Two new phenolic compounds from the leaves of Alnus sibirica Fisch. ex Turcz.

Abstract

Two new phenolic compounds, 4- O-glucopyranosyl-5- O-caffeoylshikimic acid ( 1) and 2,3-digalloyl oregonin ( 2), were isolated along with eight known phenolic compounds ( 3– 10) from an 80% acetone extract of Alnus sibirica leaves. The chemical structures of these compounds were elucidated using 1D/2D nuclear magnetic resonance and high resolution-MS. The anti-oxidative activities of these compounds were determined by assaying their 1,1-diphenyl-2-picrylhydrazyl radical and nitroblue tetrazolium superoxide anion scavenging activity. All of the isolated phenolic compounds ( 1– 10) exhibited potent anti-oxidative activities. In particular, 2 and 4, which are diarylheptanoids, and 10 which is ellagitannin exhibited excellent anti-oxidative activities with almost the same potency as that of the positive controls L-ascorbic acid and allopurinol.

Abstract