lower concentrations—0.1 % (w/w)—systolic blood pressure readings at 10, 18, and 26 days were significantly lower in rats consuming ramson compared to the animals consuming common garlic. Authors concluded that these effects may be associated with high concentration of glutamyl peptides, adenosine or phenolic compounds in ramson. They suggested that consuming A. ursinum may result in a greater therapeutic benefit when compared to A. sativum at a given concentration. Animal studies demonstrated that ramson-containing diet may reduce the size of the ischemic zone and ischemia and reperfusion—induced arrhythmias (Rietz et al. 1993).

Ramson showed in vitro inhibitory activity on cholesterol synthesis. Chloroform and chloroform/acetone extracts from A. ursinum bulbs, at concentrations of 166 μg/ml, inhibited cholesterol biosynthesis by 49.3 and 48.9 %, respectively. The results were nearly identical to those obtained for garlic extracts. Of the pure investigated components present in the extracts ajoene, methyl ajoene, 2-vinyl-4H-1,3-dithiin and allicin were the strongest cholesterol synthesis inhibitors, providing at the concentration of 10−3 M the inhibition values of 69.5, 72, 58.4, and 52.2 %, respectively (Sendl et al. 1992b). Pharmacological studies have also revealed that chloroform and acetone/chloroform extracts from ramson exerted in vitro inhibitory activity on 5-lipoxygenase and cyclooxygenase, however they were less effective than the corresponding garlic extracts (Sendl et al. 1992a). Thrombocyte aggregation test revealed no differences between A. ursinum and A. sativum extracts (Sendl et al. 1992a).

As was mentioned above, A. ursinum has been valued in traditional medicine as an antimicrobial agent used either internally or externally. There is a substantial number of reports in which the antimicrobial activity of various extracts prepared from different plant parts were tested in vitro against a wide array of bacterial and fungal strains.

Comparative analysis of water and methanol extracts from ramson herb (at the concentration range 0.16–83.7 and 0.06–35.5 mg/ml, respectively) showed that the latter was more active against microbes. It inhibited the growth of the following bacteria: Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Proteus mirabilis, Salmonella enteritidis, and fungi: Cladosporium sp., Aspergillus niger, Rhizopus nigricans, Geotrichum candidum, Penicillium expansum, Candida lipolytica, Mycoderma, Saccharomycopsis fibuligera (Synowiec et al. 2010). The average antibacterial MIC value was 35 mg/ml with the exception of S. aureus ATTC 25923 strain, in the case of which the MIC was 17.7 mg/ml. The highest antifungal effect was observed against C. lipolytica (MIC = 8.9 mg/ml), whereas for other tested strains it was less pronounced (MIC = 17.7 mg/ml), however still much higher in comparison to the water extract (concs. 41.9–83.7 mg/ml). The antibacterial activity of the water extract was seen only against B. subtilis ATTC 6633 (at 83.7 mg/ml). A water extract (at pH 7.0, adjusted with 0.1 mol/l K2HPO4) from A. ursinum leaves exhibited antibacterial activity in vitro against Listeria monocytogenes, S. aureus, E. coli, and Salmonella enterica subsp. enterica (Sapunjieva et al. 2012). The inhibition zones were greater in the case of Gram (+) bacteria.

A comparative analysis of the in vitro germination and growth inhibitory effects of the ethanol extracts from flowers and leaves of A. ursinum against A. niger, Botrytis cinerea, Botrytis paeoniae, Fusarium oxysporum f.sp. tulipae, Penicilium gladioli and Sclerotina sclerotiorum showed that the flower extract possessed the highest antifungal activity (MIC 100, 60, 70, 140, 90, and 60 μg/ml, respectively). The authors claimed that the antifungal effects of the extracts could be positively correlated with allicin content: 1.946 mg allicin/ml flower extract versus 0.028 mg allicin/ml leaf extract (Parvu et al. 2011). Pure allicin at concentrations 1.57–6.25 μg/ml showed inhibitory activity against Candida, Cryptococcus, Trichophyton, Epidermophyton, and Microsporum strains (Ankri and Mirelman 1999).

