Reassessment of the polar fraction of Stachys alopecuros (L.) Benth. subsp. divulsa (Ten.) Grande (Lamiaceae) from the Monti Sibillini National Park and its potential pharmacologic uses

In this paper is reported an in deep study of the glycosidic fraction of S. alopecuros subsp. divulsa which permitted to expand the knowledge on its iridoid pattern, being constituted also by ajugoside (1), reptoside (6) and 6-O-acetyl-ajugol (7), besides 8-O-acetylharpagide (2), harpagide (3), allobetonicoside (4), 4′-O-galactopyranosyl-teuhircoside (5) already isolated from this species. The phenolic compounds isolated during the study resulted to be chlorogenic acid (8), β-arbutin (9), verbascoside (10) and stachysoside A (11). Apart from the reconfirmed verbascoside (10), the other phenolics were recognized for the first time in the studied species. The complete NMR assignment of compound (1) by means of bidimensional techniques is reported and both the chemotaxonomic and pharmacologic relevance of the isolated compounds are discussed.