Die Droge Maisgriffel (Maydis stigmata) aus Zea mays L. wird traditionell zur Behandlung unkomplizierter Infektionen der ableitenden Harnwege eingesetzt. Kürzlich publizierte In-vitro-Untersuchungen aus einem Screening zeigen, dass alkoholische Extrakte aus dieser Droge die Adhäsion uropathogener E. coli (UPEC) an T24-Blasenzellen verhindern. Zur genaueren Untersuchung wurden aus 4 unterschiedlichen Chargen Maydis stigmata Ethanol-Wasser (1 : 1)-Extrakte hergestellt. Innerhalb eines In-vitro-Adhäsionassays (UPEC-Stamm 2980 und humane T24-Blasenzellen) wurde eine konzentrationsabhängige antiadhäsive Aktivität gegen UPEC bestätigt (IC50 = 1040 µg/ml). Eine aktivitätsgeleitete Fraktionierung an Sephadex LH20 ergab die aktive Fraktion XI, die wiederum mittels MPLC und präparativer HPLC weiter aufgetrennt wurde. Dies führte zur Isolierung der Subfraktion XIG, die mittels UHPLC/+ESI-QTOF-MS analysiert wurde. Hieraus resultierte das wahrscheinliche Vorliegen der ungewöhnlichen Flavon-C-glykoside Derhamnosylmaysin, 3’-Deoxyrhamnosylmaysin, 3’-O-Methylderhamnosylmaysin, Apiferol und Alternanthin, für die eine Mitbeteiligung an der beobachteten antiadhäsiven Wirkung diskutiert werden kann.
Summary
Uncomplicated urinary tract infections: The efficacy of extracts from corn silk (Zea mays L.) against uropathogenic E. coli
The dried corn silk (Maydis stigmata) from Zea mays L. is used traditionally for the treatment of uncomplicated urinary tract infections. A recent screening has indicated that hydroalcoholic extracts of the herbal material inhibit the adhesion of uropathogenic E. coli (UPEC) to T24 bladder cells. For verification of these data EtOH-water (1 : 1) extracts from 4 different batches of Maydis stigmata were investigated. Within an in vitro adhesion assay (UPEC strain 2980 and human T24 bladder cells) a dose-dependent antiadhesive activity against UPEC was verified (IC50 1040 µg/mL). Bioassay guided fractionation of Maydis stigmata by ethanol-water extraction, followed by chromatography on Sephadex LH20 revealed the active fraction XI which was further fractionated by MPLC and preparative HPLC, leading to a still complex subfraction XIG, which was analysed by UHPLC/+ESI-QTOF-MS analysis. Advanced data processing and species-metabolite relationship database revealed the tentative existence of the unusual C-glycosidic flavones derhamnosylmaysin, 3’-deoxyrhamnosylmaysin, 3’-O-methylderhamnosylmaysin, apiferol and alternanthin which might be related to the antiadhesive activity of this subfraction against UPEC.
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