Synthese von polyhydroxy-flavonolmethyläthern mit potentieller cytotoxischer wirksamkeit—I

Identification of the Key Astringent Compounds in Spinach (Spinacia oleracea) by Means of the Taste Dilution Analysis

“…In contrast to astringent compound 1, the sugar moiety was found to be linked to position C(4′) of the Bring system of the aglycone. This is well in agreement with data published earlier (Wagner and Maurer 1977;Kidmose et al 2001;Bergquist et al 2005), whereas others claimed that the glucuronide moiety is always linked to the hydroxyl group at position C(3) (Edenharder et al 2001). Taking all the spectroscopic data into account, the astringent compound in fraction I-9 was identified as 3′,5,7-trihydroxy-3,6-dimethoxy-flavon-4′-O-β-D-glucuronide (2, Fig.…”

“…3). Although the compounds 1, 4, 5 (Aritomi et al 1986), 2 (Wagner and Maurer 1977), 3, 10, 11 (Aritomi and Kawasaki 1984), and 6-9 (Ferreres et al 1997) were found already as natural products, the full spectroscopic data set as well as their sensory activity was not reported yet. Compound 7 has not been previously published.…”

“…Although methoxylated flavonoids, flavon-3-ols, flavon-3-ol glycosides, and hydroxycinnamoyl derivatives were reported as constituents in spinach (Aritomi and Kawasaki 1984;Aritomi et al 1986;Wagner and Maurer 1977;Ferreres et al 1997;Berahia et al 1994;Winter and Herrmann 1986), it is not yet known which of these compounds are responsible for the astringent mouthfeel of blanched spinach leaves or if other unknown compounds are contributing that oral sensation.…”

Phenolics in cereals, fruits and vegetables: Occurrence, extraction and analysis

“…Patuletin (quercetagetin 6-methyl ether), jaceidin and spinacetin (quercetagetin 6,3 -dimethyl ether) conjugates [211,212] are the major flavonoids in spinach leaves [210]. In addition a number of antimutagenic flavonoids, including flavonol glucuronides and disaccharides, methylenedioxyflavonol glucuronides, flavanones [213] and methoxyflavone glucuronides [210,214] were also identified.…”

The Flavonoids

“…As a result the past five years have seen a dramatic increase in the number of publications on, or involving, 13C-NMR spectroscopy offlavonoids. For example major compilations include those ofTernai and , Markham and Ternai (1976), , Wagner et al (1976), Chari et al (1977a and Wenkert and Gottlieb (1977). The increasing availability and sensitivity of modern FT-NMR spectrometers is assurance that this powerful technique will become a major tool for the structure elucidation of flavonoids and their glycosides.…”