Flavonoids and Condensed Tannins from Leaves of Hawaiian Vaccinium reticulatum and V. calycinum (Ericaceae)

Abstract

The flavonoids and condensed tannins of Hawaiian Vaccinium
\nreticulatum Smith and V. calycinum Smith have been isolated and their structures
\ndetermined. Flavonoids present in both species were quercetin, quercetin-3-
\n0-glucoside, quercetin-3-0-galactoside, quercetin-3-0-methyl ether, isorhamnetin,
\nand (-)-epicatechin. The condensed tannin contained procyanidin units
\nwith cis stereochemistry only. Extension and terminal units, and number-average
\nmolecular weight of the polymer were determined. A large quantity of
\nneochlorogenic acid (a caffeic acid derivative) was also detected. The phenolic
\ncompounds of V reticulatum from a population on Mauna Kea and two populations
\nnear K11auea, both on the island of Hawai'i, and from one population
\nof V calycinum on Kaua'i were qualitatively identical. The high degree of
\nsimilarity supports the view that these species are closely related. It is suggested
\nthat the phenolic chemistry of the species may have been fixed in the progenitor
\nof the Hawaiian Vaccinium.