3,4’-Dimethoxy-3’,5,7-trihydroxyflavon

The most widespread flavonoids reported in the Baccharis genus are flavones, but flavonols and flavanones have also been isolated. For example, Kupchan and Baverschmidt [74] reported the isolation and identification of two methylated flavonols, 3,4 -dimethoxy-3 ,5,7-trihydroxyflavone, Fig. (43) and centaureidin, Fig. (44) from B. sarolhroides. 

Dimethoxy-3, 5,6-trihydroxyflavone has been synthesized and a new natural flavone, called nuchensein, has thus been shown not to have this structure. ... 

The structures originally assigned to three flavones present in Lychnophera affinis have now been revised, and all are derivatives of 3,7-dimethoxy-5,3, 4 -trihydroxyflavone/ A new dihydrofuro[2,3-/i]flavone (219), called polystachin, has been isolated from Tephrosia polystachya, and two furo[2,3-ft]flavones (220) and (221) are present in the roots of Derris mollis. ... 

The lipid system also influences the effectiveness of flavonoids as antioxidants. For example, (+)-catechin was more effective than quercetin in an aqueous-based system (Meyer et al., 1998b). Wang et al. (1999b) found that 6,7-dimethoxy-5,8,4 -trihydroxyflavone was the most active of the polyphenols isolated from tart cherries. These researchers also noted that the pure compound was more effective than a mixture of the isolated phenols at the concentrations originally found in the extract. 

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