We report the isolation of several coumarins and the stereochemical assessment of some pyranocoumarins, as well as the antibacterial and antioxidant activities of the three most abundant ones (grandivittin, agasyllin and aegelinol benzoate) isolated from the roots of Ferulago campestris collected in Sicily and of the hydrolysis product (aegelinol). Aegelinol and agasyllin showed antibacterial activity against nine ATCC and the same clinically isolated Gram-positive and Gram-negative bacterial strains. At a concentration between 16 and 125 mg/mL both coumarins showed a significant antibacterial effect against both Gram-negative and Gram-positive bacteria. In particular the ATCC strains Staphylococcus aureus, Salmonella thypii, Enterobacter cloacae and Enterobacter earogenes (MIC = 16 and 32 mg/mL for aegelinol and agasyllin, respectively) were the most inhibited. Antibacterial activity was also found against Helicobacter pylori: a dose-dependent inhibition was shown between 5 and 25 mg/mL. The antioxidant activity of the coumarins was evaluated by their effects on human whole blood leukocytes (WB) and on isolated polymorphonucleate (PMN) chemiluminescence (CL), PMA-stimulated and resting.

The phytochemical investigation of the acetone and methanol extracts of the flowers of Magydaris tomentosa (Desf.) DC afforded six known coumarins as well as (+)-meranzin hydrate (7), not previously reported as a natural product. The antibacterial activity of umbelliprenin (1), osthol (2), imperatorin (3), citropten (4) and (+)-meranzin hydrate (7) was tested against Gram-positive and Gram-negative bacteria. All coumarins (1 - 7) isolated in this study inhibited growth of all bacterial strains tested (MIC between 16 and 256 μg/mL), the most active being imperatorin (3) (MICs between 32 and 128 μg/mL) and citropten (4) (MICs between 16 and 256 μg/mL). The anticoagulant activity of compounds 1 - 4 and 7 was also evaluated.

Covering: Up to June 2001. Previous review: on the clerodanes, Nat. Prod. Rep., 1992, 9, 243. The genus Scutellaria (Labiatae) is a very rich source of neoclerodane diterpenoids, with interesting structural features. These secondary metabolites show several biological properties, the most important being the antifeedant activity against pest insects. The present review reports on natural and hemisynthetic diterpenoids and their antifeedant activity.