Phytochemical and chemotaxonomic study on Thymus quinquecostatus Cêlak

Seventeen compounds, including one sesquiterpene (1), two diterpenoids (2 and 3), four monoterpenes (4–7), one phenolic acid (8), seven flavonoids (9–15), one lignan (16), and one sterol (17), have been isolated from the whole herb of Thymus quinquecostatus Cêlak., Lamiaceae. Among them, compounds 1–3, 9, 10, 12, 14, 15, and 16 were isolated from the genus Thymus for the first time; and compounds 5–7 were first isolated from this plant. Their structures were determined using 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and compared with known data. To the best of our knowledge, their chemotaxonomic significance was explored in the present study for the first time.