Guaianolide and seco-Guaianolide from Salvia nubicola (Lamiaceae)

Salvia is one of the famous genera of the family Lamiacea previously called Labiatae comprising about 800 species throughout the world [1]. Most of the members of this genus are known due to their biologically active chemical constituents specifically reported for anti-tumor activity [2]. A number of Salvia species are used in folk medicines. For example, S. cavaleriei is used for the treatment of dysentery, boils and fall injuries [3], S. desoleria for the treatment of menstrual, digestive and CNS diseases [4] and S. bucharica as traditional medicine for the treatment of hepatic problems. Most of the Salvia plants are rich in essential oils and among their constituents guaiane-sesquiterpenes are the most common [5 – 9]. In continuation of our research on the chemical constituents of Salvia [10 – 19], we have recently published two articles on S. hypoleuca [18] and S. nubicola [19]. Now we wish to report the isolation and spectroscopic characterization of further new sesquiterpenes: guaianolide (1, nubenone) and a secoguaianolide (2, nubenoic acid).