New Cyclolignans from Origanum glandulosum Active Against beta-amyloid Aggregation

Origanum glandulosum Desf is an endemic flavoring herb widely distributed in North Africa that is commonly used in traditional medicine. This oregano species is rich in essential oils but little is known about its phenolic composition. In the present study, a crude extract of O. glandulosum was prepared in order to isolate and investigate its neuroprotective potential to inhibit beta-amyloid peptide (A beta) aggregation. The three major compounds of the extract were isolated: rosmarinic acid and two cyclolignans in Origanum genus, globoidnan A and a new derivative named globoidnan B. Rosmarinic acid and globoidnan A showed significant anti-aggregative activity against beta amyloid aggregation (IC50 7.0 and 12.0 mu M, respectively). In contrast, globoidnan B was found to be less active.