Fatimanols Y and Z: two neo-clerodane diterpenoids from Teucrium yemense

Teucrium yemense (Defl.), a medicinal plant, grows in Yemen and Saudi Arabia and is also referred to as Reehal Fatima. The plant has a long history of use in these regions for the treatment of diabetes, rheumatism, and renal conditions. Phytochemical investigation of the aerial parts of T. yemense yielded two previously undescribed neo-clerodane diterpenoids, namely fatimanols Y and Z (1 and 2) along with the known teulepicephin (3), 8-acetylharpagide (4) and teucardosid (5). Structure elucidation was accomplished from their 1D and 2D NMR, ECD, and MS characteristics as well as by comparing them to related reported compounds. The new molecules expand understanding of secondary metabolites of this genus. Compounds 1–5 did not show antimicrobial activity against various bacterial and fungal strains.