title: Sylvatiins, acetylglucosylated hydrolysable tannins from the petals of Geranium sylvaticum show co-pigment effect.
abstract: Four hydrolysable tannins, named as sylvatiins A (1), B (2), C (3) and D (4), were isolated from the petals of Geranium sylvaticum. On the basis of spectrometric evidence of NMR analysis ((1)H NMR, (13)C NMR, DQF-COSY, TOCSY, NOESY, HSQC and HMBC), circular dichroism (CD) and ESI-MS/MS, sylvatiins A, B and C were characterized as galloyl glucoses containing one or two acetylglucoses attached to the 3-OH of the galloyl group, whereas sylvatiin D was found to have a chebulinic acid core containing acetylglucose attached in a similar way. The potential of these compounds to act as defensive compounds against herbivores was evaluated using the radial diffusion assay that measures the protein precipitation capacity. In addition, the capacity of sylvatiins to act as co-pigments with anthocyanins of G. sylvaticum petals was measured in vitro at different pH values. Sylvatiins A and D maintained efficiently the purple flower color near the natural pH of petal cells. The amount of sylvatiins was changed according to the flower color; deep purple petals with higher amount of anthocyanin contained more sylvatiins A and C than whiter petals. It was concluded that G. sylvaticum petal cells may accumulate sylvatiins for intermolecular co-pigmentation purposes.
authors: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, FI-20014, University of Turku, Finland. Electronic address: ankatu@utu.fi.
authors: Anu
authors: A
authors: Tuominen
authors: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, FI-20014, University of Turku, Finland.
authors: Jari
authors: J
authors: Sinkkonen
authors: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, FI-20014, University of Turku, Finland.
authors: Maarit
authors: M
authors: Karonen
authors: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, FI-20014, University of Turku, Finland.
authors: Juha-Pekka
authors: JP
authors: Salminen
mesh_terms: D000872:Anthocyanins / Q000032:analysis / Q000737:chemistry; D035264:Flowers / Q000737:chemistry; D031315:Geranium / Q000737:chemistry*; D060434:Herbivory / Q000502:physiology; D047348:Hydrolyzable Tannins / Q000737:chemistry / Q000302:isolation & purification*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010858:Pigmentation / Q000502:physiology
chemical_list: D000872:Anthocyanins; D047348:Hydrolyzable Tannins; C000606011:sylvatiin A; C103481:chebulinic acid
keywords: Circular dichroism; Co-pigmentation in the flower color manifestation; ESI-MS/MS; Ellagitannins; Galloyl glucoses; Geraniaceae; Geranium sylvaticum; NMR; Protein precipitation capacity; Wood cranesbill