Ellagitannin Oligomers from Leaves and Their Role in the Detoxification of Aluminum.

of the Myrtaceae family shows high resistance to aluminum (Al) ions and contains various compounds such as steroids, terpenoids, saponins, flavonoids, glycosides, alkaloids, and tannins. Although the ellagitannin oenothein B () isolated from exhibits remarkable properties for Al detoxification, likely contributing to its Al resistance, other ellagitannin oligomers present in have not been investigated in detail. In this study, novel dimeric and trimeric ellagitannin oligomers eucarpanin D () and eucamalin A (), together with known gallotannins (, , and ), monomeric ellagitannins (-, and ), and dimeric ellagitannins (, , and -), were isolated from leaves. The structures of these novel compounds were elucidated based on their chemical and physicochemical properties, including the orientations of tergalloyl groups in compounds and . Similar to compound , previously isolated from the roots of , the ellagitannins demonstrated good Al detoxification properties. Hence, these tannins may play a critical role in the high Al resistance of in acidic soils. This paper reports for the first time the isolation of ellagitannin oligomers from the leaves of .