New α‐Glucosidase Inhibitors and Antibacterial Compounds from Myrtus communis L

Three new acylphloroglucinols – myrtucommulone D ( 1 ), myrtucommulone E ( 2 ), and myrtucommulone C ( 3 ) – and a new usnic acid derivative usnone A ( 4 ) have been isolated from Myrtus communis L., along with the known acylphloroglucinol myrtucommulone B ( 5 ), one sterol 8 and six triterpenes 10 – 15 , two flavonoids 6 and 9 , and 2,5‐dihydroxy‐4‐methoxybenzophenone (cearoin; 7 ). The structures of compounds 1 , 2 , 4 , and 5 were also unambiguously determined by single‐crystal X‐ray diffraction analysis. The compounds 1 – 3 and 5 were found to be more potent α‐glucosidase inhibitors than the clinically used standard acarbose. Compound 3 exhibited the highest activity among all the acylphloroglucinols, with an IC 50 (inhibition concentration) = 35.4 ± 1.15 μ M . Compounds 1 , 2 , 4 , 7 , and 11 – 15 also exhibited antibacterial activities.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)