Antimicrobial activity of the bulb juice of A. ursinum was correlated with storage temperature and pH levels. Its activity against selected bacteria and fungi decreased on storage at the temperature above 4 °C and with an increase in the pH value (Tynecka et al. 1993).

The antimicrobial activity of different extracts (acetone, chloroform, ethyl acetate, n-butanol and water) from fresh flowers and leaves of Bulgarian ramson was studied. Acetone extracts from both parts and chloroform extract from the leaves were active against S. aureus (MIC 625 μg/ml), while none of the extracts inhibited the growth of E. coli. The chloroform extract from the leaves showed inhibitory effect on Candida albicans (MIC 312 μg/ml), as well (Ivanova et al. 2009). The fresh water extract from the bulbs inhibited the growth of different Candida strains, with MIC ranging from 1 mg/ml to 4 mg/ml depending on the particular yeast strain. The adhesion of Candida ssp. isolates to catheters (silicone-elastomer—coated latex urinary Foley catheter and PCV Thorax catheter) was not prevented by the extract even at the maximal concentration of 4.0 mg/ml (Chudzik et al. 2010). The extracts prepared from fresh A. ursinum leaves collected in Romania during blossoming phase inhibited the growth of Candida ssp. (C. albicans, C. famata, C. glabrata, C. krusei) at concentrations ranging from 0.5 to 4.0 mg/ml (Bagiu et al. 2010).

The broad spectrum of antimicrobial activity of Allium plants is generally associated with sulfur-containing compounds, however our own studies have shown that other constituents may as well contribute to that effect, to some extent. The inhibitory activity of a mixture of diosgenin tetrasaccharide and (25R)-spirost-5,25(27)-dien-3β-ol tetrasaccharide isolated from the bulbs against Candida glabrata and C. parapsilosis was determined, with MIC values of 200 and 250 μg/ml, respectively (Sobolewska et al. 2003). Both compounds however, were ineffective against Pseudomonas aeruginosa and A. niger at concentrations up to 400 μg/ml, by the disc diffusion method. With regard to antifungal properties against Trichophyton mentagrophytes and Microsporum canis the saponin mixture was active at the concentration 400 μg/ml (Sobolewska et al. 2006).

There were also some studies which evaluated the potential of ramson against parasites. For example, the juice from the bulbs was effective against free living nematode Rhabditis sp., larvae of Nippostrongylus brasiliensis, and hindered the development of Ascaris suum eggs (Chybowski 1997).

Isolated ramson’s lectins were assessed for potential inhibitory effect against HIV-1- and HIV-2-induced cytopathicity in MT4 cells (Smeets et al. 1997). The EC50 values (the concentration required to protect MT4 cells against cytopathicity of HIV by 50 %) of bulbs and leaf lectins were about 3 and 5 μg/ml for HIV-1 and HIV-2, respectively. The specific agglutination activity (the lowest concentration which still yields a visible agglutination of a 1 % suspension of erythrocytes) of AUAL, AUAI and AUAII was the same (being 1.2 μg/ml). A. ursinum lectins were more potent agglutinins than the A. sativum bulb lectins ASAI and ASAII (specific activities being 6 and 100 μg/ml, respectively), but less active than the garlic leaf lectin (0.2 μg/ml).

The occurrence in various parts of the plant of constituents with well-known antioxidant properties, such as flavonoids or carotenoids, urged investigations that would confirm ramson’s antioxidative potential. As was shown, extracts from different parts exhibited high free radicals scavenging activity. The antioxidant effect of ramson leaves may be associated not only with the presence of phenolic compounds but also with high activity of antioxidant enzymes, like catalase and peroxidase (11.48 ± 2.90 U/mg protein and 8.85 ± 0.19 U/mg protein, respectively), whereas in the bulbs, with superoxide dismutase (31.43 ± 6.96 U/mg protein) (Štajner et al. 2008; Štajner and Szöllosi Varga 2003).

