Phloroglucinol derivatives and a chromone glucoside from the leaves of Myrtus communis

Seven new phloroglucinol derivatives, myrtucommunins A D (1-4), 6-methylisomyrtucommulone B (5), 4-methylmyrtucommulone B (6), and 2-isobutyryl-4-methylphloroglucinol 1-O-beta-D-glucopyranoside (7), and one new chromone derivative, undulatoside A 6'-O-gallate (8), were isolated from the leaves of Myrtus communis (Myrtaceae). Myrtucommunins A D (1-4) were conjugates of polymethylated acylphloroglucinol and flavonol rhamnoside. The absolute configurations of the rhamnosyl moieties for 1-4 were confirmed to be L in each case by HPLC analyses, while those of the aglycones were assigned by comparisons of the experimental and TDDFI' calculated ECD spectra. 6-Methylisomyrtucommulone B (5) and 4-methylmyrtucommulone B (6) were assigned as 616/6 tricyclic acylphloroglucinol derivatives with a racemic nature. Antimicrobial activities of 1-8 and related known compounds were evaluated. (C) 2017 Elsevier Ltd. All rights reserved.