Two flavonoids and three ellagitannins, squarrosanins A, B, and C, were isolated from the leaves of Melaleuca squarrosa. The flavonoids were characterized structurally as kaempferol-3-O-(2″-O-galloyl)-glucuronide and herbacetin-3-O-glucuronide, while the ellagitannins were characterized as monomeric and dimeric C-glucosidic ellagitannins by application of spectroscopic and chemical methods. The antioxidant effect of the polyphenolic constituents of the M. squarrosa leaves was also examined in vitro, and C-glucosidic tannins including oligomers were shown to be more effective radical scavengers against 1,1-diphenyl-2-picrylhydrazyl (DPPH) than flavonoids and ordinary ellagitannins.
|出版ステータス||Published - 12月 2008|
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