Pinocembrin

Each plant tissue tends to have an obviously distinctive profile of flavonoids. The flavonoid content can reach about 0.5% in pollen, 10% in propolis, and about 6 mg/kg in honey. Havonoid aglycones appear to be present only in propolis and honey, while pollen contains flavanols in herosidic forms. The flavonoids in honey and propolis have been identified as flavanones and flavanones/flavanols (Campos et ah, 1990). The antimi-crobially active flavanone pinocembrine was foimd to be a major flavonoid in honey (Bogdanov, 1989). Amiot et ah (1989) studied two blossom and two honeydew Swiss honey samples and foimd that pinocembrine was the main flavonoid. Pinocembrine concentration varied between 2 and 3 mg/kg (Bogdanov, 1989). Berahia et ah (1993) analyzed sunflower honey samples and detected six flavone/flavols, four flavanone/ flavols, and pinocembrin, of which pinocembrin is the main flavonoid. The flavonoids in sunflower honey and propolis were characterized and assessed for their effects on hepatic drug-metabolizing enzymes and benzo [fl]pyrene-DNA adduct formation (Sabatier et ah, 1992 Siess et ah, 1996). 

Pinocembrin, chrysin, galangin, and pinobanksin are main flavonoids in honey and propolis. 

Some phenolic acids such as ellagic acid can be used as floral markers of heather honey (Cherchi et al., 1994 Ferreres et al., 1996a,b), and the hydroxyciimamates (caffeic, p-coumaric, and ferulic acids) as floral markers of chestnut honey (Cherchi et al., 1994). Pinocembrin, pinobanksin, and chrysin are the characteristic flavonoids of propolis, and these flavo-noid compounds have been found in most European honey samples (Tomas-Barberan et al., 2001). However, for lavender and acacia honeys, no specific phenolic compoimds could be used as suitable floral markers (Tomas-Barberan et al., 2001). Other potential phytochemical markers like abscisic acid may become floral markers in heather honey (Cherchi et al., 1994). Abscisic acid was also detected in rapeseed, lime, and acacia honey samples (Tomas-Barberan et al., 2001). Snow and Manley-Harris (2004) studied antimicrobial activity of phenolics. 

Bogdanov, S. (1989). Determination of pinocembrin in honey using HPLC. /. Apicult. Res. 28, 55-57. 

DiOH-flavanone (pinocembrin) 7-O-benzoate C22H16O5 360 Lophopappus tarapacanus Asteraceae Aerial 47... 

The triketo ester (602) undergoes a Claisen condensation in aqueous potassium hydroxide yielding the chalcone (603). On heating, cyclization to the flavanone, pinocembrin (604), occurred (67JA6734). Methanolic potassium hydroxide effects an alternative cyclization to methyl 2,4-dihydroxy-6-styrylbenzoate. 

Honey contains an extensive diversity of phenolic compounds as secondary constituents, notably flavonoids and phenolic acids (Arraez-Roman et al., 2006 Baltrusaityte et al., 2007 Estevinho et al., 2008). The flavonoid content reaches about 6000 mg/kg, consisting mainly of flavanones and flavones (Anklam, 1998). The main flavonoids are myricetin, tricetin, quercetin, hesperidin, luteolin, kaempferol, pinocembrin, chrysin, pinobanksin,... 

Pinocembrin 7-0-Rha-Glc (= 5,7-Dihydroxyflavone 7-0-Rha-Glc Saratonoside) (flavone O-glycoside) Puerarin (iso flavone)... 

Aglycone Pinocembrin in Helichrysum spp. (Asteraceae), Glycyrrhiza spp. (Fabaceae), Pinus cembra (Pinaceae), Prunus spp. (Rosaceae)... 

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