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DOI: 10.1055/s-0030-1265840
Polyphenols in myrtaceous plant: Polyphenolic compounds in clove and pimento and their antioxidative activities
In our continuing study on natural polyphenolic compounds from the myrtaceous plants [1], we herein isolated and characterized two new polyphenolic glucosides (1 and 2) from clove (Syzygium aromaticum) and pimento (Pimenta dioica). Compound 1 was isolated together with 15 known compounds (5 hydrolysable tannins and 10 related polyphenols) from flower buds of S. aromaticum, and its structure was characterized as 6'-O-acetylisobiflorin. Structure of compound 2, obtained from berries of P. dioica along with 14 known compounds (3 hydrolysable tannins and 11 related polyphenols) was elucidated as (2S)-3-(4-hydroxy-3-methoxyphenyl)-propane-1,2-diol 1-O-(6'-O-galloyl)-β-D-glucoside on the basis of spectral analysis (NMR, MS and [α]D) and chemical conversions. Additionally, antioxidative activity of their extracts and the isolated compounds was estimated by using ORAC (oxygen radical absorbance capacity) assay. Among them, eugenol (3) showed the most potent antioxidative activity [ORAC value: 39,270µmol TE (=trolox equivalent)/g].
References: 1. Yoshida T. et al (2010) Int. J. Mol. Sci. 11:79–106.