Saponins from Allium minutiflorum with antifungal activity

• Published in: Phytochemistry (Oxford) Vol. 68; no. 5; pp. 596 - 603
• Main Authors: Barile, Elisa, Bonanomi, Giuliano, Antignani, Vincenzo, Zolfaghari, Behzad, Sajjadi, S. Ebrahim, Scala, Felice, Lanzotti, Virginia
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 01.03.2007; Elsevier
• Subjects: alliogenin; Allium; Allium - chemistry; Allium minutiflorum; Antifungal activity; Antifungal Agents - chemistry; Antifungal Agents - isolation & purification; Antifungal Agents - pharmacology; antifungal properties; Bacteria - drug effects; Biochemistry & Molecular Biology; Biological and medical sciences; Carbohydrate Sequence; Chemical constitution; Chemical control; chemical structure; Control; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Fungi - drug effects; Furostanol-type; Glycosides - chemistry; Glycosides - isolation & purification; Glycosides - pharmacology; Life Sciences & Biomedicine; Magnetic Resonance Spectroscopy; minutoside; Minutosides; Models, Molecular; neoagigenin; Phytopathology. Animal pests. Plant and forest protection; plant pathogenic fungi; Plant physiology and development; Plant Sciences; Pythium; Rhizoctonia; Saponins; Saponins - chemistry; Saponins - isolation & purification; Saponins - pharmacology; Science & Technology; spectral analysis; Spectrometry, Mass, Electrospray Ionization; spirostanol; Spirostanol-type; stereochemistry; Steroids - chemistry; Steroids - isolation & purification; Steroids - pharmacology; Structure–activity relationships; Iran; Spirostanol-type; Saponins; Antifungal activity; Minutosides; Structure–activity relationships; Furostanol-type; Allium; PLANT; structure-activity relationships; RESISTANCE; SENSITIVITY; furostanol-type; spirostanol-type; minutosides; antifungal activity; ANTIMICROBIAL ACTIVITY; saponins; Monocotyledones; Molecular structure; Interaction; Sapogenin; Structure-activity relationships; Antimicrobial agent; Saponin; Liliaceae; Bulb; Angiospermae; Isolation; Spermatophyta; Mass spectrometry
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2006.10.009

Three saponins, minutoside A–C, were isolated from the bulbs of Allium minutiflorum Regel. Their stereostructure was carried out by spectroscopic analyses, including 2D NMR spectroscopy and mass spectrometry, and chemical methods. The isolated compounds showed a significant antifungal activity depending on their concentration and with the following rank: minutoside B > minutoside C ≫ minutoside A. Three saponins, named minutoside A ( 1), minutoside B ( 2), minutoside C ( 3), and two known sapogenins, alliogenin and neoagigenin, were isolated from the bulbs of Allium minutiflorum Regel. Elucidation of their structure was carried out by comprehensive spectroscopic analyses, including 2D NMR spectroscopy and mass spectrometry. The structures of the new compounds were identified as (25R)-furost-2α,3β,6β,22α,26-pentaol 3- O-[β- d-xylopyranosyl-(1 → 3)- O-β- d-glucopyranosyl-(1 → 4)- O-β- d-galactopyranosyl] 26- O-β- d-glucopyranoside ( 1), (25S)-spirostan-2α,3β,6β-triol 3- O-β- d-xylopyranosyl-(1 → 3)- O-β- d-glucopyranosyl-(1 → 4)- O-β- d-galactopyranoside ( 2), and (25R)-furost-2α,3β,5α,6β,22α,26-esaol 3- O-[β- d-xylopyranosyl-(1 → 3)- O-β- d-glucopyranosyl-(1 → 4)- O-β- d-galactopyranosyl] 26- O-β- d-glucopyranoside ( 3). The isolated compounds were evaluated for their antimicrobial activity. All the novel saponins showed a significant antifungal activity depending on their concentration and with the following rank: minutoside B > minutoside C ≫ minutoside A. No appreciable antibacterial activity was recorded. The possible role of these saponins in plant–microbe interactions is discussed.