Flavonoids, benzoic acids and cinnamic acids isolated from shoots and roots of Italian rye grass (Lolium multiflorum Lam.) with and without endophyte association and arbuscular mycorrhizal fungus

Phenolic compounds present in Lolium multiflorum Lam. were isolated and characterized. Significant differences in their distribution were found, in shoots and roots of plants with (Lm+) and without (Lm-) endophyte association, grown with (Mic+) and without (Mic-) mycorrhizal fungi Glomus intraradices, indicating a systemic effect of these microorganisms on the phenolics metabolism of L multiflorum. We report the isolation of eight new flavonoids 7,8-dihydroxy-2-(4-hydroxyphenyl)-5-methoxy-4H-1-benzopyran-4-one (1), 3,7-dihydroxy-8-methoxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one (2), 7,8-dihydroxy-2-(2,4-dihydroxyphenyl)-4H-1-benzopyran-4-one (3), 3,7-dihydroxy-2-(4,5-dihydroxy-3-methoxyphenyl)-4H-1-benzopyran-4-one (4), 5,6-dihydroxy-2-(4-hydroxyphenyl)-3-methoxy-4H-1-benzopyran-4-one (5), 7-hydroxy8-methoxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one (6), 3,7,8-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one (7) and 7,8-dihydroxy-2-(2,3-dihydroxyphenyl)-4H-1-benzopyran-4-one (8), and two new benzoic acids 2-hydroxy-4-methoxy-1,3-benzenedicarboxylic acid (9) and 3,6-dimetlioxy-2-hydroxy-benzoic acid (10), found with the known deoxykaempferol (11), 2',7-dihydroxyflavone (12), 2',3,5',7,8-pentahydroxyflavone (13), 3',4'-dihydroxy-3-methoxyflavone (14), 3,4'-dihydroxy-3-methoxyflavone (15), galangin (16), gentisic acid (17), isoferulic acid (18), 4-hydroxy-1.2,3-benzenetricarboxylic acid (19), 3,4-dihydroxyphthalic acid (20), 2,5-dimethoxy-benzoic acid (21), p-methoxicinnamic acid (22) and 2,4-dimethoxyisophthalic acid (23). Compounds 11, 12,13,14, 15, 18, 20, 21 and 23, have not been isolated from plants before. (C) 2009 Elsevier Ltd. All rights reserved.