Also, the volatile oil of ramson has been tested, however it demonstrated poor antioxidant activity against DPPH+ and ABTS+ in comparison to BHT (butylated hydroxytoluene) and Trolox. On the other hand, in the beta-carotene-linoleic bleaching test the oil showed an effect comparable to that of BHT (Godevac et al. 2008). Based on these results, the authors concluded that the antioxidant effect depends on the method used, and also on which free radical generator or oxidant is involved (Godevac et al. 2008). It seems therefore mandatory to employ different analytical methods that would varying oxidation initiators and targets.

Nevertheless, some isolated ramson volatile oil constituents have revealed promising antioxidant properties. Diallyl disulfide increased the intracellular content of reduced glutathione in rat red blood cells, while diallyl sulfide enhanced the activity of antioxidative enzymes, and activated Nrf2 protein, what resulted in suppression of inflammatory cytokines (Wu et al. 2001; Kalayarasan et al. 2009).

Other pharmacological activities which were reported for A. ursinum include in vitro cytotoxicity. Nine different extracts (chloroform, methanol, and water) prepared by hot extraction of fresh leaves, flowers, and flower stems were analysed in vitro against murine cancer cell lines melanoma B16 and sarcoma XC (Trypan Blue Exclusion Test of Cell Viability) (Sobolewska et al. 2012). The methanol extracts from the aerial parts and the aqueous extracts from leaves and flowers were inactive or only slightly active over the entire concentration range (10–200 μg/ml) against both cell lines, while the aqueous extracts from flower stems showed no activity towards melanoma B16 cells. The chloroform extract from flower stems showed the most promising cytotoxic activity: at the concentration of 60 μg/ml of this extract 100 % of melanoma B16 cells were killed after 24 h, while at the concentration of 20 μg/ml—after 48 h. In both cell lines colchicine had an ED50 value lower than 2 μg/ml (0.5 ± 0.003—melanoma B16; 1.5 ± 0.005—sarcoma XC) after 24 h (Sobolewska et al. 2012). Moreover, cytotoxic activity of a mixture of diosgenin tetrasaccharide and (25R)-spirost-5,25(27)-dien-3β-ol tetrasaccharide on melanoma B16, sarcoma XC and human fibroblasts HSF was evaluated as well. The saponin mixture was found active against murine melanoma B16 and sarcoma XC. It exhibited 100 % effect at 2 μg/ml on both strains. It showed no activity towards human fibroblasts HSF at concentrations below 3 μg/ml (Sobolewska et al. 2006).

Diallyl disulfide (a component of ramson volatile oil) inhibited the proliferation of various human cancer cell lines, including breast, lung, colon cancers, lymphomas and neuroblastoma. The mechanism of action involved cell cycle arrest or apoptosis. Also, diallyl trisulfide induced apoptosis in human prostate cancer cell lines PC-3 and DU-145 (Lai et al. 2012).

Adverse reactions

Generally, A. ursinum is recognized as safe. However, there is some evidence of hemolytic anemia due to oxidative damage to erythrocytes following the consumption of other Alliums by domestic and farm animals (Munday et al. 2003). It seems that diallyl tri- and tetrasulfides, which are highly toxic to erythrocytes, may be largely responsible for this effect, and these compounds are present in ramson volatile oil, as well. Even though there were no reports of hemolysis associated with Allium plants consumption in humans, certain individuals whose erythrocytes are unusually vulnerable to oxidative damage, should consume garlic with caution. Case reports of allergic reactions to some garlic constituents have been also described (Borelli et al. 2007), and such compounds as diallyl disulfide, allylpropyl sulfide and allicin were identified as allergens. All are present in various A. ursinum preparations as well. The study on garlic-allergic patients in Taiwan revealed that garlic C,S-lyase (alliinase) was a major Allium sativum allergen (Kao et al. 2004). As this enzyme showed cross-reactivity with C,S-lyases from other species, the authors concluded that this molecule is a common allergen in Allium plants. The potential of A. ursinum to enhance existing anticoagulant therapy should be taken into consideration, as well.

