Isolation and antibacterial activity of phenylpropanoid derivatives from Ballota nigra

In addition to the previously isolated phenylpropanoid glycosides verbascos ide 1, forsythoside B 2, arenarioside 3 and ballotetroside 4, another four compounds were isolated from generative aerial parts of Ballota nigra: thre e phenylpropanoid glycosides, alyssonoside 5, lavandulifolioside 6 and ango roside A 7 and a non-glycosidic derivative (+)-(E)-caffeoyl-L-malic acid 8. The antibacterial activity of the five major compounds (1-4 and 8) was tes ted against Gram-positive and Gram-negative bacteria. Three of them (1-3) e xhibited a moderate antimicrobial activity against Proteus mirabilis and St aphylococcus aureus including one methicillin-resistant strain. (C) 1999 El sevier Science Ireland Ltd. All rights reserved.