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Context: The genus Sideritis L. (Lamiaceae) is represented by 46 species in Turkey with an 79% endemism ratio, 42 of 46 belonging to the section Empodoclia., Objective: In this review article, Sideritis species growing in Turkey have been evaluated for phytochemical constituents and biological activities., Methods: The data for the isolates, components and extracts of the Anatolian Sideritis species and their bioactivity studies were retrieved from the main databases WoS, Scopus and PubMed from 1975 until 31 December 2022., Results: In this review article, terpenoids, flavonoids, phenolics and other secondary metabolites isolated from Turkish Sideritis species were reported. Anatolian Sideritis species, which primarily consist of monoterpenes and sesquiterpenes, were studied in detail. Sideritis plants are represented by 46 species in Turkey, and 25 of them were investigated for their diterpenoids through isolation or LC-MS studies. Most of the diterpenoids of Turkish Sideritis species have ent -kaurene skeleton, among them linearol, siderol, 7- epi candicandiol and sideridiol were found to be the main compounds. Exceptionally, labdane, pimarane and beyerene diterpenoids were only found in a few species. For phenolics and flavonoids, only 12 species were investigated until now, and they were found to be rich in phenylethanoid glycosides and flavonoid glycosides. In terms of activity, most of the species were tested for antioxidant activity, followed by antimicrobial and anti-ulcer/anti-inflammatory activities. Their cytotoxic, enzyme inhibitory, antinociceptive and antistress activities were less frequently studied., Conclusions: Sideritis species should be considered promising therapeutic agents in the treatment of upper respiratory tract and ulcer/inflammatory diseases.

Six known ent-kaurene, a new ent-kaurane and a new pimarane diterpenes were isolated from Sideritis trojana. The structures of new compounds were determined as ent-7alpha-15beta,16beta-epoxykaurane (1), and ent-2alpha-hydroxy-8(14),15-pimaradiene (2) along with the known compounds siderol (3), sideridiol (4), 7-epicandicandiol (5), isocandol B (6), candol A acetate (7) ent-7alpha-acetoxykaur-15-ene (8) by IR, 1D and 2D NMR techniques and HRMS.

The known ent-kaurene diterpenes 1-9 and a new ent-labdane, ent-6beta,8alpha-dihydroxylabda-13(16),14-diene (10), were isolated from the whole plant of Sideritis argyrea. Their structures were elucidated based on one- and two-dimensional NMR techniques and HRMS.

The acetone extract of Nepeta caesarea yielded four new nepetalic acid derivatives, 3'alpha-[beta-sitosteryl-3beta-oxy]dihydronepetalactone (1), 3'beta-[5alpha-stigmast-7-ene-3beta-oxy]dihydronepetalact one (2), 3'alpha-[olean-12-ene-28-oyl-3beta-oxy]dihydronepetalactone (3), and 3'alpha-[lup-20(29)-ene-28-ol-3beta-oxy]dihydronepetalactone (4). The structures were elucidated by NMR and MS techniques.