Even though the garlic-like odor of ramson should enable its unambiguous identification, it should be noted that there were some cases of fatal poisoning by ingestion of toxic plants, the leaves of which, due to a similar shape, were mistakenly wild-harvested as ramson. These were, in particular, autumn crocus (meadow saffron, Colchicum autumnale), the lily-of-the-valley (Convallaria majalis), and white hellebore (Veratrum album) (Colombo et al. 2010; Sundov et al. 2005; Gilotta and Brvar 2010; Klintschar et al. 1999).

Conclusions

Despite centuries of use of ramson as a substitute for garlic (A. sativum), pharmacological studies on A. ursinum bulbs and leaves have begun fairly recently, that is about 20 years ago. Thus, data referring to A. sativum, which is a species much valued for its therapeutic potential are much more abundant, even though the conclusions related to its clinical efficacy are often inconsistent. A broad spectrum of biological activities recorded for ramson extracts and the presence of chemical compounds with high therapeutic potential, makes this plant species a possible candidate for future development as a medicinal product. Undoubtedly, some problems that may appear are associated with producing a uniform plant material as ramson composition is very sensitive to changes in growth conditions what could hinder large scale production and standardization. Nevertheless, it is worth noting, that definitely in recent years as been recognized as a valuable spice plant.

References


Daslook meer dan eetbaar. Recepten.

Daslook, Allium ursinum L., is een plant uit de de Lookfamilie. Ze heeft een sterke knoflookgeur, die nog toeneemt als de soort in de zomer begint af te sterven.

De aanduiding ursinum (= van de beren, Ursus = beer) is mogelijk ontstaan door het geloof dat beren na hun winterslaap zich eerst aan deze plant te goed deden. Dit is er ook de oorzaak dat de plant af en toe ook berenlook wordt genoemd. De Duitse benaming Bärlauch duidt daarop. De naam Daslook kan afgeleid zijn van dassen, die in burchten in de grond leven en waar daslook veel voorkomt.

De elliptisch tot lancetvormige bladeren zijn 3-5 cm breed, donkergroen en parallelnervig. Ze zitten zo aan de ondergrondse bol dat ze een draaiing hebben in hun steel, waardoor de onderkant eigenlijk van boven te zien is.

De zuiver witte bloemen hebben zes witte bloemdekbladen en zijn in losse bolvormige schermen gegroepeerd. De bloemdekbladen zijn ongeveer 1 cm groot. De plant bloeit van april tot juni, soms tot juli. Voor het scherm zich ontvouwt zitten de bloemknoppen binnen een bloeischede, die uit twee kleppen bestaat en met de steel een speervormig uiterlijk heeft. De twee kleppen vallen af als de bloeiwijze zich opent. De plant wordt 20-40 cm hoog. De bloem heeft zes meeldraden en een driehokkig bovenstandig vruchtbeginsel. De zaden zijn zwartbruin. En de soort vermeerdert zich vooral via zaadverspreiding.  De vroeg in het jaar bloeiende soort wordt vanwege het stuifmeel bezocht door insecten, die voor de bestuiving en dus bevruchting zorg dragen.

Jong blad van de Daslook wordt van oudsher vanwege zijn lekkere smaak gebruikt om te verwerken in soep en sla. De Duitsers, zij noemen de Daslook Bären-Lauch, zijn gek op Bärlauchsuppe.

Daslook / Brandnetelsoep

Ingrediënten

Bereidingswijze

Daslookpesto

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Bereidingswijze

https://kruidwis.blogspot.com/2014/03/pesto-pasta.html