Constituents of sage (Salvia officinalis) with in vitro affinity to human brain benzodiazepine receptor.

Benzodiazepine receptor binding assay-guided fractionation of the methanol extract from sage leaves ( Salvia officinalis L.) revealed three flavones and two abietane diterpenes functioning as benzodiazepine receptor-active components. Structural elucidation of the isolated pure compounds was performed by UV, EI-MS, ESI(pos)-MS/MS, as well as 1H- and 13C-NMR techniques. The flavones apigenin, hispidulin and cirsimaritin competitively inhibited 3H-flumazenil binding to the benzodiazepine receptor with IC50 values of 30, 1.3 and 350 microM, respectively. In addition, the affinities of the newly discovered diterpene receptor ligands, i. e., 7-methoxyrosmanol and galdosol, were characterized. 7-Methoxyrosmanol exhibited an IC50 value of 7.2 microM and galdosol showed the strongest binding activity to the benzodiazepine receptor with an IC50 value of 0.8 microM.